an1419

ISL282X8MSOPEVAL1Z ISL282X8SOICEVAL1Z
Evaluation Board User’s Guide
®
Application Note
August 28, 2008
AN1419.0
Introduction
J6
J11
V-
V+
The ISL28238 and ISL28248 high-speed operational
amplifiers feature low power consumption, while ISL28258
and ISL28268 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.
R31
C2
C4
4.7µF
C3
4.7µF
C5
0.01µF
• ISL28248 Data Sheet, FN6337
• ISL28258 Data Sheet, FN6377
• ISL28268 Data Sheet, FN6378
Evaluation Board Key Features
The ISL282xEVAL1Z 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
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.
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
External power connections are made through the +V, -V,
VREF and Ground connections on the evaluation board.
RF
ISL282X8 (1/2)
100kΩ
IN RIN-
VP
IN-
IN-
V+
10kΩ
RIN+
IN+
VREF
0.01µF
D1
Amplifier Configuration
Power Supplies
VREF
J14
User-selectable SMA edge connectors are also provided for
+V and -V. 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 0Ω resistors. These resistors 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, 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 (see Figure 1).
• ISL28238 Data Sheet, FN6336
VCM
J13
FIGURE 1. POWER SUPPYLY CIRCUIT
Reference Documents
IN +
VREF
J12
0
R16
J8
0
The ISL282X8MSOPEVAL1Z and ISL282X8SOICEVAL1Z
evaluation board are design platforms containing all the
circuitry needed to characterize critical performance
parameters of the ISL282X8 operational amplifiers in both
MSOP-8 and SOIC-8 packages, using a variety of user
defined test circuits.
IN+
0Ω
VOUT
V-
+
VM
10kΩ
REF+
RL
100kΩ
10kΩ
GND
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. 2008. All Rights Reserved
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Application Note 1419
jumper placements for loading and/or measurement of
frequency sensitive parameters.
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.
The outputs (see Figure 4) have a 10kΩ load resistor to
ground and have additional resistor and capacitor
placements for loading.
User-selectable Options
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
(see Figure 3) have additional resistor and capacitor, and
DNP
R15
R18
DNP
100k
OPEN
R26
0
10k
C6
FROM
OUTPUT
OPEN
R28
VREF
10k
TO OUTPUT
TO INTO IN+
C8
DNP
R2
OPEN
R14
DNP
J20
R13
100k
C1
R17
J19
DNP
R11
10k
DNP
R3
R12
DNP
0
R6
J2
R10
R4
R1
DNP
OUT
DNP
R5
J1
NODE
J18
IN+
J17
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
FIGURE 3. INPUT STAGE
TABLE 1. ISL282X8EVAL1Z COMPONENTS PARTS LIST
DEVICE #
COMMENTS
DESCRIPTION
C2, C4
CAP-TANTALUM, SMD, D, 4.7µF, 50V, 10% LOW ESR, ROHS Power Supply Decoupling
C3, C5
CAP, SMD, 0603,1µF, 25V,10%, X7R, ROHS
Power Supply Decoupling
C1, C6 to C10
CAP, SMD, 0603, DNP-Place Holder, ROHS
User-Selectable Capacitors - Not Populated
D1
Diode-Schottky Barrier, SMD, SOT-23, 3P, 40V, ROHS
Reverse Power Protection
U1 (ISL28238FUZ)
IC-5 MHz RRIO OP AMP, 8P, MSOP, ROHS
U1 (ISL28238FBZ)
IC-5 MHz RRIO OP AMP, 8P, SOIC, ROHS
U1 (ISL28248FUZ)
IC-5 MHz RRIO OP AMP, 8P, MSOP, ROHS
U1 (ISL28248FBZ)
IC-5 MHz RRIO OP AMP, 8P, SOIC, ROHS
U1 (ISL28258FUZ)
IC-39µA RRIO OP AMP, 8P, MSOP, ROHS
U1 (ISL28258FBZ)
IC-39µA RRIO OP AMP, 8P, SOIC, ROHS
U1 (ISL28268FUZ)
IC-39µA RRIO OP AMP, 8P, MSOP, ROHS
U1 (ISL28268FBZ)
IC-39µA RRIO OP AMP, 8P, SOIC, ROHS
R30, R32, R34 to R36
RES, SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER
User-Selectable Resistors - Not Populated
R4, R16, R25 to R27, R31
RES, SMD, 0603, 0Ω, 1/10W, TF, ROHS
0Ω User-Selectable Resistors
R11, R14, R21, R24, R28, R29 RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS
Gain and Other User-Selectable Resistors
R13, R18, R19, R23
Gain Resistors
RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS
2
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Application Note 1419
ISL282X8EVAL1Z Top View (SOIC Shown)
3
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Application Note 1419
J16
OPEN
OPEN
0
C7
R29
DNP
C9
OPEN
R27
0
R28
DNP
C8
OPEN
R26
C6
J15
ISL282X8EVAL1Z Schematic Diagram
R36
0
DNP
100k
100k
DNP
VREF
8
1
8
U1
7
2
7
SOIC 8
6 6
3
MSOP 8
5
5
4
R13
100k
DNP
J19
J17
R11
10k
J18
DNP
DNP
R6
R5
R4
0
IN-
R17
1
OPEN 2
3
10k 4
D1
DNP
J20
10k
R24
DNP
OPEN
J21
10k
DNP
R34
DNP
J22
R23
100k
C10
0.01µF
DNP
R25
DNP
0
R35
J23
2
1
NODE OUT
R16
J24
R30
IN+
J6
C2
V-
J8
4.7µF
C3
3
0.01µF
C4
J11
4.7µF
C5
V+
R31
0
J12
DNP
R20
R32
DNP
J13
OUT NODE IN+
IN-
VREF
J14
R3
R8
DNP
J4
R7
DNP
J3
DNP
DNP
R2
J2
J1
R1
DNP
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
4
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