an1339

ISL284xxEVAL1Z Evaluation Board User’s Guide
Application Note
July 23, 2007
Introduction
AN1339.0
2
• ISL28476 Data Sheet, FN6301
R37
• ISL28478 Data Sheet, FN6339
• ISL28486 Data Sheet, FN6312
2
C4
D2
0
1
J1
R1
0
2
C3
1
VM
Evaluation Board Key Features
The schematic of each of the 4 op amps 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 2.4VDC to
+5VDC supply, or from dual supplies from ±1.2VDC to
±2.5VDC. 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.
External power connections are made through the V+, Vand GND connections on the evaluation board. For single
RF
+
IN(A,B,C,D)RIN-
IN-
INRIN+
IN+
1/4 ISL284xx
100kΩ
VP
0Ω
V+
10kΩ
IN+
VOUT(x)
V-
+
VM
10kΩ
10kΩ
RREF(A,B,C,D)+
VREF
0Ω
VP
Amplifier Configuration (Figure 2)
Power Supplies (Figure 1)
VCM
2
0.1UF
FIGURE 1. POWER SUPPLY CIRCUIT
The ISL284xxEVAL1Z is designed to enable the IC to
operate from a single supply (+2.4VDC to +5VDC), or from
split supplies (±1.2VDC to ±2/5V). The board is configured
for 4 independent op amps connected for differential input
with a closed loop gain of 10. A single external reference
voltage (VREF) pin and provisions for a user-selectable
voltage divider (filter is included).
IN(A,B,C,D)+
1
4.7UF
1
D1
1
• ISL28488 Data Sheet, FN6339
C1
2
R48
4.7UF
2
R44
1
1
C2
1
Reference Documents
V+
0
V-
1
The ISL284xx are quad operational amplifiers featuring low
noise, low distortion, and rail-to-rail output drive capability.
They are designed to operate with single and dual supplies
from +5VDC (±2.5VDC) down to +2.4VDC (±1.2VDC).
J3
The ISL284xxEVAL1Z 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.
J2
supply operation, the V- and GND 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 C1 and C2, connect to
GND through R1 and R2, 0Ω resistors. Resistors R3 and R4
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. Anti-reverse diodes D1 and D2 protect the
circuit in the case of accidental polarity reversal.
0
®
100kΩ
0Ω
TO OTHER CHANNELS
VREF
GND
10kΩ
FIGURE 2. BASIC AMPLIFIER CONFIGURATION
1
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.
Copyright Intersil Americas Inc. 2007. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
Application Note 1339
User-selectable Options (Figure 3)
J4
.
Component pads are included to enable a variety of
user-selectable circuits to be added to the amplifier inputs,
the VREF input, and the amplifier feedback loops. A voltage
divider and filter option 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.
RREF
C5
4.7UF
2
R33
10K
1
0
R32
1
REF1
R14
IN(A,B,C,D)R6
R28
2
DNP
DNP
RINA2-
RINA1+
RREFA+
R24
R5
C7
OPEN
100K
RINA+
2
R15
IN+A
0
DNP
4
3
10K
1
R21
1
2
5
C6
OPEN
R11
R2
DNP
4
3
IN(A,B,C,D)+
J6
1
0
R20
1
2
5
IN-A
RREFA-
DNP
J5
RINA-
10K
RGA+
FIGURE 3. COMPONENT-SELECTABLE OPTIONS
ISL284xxEVAL1Z Components Parts List
DEVICE NUMBER
DESCRIPTION
C1, C2, C5
COMMENTS
CAP-TANTALUM, SMD, 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-C25
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 (ISL28476EVAL1Z)
ISL28476FAZ, IC-RAIL-TO-RAIL PRECISION OP AMP, 16P, QSOP, ROHS
U1 (ISL28478EVAL1Z)
ISL28478FAZ, IC-RAIL-TO-RAIL PRECISION OP AMP, 16P, QSOP, ROHS
U1 (ISL28486EVAL1Z)
ISL28486FAZ, IC-RAIL-TO-RAIL PRECISION OP AMP, 16P, QSOP, ROHS
U1 (ISL28488EVAL1Z)
ISL28488FAZ, IC-RAIL-TO-RAIL PRECISION OP AMP, 16P, QSOP, ROHS
R2-R4, R11-R13, R20-R23, R25, RESISTOR, SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER
R26, R28, R30, R31, R34, R38,
R42, R43, R46, R55-R58,
R59-R62
User selectable resistors - not
populated
R6, R8, R10, R15, R17, R19, R36, RES, SMD, 0603, 0Ω, 1/16W,TF, ROHS
R41, R51-R54, R63-R66
0Ω user selectable resistors
R5, R7, R9, R14, R16, R18, R33, RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS
R35, R40, R67-R70
RG gain resistors
R24, R27, R29, R39, R45, R47,
R49, R50
R1, R32, R37, R44, R48
2
RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS
RF gain resistors
RES, SMD, 0805, 0Ω, 1/8W, TF, ROHS
0Ω user selectable resistors
AN1339.0
July 23, 2007
Application Note 1339
ISL28xxEVAL1Z Top View
3
AN1339.0
July 23, 2007
5
5
IN1+J10
C
5
IN- J9
IN1+ J8
B
5
J7
5
J6
IN-
IN1+
A
5
4
4
1
2
1
2
1
R2
2
1
2
1
1
1
2
1
2
1
10K
C7
R5
1
1
10K
C9
R7
1
1
OPEN
10K
C11
2
2
10K
C8
2
2
1
2
2
0
R19
RINA+
OPEN
10K
C10
2
1
IN+B
2
1
IN+C
RGA+
100K
R29
RREFA+
DNP
R31
RREFA-
IN-C
RGA+
100K
R27
RREFA+
DNP
R30
IN-B
RREFA-
R18 RINA-
0
R17
RINA+
IN+A
RGA+
100K
R16 RINA-
OPEN
1
RINA1+
R9
1
1
0
R15
1
RREFA+
DNP
R28
R24
2
2
RINA+
OPEN
2
RINA2-
0
R10
2
2
RINA1+
OPEN
1
2
RINA2-
0
R8
2
2
RINA1+
OPEN
1
1
2
RINA2-
0
R6
RREFAR20
J4
RREF
REF1
D
5
5
IN-J11
IN1+J12
1
R32
R33
IN- J5
3
4
3
3
3
4
4
3
3
4
DNP
DNP
DNP
0
10K
10K
C6
R13
R3
R4
R11
DNP
DNP
DNP
DNP
DNP
R12
DNP
R21
R22
R23
R25
R26
1
C5
2
IN-A
4
4
4.7UF
3
3
2
1
2
1
2
1
1
2
C4
V-
1
1
OPEN
10K
C13
2
2
RINA1+
R35
C2
1
D2
1
0
R44
100K
OPEN
R39
C23
1
8
7
6
5
4
3
2
1
2
2
2
0
R41
RINA+
OPEN
10K
C12
R40
RINA-
OUTA
IN-A
IN+A
VP
IN+B
IN-B
OUTB
1
VM
J2
2
IN+D
1
RGA+
100K
R45
RREFA+
DNP
R46
D1
2
1
4.7UF
C1
15
16
1
9
10
11
12
C3
2
0.1UF
9
10 OUTC
11 IN-C
12 IN+C
13 VM
14 IN+D
15 IN-D
16 OUTD
100K
R47
OPEN
C22
1
2
CLOSE TO PART
0
2
R1
U1
QSOP16 14
Generic 13
Pack.
1
IN-D
RREFA-
8
7
6
5
4
3
2
1
CLOSE TO PART
2
4.7UF
1
2
J3
1
2
RINA2-
0
R36
0.1UF
DNP
0
R38
R37
DNP
DNP
DNP
DNP
DNP
DNP
1
0
VP
V+
1
1
2
100K
R50
OPEN
C25
100K
R49
OPEN
C24
2
0
R54
0
R53
0
R52
0
R51
OPEN
R14 RINA-
R42
R43
J1
1
R48
2
C14
1
2
C16
1
2
C18
1
2
C20
1
OPEN
OPEN
OPEN
R55
1
C15
2
R56
1
C17
2
R57
1
C19
OPEN
OPEN
OPEN
OPEN
2
R58
1
C21
2
2
DNP
R59
1
2
DNP
R60
1
0
R66
0
R65
0
R64
0
R63
R68
R69
DNP
DNP
DNP
DNP
2
DNP
R61
1
2
DNP
R62
1
2
R67
1
2
R70
1
2
2
1
10K
2
1
10K
2
1
10K
1
2
1
2
1
3
3
4
3
3
4
4
4
4
10K
1
5
J16
5
J15
5
J14
5
J13
OUT
OUT
OUT
OUT
Application Note 1339
ISL284XXEVAL1Z Schematic Diagram
Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to
verify that the Application Note or Technical Brief is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
AN1339.0
July 23, 2007
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