MIC841 - Micrel

MIC841/842
Comparator with 1.25% Reference and
Adjustable Hysteresis
General Description
Features
The MIC841 and MIC842 are micro-power, precisionvoltage comparators with an on-chip voltage reference.
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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 voltage).
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 4pin 1.2mm × 1.6mm Thin DFN (MIC842) packages.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
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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
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Smart phones
PDAs
Precision battery monitoring
Battery chargers
Typical Application
Threshold Detection with Adjustable Hysteresis
Threshold Detector with Internal Fixed 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
July 24, 2015
Revision 5.0
Micrel, Inc.
MIC841/842
Ordering Information
Part Number
Marking
Hysteresis
Adjustment
Output
Stage
Output
Function
Temperature
Range
Pb-Free
Package
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
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Micrel, Inc.
MIC841/842
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
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.
OUT
(“H” Version) Active-Low Push-Pull Output. OUT asserts low when VLTH < VREF. OUT
remains low until VHTH > VREF.
OUT
(“L” Version) Active-High Push-Pull Output. OUT asserts 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.
Power Supply Input
4
6
5
4
VDD
−
5
NC
−
EP
ePad
Pin Function
No Connect. Not internally connected
Heatsink Pad. Connect to GND for best thermal performance.
MIC842 Pin Description
Pin Number
SC-70
Pin Number
TDFN
Pin Name
1
3
INP
Threshold Input. INP monitors an external voltage.
2
2
GND
Ground
3
−
NC
4
1
Pin Function
No Connect. Not internally connected.
OUT
(“H” Version) Active-Low, Push-Pull Output. OUT asserts low when VINP < VREF. OUT
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 > (VREF+ 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.
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Micrel, Inc.
MIC841/842
Absolute Maximum Ratings(1)
Operating Ratings(2)
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
(3)
ESD Rating .................................................................. 1kV
Supply Voltage (VDD) ................................... +1.5V to +5.5V
Input Voltage (VINP VLTH, VLTL)................................ 0V to 6V
VOUT (‘H’ and ‘L’ versions)............................................... VDD
VOUT (‘N’ version) ............................................................. 6V
Ambient Temperature Range (TA) ............. –40°C to +85°C
Package Thermal Resistance
SC-70-5 (θJA) ............................................... 256.5°C/W
6-pin 1.6mm × 1.6mm TDFN ............................. 92°C/W
4-pin 1.2mm × 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
IDD
Supply Current
Output not asserted
IINP
Input Leakage Current
VREF
Reference Voltage
VHYST
Hysteresis Voltage
tD
Propagation Delay
(5)
Output Voltage-Low
VOUT
(6)
Output Voltage-High
Min.
Typ.
Max.
Units
1.5
3
µA
0.005
10
nA
0°C to 85°C
1.225
1.240
1.256
–40°C to 85°C
1.219
1.240
1.261
8
20
35
VINP = 1.352V to 1.128V
12
50
VINP = 1.143V to 1.367V
8
50
ISINK = 1.6mA, VDD ≥ 1.6V
0.05
0.3
ISINK = 100µA, VDD ≥ 1.2V
0.005
0.4
MIC842 only
ISOURCE = 500µA, VDD ≥ 1.6V
0.99VDD
ISOURCE = 50µA, VDD ≥ 1.2V
0.99VDD
V
mV
µs
V
V
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
4. Specification for packaged product only.
5. VHTH = VREF + VHYST.
6. VDD operating range is 1.5V to 5.5V. Output is guaranteed to be de-asserted down to VDD = 1.2V.
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Micrel, Inc.
MIC841/842
Block Diagrams(7)
Note:
7. SC-70 package pin numbers shown.
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MIC841/842
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).
In order to provide the additional criteria needed to solve
for the resistor values, the resistors can be selected such
that they have a given total 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.
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 based upon the accuracy required by the system.
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).
Figure 1. MIC841 Example Circuit
Once the desired trip points are determined, set the VIN(HI)
threshold first.
Programming the MIC841 Thresholds
The low-voltage threshold is calculated using Equation 1:
 R1 + R 2 + R3 
VIN(LO) = VREF 

 R 2 + R3 
For example, use a total of 1MΩ = R1 + R2 + R3. For a
typical single-cell lithium ion battery, 3.6V is a good “high
threshold” because at 3.6V the battery is moderately
charged. Solving for R3:
Eq. 1
 1MΩ 
VIN(HI) = 3.6V = 1.24V 

 R3 
The high-voltage threshold is calculated using Equation
2:
Eq. 3
Where:
 R1 + R 2 + R3 
VIN(HI) = VREF 

R3


R3 = 344kΩ
Eq. 2
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.
Where, for both equations:
VREF = 1.240V
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MIC841/842
Using 3.1V for the VIN(LO) threshold allows calculation of
the two remaining resistor values:
1MΩ


VIN(LO) = 3.1V = 1.24V 

 R 2 + 344kΩ 
Eq. 4
Where:
R2 = 56kΩ
Figure 3. MIC842 Example Circuit
R1 = 1MΩ − R2 − R3
R1 = 600kΩ
In order to provide the additional criteria needed to solve
for the resistor values, the resistors can be selected such
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.
The accuracy of the resistors can be chosen based upon
the accuracy required by the system.
VIN
VIN(HI)
VIN(LO)
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.
VHYSTERISIS
0V
As shown in Figure 4, the narrower the transient, the
deeper the threshold overdrive that will be ignored by the
MIC841/2. The graph represents the typical allowable
transient duration for a given amount of threshold
overdrive that will not generate an output.
OUT
H AND N VERSIONS
0V
OUT
L VERSION
0V
Figure 2. Output Response and Hysteresis
Programming the MIC842 Thresholds
The voltage threshold is calculated using Equation 5:
 R1 + R 2 
VIN(LO) = VREF 

 R2 
Eq. 5
Where:
VREF = 1.240V
Figure 4. Input Transient Response
July 24, 2015
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Micrel, Inc.
MIC841/842
Package Information(8) and Recommended Landing Patterns
5-Pin SC-70 (C5)
Note:
8. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com.
July 24, 2015
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Revision 5.0
Micrel, Inc.
MIC841/842
Package Information(8) and Recommended Landing Patterns (Continued)
6-Pin 1.6mm × 1.6mm TDFN (MT)
July 24, 2015
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Revision 5.0
Micrel, Inc.
MIC841/842
Package Information(8) and Recommended Landing Patterns (Continued)
4-Pin 1.2mm × 1.6mm TDFN (MT)
July 24, 2015
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Revision 5.0
Micrel, Inc.
MIC841/842
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, Inc. is a leading global manufacturer of IC solutions for the worldwide high performance linear and power, LAN, and timing & communications
markets. The Company’s products include advanced mixed-signal, analog & power semiconductors; high-performance communication, clock
management, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs. Company customers
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Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this datasheet. 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
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