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Application Note 1764
Author: Dan Goodhew
ISL21090XXEV1Z User’s Guide
Introduction
The ISL21090XXEV1Z evaluation board is designed to
measure the performance of the high precision ISL21090
voltage reference. The reference has a wide input voltage
range from the individual threshold voltage to 36V and an
initial accuracy of 0.02% to 0.035%. The voltage noise of
1µV
P-P
in the 0.1Hz to 10Hz range (1.25V option) and
maximum output voltage temperature coefficient of 7 ppm/°C
make the ISL21090 ideal for high end applications.
The evaluation board includes voltage input test points (VIN
and GND) for a power supply input, as well as a pair of test
points for the output (VOUT and GND). Additionally, a
jumperable R-C damper network can connectL to VOUT (J1),
and R2 accepts surface mount or through-hole style resistors
for output load testing.
Reference Documents
• ISL21090 Datasheet FN6993
ISL21090XXEV1Z Board
The schematic of the evaluation board is shown in Figure 5.
The ISL21090XXEV1Z contains the ISL21090 voltage
reference (U1), input decoupling capacitors (C1, C2), a
compensation capacitor (C5), and a load capacitor (C3).
The power supply leads attach to TP1 and TP2 (VIN, GND). The
output is measured at test points TP3 and TP4 (VOUT, GND), and
is best measured with a high quality voltmeter.
The R-C damper network is populated and can be connected to
the reference output by adding a shunt to the R-C jumper (J1).
The damper network improves stability by reducing transient
load ringing with high value (>0.47µF) capacitors.
TABLE 1. ORDERING INFORMATION
BOARD NUMBER
OUTPUT VOLTAGE
(V) TYPE
ISL2109012EV1Z 1.25 Evaluation Board
ISL2109025EV1Z 2.5 Evaluation Board
ISL2109050EV1Z 5.0 Evaluation Board
ISL2109075EVAL1Z 7.5 Evaluation Board
TABLE 2. COMPONENTS PARTS LIST
DEVICE # VALUE DESCRIPTION
C1 10µF Bypass Capacitor
C2 0.01µF Bypass Capacitor
C3 0.1µF Load Capacitor
C4 10µF Damper Capacitor
C5 1nF Compensation Capacitor
R1 2.21kΩ Damper Resistor
R2 DNP Optional Load Resistor
U1 ISL21090 SOIC 8-Pin Package
J1 DNP Damper Jumper
FIGURE 1. VOLTAGE REFERENCE EVALUATION BOARD
February 25, 2013
AN1764.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
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