ISL28156_08 Datasheet, PDF (9/13 Pages) Intersil Corporation – 39μA Micropower Single and Dual Precision Rail-to-Rail Input-Output (RRIO) Low Input Bias Current Op Amps

Pin Descriptions
ISL28156
(6 Ld SOT-23)
ISL28156
(8 Ld SOIC)
1, 5
4
2
3
3
2
4
1
6
ISL28156, ISL28256
ISL28256
(8 Ld MSOP)
2 (A)
6 (B)
3 (A)
5 (B)
4
1 (A)
7 (B)
PIN NAME
NC
IN-
IN-_A
IN-_B
FUNCTION
Not connected
Inverting input
EQUIVALENT CIRCUIT
V+
IN-
IN+
IN+
IN+_A
IN+_B
V-
OUT
OUT_A
OUT_B
Non-inverting
input
(See Circuit 1)
Negative supply
Output
V-
Circuit 1
V+
OUT
6
7
5
8
8
V+
Positive supply
ENABLE Chip enable
V-
Circuit 2
V+
CE
Applications Information
Introduction
The ISL28156 is a single BiMOS rail-to-rail input, output
(RRIO) operational amplifier with an enable feature. The
ISL28256 is a dual version without the enable feature. Both
devices are designed to operate from single supply (2.4V to
5.0V) or dual supplies (±1.2V to ±2.5V) while drawing only
39µA of supply current per amplifier. This combination of low
power and precision performance makes this device suitable
for a variety of low power applications including battery
powered systems.
Rail-to-Rail Input/Output
These devices feature bi-polar inputs, which have an input
common mode range that extends up to 0.5V beyond the V+
rail, and to within 10mV of the V- rail. The CMOS outputs
typically swing to within about 4mV of the supply rails with a
100kΩ load. The NMOS sinks current to swing the output in
the negative direction. The PMOS sources current to swing the
output in the positive direction.
V-
Circuit 3
Input Protection
All input terminals have internal ESD protection diodes to both
positive and negative supply rails, limiting the input voltage to
within one diode beyond the supply rails. They also contain
back-to-back diodes across the input terminals. For
applications where the input differential voltage is expected to
exceed 0.5V, external series resistors must be used to ensure
the input currents never exceed 5mA (Figure 35).
-
R_IN
V_IN
+
R_L
V_OUT
FIGURE 35. INPUT CURRENT LIMITING
Enable/Disable Feature
The ISL28156 offers an EN pin that disables the device when
pulled up to at least 2.0V. In the disabled state (output in a
high impedance state), the part consumes typically 10µA. By
disabling the part, multiple ISL28156 parts can be connected
together as a MUX. In this configuration, the outputs are tied
together in parallel and a channel can be selected by the EN
9
FN6154.4
February 11, 2008