an1600

Application Note 1600
Author: Huong Doan
Dual 800mA Low Quiescent Current High Efficiency
Synchronous Buck Regulator-Small Form Factor
Description
Key Features
The ISL8088EVAL2Z kit is intended for use by individuals with
requirements for Point-of-Load applications sourcing from 2.75V
to 5.5V. The ISL8088EVAL2Z board is used to demonstrate the
performance of the ISL8088 low quiescent current mode
converter.
• Dual 800mA High Efficiency Synchronous Buck Regulator with
up to 97% Efficiency
The ISL8088 is offered in a 3mmx3mm 10 Ld DFN package with
1mm maximum height. The complete converter occupies less
than 0.120in2 area.
• 800mA Guaranteed Output Current per channel
• Power-Goods (PG) output with 1ms Delay
• 2.75V to 5.5V Supply Voltage
• 3% Output Accuracy Over-Temperature/Load/Line
• Start up with Pre-biased Output
• Internal Digital Soft-Start - 2ms
Recommended Equipment
• Soft-Stop Output Discharge During Disabled
The following materials are recommended to perform testing:
• 30µA Quiescent Supply Current in PFM Mode
• 0V to 10V Power Supply with at least 3A source current
capability or 5V battery
• Selectable Forced PWM Mode and PFM Mode
• External Synchronization up to 4MHz
• Electronic Loads capable of sinking current up to 3A
• Typical 6.5µA Logic Controlled Shutdown Current
• Digital Multimeters (DMMs)
• 100% Maximum Duty Cycle for Lowest Dropout
• 100MHz quad-trace oscilloscope
• Internal Current Mode Compensation
• Signal generator
• Peak Current Limiting.
Quick Setup Guide
• Over-Temperature Protection
1. Ensure that the circuit is correctly connected to the supply and
loads prior to applying any power.
• Independent Enable
2. Connect the bias supply to VIN. Plus terminal to VIN and
negative return to P1.
3. Turn on the power supply.
4. Verify the output voltage is 2.5V for VOUT1 and 1.8V for VOUT2.
VIN
PFM
VIN
R1
100k
SYNC
U1
R9
OPEN
PWM
L1
1
1
2
3
4
5
11
2
2.2µH
A
C1
10µF
VOUT1
C5
OPEN
C8
10µF
C2
10µF
C3
10PF
ISL8088IRZ
R2
316k
P1
10
9
8
7
6
A
L2
1
2
2.2µH
VOUT2
VOUT2
R5
200k
C5
C4
10PF 10µF
C7
OPEN
A
A
P2
PGND1
FB1
FB2
EN1
EN2
VIN
PG
LX1
LX2
NC SYNCH
EP
A
R6
100k
R3
100k
A
A
Note: Please keep FB1, FB2 pins traces short
FIGURE 1. ISL8088EVAL2Z SCHEMATIC
May 20, 2013
AN1600.1
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2010, 2013. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
2
FIGURE 3. BOTTOM SILK SCREEN
TABLE 1. BILL OF MATERIALS
PART NUMBER
QTY
UNIT
ISL8088EVAL2ZREVAPCB
1
ea
GRM21BR60J106KE01-T
4
ea
H1046-DNP
0
REFERENCE
DESIGNATOR
DESCRIPTION
MANUFACTURER
PART
MANUFACTURER
AN1600.1
May 20, 2013
PWB-PCB, ISL8088EVAL2Z, REVA, ROHS
IMAGINEERING INC
ISL8088EVAL2ZREVAPCB
C1, C2, C4, C8
CAPACITOR, SMD, 0805, 10µF, 6.3V, 10%, X5R
MURATA
GRM21BR60J106KE01L
ea
C6, C7
CAP,SMD, 0805, DNP-PLACE HOLDER, ROHS
500R07S100JV4T-T
2
ea
C3, C5
CAP-RF HIQ, SMD, 0402, 10pF, 50V, 5%, COG, ROHS
JOHANSON TECHNOLOGY
500R07S100JV4T
MDT2520-CR2R2M
2
ea
L1, L2
COIL-PWR INDUCTOR, SMD, 2520, 2.2µH, 20%, 1.35A,
ROHS
TOKO
MDT2520-CR2R2M
5000
3
ea
VIN, VOUT1, VOUT2
CONN-MINI TEST PT, VERTICAL, RED, ROHS
KEYSTONE
5000
5001
2
ea
P1, P2
CONN-MINI TEST PT, VERTICAL, BLK, ROHS
KEYSTONE
5001
ISL8088IRZ
1
ea
U1
IC-DUAL SYNC. BUCK REGULATOR, 10P, DFN, 3X3, ROHS INTERSIL
ISL8088IRZ
H2510-01003-1/16W1-T
3
ea
R1, R3, R6
RES, SMD, 0402, 100k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ2RKF1003
H2510-02003-1/16W1-T
1
ea
R5
RES, SMD,0402, 200k, 1/16W, 1%, TF, ROHS
ROHM
MCR01MZPF2003
H2510-03163-1/16W1-T
1
ea
R2
RES, SMD, 0402, 316k, 1/16W, 1%, TF, ROHS
PANASONIC
ERJ-2RKF3163X
H2510-DNP
0
ea
R9
RES, SMD, 0402, DNP, DNP, DNP, TF, ROHS
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
Application Note 1600
FIGURE 2. TOP COMPONENTS
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