ISL9444_1107 Datasheet, PDF (1/24 Pages) Intersil Corporation – Triple, 180° Out-of-Phase, Synchronous Step-Down PWM Controll

Triple, 180° Out-of-Phase, Synchronous Step-Down
PWM Controller
ISL9444
The ISL9444 is a triple-output synchronous buck controller that
integrates three PWM controllers which are fully featured and
designed to provide multi-rail power for use in products such as
cable and satellite set-top boxes, VoIP gateways, cable modems,
and other home connectivity products as well as a variety of
industrial and general purpose applications. Each output is
adjustable down to 0.7V. The PWMs are synchronized at 180°
out-of-phase, thus reducing the input RMS current and ripple
voltage.
The ISL9444 offers independent power-good indicators,
programmable soft-start and tracking functions for ease of
supply rail sequencing and integrated UV/OV/OC/OT
protections in a space conscious 5mmx5mm QFN package.
Switching frequency can be set between 200kHz and 1200kHz
using a resistor. The ISL9444 can be synchronized to another
ISL9444 to reduce any beat frequency.
The ISL9444 utilizes internal loop compensation to keep
minimum peripheral components for a compact design and a
low total solution cost. These devices are implemented with
current mode control with feed-forward to cover various
applications even with fixed internal compensations.
Related Literature
• Technical Brief TB389 “PCB Land Pattern Design and
Surface Mount Guidelines for QFN (MLFP) Packages”
Features
• Three Integrated Synchronous Buck PWM Controllers
- Internal Bootstrap Diodes
- Independent Programmable Output Voltage
- Independent Power-Good Indicators, Soft-Starting and
Tracking
• Power Failure Monitor
• Light Load Efficiency Enhancement
- Low Ripple Diode Emulation Mode with Pulse Skipping
• Supports Pre-Biased Output
• Programmable Frequency: 200kHz to 1200kHz
• Adaptive Shoot-through Protection
• Out-of-Phase Switching (0°/180°/0°)
• No External Current Sense Resistor
- Uses Lower MOSFET’s r_DS(ON)
• Complete Protection
- Overcurrent, Overvoltage, Over-Temperature
• Wide Input Voltage Range: 4.5V to 26V
• Pb-Free (RoHS Compliant)
Applications
• VoX Gateway Devices
• NAS/SAN Devices
• ATX Power Supplies
+12V
+
Q1
CIN1 CIN2
VOUT1
+1.0V, 6A
+
CO1
100µF
L1
1.0µH
R4
15.8kΩ
RESN1
1.3kΩ
+12V
R2
62kΩ
R1
10kΩ
C1
4.7µF
R3
31.6kΩ
RT
49.9kΩ
CSS
10nF
0.1µF
CB1
0.1µF
CB2
ISEN1
VIN
VCC_5V
EXTBIAS
PFI
PFO
EN2,3
FB1
RT
EN/SS1
ISL9444
R5
R6
100kΩ 200kΩ
R7
200kΩ
FIGURE 1. TYPICAL APPLICATION
Q2
L2 2.2µH
RESN2
1.3kΩ
R9
11.5kΩ
VOUT2
+3.3V, 6A
+ _CO2
100µF
ISEN2
FB2
UGATE3
BOOT3
PHASE3
LGATE3
ISEN3
+12V
R8
3.09kΩ
CB3
0.1µF
Q3
L3 3.3µH
RESN3
1.3kΩ
R4
VOUT3
+5.0V, 6A
+ _CO3
100µF
R3
1.74kΩ
10.7kΩ
July 19, 2011
1
FN7665.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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