®
ISL8011EVAL1Z: 1.2A Integrated FETs, High
Efficiency Synchronous Buck Regulator
Application Note
June 7, 2007
AN1329.0
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 1cm
2
area.
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)
Ordering Information
PART NUMBER
PART
(Note)
MARKING
ISL8011IRZ
ISL8011IRZ-T
011Z
011Z
TEMP.
RANGE
(°C)
PACKAGE
(Pb-Free)
PKG.
DWG. #
Applications
• DC/DC POL Modules
• µC/µP, FPGA and DSP Power
• Plug-in DC/DC Modules for Routers and Switchers
• Portable Instruments
• Test and Measurement Systems
-40 to +85 10 Ld 3x3 DFN L10.3x3C
-40 to +85 10 Ld 3x3 DFN L10.3x3C
Tape and Reel
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.
Pinout
ISL8011
(10 LD 3x3 DFN)
TOP VIEW
PVIN
VCC
EN
POR
GND
1
2
3
4
5
10 PHASE
9 PGND
8 SGND
7 FB
6 N/C
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. 2007. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
Application Note 1329
What’s inside
The Evaluation Board Kit contains the following materials:
• The ISL8011EVAL1Z Rev A board
• The ISL8011 datasheet
• This EVAL KIT document
Evaluating the Other Output Voltage
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:
R2
-
VOUT
=
0.8
⎛
1
+ -------
⎞
⎝
R1
⎠
(EQ. 1)
Recommended Equipment
The following materials are recommended to perform
testing:
• 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)
• 100MHz quad-trace Oscilloscope
• Signal generator
Let’s set R
2
= 100kΩ
(
R
2
)
-
R
1
= ------------------------------
V
OUT
⎛
---------------
⎞
–
1
-
⎝
0.8
⎠
(EQ. 2)
where the 0.8V is the reference voltage. To minimize the
accuracy impact on the output voltage, select the R
1
and R
2
no larger than 100kΩ.
TABLE 1. SWITCH 1 SETTINGS
J1
1
2
ENABLE
Center post to top
Center post to bottom
Enable V
OUT
Disable V
OUT
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. Plus terminal to (VIN)
and negative return to (GND).
3. Verify that position is ON for JP1 jumper.
4. Turn on the power supply. V
IN
= 2.7V to 5.5V.
5. Verify the output voltage is 1.6V for V
OUT
2
AN1329.0
June 7, 2007
Application Note 1329
Schematic
U1
J1
VIN
1
PVIN
PHASE
10
TP1
L1
22µH
TP2
J4
VO
C1
10µF/6.3V
R3
100k
2
C3
0.1µF
3
VCC
PGND
9
C2
10µF/6.3V
R2
100k
EN
ISL8011
SGND
8
J2
POR
1
4
POR
FB
7
5
2
GND
NC
6
R1
100k
J3
GND
3
J5
GND
TABLE 2. COMPONENT LIST
REF
DES
C3
L1
C1
C2
R2
R3
R1
U1
QTY VALUE TOL. VOLTAGE PACKAGE
1
1
1
1
1
1
1
1
0.1µF
2.2µH
10µF
10µF
100k
100k
100k
ISL8011
20%
20%
1%
1%
1%
6.3V
6.3V
100V
100V
100V
603
4028
805
805
603
603
603
DFN-10
PART NUMBER
EMK107BJ104MA
CDRH2D14-2R2
C1608X5R0J106M
C1608X5R0J106M
various
various
various
ISL8011
Intersil
MANUFACTURER
Taiyo Yuden
Sumida
Panasonic
Panasonic
Capacitor
Inductor
CAP, SMD, 0603, 10µF, 6.3V, 20%,
X5R, ROHS
CAP, SMD, 0603, 10µF, 6.3V, 20%,
X5R, ROHS
RES, SMD, 0603, 100k, 1/10W, 1%,
TF, ROHS
RES, SMD, 0603, 100k, 1/10W, 1%,
TF, ROHS
RES, SMD, 0603, 100k, 1/10W, 1%,
TF, ROHS
DESCRIPTION
3
AN1329.0
June 7, 2007
Microchip MCU
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