AS1976, AS1977
U l t r a - L o w C u r r e n t , 1 . 8 V C o m pa r a t o r s
D a ta S he e t
1 General Description
The AS1976/AS1977 are very low-current comparators
that can operate beyond the rail voltages and are guar-
anteed to operate down to 1.8V
Low input bias current, current-limiting output circuitry,
and ultra-small packaging make these comparators
ideal for low-power 2-cell applications including power-
management and power-monitoring systems.
The comparators are available as the standard products
listed in
Table 1.
Table 1. Standard Products
2 Key Features
!
CMOS Push/Pull Output Sinks and Sources 8mA
(AS1976)
CMOS Open-Drain Output Voltage Extends Beyond
V
CC
(AS1977)
Ultra-Low Supply Current: 200nA
Internal Hysteresis: 3mV
3V-to5V Logiv-Level Translation
Guaranteed to Operate Down to +1.8V
Input Voltage Range Operates 200mV Beyond the
Rails
Crowbar Current-Free Switching
No Phase Reversal for Overdriven Inputs
5-pin SOT23 Package
!
!
!
!
Model
AS1976
AS1977
Output Type
Push/Pull
Open-Drain
Current
200nA
200nA
!
!
The AS1976 push/pull output can sink or source current.
The AS1977 open-drain output can be pulled beyond
V
CC
to a maximum of 6V > V
EE
. This open-drain model
is ideal for use as a logic-level translator or bipolar-to-
unipolar converter.
Large internal output drivers provide rail-to-rail output
swings with loads up to 8mA. Both devices feature built-
in battery power-management and power-monitoring cir-
cuitry.
The AS1976/AS1977 are available in a 5-pin SOT23
package.
!
!
!
3 Applications
The devices are ideal for battery monitoring/manage-
ment, mobile communication devices, laptops and
PDAs, ultra-low-power systems, threshold detectors/dis-
criminators, telemetry and remote systems, medical
instruments, or any other space-limited application with
low power-consumption requirements.
Figure 1. Block Diagram
5
V
CC
AS1976/
AS1977
+
–
1
OUT
3
IN+
4
IN-
2
V
EE
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AS1976/AS1977
Data Sheet - P i n o u t
4 Pinout
Pin Assignments
Figure 2. Pin Assignments (Top View)
OUT 1
5 V
CC
V
EE
2
AS1976/
AS1977
IN+ 3
4 IN-
Pin Descriptions
Table 2. Pin Descriptions
Pin
Number
1
2
3
4
5
Pin Name
OUT
V
EE
IN+
IN-
V
CC
Comparator Output
Negative Supply Voltage
Comparator Non-Inverting Input
Comparator Inverting Input
Positive Supply Voltage
Description
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AS1976/AS1977
Data Sheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in
Table 3
may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in
Section 6 Electrical
Characteristics on page 4
is not implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
Table 3. Absolute Maximum Ratings
Parameter
Supply Voltage V
CC
to V
EE
Voltage Inputs IN+, IN-
Output Voltage AS1976, AS1978
Output Current
Output Short-Circuit Duration
Continuous Power Dissipation
Operating Temperature Range
Storage Temperature Range
-40
-65
V
EE
- 0.3
V
EE
- 0.3
-50
Min
Max
+7
V
CC
+ 0.3
V
CC
+ 0.3
+50
10
571
+85
+150
Units
V
V
V
mA
s
mW
ºC
ºC
The reflow peak soldering temperature (body
temperature) specified is in accordance with
IPC/
JEDEC J-STD-020C “Moisture/Reflow Sensitivity
Classification for Non-Hermetic Solid State
Surface Mount Devices”.
The lead finish for Pb-free leaded packages is
matte tin (100% Sn).
Derate at 7.31mW/ºC above +70ºC
Comments
Package Body Temperature
+260
ºC
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AS1976/AS1977
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
V
CC
= +5V, V
EE
= 0, V
CM
= 0, T
AMB
= -40 to +85ºC (unless otherwise specified). Typ values are at T
AMB
= +25ºC.
Table 4. AS1976/AS1977 Electrical Characteristics
Symbol
V
CC
I
CC
Parameter
Supply Voltage Range
Supply Current
Input Common-Mode
Voltage Range
Conditions
Inferred from the PSRR test
V
CC
= 1.8V
V
CC
= 5V, T
AMB
= +25ºC
V
CC
= 5V, T
AMB
= T
MIN
to T
MAX
V
CM
Inferred from CMRR test
-0.2V
≤
V
CM
≤
(V
CC
+ 0.2V),
1
T
AMB
= +25ºC
-0.2V
≤
V
CM
≤
(V
CC
+ 0.2V),
T
AMB
= T
MIN
to T
MAX
-0.2V
≤
V
CM
≤
(V
CC
+ 0.2V)
3
2
Min
1.8
Typ
0.2
0.21
Max
5.5
0.5
0.9
V
CC
+ 0.2
Units
V
µA
V
EE
- 0.2
1
V
5
mV
10
V
OS
Input Offset Voltage
V
HB
I
B
I
OS
PSRR
CMRR
Input-Referred
Hysteresis
Input Bias Current
3
0.15
10
1
2
mV
nA
pA
1
3
500
650
mV
mV/V
mV/V
T
AMB
= +25ºC
T
AMB
= T
MIN
to T
MAX
Input Offset Current
Power-Supply
Rejection Ratio
Common-Mode
Rejection Ratio
V
CC
= 1.8 to 5.5V, T
AMB
= +25ºC
(V
EE
- 0.2V)
≤
V
CM
≤
(V
CC
+ 0.2V),
T
AMB
= +25ºC
T
AMB
= +25ºC,
AS1976 only V
CC
= 5.5V, I
SINK
= 8mA
Output Voltage Swing
High
T
AMB
= T
MIN
to T
MAX
,
AS1976 only V
CC
= 5.5V, I
SINK
= 8mA
T
AMB
= +25ºC
AS1976 only V
CC
= 1.8V, I
SOURCE
= 1mA
T
AMB
= T
MIN
to T
MAX
,
AS1976 only V
CC
= 1.8V, I
SOURCE
= 1mA
T
AMB
= +25ºC,
AS1976 only V
CC
= 5.5V, I
SINK
= 8mA
Output Voltage Swing
Low
T
AMB
= T
MIN
to T
MAX
,
AS1976 only V
CC
= 5.5V, I
SINK
= 8mA
T
AMB
= +25ºC,
V
CC
= 1.8V, I
SOURCE
= 1mA
T
AMB
= T
MIN
to T
MAX
,
V
CC
= 1.8V, I
SOURCE
= 1mA
0.05
0.2
220
V
CC
- V
OH
80
200
300
220
500
650
mV
V
OL
70
200
300
I
LEAK
Output Leakage
Current
AS1977 only, V
OUT
= 5.5V
Sourcing, V
OUT
= V
EE
, V
CC
= 5.5V
0.001
50
6
70
5
10
12
1
µA
I
SC
Output Short-Circuit
Current
Sourcing, V
OUT
= V
EE
, V
CC
= 1.8V
Sinking, V
OUT
= V
CC
, V
CC
= 5.5V
Sinking, V
OUT
= V
CC
, V
CC
= 1.8V
V
CC
= 1.8V
V
CC
= 5.5V
mA
t
PD
-
High-to-Low
4
Propagation Delay
µs
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AS1976/AS1977
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
Table 4. AS1976/AS1977 Electrical Characteristics (Continued)
Symbol
Parameter
Conditions
AS1976 only, V
CC
= 1.8V
t
PD+
Low-to-High
4
Propagation Delay
AS1976 only, V
CC
= 5.5V
AS1977 only, V
CC
= 1.8V, R
PULUP
= 100kΩ
AS1977 only, V
CC
= 3.6V, R
PULUP
= 100kΩ
t
RISE
t
FALL
t
ON
Rise Time
Fall Time
Power-Up Time
AS1976 only, C
LOAD
= 15pF
C
LOAD
= 15pF
Min
Typ
13
15
16
18
10
10
100
ns
ns
ns
µs
Max
Units
1. V
OS
is defined as the center of the hysteresis band at the input.
2. The hysteresis-related trip points are defined as the edges of the hysteresis band, measured with respect to the
center of the band (i.e., V
OS
)
(see Figure 26 on page 11).
3. Guaranteed by design.
4. Specified with an input overdrive voltage (V
OVERDRIVE
) = 100mV, and load capacitance (C
LOAD
) = 15pF. V
OVER-
DRIVE
is defined above and beyond the offset voltage and hysteresis of the comparator input. A reference volt-
age error should also be added.
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