MIC841/842
Comparator with 1.25% Reference and
Adjustable Hysteresis
Teeny is a trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 29, 2013
Revision 4.1
General Description
The MIC841 and MIC842 are micropower, precision
voltage comparators with an on-chip voltage reference.
Both devices are intended for voltage monitoring
applications. External resistors are used to set the voltage
monitor threshold. When the threshold is crossed,
the outputs switch polarity.
The MIC842 incorporates a voltage reference and
comparator with fixed internal hysteresis; two external
resistors are used to set the switching threshold voltage.
The MIC841 provides a similar function with user
adjustable hysteresis; this part requires three external
resistors to set the upper and lower thresholds
(the difference between the threshold voltages being the
hysteresis vo lta ge) .
Both the MIC841 and MIC842 are available with push-pull
or open-drain output stage. The push-pull output stage is
configured either active high or active low; the open-drain
output stage is only configured active low.
Supply current is extremely low (1.5μA, typical), making it
ideal for portable applications.
The MIC841/2 is supplied in Micrel’s Teeny™ 5-pin
SC-70, 6-pin 1.6mm × 1.6mm Thin DFN ( MIC841), and 4-
pin 1.2mm × 1.6mm Thin DFN (MIC842) packages.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• 1.5V to 5.5V operating range
• 1.5μA typical supply current
• ±1.25% voltage threshold accuracy
• 10nA maximum input leakage current overtemperature
• 10µs propagation delay
• Externally adjustable hysteresis (MIC841)
• Internal 20mV hysteresis (MIC842)
• Output options
− Push-pull, active high
− Push-pull, active low
− Open drain, active low
• Open drain output can be pulled to 6V regardless of VDD
• Immune to brief input transients
• Teeny 5-pin SC -70 package
• 6-pin 1.6mm × 1.6mm TDFN (MIC841)
• 4-pin 1.2mm × 1.6mm TDFN (MIC842)
Applications
• Smart phones
• PDAs
• Precision battery monitoring
• Battery chargers
Typical Application
Threshold Detection with Adjustable Hysteresis
Threshold Detector with Internal Fixed Hysteresis
Micrel, Inc.
MIC841/842
October 29, 2013
2 Revision 4.1
Ordering Information
Part Number Marking Hysteresis
Adjustment Output
Stage Output
Function Temperature
Range Pb-Free Package
MIC841HBC5 B13 External Push Pull Active Low –40°C to +85°C SC-70-5
MIC841LBC5 B14 External Push Pull Active High –40°C to +85°C SC-70-5
MIC841NBC5 B15 External Open Drain Active Low –40°C to +85°C SC-70-5
MIC842HBC5 B16 Internal Push Pull Active Low –40°C to +85°C SC-70-5
MIC842LBC5 B17 Internal Push Pull Active High –40°C to +85°C SC-70-5
MIC842NBC5 B18 Internal Open Drain Active Low –40°C to +85°C SC-70-5
MIC841HYC5 B13 External Push Pull Active Low –40°C to +85°C SC-70-5
MIC841HYMT BH External Push Pull Active Low –40°C to +85°C 1.6mm × 1.6mm TDFN
MIC841LYC5 B14 External Push Pull Active High –40°C to +85°C SC-70-5
MIC841LYMT BL External Push Pull Active High –40°C to +85°C 1.6mm × 1.6mm TDFN
MIC841NYC5 B15 External Open Drain Active Low –40°C to +85°C SC-70-5
MIC841NYMT BN External Open Drain Active Low –40°C to +85°C 1.6mm × 1.6mm TDFN
MIC842HYC5 B16 Internal Push Pull Active Low –40°C to +85°C SC-70-5
MIC842HYMT HB Internal Push Pull Active Low –40°C to +85°C 1.2mm × 1.6mm TDFN
MIC842LYC5 B17 Internal Push Pull Active High –40°C to +85°C SC-70-5
MIC842LYMT HL Internal Push Pull Active High –40°C to +85°C 1.2mm × 1.6mm TDFN
MIC842NYC5 B18 Internal Open Drain Active Low –40°C to +85°C SC-70-5
MIC842NYMT HN Internal Open Drain Active Low –40°C to +85°C 1.2mm × 1.6mm TDFN
Micrel, Inc.
MIC841/842
October 29, 2013
3 Revision 4.1
Pin Configurations
MIC841
SC-70-5 (CS)
(Top View)
MIC841
6-Pin 1.6mm × 1.6mm TDFN (MT)
(Top View)
MIC842
SC-70-5 (CS)
(Top View)
MIC842
4-Pin 1.2mm × 1.6mm TDFN (MT)
(Top View)
MIC841 Pin Description
Pin Number
SC-70 Pin Number
TDFN Pin Name Pin Function
1 3 HTH High Threshold Input. HTH and LTH monitor external voltages .
2 2 GND Ground.
3 1 LTH Low Threshold Input. LTH and HTH monitor external voltages.
4 6
OUT (“H” Version) Active-Low Push-Pull Output. OUT asserts low when VLTH < VREF. OUT
remains low until VHTH > VREF.
OUT (“L” Version) Active-H igh Push-Pull Output. OUT as serts high when VLTH < VREF. OUT
remains high until VHTH > VREF.
OUT (“N” Version) Active-Low, Open-Drain Output. OUT asserts low when VLTH < VREF.
OUT remains low until VHTH > VREF.
5 4 VDD Power Supply Input
− 5 NC No Connect. Not internally connected
− EP ePad Heatsink Pad. Connect to GND for best thermal performance.
MIC842 Pin Description
Pin Number
SC-70 Pin Number
TDFN Pin Name Pin Function
1 3 INP Threshold Input. INP monitors an external voltage.
2 2 GND Ground
3 − NC No Connect. Not internally connected.
4 1
OUT (“H” Version) Active-Low, Push-Pull Output. OUT asserts low when VINP < VREF. O UT
remains low until VINP > (VREF+ VHYST).
OUT (“L” Version) Active-High, Push-Pull Output. OUT asserts high when VINP < VREF. OUT
remains high until VINP > (V REF+ VHYST).
OUT (“N” Version) Active-Low, Open-Drain Output. OUT asserts low when VINP < VREF. OUT
remains low until VINP > (VREF+ VHYST).
5 4 VDD Power Supply Input
− EP ePad Heatsink Pad. Connect to GND for best thermal performance.
Micrel, Inc.
MIC841/842
October 29, 2013
4 Revision 4.1
Absolute Maximum Ratings(1)
Supply Voltage (VDD) ....................................... –0.3V to +7V
Input Voltage (VINP, VLTH, VLTL) ....................................... +7V
Output Current (IOUT) ................................................. ±20mA
Storage Temperature (TS) ........................ –65°C to +150°C
Junction Temperature (TJ) ...................................... +150°C
ESD Rating(3) .................................................................. 1kV
Operating Ratings(2)
Supply Voltage (VDD) ................................... +1.5V to +5.5V
Input Voltage (VINP VLTH, VLTL) ................................ 0V to 6V
VOUT (‘H’ and ‘L’ versions)............................................... VDD
VOUT (‘N’ ver s ion) ............................................................. 6V
Ambient Temperature Range (TA) ............. –40°C to +85°C
Package Thermal Resistance
SC-70-5 (θJA) ............................................... 256.5°C/W
6-pin 1.6m m × 1.6mm TDFN ............................. 92°C/W
4-pin 1.2m m × 1.6mm TDFN ........................... 173°C/W
Electrical Characteristics(4)
1.5V ≤ VDD ≤ 5.5V; TA = +25°C, bold values indicate –40°C≤ TA ≤ +85°C, unless noted.
Symbol Parameter Condition Min. Typ. Max. Units
IDD Supply Current Output not asserted 1.5 3 µA
IINP Input Leakage Curr e nt 0.005 10 nA
VREF Reference Voltage 0°C to 85°C 1.225 1.240 1.256 V
–40°C to 85°C 1.219 1.240 1.261
VHYST Hysteresis Voltage(5) MIC842 only 8 20 35 mV
tD Propagation Delay VINP = 1.352V to 1.128V 12
50
µs
VINP = 1.143V to 1.367V 8
50
VOUT(6)
Output Voltage-Low ISINK = 1.6mA, VDD ≥ 1.6V 0.05 0.3 V
ISINK = 100µA, VDD ≥ 1.2V 0.005 0.4
Output Voltage-High ISOURCE = 500µA, VDD ≥ 1.6V 0.99VDD V
ISOURCE = 50µA, VDD ≥ 1.2V 0.99VDD
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to functi on outside its operat i ng rating.
3. Devices are ESD sensitive. Handling precauti ons recommended. Human body model, 1.5kΩ in series w ith 100pF.
4. Specific at i on for packaged product only.
5. VHTH = V REF + VHYST.
6. VDD operating range is 1.5V to 5.5V. Output is guaranteed to be de-asserted down to VDD = 1.2V.
Micrel, Inc.
MIC841/842
October 29, 2013
6 Revision 4.1
Application Information
Output
The MIC841N and MIC842N outputs are an open-drain
MOSFET, so most applications will require a pull-up
resistor. The value of the resistor should not be too large
or leakage effects may dominate. 470kΩ is the maximum
recommended value. Note that the output of “N” version
may be pulled up as high as 6V regardless of the ICs
supply voltage. The “H” and “L” versions of the MIC841
and MIC842 have a push-pull output stage, with a diode
clamped to VDD. Thus, the maximum output voltage of
the “H” and “L” versions is VDD (see Electrical
Characteristics).
When working with large resistors on the input to the
devices, a small amount of leakage current can cause
voltage offsets that degrade system accuracy. The
maximum recommended total resistance from VIN to
ground is 3MΩ. The accuracy of the resistors can be
chosen b ased up on t he ac cur acy req uired b y the syst em.
The inputs may be subjected to voltages as high as 6V
steady-state without adverse effects of any kind
regardless of the ICs supply voltage. This applies even if
the supply voltage is zero. This permits the situation in
which the IC’s supply is turned off, but voltage is still
present on the inputs (see Electrical Characteristics).
Programmin g th e MIC841 Thresholds
The low-voltage thresho ld is calculat ed us ing Equation 1:
VIN(LO) = VREF
+
++ 3
R
2R 3
R2
R
1R
Eq. 1
The high-voltage threshold is calculated using Equation
2:
VIN(HI) = VREF
+
+3R 3
R2
R1
R
Eq. 2
Where, for both equations:
VREF = 1.240V
In order to provide the additional criteria needed to solve
for the r esistor val ues, the resistors can be select ed suc h
that they have a gi ve n t ota l value , that is, R1 + R2 + R3 =
RTOTAL. A value such as 1MΩ for RTOTAL is a reasonable
value because it draws minimum current but has no
significant effect on accuracy.
Figure 1. MIC841 Example Circuit
Once the d esir ed trip poi nts are det ermined, set th e V IN(HI)
threshold first.
For example, use a total of 1MΩ = R1 + R2 + R3. For a
typic al single -cell lithium ion battery, 3. 6V is a good “ high
threshold” because at 3.6V the battery is moderately
charged. Solving for R3:
VIN(HI) = 3.6V = 1.24V
Ω
3R
M1
Eq. 3
Where:
R3 = 344kΩ
Once R3 is determined, the equation for VIN(LO) can be
used to determine R2. A single lithium-ion cell, for
example, should not be discharged below 2.5V. Many
applications limit the drain to 3.1V.
Micrel, Inc.
MIC841/842
October 29, 2013
7 Revision 4.1
Using 3.1V for the VIN(LO) threshold allows calculation of
the two remaining resistor values:
VIN(LO) = 3.1V = 1.24V
Ω+
Ωk3442R M1
Eq. 4
Where:
R2 = 56kΩ
R1 = 1MΩ − R2 − R3
R1 = 600kΩ
The acc uracy of the resist ors can be c hosen based upon
the accuracy required by the system.
V
IN
OUT
V
IN(LO)
0V
0V
V
IN(HI)
OUT
0V
H AND N VERSIONS
L VERSI O N
V
HYSTERISIS
Figure 2. Output Response and Hysteresis
Programmin g th e MIC842 Thresholds
The voltage threshold is calculated using Equation 5:
VIN(LO) = VREF
+2R 2R1R
Eq. 5
Where:
VREF = 1.240V
Figure 3. MIC842 Example Circuit
In order to provide the additional criteria needed to solve
for the r esistor val ues, the resistors can be select ed suc h
that they have a given total value, that is, R1 + R2 =
RTOTAL. A value such as 1MΩ for RTOTAL is a reasonable
value because it draws minimum current but has no
significant effect on accuracy.
Input Transients
The MIC841/2 is inherently immune to very short
negative-going “glitches.” Very brief transients may
exceed the VIN(LO) threshold without tripping the output.
As shown in Figure 4, the narrower the transient, the
deeper the thres hold overd rive that will be ignored b y the
MIC841/2. The graph represents the typical allowable
transient duration for a given amount of threshold
overdrive that will not generate an output.
Figure 4. Input Transient Response
Micrel, Inc.
MIC841/842
October 29, 2013
11 Revision 4.1
MICREL, INC. 2180 FORTUNE DRIVE SA N JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
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