Intersil ISL28470EVAL1Z User Manual

®

Introduction

The ISL28470EVAL1Z evaluation board is a design platform
containing all the circuitry needed to characterize critical
performance parameters of the ISL28470 Quad
Instrumentation Amplifier using a variety of user defined test
circuits.
The ISL28470 is a quad channel instrumentation amplifier
optimized for 2.4V to 5V single supplies. The device features
an Input Range Enhancement Circuit (IREC) which
maintains CMRR performance for input voltages equal to the
positive supply and down to 50mV above the negative
supply rail. The input signal is capable of swinging above the
positive supply rail and to the negative supply with only a
slight degradation of the CMRR performance. The output
operation is rail to rail. The ISL28270 is compensated for a
minimum gain of 100.

Reference Documents

• ISL28470 Data Sheet, FN6260

Evaluation Board Key Features

The ISL28470EVAL1Z is designed to be operated from a
single supply (+2.4VDC to +5VDC), or from split supplies
(±1.2VDC to ±2/5V). The board is configured for 4
independent instrumentation amplifiers connected for a
closed loop gain of 101 with inverting and non-inverting high
impedance terminated with 100k resistors to ground. Each
amplifier contains it's own VREF input to establish an input
common mode reference. An ENABLE select switch is
provided for each amplifier to be used to save power by
powering the device down.
IN+
IN-
VCM
VREF
Application Note
IN+(x)
100kΩ
IN-(x)
100kΩ
VREF(x)
R
G
1kΩ
GND
FIGURE 2. BASIC AMPLIFIER CONFIGURATION
1
1-888-INTERSIL or 1-888-468-3774
ISL28470EVAL1Z Evaluation
February 12, 2007
V+
J
3
V+
C
2
+
4.7µF
1
R
0
4
2
VP
FIGURE 1. POWER SUPPLY CIRCUIT

Power Supplies

External power connections are made through the +V, -V
and Ground connections on the evaluation board. For single
supply operation, the -V and Ground pins are tied together to
the power supply negative terminal. For split supplies, +V
and -V terminals connect to their respective power supply
terminals. De-coupling capacitors, C
ground through R
R are 0Ω but can be changed by the user to provide power
4
supply filtering, or to reduce the voltage rate-of-rise to less
than ±1V/µs. Anti-reverse diodes D
circuit in the case of accidental polarity reversal.
VP
ENABLE
IN+
+
IN-
-
FB+
+
-V
FB-
-
VM
R
F
100kΩ
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
|
Intersil (and design) is a registered trademark of Intersil Americas Inc.
All other trademarks mentioned are the property of their respective owners.
Board User's Guide
GND
J
2
R R
2 1
+
0 0 4.7µF
D D
1
2
2 1
C C
9 10
1 2
0.1µF 0.1µF
(Refer to Figure 1)
and C
1 2
and R , 0Ω resistors. Resistors R
1 2
and D
1 2
1/4 ISL28470
0Ω
10kΩ
Copyright Intersil Americas Inc. 2007. All Rights Reserved
AN1289.0
V-
J
1
V-
C
1
2
R
0
3
1
VM
, connect to
and
3
protect the
VOUT(x)