MIC5281
120VIN, 25mA, Ultra-Low IQ, High-PSRR
Linear Regulator
4-0Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 94 800 • fax + 1 (408) 474-1000 • http://www.micrel.com
June 2011
General Description
The MIC5281 high-performance linear regulator offers a
very-wide input operating voltage range, up to 120V DC,
and supplies an output current of up to 25mA.
Ideal for high input voltage applications such as industrial
and telecom, the MIC5281 offers ±3% initial accuracy,
extremely high-power supply rejection ratio (>90db) and
ultra-low quiescent current of 6µA. The MIC5281 is
optimized for high-voltage line transients, making it ideal
for harsh environment applications.
The MIC5281 is offered in both fixed output voltage
(3.3V/5.0V) and adjustable output voltage (1.27V to 5.5V)
options.
The MIC5281 operates over a −40ºC to +125ºC
temperature range and is available in lead-free, RoHS-
compliant, 8-pin ePad MSOP and 8-pin MSOP packages.
Data sheet and support documentation are found on the
Micrel website: www.micrel.com.
Features
• Wide input voltage range: 6V to 120V DC
• Ultra-low quiescent current: 6µA
• 25mA guaranteed output current
• Adjustable output from 1.27V to 5.5V
• Withstands up to +120V DC at the input
• Stable with ceramic capacitors
• Ultra-high PSRR >90dB
• Ultra-high line rejection (load dump)
• High output accuracy:
– ±3% initial accuracy
• Thermal-shutdown and current-limit prot ection
• Thermally-efficient, 8-pin MSOP and 8-pin ePad MSO P
packages
Applications
• Industrial applications
• Remote keyless entry power supply
• Telecom applications
• Off-line power supplies
___________________________________________________________________________________________________________
Typical Applications
Quiescent Suppl
y
Curre n t
vs. I nput Vol tage
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
0 20 40 60 80 100 120
I N PUT V O L TAGE ( V)
Q UIESCENT CURRENT (µ A)
VOUT = 5V
IOUT = 0
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June 2011 2 M9999-062411-A
Ordering Information
Part Number Output Voltage Top Mark Temperature Range Package Lead Finish
MIC5281YMME Adjustable 781A
–40°C to +125°C 8-Pin ePad MSOP Pb-Free
MIC5281-3.3YMME 3.3V 781S
–40°C to +125°C 8-Pin ePad MSOP Pb-Free
MIC5281-5.0YMME 5.0V 7815
–40°C to +125°C 8-Pin ePad MSOP Pb-Free
MIC5281YMM Adjustable
− –40°C to +125°C 8-Pin MSOP Pb-Free
MIC5281-3.3YMM 3.3V − –40°C to +125°C 8-Pin MSOP Pb-Free
MIC5281-5.0YMM 5.0V − –40°C to +125°C 8-Pin MSOP Pb-Free
Pin Configur ation
8-Pin ePAD MSOP
MIC5281-x.xYMME
(TOP VIEW)
8-Pin MSOP
MIC5281-x.xYMM
(TOP VIEW)
8-Pin ePAD MSOP
MIC5281YMME
(TOP VIEW)
8-Pin MSOP
MIC5281YMM
(TOP VIEW)
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June 2011 3 M9999-062411-A
Pin Description
Pin
MIC5281YMME MIC5281-x.xYMME MIC5281YMM MIC5281-x.xYMM Name Function
1 1 1 1 VIN
Supply Voltage Input. Connect 1µF
capacitor from VIN to GND.
2, 3, 7 2, 3, 7 2, 3, 7 2, 3, 7 NC Not internally connected. Connect
NC to GND or leave unconnected.
4 4 4 4 CPSRR
Bypass Capacitor Connection.
Connect 0.1µF capacitor from
CPSRR to GND.
5 5 5 5 GND Ground.
6 − 6 − FB Feedback Connection. For external
resistor divider to set VOUT.
− 6 − 6 SNS
Sense input. Connect SNS to
VOUT.
8 8 8 8 VOUT
Regulator Output. Connect 10µF
capacitor from VOUT to GND.
EP EP − − EP Exposed Pad (ePad) for Thermal
Relief. Connect EP to GND.
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June 2011 4 M9999-062411-A
Absolute Maximum Ratings(1)
VIN to GND...................................................–0.3V to +125V
VCPSRR to GND..................................................–0.3 to +14V
VFB, VSNS, VOUT to GND...................................–0.3V to +6V
Lead Temperature (solderi ng, 10s)..........................+260°C
Junction Temperature.........................–40°C ≤ TJ ≤ +125°C
Storage Temperature .........................–65°C ≤ TA ≤ +150°C
ESD Ratings(4)
HBM.........................................................................2kV
MM.........................................................................200V
Operating Ratings(2)
VIN .................................................................+6V to +120V
VOUT Adjust Range.....................................+1.27V to +5.5V
Junction Temperature.........................–40°C ≤ TJ ≤ +125°C
Power Dissipation (PD)...........................Internally Limited(3)
Junction Thermal Resistance (θJA)
8-pin ePad MSOP..............................................64°C/W
8-pin MSOP.....................................................160°C/W
Electrical Characteristics(5)
VIN = 12V, CIN = 1.0µF, CPSRR = 0.1µF, COUT = 10µF, VOUT = 5.0V or 3.3V, IOUT = 100µA, TA = 25°C, bold values indicate
–40°C ≤ TJ ≤ +125°C, unless noted.
Parameter Condition Min. Typ. Max. Units
Power Supply Input
Input Voltage Range(6) 6 120 V
Quiescent Supply Current IOUT = 0 6 11 µA
Output Voltage
Adjustable 1.27 5.5
3.2 3.3 3.4
Fixed 3.3V 3.13 3.3 3.47
4.85 5.0 5.15
Output Voltage
Fixed 5.0V 4.75 5.0 5.25
V
−3 +3 %
Output Voltage Accuracy Variation from nominal VOUT −5 +5 %
Load Regulation IOUT = 100µA to 25mA −0.5 0.2 +0.5 %
Line Regulation(7) VIN = 10V to 120V −0.5 0.04 +0.5 %/V
Feedback Input (Adjustable) 1.232 1.270 1.308
FB Voltage 1.206 1.270 1.333 V
FB Current VFB = 1.27V 3.2 nA
Current Limit
Current Limit VOUT = 0V 30 65 130 mA
Ripple Rejection
Power Supply Rejection Ratio f = 20kHz to 2MHz >90 dB
Notes:
1. Exceeding an absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation at any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA. Exceeding the maximum allowable power
dissipation results in excessive die temperature, and causes the regulator to enter thermal shutdown.
4. Devices are ESD sensitive; use proper handling precautions.
5. Specifications are for packaged products only.
6. Assure that VIN ≥ (VOUT + 3V) and VIN ≥ 6V.
7. Line regulation is a percentage of VOUT.
Micrel, Inc. MIC5281
June 2011 5 M9999-062411-A
Electrical Characteristics(5) (Continued)
VIN = 12V, CIN = 1.0µF, CPSRR = 0.1µF, COUT = 10µF, VOUT = 5.0V or 3.3V, IOUT = 100µA, TA = 25°C, bold values indicate
–40°C ≤ TJ ≤ +125°C, unless noted.
Parameter Condition Min. Typ. Max. Units
Power Dropout Voltage
Dropout Voltage IOUT = 25mA 2 3 V
Thermal Protection
Thermal-Shutdo wn Temperature TJ rising 157 °C
Thermal-Shutdown Hysteresis 15 °C
Micrel, Inc. MIC5281
Typical Characteristics
Output V oltage
vs. Input Voltage
4.90
4.95
5.00
5.05
5.10
5.15
Quiescent Supply Current
vs. Input Vo l tage
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
Quiescent Supply Current
vs. Temperature
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
June 2011 6 M9999-062411-A
0.0
Q UI ESCENT CURRENT (µA)
0 20 40 60 80 100 120
I NPUT VOLTA G E (V)
V
OUT
= 5V
I
OUT
= 0
0.0
Q UIESCENT CURRENT ( µA)
-50 -25 0 25 50 75 100 125
TEMPERA TURE (° C)
VIN = 12V
VOUT = 5V
IOUT = 0mA
4.85 0 20 40 60 80 100 120
O UTPUT VO LTAGE ( V)
I NPUT VOLTAGE ( V)
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 5mA
Out put Voltage
vs. O utput Current
4.75 0 5 10 15 20 25
O UTP UT CURRENT (mA)
Out put Vol tage
vs. Temperature
4.75
4.80
4.85
4.90
4.95
5.00
5.05
5.10
5.15
5.20
5.25
-50 -25 0 25 50 75 100 125
TEM PERATURE ( °C)
Dropout Voltage
vs. Output Current
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 5 10 15 20 25
O U TPUT CU RRENT (mA)
4.80
4.85
4.90
4.95
5.00
5.05
5.10
5.15
5.20
5.25
O UTPUT VOLTAGE ( V)
V
IN
= 12V
V
OUT
= 5V V
IN
= 12V
V
OUT
= 5V
I
OUT
= 5mA
V
OUT
= 5V
DROPO UT VOLTAG E (V)
A
DJUSTABLE OPTION
O UT PUT VOLTAG E ( V )
Dropout Voltage
vs. Temperature
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
DRO POUT VO LT AG E (V)
-50 -25 0 25 50 75 100 125
TEM P ERA T URE ( °C)
V
OUT
= 5V
I
OUT
= 25mA
FB Voltage
vs. Input Voltage
1.23
1.24
1.25
1.26
1.27
1.28
1.29
1.30
1.31
FB VOLTAG E ( V)
0 20406080100120
I NPUT VOLTA GE ( V)
V
OUT
= 5V
I
OUT
= 5mA
FB Current
vs. Input Volt age
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
FB CURRENT (nA)
0 20 40 60 80 100 120
I NPUT VO LT AGE ( V )
V
OUT
= 5V
V
FB
= 1. 267V
Micrel, Inc. MIC5281
Typical Characteristics (Continued)
FB Vol tage
vs. Temperature
1.24
1.25
1.26
1.27
1.28
1.29
1.30
1.31
-50 -25 0 25 50 75 100 125
TEM PERATURE ( °C)
FB Current
vs. Temperature
0.0
0.5
1.0
1.5
2.0
2.5
-50 -25 0 25 50 75 100 125
TEM PERATURE ( °C)
FB Voltage
vs. O utput Current
1.266
1.268
1.270
1.272
1.274
1.276
0 5 10 15 20 25
O UTP UT CURRENT (mA)
V
IN
= 12V
V
OUT
= 5. 0V
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 5mA
V
IN
= 12V
V
FB
= 1. 267V
I
OUT
= 0
FB VO LTAG E ( V)
FB VO L TAG E (V)
FB CURRENT ( n A)
Current Li m it
vs. Temperature
50
55
60
65
70
75
80
-50 -25 0 25 50 75 100 125
TEMPERA TURE ( °C)
Load Regulation
vs. Temperature
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
0.26
0.28
0.30
-50 -25 0 25 50 75 100 125
TEM P ERATURE ( ° C)
Li ne Regulation
vs. Temperat ure
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
-50 -25 0 25 50 75 100 125
TEMPERATURE (°C)
V
IN
= 10V to 120V
V
OUT
= 5V
I
OUT
= 100µA
V
IN
= 12V
V
OUT
= 5V
I
OUT
=100µA to 25mA
LI NE REGULATI O N (%/V)
LO AD REGULATIO N ( %)
V
IN
= 12V
V
OUT
= 0V
CURRENT LIMIT ( mA)
Power Dissipation
vs. Output Current
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
PO W ER DISSI PATIO N ( W )
0 5 10 15 20 25
O UTP UT CURRENT (mA)
V
IN
= 12V
V
OUT
= 4. 5V
Case Temperature (MME)
vs. O utput C urrent
24
26
28
30
32
34
36
38
40
CASE TEM PERATURE (°C)
0 5 10 15 20 25
O UTP UT CURRENT (mA)
V
IN
= 12V
V
OUT
= 4. 5V
PSRR vs. Frequency
-130
-110
-90
-70
-50
-30
-10
10
30
PSRR ( d B )
0.01 0.1 1 10 100 1000 10000
FREQUENCY (kHz)
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 5mA
C
IN
= None
C
PSRR
= 0. 1µF
C
OUT
= 10µF
June 2011 7 M9999-062411-A
Micrel, Inc. MIC5281
June 2011 8 M9999-062411-A
Functional Characteristics
Micrel, Inc. MIC5281
June 2011 9 M9999-062411-A
Functional Characteristics (Continued)
Micrel, Inc. MIC5281
June 2011 10 M9999-062411-A
Detailed Description
The MIC5281 voltage regulator accepts a 6V to 120V input
and has an ultra-low 6µA typical quiescent current while
offering an excellent line transient response and PSRR.
These features make it ideal for harsh, noisy
environments. All options of the device offer 25mA of
output current. The MIC5281YMM and MIC5281YMME
offer an adjustable output voltage from 1.27V to 5.5V. The
MIC5281-3.3YMME and MIC5281-3.3YMM offer fixed
3.3V outputs and the MIC5281-5.0YMME and MIC5281-
5.0YMM offer fixed 5.0V outputs. The YMME packaged
devices feature a heat slug to more effectively remove
heat from the die.
Applications Information
Thermal Protection
MIC5281 has internal thermal shutdown to protect it from
excessive heating of the die. When the junction
temperature exceeds approximately +155°C, the output is
disabled and the device begins to cool down. The device
turns back on when the junction temperature cools by
15°C. This will result in a cycled output during continuous
thermal-overload conditions.
Current Limit
MIC5281 features output current-limit protection. The
output sustains a continuous short circuit to GND without
damage to the device, but thermal shutdown often results.
Input Capacitor
Connect a 1.0µF capacitor from VIN to GND. Micrel
recommends the C5750X7R2E105M, 1.0µF, 250V
capacitor made by TDK. When using a different capacitor,
assure that the voltage rating of the capacitor exceeds any
potential transient.
CPSRR Capacitor
Connect a 0.1µF capacitor from CPSRR to GND to
maintain high power supply rejection. The voltage rating of
the capacitor must be at least 14V.
Output Capacitor
Connect a 10µF capacitor from VOUT to GND. Assure that
the voltage rating of the capacitor exceeds the designed
output voltage of the MIC5281.
Output Voltage Setting
For the MIC5281YMME and MIC5281YMM, VOUT is
programmed from 1.27V to 5.5V using:
⎟
⎠
⎞
⎜
⎝
⎛+×= 1
R2
R1
VV REFOUT
where VREF = 1.267V, and R1 and R2 are shown in the
Typical Applications circuit.
Thermal Measurements
It is always wise to measure an IC’s case temperature to
make sure that it is within operating limits, but it is easy to
get erroneous results. The standard thermal couple that
comes with many voltage meters uses a large wire gauge
that behaves like a heat-sink, resulting in artificially low
case temperature measurements. Use a thermocouple of
36-gauge wire or smaller, such as the Omega (5SC-TT-K-
36-36), to minimize the heat-sinking effect. Also, apply
thermal compound to maximize heat transfer between the
IC and the thermocouple.
An infrared thermometer is a recommended alternative.
The IR thermometer from Optris has a 1mm spot size,
ideal for monitoring small surface mount packages. Also,
the optional stand makes it easy to keep the beam on the
IC for long periods of time.
Micrel, Inc. MIC5281
June 2011 11 M9999-062411-A
Functional Diagram
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June 2011 12 M9999-062411-A
MIC5281 Evaluation Board Schematic
MIC5281 Evaluation Board Schematic
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June 2011 13 M9999-062411-A
Bill of Materials
Item Part Number Manufacturer Description Qty.
C1 C5750X7R2E105M TDK(1) 1.0µF, 250V, 20%, X7R capacitor (2220) 1
C2 08053C104KAT2A AVX(2) 0.1µF 25V 20%, X5R capacitor (0805) 1
C3 0805ZD106KAT2A AVX(2) 10µF, 10V, 20%, X5R, capacitor (0805) 1
C4 OPEN Panasonic(3) 100 µF, 160V, 20% capacitor (ALU, 0.492"diameter can 0.197"lead
spacing - Part # ECA-2CM101) 0
C5 OPEN ANY Capacitor 0
R1 CRCW06030000F Vishay/Dale(4) 0Ω, 1% resistor, 0603 1
R2 CRCW06032942F Vishay/Dale(4) 29.4kΩ, 1% resistor, 0603 1
R3 CRCW06031002F Vishay/Dale(4) 10.0kΩ, 1% resistor, 0603 1
R4 CRCW06031822F Vishay/Dale(4) 18.2kΩ, 1%, resistor, 0603 1
R5 CRCW06033012F Vishay/Dale(4) 30.1kΩ, 1% resistor chip, 0603 1
R6 CRCW06036982F Vishay/Dale(4) 69.8kΩ, 1%, resistor, 0603 1
U1 MIC5281YMME Micrel(5) 120VIN, 25mA, Ultra-Low IQ, High-PSRR Linear Regulator 1
Notes:
1. TDK: www.tdk.com.
2. AVX.: www.avx.com.
3. Panasonic: www.panasonic.com.
4. Vishay Tel: www.vishay.com.
5. Micrel, Inc.: www.micrel.com.
Micrel, Inc. MIC5281
June 2011 14 M9999-062411-A
PCB Evaluation Board Layout
Top Layer Silk Screen
Top Layer Traces
Micrel, Inc. MIC5281
June 2011 15 M9999-062411-A
PCB Evaluation Board Layout (Continued)
Bottom Layer Traces
Bottom Layer Silk Screen
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June 2011 16 M9999-062411-A
PCB Evaluation Board Layout (Continued)
EV Board Dimensions
Micrel, Inc. MIC5281
June 2011 17 M9999-062411-A
Package Information
8-Pin MSOP
Micrel, Inc. MIC5281
June 2011 18 M9999-062411-A
Package Information (Continued)
8-Pin Exposed Pad (ePad) MSOP
Micrel, Inc. MIC5281
June 2011 19 M9999-062411-A
Recommended Landing Pattern
8-Pin MSOP
Micrel, Inc. MIC5281
June 2011 20 M9999-062411-A
Recommended Landing Pattern (Continued)
8-Pin Exposed Pad (ePad) MSOP
Red circle indicates Thermal Via. Size should be .300mm − .350mm in diameter, 1.00mm pitch, and it should be
connected to GND plane for maximum thermal perfo r mance.
Micrel, Inc. MIC5281
June 2011 21 M9999-062411-A
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical impla
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
can nt
© 2011 Micrel, Incorporated.
