ISL28288_11 Datasheet, PDF (11/20 Pages) Intersil Corporation – Digital DC/DC PMBus 12A Module

ISL28288, ISL28488
Pin Descriptions
ISL28288 ISL28288
ISL28488
ISL28488
(8 LD SOIC) (10 LD MSOP) (14 LD TSSOP) (16 LD QSOP) PIN NAME
3
1
3
3
IN+_A
-
2
-
-
EN_A
4
3
-
4
11
13
V_-
-
-
EN_B
5
5
6
6
7
7
8
8
1
9
2
10
-
-
-
-
-
-
-
-
-
-
-
-
-
-
5
5
IN+_B
6
6
IN-_B
7
7
OUT_B
4
4
V₊
1
1
OUT_A
2
2
IN-_A
8
10
OUT_C
9
11
IN-_C
10
12
IN+_C
12
14
IN+_D
13
15
IN-_D
14
16
OUT_D
-
8, 9
NC
EQUIVALENT
CIRCUIT
DESCRIPTION
Circuit 1 Amplifier A non-inverting input
Circuit 2
Amplifier A enable pin internal pull-down; Logic “1”
selects the disabled state; Logic “0” selects the
enabled state.
Circuit 4 Negative power supply
Circuit 2
Amplifier B enable pin with internal pull-down; Logic
“1” selects the disabled state; Logic “0” selects the
enabled state.
Circuit 1 Amplifier B non-inverting input
Circuit 1 Amplifier B inverting input
Circuit 3 Amplifier B output
Circuit 4 Positive power supply
Circuit 3 Amplifier A output
Circuit 1 Amplifier A inverting input
Circuit 3 Amplifier C output
Circuit 1 Amplifier C inverting input
Circuit 1 Amplifier C non-inverting input
Circuit 1 Amplifier D non-inverting input
Circuit 1 Amplifier D inverting input
Circuit 3 Amplifier D output
-
No internal connection
IN-
CIRCUIT 1
V₊
IN+
V_-
V₊
EN
V_-
CIRCUIT 2
V₊
OUT
V_-
CIRCUIT 3
V₊
CAPACITIVELY
COUPLED
V_-
CIRCUIT 4
Applications Information
Introduction
The ISL28288 and ISL28488 are dual and quad CMOS rail-to-rail
input, output (RRIO) micropower operational amplifiers. These
devices are designed to operate from a single supply (2.4V to
5.5V) or dual supplies (±1.2V to ±2.75V) while drawing only 60µA
of supply current per amplifier. This combination of low power
and precision performance makes these devices suitable for
solar and battery power applications.
Rail-to-Rail Input
Many rail-to-rail input stages use two differential input pairs, a
long-tail PNP (or PFET) and an NPN (or NFET). Severe penalties
have to be paid for this circuit topology. As the input signal moves
from one supply rail to another, the operational amplifier
switches from one input pair to the other causing drastic changes
in input offset voltage and an undesired change in magnitude
and polarity of input offset current.
These amplifiers achieve rail-to-rail input operation without
sacrificing important precision specifications and degrading
distortion performance. The devices’ input offset voltage exhibits
a smooth behavior throughout the entire common-mode input
range. The input bias current vs the common-mode voltage range
gives us an undistorted behavior from typically 100mV below the
negative rail and 10% higher than the V₊ rail (0.5V higher than V₊
when V₊ equals 5.5V).
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. There is an additional
pair of back-to-back diodes across the input terminals. For
applications where the input differential voltage is expected to
11
FN6339.4
July 26, 2011