2014-2015 Microchip Technology Inc. DS20005315B-page 1
MCP1661
Features
•36V, 800m Integrated Switch
• Up to 92% Efficiency
• High Output Voltage Range: up to 32V
• 1.3A Peak Input Current Limit:
-I
OUT > 200 mA @ 5.0V VIN, 12V VOUT
-I
OUT > 125 mA @ 3.3V VIN, 12V VOUT
-I
OUT > 100 mA @ 4.2V VIN, 24V VOUT
• Input Voltage Range: 2.4V to 5.5V
• Undervoltage Lockout (UVLO):
-UVLO@V
IN Rising: 2.3V, typical
-UVLO@V
IN Falling: 1.85V, typical
• No Load Input Current: 250 µA, typical
• Sleep mode with 200 nA Typical Quiescent
Current
• PWM Operation with Skip mode: 500 kHz
• Feedback Voltage Reference: VFB = 1.227V
• Cycle-by-Cycle Current Limiting
• Internal Compensation
• Inrush Current Limiting and Internal Soft Start
• Output Overvoltage Protection (OVP) in the event
of:
- Feedback pin shorted to GND
- Disconnected feedback divider
• Overtemperature Protection
• Easily Configurable for SEPIC or Flyback
Topologies
• Available Packages:
- 5-Lead SOT-23
- 8-Lead 2x3 TDFN
Applications
• Two and Three-Cell Alkaline, Lithium Ultimate and
NiMH/NiCd Portable Products
• Single-Cell Li-Ion to 5V, 12V or 24V Converters
• LCD Bias Supply for Portable Applications
• Camera Phone Flash
• Portable Medical Equipment
• Hand-Held Instruments
• Single-Cell Li-Ion to 3.0V or 3.3V SEPIC
Applications (see Figure 6-3)
General Description
The MCP1661 device is a compact, high-efficiency,
fixed-frequency, non-synchronous step-up DC-DC
converter which integrates a 36V, 800 m NMOS
switch. It provides a space-efficient high-voltage
step-up power supply solution for applications powered
by either two-cell or three-cell alkaline, Ultimate Lithium,
NiCd, NiMH, one-cell Li-Ion or Li-Polymer batteries.
The integrated switch is protected by the 1.3A
cycle-by-cycle inductor peak current limit operation.
There is an output overvoltage protection which turns
off switching in case the feedback resistors are
accidentally disconnected or the feedback pin is
short-circuited to GND.
Low-voltage technology allows the regulator to start-up
without high inrush current or output voltage overshoot
from a low-voltage input. The device features a UVLO
which avoids start-up and operation with low inputs or
discharged batteries for two cell-powered applications.
For standby applications (EN = GND), the device stops
switching, enters Sleep mode and consumes 200 nA
(typical) of input current.
MCP1661 is easy to use and allows creating classic
boost, SEPIC or flyback DC-DC converters within a
small Printed Circuit Board (PCB) area. All
compensation and protection circuitry is integrated to
minimize the number of external components. Ceramic
input and output capacitors are used.
Package Types
* Includes Exposed Thermal Pad (EP); see Table 3 -1.
SW
EN
VIN
GND
MCP1661
SOT-23
VFB
MCP1661
2x3 TDFN*
1
2
3
5
4
SW
SGND
NC
PGND
NC
1
2
3
4
8
7
6
5VIN
ENVFB
EP
9
High-Voltage Integrated Switch PWM Boost Regulator with UVLO
MCP1661
DS20005315B-page 2 2014-2015 Microchip Technology Inc.
Typical Applications
V
IN
GND
V
FB
V
OUT
12V, 75 mA-125 mA
C
OUT
4.7-10 μF
C
IN
4.7-10 μF
L
4.7 μH
SW
1.05 M
Ω
120 k
Ω
EN
+
-
ALKALINE
ON
OFF
+
-
ALKALINE
R
TOP
R
BOT
V
IN
2.4V
-3.0V
D
MCP1661
PMEG2005
D
V = 1.227V
FB
V
IN
GND
V
FB
V
OUT
24V, 50 mA-125 mA
C
OUT
10 μF
C
IN
10 μF
L
10 μH
SW
1.05 M
Ω
56 k
Ω
EN
+
-
ALKALINE
+
-
ALKALINE
R
TOP
R
BOT
V
IN
3.0V
- 4.2V
D
MCP1661
MBR0540
D
0
50
100
150
200
250
300
2.4 2.8 3.2 3.6 4 4.4 4.8
I
OUT
(mA)
V
IN
(V)
VOUT
= 12V
VOUT
= 24V
Maximum Output Current vs. VIN
2014-2015 Microchip Technology Inc. DS20005315B-page 3
MCP1661
1.0 ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings †
VSW – GND .....................................................................+36V
EN, VIN – GND...............................................................+6.0V
VFB .................................................................................+1.3V
Power Dissipation .......................................Internally Limited
Storage Temperature .................................... -65°C to +150°C
Ambient Temperature with Power Applied .... -40°C to +125°C
Operating Junction Temperature................... -40°C to +150°C
ESD Protection On All Pins:
HBM ................................................................. 4 kV
MM..................................................................300V
† Notice: Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of
the device at those or any other conditions above those
indicated in the operational sections of this
specification is not intended. Exposure to maximum
rating conditions for extended periods may affect
device reliability.
DC AND AC CHARACTERISTICS
Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature
TA=+25°C, V
IN = 3.3V, IOUT =20mA, V
OUT =12V, C
IN =C
OUT = 10 µF, X7R ceramic, L = 4.7 µH.
Boldface specifications apply over the controlled TA range of -40°C to +125°C.
Parameters Sym. Min. Typ. Max. Units Conditions
Input Voltage Range VIN 2.4 — 5.5 V Note 1
Undervoltage Lockout
(UVLO)
UVLOSTART —2.3— VV
IN rising,
IOUT =1mA resistive load
UVLOSTOP —1.85— VV
IN falling,
IOUT =1mA resistive load
Output Voltage Adjust Range VOUT ——32 VNote 1
Maximum Output Current IOUT —125— mA3.3V V
IN, 12V VOUT
200 — mA 5.0V VIN, 12V VOUT
100 — mA 4.2V VIN, 24V VOUT
Feedback Voltage VFB 1.190 1.227 1.264 V
VFB Accuracy -3 — 3 %
Feedback Input Bias Current IVFB —0.005— µA
No Load Input Current IIN0 — 250 — µA Device switching, no load,
3.3V VIN, 12V VOUT (Note 2)
Shutdown Quiescent Current IQSHDN — 200 — nA EN = GND,
feedback divider current not
included (Note 3)
Peak Switch Current Limit IN(MAX) —1.3— ANote 4
NMOS Switch Leakage INLK —0.4— µAV
IN =V
SW =5V; V
OUT =5.5V
VEN =V
FB =GND
NMOS Switch ON Resistance RDS(ON) —0.8— VIN =5V, V
OUT = 12V,
IOUT =100mA (Note 4)
Note 1: Minimum input voltage in the range of VIN (VIN <5.5V<V
OUT) depends on the maximum duty cycle
(DCMAX) and on the output voltage (VOUT), according to the boost converter equation:
VINmin =V
OUT x(1–DC
MAX).
2: IIN0 varies with input and output voltage (Figure 2-8). IIN0 is measured on the VIN pin when the device is
switching (EN = VIN), at no load, with RTOP = 120 k and RBOT =1.05M.
3: IQSHDN is measured on the VIN pin when the device is not switching (EN = GND), at no load, with the
feedback resistors (RTOP +R
BOT) disconnected from VOUT
.
4: Determined by characterization, not production tested.
MCP1661
DS20005315B-page 4 2014-2015 Microchip Technology Inc.
Line Regulation |(VFB/VFB)/
VIN|
— 0.05 0.5 %/V VIN = 3V to 5V,
IOUT =20mA, V
OUT =12.0V
Load Regulation |VFB/VFB|—0.51.5 %I
OUT = 20 mA to 100 mA,
VIN = 3.3V, VOUT =12.0V
Overvoltage Reference OVP_REF — 80 — mV VFB to GND transition
(Note 4)
Maximum Duty Cycle DCMAX 88 90 — % Note 4
Switching Frequency fSW 425 500 575 kHz ±15%
EN Input Logic High VIH 85 ——% of V
IN IOUT =1mA
EN Input Logic Low VIL ——7.5 % of VIN IOUT =1mA
EN Input Leakage Current IENLK —0.025— µAV
EN =5V
Soft-Start Time tSS —3—msT
A, EN Low-to-High,
90% of VOUT
Thermal Shutdown
Die Temperature
TSD —150— °C
Die Temperature Hysteresis TSDHYS —15— °C
TEMPERATURE SPECIFICATIONS
Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature
TA=+25°C, V
IN = 3.3V, IOUT =20mA, V
OUT =12V, C
IN =C
OUT = 10 µF, X7R ceramic, L = 4.7 µH and 5-lead
SOT-23 package.
Boldface specifications apply over the controlled TA range of -40°C to +125°C.
Parameters Sym. Min. Typ. Max. Units Conditions
Temperature Ranges
Operating Junction Temperature
Range
TJ-40 — +125 °C Steady State
Storage Temperature Range TA-65 — +150 °C
Maximum Junction Temperature TJ— — +150 °C Transient
Package Thermal Resistances
Thermal Resistance, 5LD-SOT-23 JA — 201.0 — °C/W
Thermal Resistance, 8LD-2x3 TDFN JA —52.5 —°C/W
DC AND AC CHARACTERISTICS (CONTINUED)
Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature
TA=+25°C, V
IN = 3.3V, IOUT =20mA, V
OUT =12V, C
IN =C
OUT = 10 µF, X7R ceramic, L = 4.7 µH.
Boldface specifications apply over the controlled TA range of -40°C to +125°C.
Parameters Sym. Min. Typ. Max. Units Conditions
Note 1: Minimum input voltage in the range of VIN (VIN <5.5V<V
OUT) depends on the maximum duty cycle
(DCMAX) and on the output voltage (VOUT), according to the boost converter equation:
VINmin =V
OUT x(1–DC
MAX).
2: IIN0 varies with input and output voltage (Figure 2-8). IIN0 is measured on the VIN pin when the device is
switching (EN = VIN), at no load, with RTOP = 120 k and RBOT =1.05M.
3: IQSHDN is measured on the VIN pin when the device is not switching (EN = GND), at no load, with the
feedback resistors (RTOP +R
BOT) disconnected from VOUT
.
4: Determined by characterization, not production tested.
2014-2015 Microchip Technology Inc. DS20005315B-page 5
MCP1661
2.0 TYPICAL PERFORMANCE CURVES
Note: Unless otherwise indicated, VIN =3.3V, I
OUT =20mA, V
OUT =12V, C
IN =C
OUT = 10 µF, X7R ceramic,
L=4.7µH, T
A= 25°C, 5-lead SOT-23 package.
FIGURE 2-1: Undervoltage Lockout
(UVLO) vs. Ambient Temperature.
FIGURE 2-2: VFB Voltage vs. Ambient
Temperature and VIN.
FIGURE 2-3: Maximum Output Current
vs. VIN.
FIGURE 2-4: 9.0V VOUT Efficiency vs.
IOUT
.
FIGURE 2-5: 12.0V VOUT Efficiency vs.
IOUT
.
FIGURE 2-6: 24.0V VOUT Efficiency vs.
IOUT
.
Note: The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
1.7
1.8
1.9
2
2.1
2.2
2.3
-40 -25 -10 5 20 35 50 65 80 95 110 125
UVLO Thresholds (V)
Ambient Temperature (°C)
UVLO Start
UVLO Stop
1.210
1.215
1.220
1.225
1.230
-40 -25 -10 5 20 35 50 65 80 95 110 125
Feedback Voltage (V)
Ambient Temperature (°C)
0
100
200
300
400
500
600
700
800
900
2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1
I
OUT
(mA)
VIN (V)
VOUT = 12V
VOUT = 6.0V
VOUT = 9.0V
VOUT = 24V
L = 4.7 μH, V
OUT
= 6V, 9V and 12V
L = 10 μH, VOUT = 24V
20
30
40
50
60
70
80
90
100
0.1 1 10 100 1000
Efficiency (%)
IOUT (mA)
VOUT = 9.0V
VIN = 3.0V
VIN = 2.3V VIN = 4.0V
VIN = 5.5V
L = 4.7 μH
20
30
40
50
60
70
80
90
100
0.1 1 10 100 1000
Efficiency (%)
IOUT (mA)
VOUT = 12.0V VIN = 4.0V VIN = 5.5V
VIN = 3.0V
VIN = 2.3V
L = 4.7 μH
20
30
40
50
60
70
80
90
100
0.1 1 10 100 1000
Efficiency (%)
IOUT (mA)
VOUT = 24.0V VIN = 5.5V
VIN = 3.0V VIN = 4.0V
L = 10 μH
MCP1661
DS20005315B-page 6 2014-2015 Microchip Technology Inc.
Note: Unless otherwise indicated, VIN =3.3V, I
OUT =20mA, V
OUT =12V, C
IN =C
OUT = 10 µF, X7R ceramic,
L=4.7µH, T
A= 25°C, 5-lead SOT-23 package.
FIGURE 2-7: Inductor Peak Current Limit
vs. Ambient Temperature.
FIGURE 2-8: No Load Input Current, IIN0
vs. VIN (EN = VIN).
FIGURE 2-9: Shutdown Quiescent
Current, IQSHDN vs. VIN (EN = GND).
FIGURE 2-10: No Load Input Current, IIN0
vs. Ambient Temperature.
FIGURE 2-11: fSW vs. Ambient
Temperature.
FIGURE 2-12: PWM Pulse Skipping Mode
Threshold.
0.5
0.7
0.9
1.1
1.3
1.5
-40 -25 -10 5 20 35 50 65 80 95 110 125
Inductor Peak Current (A)
Ambient Temperature (°C)
VIN = 5.0V
VOUT = 12.0V
150
175
200
225
250
275
300
2.3 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
I
IN0
No Load Input Current (μA)
Input Voltage (V)
VOUT = 6.0V
VOUT = 12.0V
0.00
0.05
0.10
0.15
0.20
0.25
0.30
1.8 2.2 2.6 3 3.4 3.8 4.2 4.6
5
I
Q
Shutdown Mode (μA)
Input Voltage (V)
Note: Without FB Resistor Divider Current
0
200
400
600
800
1000
1200
1400
1600
1800
2000
-40 -25 -10 5 20 35 50 65 80 95 110 125
I
IN0
No Load Input Current (μA)
Ambient Temperature (°C)
VIN= 3.0V
VIN = 5.5V
VOUT = 12V
VIN = 2.3V
425
450
475
500
525
550
575
-40 -25 -10 5 20 35 50 65 80 95 110 125
Switching Frequency (kHz)
Ambient Temperature (°C)
VIN = 3.0V
IOUT = 100 mA
0
1
2
3
4
5
6
0 5 10 15 20 25
30
V
IN
(V)
IOUT (mA)
VOUT = 24.0V VOUT = 12.0V VOUT = 6.0V
2014-2015 Microchip Technology Inc. DS20005315B-page 7
MCP1661
Note: Unless otherwise indicated, VIN =3.3V, I
OUT =20mA, V
OUT =12V, C
IN =C
OUT = 10 µF, X7R ceramic,
L=4.7µH, T
A= 25°C, 5-lead SOT-23 package.
FIGURE 2-13: Enable Threshold vs. Input
Voltage.
FIGURE 2-14: N-Channel Switch RDSON
vs. VIN.
FIGURE 2-15: 12.0V VOUT Light Load
PWM Mode Waveforms.
FIGURE 2-16: High Load PWM Mode
Waveforms.
FIGURE 2-17: 12.0V Start-Up by Enable.
FIGURE 2-18: 12.0V Start-Up
(VIN =V
ENABLE).
0
10
20
30
40
50
60
70
80
90
100
2.3 2.6 2.9 3.2 3.5 3.8 4.1 4.4 4.7 5
Enable Thresholds (% of V
IN
)
Input Voltage (V)
EN VIL
EN VIH
IOUT = 1 mA
0
0.2
0.4
0.6
0.8
1
2.6 2.9 3.2 3.5 3.8 4.1 4.4 4.7 5
Switch RDS(ON) (
Ω
)
Input Voltage (V)
IOUT =100mA
2 µs/div
VOUT
20 mV/div, AC Coupled
20 MHz BW
IOUT =5mA
VSW
5V/div
IL
100 mA/div
1 µs/div
VOUT
50 mV/div, AC Coupled
20 MHz BW
IOUT =100mA
VSW
5V/div
IL
400 mA/div
VOUT
3V/div
IOUT =15mA
VEN
3V/div
IL
300 mA/div
500 µs/div
VIN
3V/div
VOUT
3V/div
IOUT =15mA
VSW
5V/div
VIN
3V/div
500 µs/div
MCP1661
DS20005315B-page 8 2014-2015 Microchip Technology Inc.
Note: Unless otherwise indicated, VIN =3.3V, I
OUT =20mA, V
OUT =12V, C
IN =C
OUT = 10 µF, X7R ceramic,
L=4.7µH, T
A= 25°C, 5-lead SOT-23 package.
FIGURE 2-19: 12.0V VOUT Load Transient
Waveforms.
FIGURE 2-20: 12.0V VOUT Line Transient
Waveforms.
2ms/div
VOUT
200 mV/div, AC Coupled
IOUT
30 mA/div
Step from 20 mA to 50 mA
1ms/div
VOUT
100 mV/div, AC Coupled
VIN
1V/div
Step from 3.3V to 5.0V
IOUT =60mA
2014-2015 Microchip Technology Inc. DS20005315B-page 9
MCP1661
3.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3 - 1 .
3.1 Feedback Voltage Pin (VFB)
The VFB pin is used to provide output voltage regulation
by using a resistor divider. The VFB voltage is 1.227V
typical.
3.2 Signal Ground Pin (SGND)
The signal ground pin is used as a return for the
integrated reference voltage and error amplifier. The
signal ground and power ground must be connected
externally in one point.
3.3 Switch Node Pin (SW)
Connect the inductor from the input voltage to the SW
pin. The SW pin carries inductor current, which can be
as high as 1.3A peak. The integrated N-Channel switch
drain is internally connected to the SW node.
3.4 Not Connected (NC)
This is an unconnected pin.
3.5 Power Supply Input Voltage Pin
(VIN)
Connect the input voltage source to VIN. The input
source must be decoupled from GND with a 4.7 µF
minimum capacitor.
3.6 Power Ground Pin (PGND)
The power ground pin is used as a return for the
high-current N-Channel switch. The signal ground and
power ground must be connected externally in one
point.
3.7 Enable Pin (EN)
The EN pin is a logic-level input used to enable or
disable device switching and lower quiescent current
while disabled. A logic high (>85% of VIN) will enable
the regulator output. A logic low (<7.5% of VIN) will
ensure that the regulator is disabled.
3.8 Exposed Thermal Pad (EP)
There is no internal electrical connection between the
Exposed Thermal Pad (EP) and the SGND and PGND
pins. They must be connected to the same potential on
the PCB.
3.9 Ground Pin (GND)
The ground or return pin is used for circuit ground
connection. The length of the trace from the input cap
return, the output cap return and the GND pin must be
as short as possible to minimize noise on the GND pin.
The 5-lead SOT-23 package uses a single ground pin.
TABLE 3-1: PIN FUNCTION TABLE
MCP1661
SOT-23
MCP1661
2x3 TDFN Symbol Description
31V
FB Feedback Voltage Pin
—2S
GND Signal Ground Pin (TDFN only)
1 3 SW Switch Node, Boost Inductor Input Pin
— 4, 6 NC Not Connected
55V
IN Input Voltage Pin
—7P
GND Power Ground Pin (TDFN only)
4 8 EN Enable Control Input Pin
— 9 EP Exposed Thermal Pad (EP); must be connected to Ground.
(TDFN only)
2 — GND Ground Pin (SOT-23 only)
MCP1661
DS20005315B-page 10 2014-2015 Microchip Technology Inc.
NOTES:
2014-2015 Microchip Technology Inc. DS20005315B-page 11
MCP1661
4.0 DETAILED DESCRIPTION
4.1 Device Overview
MCP1661 is a constant frequency PWM boost (step-up)
converter, based on a peak current mode architecture
which delivers high efficiency over a wide load range
from two-cell and three-cell Alkaline, Ultimate Lithium,
NiMH, NiCd and single-cell Li-Ion battery inputs. A high
level of integration lowers total system cost, eases
implementation and reduces board area.
The device features controlled start-up voltage
(UVLO), adjustable output voltage, 500 kHz PWM
operation with Skipping mode, 36V integrated switch,
internal compensation, inrush current limit, soft start,
and overvoltage protection in case the VFB connection
is lost.
The 800 m, 36V integrated switch is protected by the
1.3A cycle-by-cycle inductor peak current operation.
When the Enable pin is pulled to ground (EN = GND),
the device stops switching, enters in Shutdown mode
and consumes approximately 200 nA of input current
(the feedback current is not included).
MCP1661 can be used to build classic boost, SEPIC or
flyback DC-DC converters.
MCP1661
DS20005315B-page 12 2014-2015 Microchip Technology Inc.
4.2 Functional Description
The MCP1661 device is a compact, high-efficiency,
fixed-frequency, step-up DC-DC converter that
provides an easy-to-use high-output power supply
solution for applications powered by either two-cell or
three-cell alkaline or Lithium Energizer, three-cell NiCd
or NiMH or one-cell Li-Ion or Li-Polymer batteries.
Figure 4-1 depicts the functional block diagram of the
MCP1661 device. It incorporates a current mode
control scheme, in which the PWM ramp signal is
derived from the NMOS power switch current
(VSENSE). This ramp signal adds slope ramp
compensation signal (VRAMP) and is compared to the
output of the error amplifier (VERROR) to control the
on-time of the power switch. A proper slope rate will be
designed to improve circuit stability.
FIGURE 4-1: MCP1661 Simplified Block Diagram.
EN
+
-
+
-
+
-
S
+
-
1.227V
SW
VFB
EA
GND
+
-
OVP_REF
VFB
VFB_FAULT
Cc
Rc
VRAMP
VERROR
VPWM
CLK
QN
VEXT
VFB
VIN_OK
EN
VBIAS VUVLO_REF
VIN_OK
1.227VOVP_REF
VUVLO_REF
VSENSE
VLIMIT
VOUT_OK
VIN
Internal Bias
and UVLO
Comparator
Gate Drive
and
Shutdown
Control
Logic
Overcurrent Comparator
Oscillator Slope
Compensation
Logic
SR Latch
Overvoltage Comparator
Thermal
Shutdown
Power Good
Comparator
and Delay
Band Gap
2014-2015 Microchip Technology Inc. DS20005315B-page 13
MCP1661
4.2.1 INTERNAL BIAS
The MCP1661 device gets its bias from VIN. The VIN
bias is used to power the device and drive circuits over
the entire operating range.
4.2.2 START-UP VOLTAGE
AND SOFT START
The MCP1661 device starts at input voltages that are
higher than or equal to a predefined set UVLO value.
MCP1661 starts switching at approximately 2.3V for
12.0V output and 1 mA resistive load. Once started, the
device will continue to operate under normal load
conditions down to 1.85V typical. There is a soft start
feature which provides a way to limit the inrush current
drawn from the input (batteries) during start-up. The
soft start has an important role in applications where
the switch will reach 32V. During start-up, excessively
high switch current, together with the presence of high
voltage, can overstress the NMOS switch.
When the device is powered (EN = VIN and VIN rises
from zero to its nominal value), the output capacitor
charges to a value close to the input voltage (or VIN
minus a Schottky diode voltage drop). The overshoot
on output is limited by slowly increasing the reference
of the error amplifier. There is an internal reference
voltage which charges an internal capacitor with a
weak current source. The voltage on this capacitor
slowly ramps the reference voltage. The soft-start
capacitor is completely discharged in the event of a
commanded shutdown or a thermal shutdown.
Due to the direct path from input to output, in the case
of start-up by enable (EN voltage switches from low-to-
high), the output capacitor is already charged and the
output starts from a value close to the input voltage.
The internal oscillator has a delayed start to let the
output capacitor be completely charged to the input
voltage value.
4.2.3 UNDERVOLTAGE LOCKOUT
(UVLO)
MCP1661 features an UVLO which prevents fault
operation below 1.85V, which corresponds to the
typical value of two discharged batteries. The device
starts its normal operation at 2.3V input. The upper limit
is set to avoid any input transients (temporary VIN
drop), which might trigger the lower UVLO threshold
and restart the device. Usually, these voltage transients
(overshoots and undershoots) have up to a few
hundred mV.
MCP1661 is a non-synchronous boost regulator. Due
to this fact, there is a direct path from VIN to VOUT
through the inductor and the diode. This means that,
while the device is not switching (VIN below UVLOSTOP
threshold), VOUT is not zero but equal to VIN –V
F
(where VF is the voltage drop on the rectifier diode).
When the input voltage is below the 2.3V UVLO start
threshold, the device is operating with limited
specification.
4.2.4 PWM MODE OPERATION
MCP1661 operates as a fixed-frequency,
non-synchronous converter. The switching frequency
is maintained at 500 kHz with a precision oscillator.
Lossless current sensing converts the peak current
signal to a voltage (VSENSE) and adds it to the internal
slope compensation (VRAMP). This summed signal is
compared to the voltage error amplifier output (VERROR)
to provide a peak current control signal (VPWM) for the
PWM control block. The slope compensation signal
depends on the input voltage. Therefore, the converter
provides the proper amount of slope compensation to
ensure stability. The peak current is set to 1.3A.
The MCP1661 device will operate in PWM even during
periods of light load operation by skipping pulses. By
operating in PWM mode, the output ripple is low and
the frequency is constant.
4.2.5 ADJUSTABLE OUTPUT VOLTAGE
The MCP1661 output voltage is adjustable with a
resistor divider over the VOUT range. High value
resistors are recommended to minimize power loss and
keep efficiency high at light loads. The device
integrates a transconductance-type error amplifier and
the values of the feedback resistors do not influence
the stability of the system.
4.2.6 MINIMUM INPUT VOLTAGE
AND MAXIMUM OUTPUT CURRENT
The maximum output current for which the device can
supply the load is dependent upon the input and output
voltage. The minimum input voltage necessary to reach
the value of the desired output depends on the
maximum duty cycle (approximately 90%) in
accordance with the mathematical relation
VOUT =V
INmin/(1 – DMAX). As there is a 1.3A inductor
peak current limit, VOUT can go out of regulation before
reaching the maximum duty cycle. (For boost
converters, the average inductor current is equal to the
input current.)
For example, to ensure a 100 mA load current for
VOUT = 12.0V, a minimum of 2.8V input voltage is
necessary. If an application is powered by one Li-Ion
battery (VIN from 3.3V to 4.2V), the minimum load
current the MCP1661 device can deliver is close to
50 mA at 24.0V output (see Figure 2-3).
MCP1661
DS20005315B-page 14 2014-2015 Microchip Technology Inc.
4.2.7 ENABLE PIN
The MCP1661 device is enabled when the EN pin is set
high. The device is put into Shutdown mode when the
EN pin is set low. To enable the boost converter, the EN
voltage level must be greater than 85% of the VIN
voltage. To disable the boost converter, the EN voltage
must be less than 7.5% of the VIN voltage.
In Shutdown mode, the MCP1661 device stops
switching and all internal control circuitry is switched
off. On boost configuration, the input voltage will be
bypassed to output through the inductor and the
Schottky diode. In the SEPIC converter, Shutdown
mode acts as output disconnect.
4.2.8 INTERNAL COMPENSATION
The error amplifier, with its associated compensation
network, completes the closed-loop system by
comparing the output voltage to a reference at the
input of the error amplifier and by feeding the amplified
and inverted error voltage to the control input of the
inner current loop. The compensation network
provides phase leads and lags at appropriate
frequencies to cancel excessive phase lags and leads
of the power circuit. All necessary compensation
components and slope compensation are integrated.
4.2.9 OUTPUT OVERVOLTAGE
PROTECTION (OVP)
An internal VFB fault signal turns off the PWM signal
(VEXT) and prevents the output from going out of
regulation in the event of:
• short circuit of the feedback pin to GND
• disconnection of the feedback divider from VOUT
In any of the above events, for a regular integrated
boost circuit (IC) without any protection implemented, if
the VFB voltage drops to ground potential, its N-channel
transistor will be forced to switch at full duty cycle and
VOUT rises. This Fault event may cause the SW pin to
exceed its maximum voltage rating and may damage
the boost regulator IC, the external components and
the load. To avoid all these, MCP1661 has
implemented an overvoltage protection (OVP) which
turns off PWM switching when an overvoltage condition
is detected. There is an overvoltage comparator with
80 mV reference which monitors the VFB voltage.
The OVP comparator is disabled during start-up
sequences and thermal shutdown.
If OVP occurs with the input voltage below the
UVLOSTART threshold and VFB remains under 80 mV
due to a low input voltage or overload condition, the
device latches its output and resumes after restart.
4.2.10 OVERCURRENT LIMIT
The MCP1661 device uses a 1.3A cycle-by-cycle
inductor peak current limit to protect the N-channel
switch. There is an overcurrent comparator which
resets the drive latch when the peak of the inductor
current reaches the limit. In current limitation, the
output voltage starts dropping.
4.2.11 OUTPUT SHORT CIRCUIT
CONDITION
Like all non-synchronous boost converters, the MCP1661
inductor current will increase excessively during a short
circuit on the converter’s output. Short circuit on the
output will cause the diode rectifier to fail and the
inductor’s temperature to rise. When the diode fails, the
SW pin becomes a high-impedance node, it remains
connected only to the inductor and the excessive resulted
ringing will damage the MCP1661 device.
4.2.12 OVERTEMPERATURE
PROTECTION
Overtemperature protection circuitry is integrated into
the MCP1661 device. This circuitry monitors the device
junction temperature and shuts the device off if the
junction temperature exceeds the typical +150°C
threshold. If this threshold is exceeded, the device will
automatically restart when the junction temperature
drops by 15°C. The output overvoltage protection
(OVP) is reset during an overtemperature condition.
2014-2015 Microchip Technology Inc. DS20005315B-page 15
MCP1661
5.0 APPLICATION INFORMATION
5.1 Typical Applications
The MCP1661 nonsynchronous boost regulator
operates over a wide output voltage range up to 32V.
The input voltage ranges from 2.4V to 5.5V. The device
operates down to 1.85V input with limited specification.
The UVLO thresholds are set to 2.3V when VIN is
ramping and to 1.85V when VIN is falling. The power
efficiency conversion is high for several decades of
load range. Output current capability increases with the
input voltage and decreases with the increasing output
voltage. The maximum output current is based on the
N-channel switch peak current limit, set to 1.3A, and on
a maximum duty cycle of 90%. Typical characterization
curves in this data sheet are presented to display the
typical output current capability.
5.2 Adjustable Output Voltage
Calculations
To calculate the resistor divider values for the
MCP1661, the following equation can be used. Where
RTOP is connected to VOUT
, RBOT is connected to GND
and both are connected to the VFB input pin.
EQUATION 5-1:
The values of the two resistors, RTOP and RBOT
, affect
the no load input current and quiescent current. In
Shutdown mode (EN = GND), the device consumes
approximately 0.2 µA. With 24V output and 1 M
feedback divider, the current which this divider drains
from input is 2.4 µA. This value is much higher than what
the device consumes. Keeping RTOP and RBOT high will
optimize efficiency conversion at very light loads. There
are some potential issues with higher value resistors, as
in the case of small surface mount resistors;
environment contamination can create leakage paths on
the PCB that significantly change the resistor divider and
may affect the output voltage tolerance.
5.2.1 OVERVOLTAGE PROTECTION
The MCP1661 features an output overvoltage
protection (OVP) in case RTOP is disconnected from
the VOUT line. A typical 80 mV OVP reference is
compared to VFB voltage. If voltage on the VFB pin
drops below the reference value, the device stops
switching and prevents VOUT from rising up to a
dangerous value.
OVP is not enabled during start-up and thermal
shutdown events.
EXAMPLE 5-1:
VOUT =12.0V
VFB = 1.227V
RBOT =120k
RTOP = 1053.6 k (VOUT = 11.96V with a standard
value of 1050 k)
EXAMPLE 5-2:
VOUT =24.0V
VFB = 1.227V
RBOT =53k
RTOP = 983.67 k (VOUT = 23.82V with a standard
value of 976 k)
RTOP RBOT
VOUT
VFB
------------- 1–


=
MCP1661
DS20005315B-page 16 2014-2015 Microchip Technology Inc.
5.3 Input Capacitor Selection
The boost input current is smoothened by the boost
inductor, reducing the amount of filtering necessary at
the input. Some capacitance is recommended to
provide decoupling from the input source. Because
MCP1661 is rated to work up to 125°C, low ESR X7R
ceramic capacitors are well suited, since they have a
low temperature coefficient and are small-sized. For
limited temperature range use at up to 85°C, a X5R
ceramic capacitor can be used. For light load
applications, 4.7 µF of capacitance is sufficient at the
input. For high-power applications that have high
source impedance or long leads, using a 20-30 µF
input capacitor is recommended to sustain high input
boost currents. Additional input capacitance can be
added to provide a stable input voltage.
Table 5-1 contains the recommended range for the
input capacitor value.
5.4 Output Capacitor Selection
The output capacitor helps provide a stable output
voltage during sudden load transients and reduces
the output voltage ripple. As with the input capacitor,
X7R ceramic capacitor is recommended for this
application. Using other capacitor types (aluminum or
tantalum) with large ESR has impact on the
converter's efficiency (see AN1337), maximum output
power and stability. For limited temperature range (up
to 85°C), X5R ceramic capacitors can be used. The
DC rating of the output capacitor should be greater
than the VOUT value. Generally, ceramic capacitors
lose up to 50% of their capacity when the voltage
applied is close to the maximum DC rating. Choosing
a capacitor with a safe higher DC rating or placing two
capacitors in parallel assure enough capacity to
correctly filter the output voltage.
The MCP1661 device is internally compensated so
output capacitance range is limited. See Table 5-1 for
the recommended output capacitor range.
An output capacitance higher than 10 µF adds a
better load step response and high-frequency noise
attenuation, especially while stepping from light to
heavy current loads. In addition, 2 x 10 µF output
capacitors ensure a better recovery of the output after
a short period of overloading.
While the N-Channel switch is on, the output current
is supplied by the output capacitor COUT
. The amount
of output capacitance and equivalent series
resistance will have a significant effect on the output
ripple voltage. While COUT provides load current, a
voltage drop also appears across its internal ESR that
results in ripple voltage.
Peak-to-peak output ripple voltage also depends on
the equivalent series inductance (ESL) of the output
capacitor. There are ceramic capacitors with special
internal architecture which minimize the ESL. Consult
the ceramic capacitor's manufacturer portfolio for
more information.
Ta b l e 5 - 1 contains the recommended range for the
input and output capacitor value.
5.5 Inductor Selection
The MCP1661 device is designed to be used with small
surface mount inductors; the inductance value can
range from 4.7 µH to 10 µH. An inductance value of
4.7 µH is recommended for output voltages below 15V.
For higher output voltages, up to 32V, an inductance
value of 10 µH is optimum. While the device operates
at low inputs, below 3.0V, a low value inductor (2.2 µH
or 3.3 µH) ensures better stability but limited output
power capability. Usually, this is a good trade-off as
boost converters powered from two-cell batteries are
low-power applications.
TABLE 5-1: CAPACITOR VALUE RANGE
CIN COUT
Minimum 4.7 µF 10 µF
Maximum — 47 µF
2014-2015 Microchip Technology Inc. DS20005315B-page 17
MCP1661
Several parameters are used to select the correct
inductor: maximum rated current, saturation current
and copper resistance (DCR). For boost converters,
the inductor current is much higher than the output
current. The average inductor current is equal to the
input current. The inductor’s peak current is 30-40%
higher than the average. The lower the inductor DCR,
the higher the efficiency of the converter: a common
trade-off in size versus efficiency.
The saturation current typically specifies a point at
which the inductance has rolled off a percentage of the
rated value. This can range from a 20% to 40%
reduction in inductance. As inductance rolls off, the
inductor ripple current increases, as does the peak
switch current. It is important to keep the inductance
from rolling off too much, causing switch current to
reach the peak limit.
5.6 Rectifier Diode Selection
Schottky diodes are used to reduce losses. The diode’s
current rating has to be equal or higher than the
maximum output current. The diode’s reverse
breakdown voltage must be higher than the internal
switch rating voltage of 36V.
The converter’s efficiency will be improved if the
voltage drop across the diode is lower. The forward
voltage rating is forward-current dependent, which is
equal in particular to the load current.
For high currents and high ambient temperatures, use
a diode with good thermal characteristics.
5.7 SEPIC Converter Considerations
One of the advantages of using MCP1661 in SEPIC
topology is the usage of an output disconnect feature.
Also, the output voltage may be lower or higher than
the input voltage, resulting in buck or boost operation.
Input voltage is limited to the 2.4-5.5V range.
One major advantage is that the SEPIC converter allows
3.0V or 3.3V buck-boost application from a Li-Ion battery
with load disconnect. Also, SEPIC is recommended for
higher output voltages where an input-to-output isolation
is necessary (due to the coupling capacitor). An
application example is shown in Figure 6-3.
The maximum output voltage, VOUTmax, must be
limited to the sum of (VIN +V
OUT) < 36V, which is the
maximum internal switch DC rating. VIN must be ≤ 5.5V.
Some extra aspects need to be taken into account
when choosing the external components:
• the DC voltage rating of the coupling capacitor
should be at least equal to the maximum input
voltage
• the average current rating of the rectifier diode’s is
equal to the output load current
• the peak current of the rectifier diode is the same
as the internal switch current, ISW =I
IN +I
OUT
.
See the notes on Figure 6-3 in Section 6.0 “Typical
Application Circuits” for some recommended 1:1
coupled inductors.
5.8 Thermal Calculations
The MCP1661 device is available in two different
packages (5-lead SOT-23 and 8-lead 2x3 TDFN). By
calculating the power dissipation and applying the
package thermal resistance (JA), the junction
temperature is estimated. The maximum continuous
junction temperature rating for the MCP1661 device is
+125°C.
To quickly estimate the internal power dissipation for
the switching boost regulator, an empirical calculation
using measured efficiency can be used. Given the
measured efficiency, the internal power dissipation is
estimated by Equation 5-2.
TABLE 5-2: MCP1661 RECOMMENDED
INDUCTORS FOR BOOST
CONVERTERS
Part Number Value
(µH)
DCR
(typ.)
ISAT
(A)
Size
WxLxH (mm)
Coilcraft
MSS5131-472 4.7 0.038 1.42 5.1x5.1x3.1
XFL4020-472 4.7 0.057 2.7 4.2x4.2x2.1
LPS5015-562 5.6 0.175 1.6 5.0x5.0x1.5
LPS6235-103 10 0.065 1.5 6.2x6.2x3.5
XAL4040-103 10 0.092 1.9 4.3x4.3x4.1
Würth Elektronik
744025004 WE-TPC 4.7 0.1 1.7 2.8x2.8x2.8
744043004 WE-TPC 4.7 0.05 1.7 4.8x4.8x2.8
744773112 WE-PD2 10 0.156 1.6 4.0x4.5x3.2
74408943100 WE-SPC 10 0.082 2.1 4.8x4.8x3.8
TDK Corporation
B82462G4472 4.7 0.04 1.8 6.3x6.3x3.0
B82462G4103 10 0.062 1.3 6.3x6.3x3.0
VLCF4024T-4R7 4.7 0.087 1.43 4.0x4.0x2.4
TABLE 5-3: RECOMMENDED SCHOTTKY
DIODES
Type VOUTmax TA
PMEG2005 18V < 85°C
PMEG4005 36V < 85°C
MBR0520 18V < 125°C
MBR0540 36V < 125°C
MCP1661
DS20005315B-page 18 2014-2015 Microchip Technology Inc.
EQUATION 5-2:
The difference between the first term, input power, and
the second term, power delivered, is the power
dissipated when using the MCP1661 device. This is an
estimate, assuming that most of the power lost is
internal to the MCP1661 and not CIN, COUT
, the diode
and the inductor. There is some percentage of power
lost in the boost inductor and rectifier diode, with very
little loss in the input and output capacitors. For a more
accurate estimation of the internal power dissipation,
subtract the IINRMS2xL
DCR and IOUT xV
F power
dissipation (where INRMS is the average input current,
LDCR is the inductor series resistance and VF is the
diode voltage drop).
5.9 PCB Layout Information
Good printed circuit board layout techniques are
important to any switching circuitry, and switching
power supplies are no different. When wiring the
switching high-current paths, short and wide traces
should be used. Therefore, it is important that the input
and output capacitors be placed as close as possible to
the MCP1661 to minimize the loop area.
The feedback resistors and feedback signal should be
routed away from the switching node and the switching
current loop. When possible, ground planes and traces
should be used to help shield the feedback signal and
minimize noise and magnetic interference.
FIGURE 5-1: 5-Lead SOT-23 Recommended Layout.
VOUT IOUT
Efficiency
-------------------------------------


VOUT IOUT
–PDis
=
COUT
L
CIN
+VIN
GND
GND
+VOUT
EN
MCP1661 RTOP
1
GND
Vias to GND Bottom Plane
RBOT
Vias to GND Bottom Plane
D
A
K
GND Bottom Plane
2014-2015 Microchip Technology Inc. DS20005315B-page 19
MCP1661
FIGURE 5-2: 8-Lead TDFN Recommended Layout.
COUT
L
CIN
+VIN
+VOUT
MCP1661
Routed to Bottom Side
RBOT
GND
Vias to GND
Bottom Plane
1
RTOP
AK
D
EN
Via to GND
EN Routed on Bottom Side
GND
GND Bottom Plane
MCP1661
DS20005315B-page 20 2014-2015 Microchip Technology Inc.
6.0 TYPICAL APPLICATION CIRCUITS
FIGURE 6-1: Two Alkaline Cells to 12V Boost Converter.
V
IN
GND
V
FB
V
OUT
12V, 75 mA
C
OUT
10 µF
C
IN
10 µF
L
4.7 µH
SW
1.05 M
120 k
EN
+
-
ALKALINE
ON
OFF
+
-
ALKALINE
R
TOP
R
BOT
V
IN
2.4V
-3.0V
D
MCP1661
Schottky
D
Component Value Manufacturer Part Number Comment
CIN 10 µF TDK Corporation C2012X7R1A106K125AC Cap. ceramic 10 µF 10V 10% X7R 0805
COUT 10 µF TDK Corporation C3216X7R1C106K160AC Cap. ceramic 10 µF 16V 10% X7R 1206
L 4.7 µH Coilcraft XFL4020-472MEB Inductor Power 4.7 µH 2A SMD
RTOP 1.05 MΩYageo Corporation RC0805FR-071M05L Res. 1.05 MΩ 1/8W 1% 0805 SMD
RBOT 120 kΩYageo Corporation RC0805FR-07120KL Res. 120 kΩ 1/8W 1% 0805 SMD
D — NXP Semiconductor PMEG2005EH,115 Diode Schottky 20V 0.5A SOD123F
2014-2015 Microchip Technology Inc. DS20005315B-page 21
MCP1661
FIGURE 6-2: Single Li-Ion Cell to 24V Output Boost Converter.
GND
VFB
VOUT
24V, 50 mA
COUT
10 µF
CIN
10 µF
L
10 µH
SW
1.05 M
56 k
EN
+
-
LI-ION
RTOP
RBOT
VIN
3.0V-4.2V
D
Component Value Manufacturer Part Number Comment
CIN 10 µF TDK Corporation C2012X7R1A106K125AC Cap. ceramic 10 µF 10V 10% X7R 0805
COUT 10 µF TDK Corporation C3216X7R1V106K160AC Cap. ceramic 10 µF 35V 10% X7R 1206
L 10 µH EPCOS AG B82462G4103M000 Inductor Power 10 µH 1.5A SMD
RTOP 1.05 MYageo Corporation RC0805FR-071M05L Res. 1.05 M 1/8W 1% 0805 SMD
RBOT 56 kYageo Corporation RC0805FR-0756KL Res. 56 k 1/8W 1% 0805 SMD
D — Micro Commercial
Components
MBR0540-TP Diode Schottky 40V 0.5A SOD123
VIN
MCP1661
Schottky
MCP1661
DS20005315B-page 22 2014-2015 Microchip Technology Inc.
FIGURE 6-3: Single Li-Ion Cell to 3.3V Output Buck-Boost (SEPIC) Converter with 1:1 Coupled
Inductors and Load Disconnect.
V
IN
GND
V
FB
V
OUT
3.3V, 250 mA
C
OUT
4.7-10 µF
C
IN
4.7-10 µF
L1A(1)
4.7 µH
SW
2.2 k
1.3 k
EN
+
-
LI-ION
ON
OFF
R
TOP
R
BOT
L1B(1)
4.7 µH
V
IN
3.0V-4.2V
D
C
C
1µF
MCP1661
Component Value Manufacturer Part Number Comment
CIN 10 µF TDK Corporation C2012X7R1A106K125AC Cap. ceramic 10 µF 10V 10% X7R 0805
COUT 10 µF TDK Corporation C3216X7R1V106K160AC Cap. ceramic 10 µF 35V 10% X7R 1206
CC1 µF TDK Corporation C2012X7R1E105K125AB Cap. ceramic 1 µF 25V 10% X7R 0805
L 4.7 µH Würth Elektronik 744878004 Inductor Array 2 Coil 4.7 µH SMD
RTOP 2.2 kYageo Corporation RC0805FR-072K2L Res. 2.2 k 1/8W 1% 0805 SMD
RBOT 1.3 kYageo Corporation RC0805FR-071K3L Res. 1.3 k 1/8W 1% 0805 SMD
D — NXP Semiconductors PMEG2020AEA,115 Diode Schottky 20V 2A SOD323
Schottky
Note 1: Recommended 1:1 coupled inductors.
2014-2015 Microchip Technology Inc. DS20005315B-page 23
MCP1661
FIGURE 6-4: Single Li-Ion Cell to 12V Flyback Converter for Low Load Currents Application
Example.
V
IN
GND
V
FB
V
OUT
12V
C
OUT
10
µF
C
IN
10
µF
SW
1.05 M
120
k
EN
ON
OFF
R
TOP
R
BOT
D
+
-
LI-ION
V
IN
3.3V-4.2V
C
FF
22-33
pF
TR
Schottky
MCP1661
Component Value Manufacturer Part Number Comment
CIN 10 µF TDK Corporation C2012X7R1A106K125AC Cap. ceramic 10 µF 10V 10% X7R 0805
COUT 10 µF TDK Corporation C3216X7R1V106K160AC Cap. ceramic 10 µF 35V 10% X7R 1206
CFF 27 pF TDK Corporation C1608NP02A270J080AA Cap. ceramic 27 pF 100V 5% NP0 0603
TR 25 µH Würth Elektronik 750310799 Trans. Flyback LT3573 25 µH SMD
RTOP 1.05 MYageo Corporation RC0805FR-071M05L Res. 1.05 M 1/8W 1% 0805 SMD
RBOT 120 kYageo Corporation RC0805FR-07120KL Res. 120 k 1/8W 1% 0805 SMD
D — Micro Commercial
Components
MBR0540-TP Diode Schottky 40V 0.5A SOD123
25 µH
MCP1661
DS20005315B-page 24 2014-2015 Microchip Technology Inc.
FIGURE 6-5: Two Alkaline Cells to 12V Boost Converter with Load Disconnect Application
Example.
VIN
GND
VFB
VOUT
12V, 50 mA
COUT
10 µF
CIN
10 µF
L
4.7 µH
SW
1.05 M
120 k
EN
+
-
ALKALINE
ON
OFF
RTOP
RBOT
VIN
2.4V-3.0V
D
RBOT
Schottky
RBOT
VOUT
IOUT
---------------- 1 0 0
+
-
ALKALINE
MCP1661
C1
0.1 µF
Component Value Manufacturer Part Number Comment
CIN 10 µF TDK Corporation C2012X7R1A106K125AC Cap. ceramic 10 µF 10V 10% X7R 0805
COUT 10 µF TDK Corporation C3216X7R1V106K160AC Cap. ceramic 10 µF 35V 10% X7R 1206
C1 0.1 µF TDK Corporation C1608X7R1E104K080AA Cap. ceramic 0.1 µF 25V 10% X7R 0603
L 4.7 µH Würth Elektronik 744043004 Inductor Power 4.7 µH 1.55A SMD
RTOP 1.05 MYageo Corporation RC0805FR-071M05L Res. 1.05 M 1/8W 1% 0805 SMD
RBOT 120 kYageo Corporation RC0805FR-07120KL Res. 120 k 1/8W 1% 0805 SMD
D — Micro Commercial
Components
MBR0540-TP Diode Schottky 40V 0.5A SOD123
Q — Micro Commercial
Components
MMBT3906-TP Trans. SS PNP 40V 300MW SOT-23
2014-2015 Microchip Technology Inc. DS20005315B-page 25
MCP1661
7.0 PACKAGING INFORMATION
7.1 Package Marking Information
8-Lead TDFN (2x3x0.75 mm) Example
5-Lead SOT-23 Example
Legend: XX...X Customer-specific information
Y Year code (last digit of calendar year)
YY Year code (last 2 digits of calendar year)
WW Week code (week of January 1 is week ‘01’)
NNN Alphanumeric traceability code
Pb-free JEDEC® designator for Matte Tin (Sn)
*This package is Pb-free. The Pb-free JEDEC designator ( )
can be found on the outer packaging for this package.
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
3
e
3
e
ABZ
525
25
AAAL5
25256
MCP1661
DS20005315B-page 26 2014-2015 Microchip Technology Inc.
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2014-2015 Microchip Technology Inc. DS20005315B-page 27
MCP1661
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
MCP1661
DS20005315B-page 28 2014-2015 Microchip Technology Inc.
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
2014-2015 Microchip Technology Inc. DS20005315B-page 29
MCP1661
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
MCP1661
DS20005315B-page 30 2014-2015 Microchip Technology Inc.
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2014-2015 Microchip Technology Inc. DS20005315B-page 31
MCP1661
APPENDIX A: REVISION HISTORY
Revision B (February 2015)
The following is the list of modifications:
1. Updated Section 6.0 “Typical Application
Circuits”.
2. Added legend tables for Figures 6-3 to 6-5.
3. Minor typographical corrections.
Revision A (June 2014)
• Original Release of this Document.
MCP1661
DS20005315B-page 32 2014-2015 Microchip Technology Inc.
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
Examples:
a) MCP1661T-E/MNY: Tape and Reel,
Extended temperature,
8LD TFDN package
b) MCP1661T-E/OT: Tape and Reel,
Extended temperature,
5LD SOT-23 package
Device: MCP1661: High-Voltage Step-Up LED Driver with UVLO and
OLP
Tape and Reel
Option:
T = Tape and Reel(1)
Temperature
Range:
E=-40C to +125C (Extended)
Package: MN* = Plastic Dual Flat, No Lead – 2x3x0.75 mm Body
(TDFN)
OT = Plastic Small Outline Transistor (SOT-23)
*Y = Nickel palladium gold manufacturing designator.
Only available on the TDFN package.
Note 1: Tape and Reel identifier only appears in the
catalog part number description. This
identifier is used for ordering purposes and
is not printed on the device package. Check
with your Microchip Sales Office for package
availability with the Tape and Reel option.
PART NO. X/XX
PackageTemperature
Range
Device
[X](1)
Tape and Reel
Option
2014-2015 Microchip Technology Inc. DS20005315B-page 33
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights.
Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
FlashFlex, flexPWR, JukeBlox, KEELOQ, KEELOQ logo, Kleer,
LANCheck, MediaLB, MOST, MOST logo, MPLAB,
OptoLyzer, PIC, PICSTART, PIC32 logo, RightTouch, SpyNIC,
SST, SST Logo, SuperFlash and UNI/O are registered
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
The Embedded Control Solutions Company and mTouch are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Analog-for-the-Digital Age, BodyCom, chipKIT, chipKIT logo,
CodeGuard, dsPICDEM, dsPICDEM.net, ECAN, In-Circuit
Serial Programming, ICSP, Inter-Chip Connectivity, KleerNet,
KleerNet logo, MiWi, MPASM, MPF, MPLAB Certified logo,
MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient Code
Generation, PICDEM, PICDEM.net, PICkit, PICtail,
RightTouch logo, REAL ICE, SQI, Serial Quad I/O, Total
Endurance, TSHARC, USBCheck, VariSense, ViewSpan,
WiperLock, Wireless DNA, and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
Silicon Storage Technology is a registered trademark of
Microchip Technology Inc. in other countries.
GestIC is a registered trademarks of Microchip Technology
Germany II GmbH & Co. KG, a subsidiary of Microchip
Technology Inc., in other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2014-2015, Microchip Technology Incorporated, Printed in
the U.S.A., All Rights Reserved.
ISBN: 978-1-63277-121-6
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
QUALITY MANAGEMENT S
YSTEM
CERTIFIED BY DNV
== ISO/TS 16949 ==
DS20005315B-page 34 2014-2015 Microchip Technology Inc.
AMERICAS
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Worldwide Sales and Service
01/27/15
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Microchip:
MCP1661T-E/MNY MCP1661T-E/OT