an1329

ISL8011EVAL1Z: 1.2A Integrated FETs, High
Efficiency Synchronous Buck Regulator
®
Application Note
ISL8011 is an integrated FET, 1.2A synchronous buck
regulator for general purpose point-of load applications. It is
optimized for generating low output voltages down to 0.8V.
The supply voltage range of 2.7V to 5.5V allows the use of
common 3.3V or 5V supply rails and Lithium ion battery
inputs. It has a guaranteed minimum output current of 1.2A
and a 1.5MHz pulse-width modulation (PWM) switching
frequency which allows the use of small external
components.
The ISL8011 includes a pair of low ON-resistance P-Channel
and N-Channel internal MOSFETs to maximize efficiency
and minimize external component count. 100% duty-cycle
operation allows less than 200mV dropout voltage at 1.2A.
The ISL8011 offers a 200ms Power-On-Reset (POR) timer
at power-up. When shut down, the ISL8011 discharges the
output capacitor. Other features include internal digital
soft-start, enable for power sequence, overcurrent
protection, and thermal shut-down.
The ISL8011 is offered in a 10 Ld 3x3mm DFN package with
1mm maximum height. The complete converter occupies
less than 1cm2 area.
Ordering Information
PART NUMBER
PART
(Note)
MARKING
TEMP.
RANGE
(°C)
June 7, 2007
AN1329.0
Features
• High Efficiency Synchronous Buck Regulator with up to
95% Efficiency
• 2.7V to 5.5V Supply Voltage
• 1.2A Guaranteed Output Current
• 100% Maximum Duty Cycle
• Peak Current Limiting, Short Circuit Protection
• 200ms Power-On Reset
• 3% Output Accuracy Over Temperature/Load/Line
• Less than 1µA Logic Controlled Shut-down Current
• Internal Loop Compensation
• Internal Digital Soft-Start
• Over-Temperature Protection
• Enable
• Small 10 Ld 3x3mm DFN Package
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
PACKAGE
(Pb-Free)
PKG.
DWG. #
• DC/DC POL Modules
• µC/µP, FPGA and DSP Power
ISL8011IRZ
011Z
-40 to +85 10 Ld 3x3 DFN L10.3x3C
• Plug-in DC/DC Modules for Routers and Switchers
ISL8011IRZ-T
011Z
-40 to +85 10 Ld 3x3 DFN L10.3x3C
Tape and Reel
• Portable Instruments
• Test and Measurement Systems
ISL8011EVAL1Z Evaluation Board
NOTE: Intersil Pb-free plus anneal products employ special Pb-free
material sets; molding compounds/die attach materials and 100%
matte tin plate termination finish, which are RoHS compliant and
compatible with both SnPb and Pb-free soldering operations. Intersil
Pb-free products are MSL classified at Pb-free peak reflow
temperatures that meet or exceed the Pb-free requirements of
IPC/JEDEC J STD-020.
1
Pinout
ISL8011
(10 LD 3x3 DFN)
TOP VIEW
PVIN
1
10 PHASE
VCC
2
9 PGND
EN
3
8 SGND
POR
4
7 FB
GND
5
6 N/C
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.
Application Note 1329
What’s inside
Evaluating the Other Output Voltage
The Evaluation Board Kit contains the following materials:
The ISL8011EVAL1Z kit output is preset to 1.6V; however,
output voltages can be adjusted from 0.8V to 3.6V by the
following equations:
• The ISL8011EVAL1Z Rev A board
• The ISL8011 datasheet
R2
VOUT = 0.8 ⎛ 1 + --------⎞
⎝
R1⎠
• This EVAL KIT document
Recommended Equipment
Let’s set R2= 100kΩ
The following materials are recommended to perform
testing:
( R2 )
R 1 = ------------------------------V OUT
⎛ ----------------⎞ – 1
⎝ 0.8 ⎠
• 0V to 10V power supply with at least 5A source current
capability, battery, notebook AC adapter
• Two Electronic Loads capable of sinking current up to 5A
• Digital Multimeters (DMMs)
(EQ. 1)
(EQ. 2)
where the 0.8V is the reference voltage. To minimize the
accuracy impact on the output voltage, select the R1 and R2
no larger than 100kΩ.
TABLE 1. SWITCH 1 SETTINGS
• 100MHz quad-trace Oscilloscope
• Signal generator
Quick Setup Guide
J1
ENABLE
1
Center post to top
Enable VOUT
2
Center post to bottom
Disable VOUT
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. Plus terminal to (VIN)
and negative return to (GND).
3. Verify that position is ON for JP1 jumper.
4. Turn on the power supply. VIN = 2.7V to 5.5V.
5. Verify the output voltage is 1.6V for VOUT
2
AN1329.0
June 7, 2007
Application Note 1329
Schematic
TP1
U1
J1
1
VIN
PVIN
PHASE
VCC
PGND
2
C1
10µF/6.3V
C3
0.1µF
R3
100k
3
J2
4
POR
1
5
10
L1
22µH
TP2
J4
VO
9
C2
10µF/6.3V
EN
ISL8011
SGND
POR
FB
GND
NC
8
7
R1
100k
6
2
J3
J5
3
GND
R2
100k
GND
TABLE 2. COMPONENT LIST
REF
DES
QTY VALUE TOL. VOLTAGE PACKAGE
PART NUMBER
MANUFACTURER
DESCRIPTION
C3
1
0.1µF
603
EMK107BJ104MA
Taiyo Yuden
Capacitor
L1
1
2.2µH
4028
CDRH2D14-2R2
Sumida
Inductor
C1
1
10µF
20%
6.3V
805
C1608X5R0J106M
Panasonic
CAP, SMD, 0603, 10µF, 6.3V, 20%,
X5R, ROHS
C2
1
10µF
20%
6.3V
805
C1608X5R0J106M
Panasonic
CAP, SMD, 0603, 10µF, 6.3V, 20%,
X5R, ROHS
R2
1
100k
1%
100V
603
various
RES, SMD, 0603, 100k, 1/10W, 1%,
TF, ROHS
R3
1
100k
1%
100V
603
various
RES, SMD, 0603, 100k, 1/10W, 1%,
TF, ROHS
R1
1
100k
1%
100V
603
various
RES, SMD, 0603, 100k, 1/10W, 1%,
TF, ROHS
U1
1
ISL8011
DFN-10
ISL8011
3
Intersil
AN1329.0
June 7, 2007
Application Note 1329
ISL8011EVAL1Z Board Layout
FIGURE 1. TOP COMPONENTS
FIGURE 2. BOTTOM LAYER
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
AN1329.0
June 7, 2007
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