an1509

Application Note 1509
ISL282X7SOICEVAL2Z Evaluation Board User’s Guide
Introduction
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, C3 and C5
are connected close to the part to filter out high frequency
noise. Anti-reverse diode D1 protects the circuit in the
case of accidental polarity reversal.
J11
V+ J12
R16
Reference Documents
• ISL28207 Data Sheet, FN6631
J8
0
V-
• ISL28217 Data Sheet, FN6632
C2
C4
1µF
1µF
• ISL28227 Data Sheet, FN6633
J13
VREF
J14
0
J6
The ISL282X7 operational amplifiers feature low bias
current, low noise, and low offset and temperature drift.
R31
The ISL282X7SOICEVAL2Z evaluation board is a design
platform containing all the circuitry needed to
characterize critical performance parameters of the
ISL282X7 operational amplifiers in SOIC-8 package,
using a variety of user defined test circuits.
D1
Evaluation Board Key Features
The ISL282X7SOICEVAL2Z is designed to enable the IC
to operate from a single supply, +4.5VDC to +40VDC or
from split supplies, ±2.25VDC to ±20V. The board is
configured for a dual op amp 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 are included.
C3
C5
0.01µF
0.01µF
FIGURE 1. POWER SUPPLY CIRCUIT
Amplifier Configuration (Figure 2)
The schematic of 1/2 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 must be connected to ground to
establish a ground referenced input for dual supply
operation, or can be externally set to any reference level for
single supply operation. VREF should not be left floating.
Power Supplies (Figure 1)
External power connections are made through the +V, -V,
VREF 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
C2 and C4 connect to their respective supplies through
R16 and R31 zero-ohm resistors. These resistors are 0Ω
RF
ISL282X7 (1/2)
100kΩ
IN RININ-
VP
IN-
V+
10kΩ
RIN+
IN+
IN +
VCM
VREF
VREF
IN+
10kΩ
0Ω
VOUT
V+
VM
RREF+
RL
100kΩ
DNP
GND
FIGURE 2. BASIC AMPLIFIER CONFIGURATION
November 6, 2009
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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Application Note 1509
User-selectable Options
(Figures 3 and 4)
The outputs (Figure 4) have additional resistor and
capacitor placements for loading.
Component pads are included to enable a variety of
user-selectable circuits to be added to the amplifier
VREF, inputs, outputs, and the amplifier feedback
loops. The Inputs (Figure 3) have additional resistor
and capacitor, and jumper placements for loading
and/or measurement of frequency sensitive
parameters.
DNP
R11
R13
10k
100k
C1
OPEN
R14
J2
R2
VREF
10k
DNP
R15
R18
DNP
100k
To Output
To INTo IN+
From Output
C6
OPEN
R26
0
FIGURE 3. INPUT STAGE (1/2)
DNP
R12
DNP
OPEN
R28
R10
DNP
OUT
R17
DNP
NODE
C8
R3
DNP
DNP
0
DNP
R4
R1
R5
J1
IN+
R6
IN-
NOTE: Operational amplifiers are sensitive to output
capacitance and may oscillate. In the event of
oscillation, reduce output capacitance by using shorter
cables, or add a resistor in series with the output.
FIGURE 4. OUTPUT STAGE (1/2)
TABLE 1. ISL282X7SOICEVAL2Z COMPONENTS PARTS LIST
DEVICE #
DESCRIPTION
COMMENTS
C2, C4
CAP, SMD, 0805, 1µF, 50V, 10%, X7R, ROHS
Power Supply Decoupling
C3, C5
CAP, SMD, 0603, 0.01µF, 50V, 10%, X7R, ROHS
Power Supply Decoupling
C1, C6-C10
CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS
User selectable capacitors - not populated
D1
DIODE-RECTIFIER, SMD, SOD-123, 2P, 40V, 0.5A, ROHS Reverse Power Protection
U1 (ISL28207FBZ)
OP AMP, SOIC, ROHS
U1 (ISL28217FBZ)
OP AMP, SOIC, ROHS
U1 (ISL28227FBZ)
OP AMP, SOIC, ROHS
R1-R3, R5-R8, R10, R12, RESISTOR, SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER
R15, R17, R20,R22,
R28-R30, R32, R34-R36
User selectable resistors - not populated
R5, R18
RES, SMD, 0603, 0Ω, 1/10W,TF, ROHS
Zero ohm user selectable resistors
R11, R14, R21, R24
RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS
Gain resistors
R13, R18, R19, R23
RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS
Gain resistors
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Application Note 1509
FIGURE 5. ISL282X7SOICEVAL2Z TOP VIEW
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
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J11
R31
0
R16
C4
1µF
VREF
J14
C2
1µF
J13
J12
J8
V+
0
J6
V-
D1
4
CLOSE
C3
TO DUT
C5
0.01µF
0.01µF
C6
10k
DNP
R30
U1
2 SOIC8 7
Generic
3 Pack. 6
4
5
J24
OPEN
C7
R21
OPEN
R27
10k
0
VREF
J3
R15
R18
R19
R22
DNP
100k
100k
DNP
R7
DNP
J4
DNP
C8
J16
R8
DNP
FIGURE 6. ISL282X7SOICEVAL2Z SCHEMATIC DIAGRAM
DNP
OPEN
R14
8
0
DNP
10k
1
DNP
R36
R24
100k
C1
R35
R23
100k
C10
R13
10k
DNP
DNP
0
R20
R34
DNP
DNP
R32
DNP
DNP
R12
DNP
R17
R10
R11
INJ23
IN+
J22
J21
J20
J19
J18
NODE
R25
R5
R3
OUT
C9
R2
OUT
OPEN
R29
J2
DNP
DNP
0
DNP
R6
R1
DNP
R4
J1
NODE
Application Note 1509
J17
IN+
OPEN
R28
J15
IN-
OPEN
R26
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