ISL28148EVAL1Z Datasheet ISL28148EVAL1Z | P1-P3

AN1350.0

ISL281x8EVAL1Z Evaluation Board User’s Guide

Introduction

The ISL281x8EVAL1Z evaluation board is a design platform

containing all the circuitry needed to characterize critical

performance parameters of the ISL281x8 operational

amplifiers, using a variety of user defined test circuits.

The ISL28138 and ISL28148 high-speed operational

amplifiers feature low power consumption, while the

ISL28158 and ISL28168 operational amplifiers feature

ultra-low power consumption. All op amps have rail-to-rail

output drive capability and are designed to operate with a

single lithium cell or two Ni_Cd batteries.

Reference Documents

• ISL28138 Data Sheet, FN6336

• ISL28148 Data Sheet, FN6337

• ISL28158 Data Sheet, FN6377

• ISL28168 Data Sheet, FN6378

Evaluation Board Key Features

The ISL281x8EVAL1Z is designed to enable the IC to

operate from a single supply, +2.4VDC to +5.5VDC or from

split supplies, ±1.2VDC to ±2.75V. The board is configured

for a single op amp connected for differential input with a

closed loop gain of 10. It also contains a single external

reference voltage (VREF) pin and provisions for a

user-selectable voltage divider (filter are included).

Power Supplies (Figure 1)

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

andC

connect to

ground through R

and R

0Ω resistors. Resistors R

and

are 0Ω but can be changed by the user to provide

additional power supply filtering, or to reduce the voltage

rate-of-rise to less than ±1V/µs. Two additional capacitors,

and C

are connected close to the part to filter out high

frequency noise. Anti-reverse diodes D

and D

protect the

circuit in the case of accidental polarity reversal.

Amplifier Configuration (Figure 2)

The schematic of the op amp with the components supplied

is shown in Figure 2. The circuit implements a differential

input amp with a closed loop gain of 10. The circuit can

operate from a single supply or from dual supplies. The

VREF pin can be connected to ground to establish a ground

referenced input for split supply operation, or can be

externally set to any reference level for single supply

operation.

0.1µF

VM VP

4.7µF

4.7µF0

0.1µF

R20

R21

R24

V+V-

FIGURE 1. POWER SUPPLY CIRCUIT

IN-

IN+

VREF

IN -

IN+

GND

100kΩ

RREF+

10kΩ

VOUT

ISL281x8

V-

0Ω

VCM

IN-

IN+

VREF

V+

RIN-

10kΩ

RIN+

10kΩ

0Ω

100kΩ

10kΩ

FIGURE 2. BASIC AMPLIFIER CONFIGURATION

Application Note August 14, 2007

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

| Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

AN1350.0

August 14, 2007

User-selectable Options (Figures 3 and 4)

Component pads are included to enable a variety of

user-selectable circuits to be added to the amplifier inputs,

the VREF input, outputs and the amplifier feedback loops.

A voltage divider and filter option (Figure 3) can be added to

establish a power supply-tracking common mode reference

at the VREF input. The inverting and non-inverting inputs

have additional resistor placements for adding input

attenuation, or to establish input DC offsets through the

VREF pin.

The output (Figure 4) has a 10kΩ load resistor to ground,

and has additional resistor and capacitor placements for

NOTE: Operational amplfiers are sensitive to output

capacitance and may oscilate. In the event of oscilation,

reduce output capacitance by using shorter cables, or add a

resistor in series with the output.

FIGURE 3. 1/2 INPUT STAGE

IN-

RINA1+ RREFA+

RREFA-

RINA2-

RINA+

RINA-

RGA+

IN1+

RREF

IN2+

RINA2+

DNP

10k

DNP

100k

OPEN

10k

4.7µF

10k

OPEN

C10

R13

R11

R14

R10

R12

R15

R18

R17

REF1

TO IN-

TO IN+

OUT

DNP

OPEN

R22

R23

R25

R26

R27

TO OUT

10k

FIGURE 4. 1/2 OUTPUT STAGE

ISL281x8EVAL1Z Components Parts List

DEVICE NUMBER DESCRIPTION COMMENTS

C1, C2, C5 CAP-TANTALUM,S MD, D, 4.7µF, 50V, 10%, LOW ESR, ROHS Power Supply Decoupling

C3, C4 CAP, SMD, 0603, 0.1µF, 25V, 10%, X7R, ROHS Power Supply Decoupling

C6 to C10 CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS User-selectable capacitors - not

populated

D1, D2 DIODE-RECTIFIER, SMD, SOD-123, 2P, 40V, 0.5A, ROHS Reverse Power Protection

U1 (ISL28138EVAL1Z) ISL28138FHZ-T7, IC-RAIL-TO-RAIL OP AMP, SOT-23, ROHS

U1 (ISL28148EVAL1Z) ISL28148FHZ-T7, IC-RAIL-TO-RAIL OP AMP, SOT-23, ROHS

U1 (ISL28158EVAL1Z) ISL28158FHZ-T7, IC-RAIL-TO-RAIL OP AMP, SOT-23, ROHS

U1 (ISL28168EVAL1Z) ISL28168FHZ-T7, IC-RAIL-TO-RAIL OP AMP, SOT-23, ROHS

R2, R3, R6, R8, R9, R12, R13,

R15, R16, R23, R25, R27

RESISTOR, SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER User-selectable resistors - not

populated

R1, R10, R11, R17, R20, R21,

R24, R26, R22

RES, SMD, 0603, 0Ω, 1/10W, TF, ROHS 0Ω user selectable resistors

R4, R5, R7, R18 RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS Gain and other user selectable

resistors

R14, R19 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS Gain resistors

Application Note 1350

AN1350.0

August 14, 2007

Application Note 1350

ISL281x8EVAL1Z Top View

P1-P3 P4-P4

ISL28148EVAL1Z

Mfr. #:

Buy ISL28148EVAL1Z

Manufacturer:

Renesas / Intersil

Description:

Amplifier IC Development Tools ISL28148 EVAL BRD 1 RHS CMPL

Lifecycle:

New from this manufacturer.

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ISL28148EVAL1Z