1
®
ISL85001EVAL1Z: 1A
Regulator Standard Buck PWM
Description
The ISL85001EVAL1Z REV A kit is intended for use by
individuals with requirements for Point-of-Load applications
sourcing from 4.5V to 25V. The ISL85001EVAL1Z evaluation
board is used to demonstrate the performance of the
ISL85001 standard buck regulator.
The ISL85001 is offered in a 4mmx3mm 12 Ld DFN package
with 1mm maximum height. The complete converter
occupies less than 0.425in
2
area.
Features
• Standard Buck Controller with Integrated Switching Power
MOSFET
• Integrated Boot Diode
• Input Voltage Range
- Fixed 5V ±10%
- Variable 5.5V to 25V
• PWM Output Voltage Adjustable from 0.6V to 19V with
Continuous Output Current up to 1A
• Voltage Mode Control with Voltage Feed-Forward
• Fixed 500kHz Switching Frequency
• Externally Adjustable Soft-Start Time
• Output Undervoltage Protection
• Enable Inputs
• PGOOD Output
• Overcurrent Protection
• Thermal Overload Protection
• Internal 5V LDO regulator
Applications
• General Purpose
• WLAN Cards-PCMCIA, Cardbus32, MiniPCI
Cards-Compact Flash Cards
• Hand-Held Instruments
• LCD Panel
• Set-top Box
What’s Inside
The Evaluation Board Kit contains the following materials:
• The ISL85001 EVAL REV A board
• The ISL85001 datasheet
• This EVAL KIT document
Recommended Equipment
The Following Materials are Recommended to Perform
Testing:
• 0V to 25V Power Supply with at Least
5A Source Current
Capability, Battery, Notebook AC Adapter
• One Electronic Load Capable of Sinking Current up to 5A
• Digital Multimeters (DMMs)
• 100MHz Quad-Trace Oscilloscope
• Signal Generator
Quick Setup Guide
1. Ensure that the circuit is correctly connected to the supply
and loads prior to applying any power.
2. Connect the bias supply to VIN, the plus terminal to TP1
(VIN) and the negative return to TP2 (GND).
3. Verify that SW1 is on ENABLE.
4. Turn on the power supply.
5. Verify the PG is on and the output voltage is 2.5V for
VOUT(TP3).
Evaluating the Other Output Voltage
The ISL85001EVAL kit outputs are preset to 2.5V; however,
it can be programmed using resistor dividers using
Equation 1:
The output voltage programming resistor R
2
will depend on
on the feedback resistor R
1
, as referred to in Figure 1. The
value of R
1
is typically between 1k
Ω
and 10k
Ω
. If the output
voltage desired is 0.6V, then R
2
is left opened.
TABLE 1. SWITCH 1 SETTINGS
SW1
ENABLE
OPERATING MODE
1
SW1
Enable or disable the buck controller
R
2
R
1
0.6V
⋅
V
OUT
0.6V
–
----------------------------------
=
(EQ. 1)
R1
R2
0.6V
EA
REFERENCE
+
-
V
OUT
FIGURE 1. EXTERNAL RESISTOR DIVIDER
December 1, 2008
AN1443.0
Application Note
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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Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2008. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
