Datasheet

Detailed Description
The MAX9025/MAX9026 feature an on-board 1.236V ±1%
reference, yet draw an ultra-low supply current of 1.0µA.
The MAX9027/MAX9028 (without reference) consume just
0.6µA of supply current. All four devices are guaranteed to
operate down to +1.8V. Their common-mode input voltage
range extends 200mV beyond-the-rails. Internal hystere-
sis ensures clean output switching, even with slow-moving
input signals. Large internal output drivers allow rail-to-rail
output swing with up to ±5mA loads.
The output stage employs a unique design that minimizes
supply-current surges while switching, virtually eliminating
the supply glitches typical of many other comparators.
The MAX9025/MAX9027 have a push-pull output stage
that sinks as well as sources current. The MAX9026/
MAX9028 have an open-drain output stage that can be
pulled beyond V
CC
to a maximum of 5.5V above V
EE
.
These open-drain versions are ideal for implementing
wire-OR output logic functions.
Input Stage Circuitry
The input common-mode voltage range extends from
V
EE
- 0.2V to V
CC
+ 0.2V. These comparators operate at
any differential input voltage within these limits. Input bias
current is typically ±0.15nA if the input voltage is between
the supply rails. Comparator inputs are protected from
overvoltage by internal ESD protection diodes connected
to the supply rails. As the input voltage exceeds the sup-
ply rails, these ESD protection diodes become forward
biased and begin to conduct.
Output Stage Circuitry
The MAX9025–MAX9028 contain a unique break-before-
make output stage capable of rail-to-rail operation with
up to ±5mA loads. Many comparators consume orders
of magnitude more current during switching than dur-
ing steady-state operation. However, with this family of
comparators, the supply-current change during an output
transition is extremely small. In the Typical Operating
Characteristics, the Supply Current vs. Output Transition
Frequency graphs show the minimal supply-current
increase as the output switching frequency approaches
1kHz. This characteristic reduces the need for power-
supply filter capacitors to reduce glitches created by
comparator switching currents. In battery-powered appli-
cations, this characteristic results in a substantial increase
in battery life.
PIN
NAME FUNCTION
MAX9025/
MAX9026
MAX9027/
MAX9028
A2 A2 OUT Comparator Output
A3 A3, B2 V
EE
Negative Supply Voltage
B1 B1 IN+
Comparator Noninverting
Input
B2 — REF 1.236V Reference Output
A1 A1 V
CC
Positive Supply Voltage
B3 B3 IN-
Comparator Inverting
Input
MAX9025
MAX9026
IN+
OUT
V
CC
V
EE
IN-
REF
1.236V
MAX9027
MAX9028
IN+
OUT
V
CC
V
EE
IN-
REF
Functional Diagrams
Pin Description
MAX9025–MAX9028 UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
www.maximintegrated.com
Maxim Integrated │ 9