Intersil ISL284xxEVAL1Z Series User manual

1
®
AN1339.0
ISL284xxEVAL1Z Evaluation Board User’s Guide
Introduction
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.
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).
Reference Documents
• ISL28476 Data Sheet, FN6301
• ISL28478 Data Sheet, FN6339
• ISL28486 Data Sheet, FN6312
• ISL28488 Data Sheet, FN6339
Evaluation Board Key Features
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).
Power Supplies (Figure 1)
External power connections are made through the V+, V-
and GND connections on the evaluation board. For single
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 R1and R2, 0Ωresistors. Resistors R3and R4
are 0Ωbut 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 D1and D2protect the
circuit in the case of accidental polarity reversal.
Amplifier Configuration (Figure 2)
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.
2
0
4.7UF
0.1UF
0
00
4.7UF
VM VP
C4
12
R37
J3
1
C2 12 R44
J2
1
R1 C1 12
C3
12
R48
J1
1
D2
1
D1
21
V- V+
FIGURE 1. POWER SUPPLY CIRCUIT
+
IN-
IN+
RF
VREF
IN(A,B,C,D)-
IN(A,B,C,D)+
GND
100kΩ
RREF(A,B,C,D)+
10kΩ
VOUT(x)
1/4 ISL284xx
VP
V-
10kΩ
0Ω
VM
VCM
IN-
IN+
VREF
V+
RIN-
10kΩ
RIN+
10kΩ
-
+
0Ω
TO OTHER CHANNELS
100kΩ0Ω
FIGURE 2. BASIC AMPLIFIER CONFIGURATION
Application Note July 23, 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.
Copyright Intersil Americas Inc. 2007. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.

2AN1339.0
July 23, 2007
User-selectable Options (Figure 3)
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.
.
RREFA-
RINA2-
RREFA+
RINA+
RINA-
RGA+
RINA1+
OPEN
5
DNP DNP
IN-A
DNP
DNP
J6
1
2
3
4
C7
12
R21
R15
J5
1
2
3
4
5
R2
R11
12
0
R20
IN+A
100K
R24
OPEN
C6R6
0
R28
DNP
R14
10K
R5
10K
RREF
4.7UF
10K
0
R33
C5 12
R32
J4
1
REF1
IN(A,B,C,D)-
IN(A,B,C,D)+
FIGURE 3. COMPONENT-SELECTABLE OPTIONS
ISL284xxEVAL1Z Components Parts List
DEVICE NUMBER DESCRIPTION COMMENTS
C1, C2, C5 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,
R26, R28, R30, R31, R34, R38,
R42, R43, R46, R55-R58,
R59-R62
RESISTOR, SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER User selectable resistors - not
populated
R6,R8,R10,R15,R17,R19,R36,
R41, R51-R54, R63-R66 RES, SMD, 0603, 0Ω, 1/16W,TF, ROHS 0Ωuser selectable resistors
R5, R7, R9, R14, R16, R18, R33,
R35, R40, R67-R70 RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS RG gain resistors
R24, R27, R29, R39, R45, R47,
R49, R50 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS RF gain resistors
R1, R32, R37, R44, R48 RES, SMD, 0805, 0Ω, 1/8W, TF, ROHS 0Ωuser selectable resistors
Application Note 1339

3AN1339.0
July 23, 2007
ISL28xxEVAL1Z Top View
Application Note 1339

4
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
ISL284XXEVAL1Z Schematic Diagram
RREFA-
IN-
RINA1+
RINA+
RGA+
RGA+
RINA-
RINA+
RREFA+
RREFA-
RINA-
RREFA+
RREFA+
D
RINA1+ RINA2-
RINA-
CLOSE TO PART
OUT
RREFA-
C B
IN-
RINA+
RINA1+
OUT OUT OUT
IN-
IN1+
RINA2-
RREFA-
IN1+
RREF
RREFA+RINA1+
RGA+
CLOSE TO PART
RINA+
RINA2-
RINA-
IN-
RGA+
IN1+
RINA2-
IN1+
A
OUTB
IN-A
2
R45
4
IN+B IN-C
2
DNP
R25
OPEN
C10
R18
OPEN
R16
10K
C8
OPEN
R17
10K
DNP
R27
R23
1
0
1
2
1
C25
2
1
C24
2
1
C22
2
1
C23
1
2
D1
1
2
D2
5
4
3
2
1
J12
5
4
3
2
1
J11
R43
2
1
C13
2
1
R35
R34
2
1
R36
R38
R41
2
1
C12
R42
2
1
R46
2
1
R40 R39
2 1
C14
R51
2 1
C15 R55
2 1
R59
R63
2 1
R67
5
4
3
2
1
J13
R50
2 1
C20
R54
2 1
C21 R58
2 1
R62
R66
2 1
R70
5
4
3
2
1
J16
R49
2 1
C18
R53
2 1
C19 R57
2 1
R61
R65
2 1
R69
5
4
3
2
1
J15
R26
5
4
3
2
1
J10
2
1
C11
2
1
R9
5
4
3
2
1
J9
R4
R19
2
1
R10
R13
2
1
R29
1
R31
2
1
5
4
3
2
1
J8
2
1
C9
2
1
R7
5
4
3
2
1
J7
R3
2
1
R8
R12
2
1
R22
2
1
R30
2
1
98
7
6 5 4
3
2
16 15 14 13 12 11 10
1
U1
R47
5
3
2
1
J14
2 1
R68
R64
2 1
R60
R56
R52
2 1
C16
2 1
C17
J4
R32
C5
R33
2
1
R28
R20
2
1
R14
2
1
C6
R11
2
1
R6
R2
5
4
3
2
1
J5
R24
R15
R21
2
1
R5
2
1
C7
5
4
3
2
1
J6
1
J1
R48
2
1
C3
2
1
C1
R1
1
J2
R44
2
1
C2
1
J3
R37
2
1
C4
IN-B
IN-D IN-C
0
DNP
DNP
DNP
DNP
DNP
100K
DNP
OPEN
DNP
DNP
0
OPEN
VP
OPEN
100K
0.1UF
0
4.7UF
OPEN
DNP
IN+C
DNP
OUTA
IN+D
DNP
0.1UF
0
DNP
0
00
00
DNP
OPEN
OPEN
00
OPEN
OPEN
00
DNP
OPEN
OPEN
0
OPEN
DNP
100K
0
DNP
DNP
4.7UF
100K
QSOP16
VM
IN-A
IN+D
IN-D
OUTD
10K
100K
OPEN
IN+C
DNP
0
OUTC
4.7UF
100K
OPEN
OPEN
VM
VP
OPEN
OPEN
100K
DNP
IN+A IN-B IN+B
DNP
OPEN
0
IN+A
100K
0
0
0
DNPDNPDNPDNP
DNP
DNP
10K
10K
10K
10K 10K
10K 10K 10K 10K
10K
Generic
Pack.
1
2 4 5 6 7 8
3
9
10 11 12 13 14 15 16
V-
REF1
V+
Application Note 1339

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