IR3531_15 Datasheet, PDF (1/39 Pages) International Rectifier – Sink and source tracking capability

4+1 Phase Dual Output Control IC ^IR3531
FEATURES
 Integrated 6.8V/0.8A Buck Regulator provides
bias to Control and Driver IC(s)
 Adjustable switching frequency from 250 KHz up
to 1.5MHz per phase based on the synchronization
SCLK input
 Sink and source tracking capability
 Margining via SVID for both rails
 Pre-bias compatible
 Soft Stop capability
 0.5% overall system set point accuracy
 Voltage Mode Modulation for excellent transient
performance
 Single NTC thermistor for current reporting, OC
Threshold, and Load Line thermal compensation
 Complete protection including over-current,
over-voltage, over-temperature, open remote
sense and open control loop
 Thermally enhanced 48L 7mm x 7mm MLPQ
package
 RoHS compliant
BASIC APPLICATION CIRCUIT
DESCRIPTION
The IR3531 control IC provides all the necessary control,
communication and protection to support compact dual
output power solutions up to 210W. The IR3531 can be
combined with either discrete IR3535 driver ICs and Direct
Fets^TM or our IR35XX family of footprint compatible and
scalable PowIRstages^TM which integrate the MOSFETs and
driver into the same package.
The IR3531 provides overall system control and current
sharing while the Driver IC or power stages senses per-
phase current locally and communicates it to the Control
IC. The IR3531 has tri-state PWM outputs to allow diode
emulation during light load events.
The IR3531 provides a high performance transient solution
through classic voltage mode control and our non-linear
transient solutions, Turbo^TM and Body Braking^TM. Turbo^TM
automatically turns on all phases to minimize load turn-on
transients while Body Braking^TM automatically turns off the
low-side MOSFET to help dissipate stored inductor energy
at load turn-off.
PIN DIAGRAM
Figure 1: IR3531 Basic Application Circuit,
showing a 4+1 Configuration
1 March 22, 2012 | FINAL | V2.27
48 47 46 45 44 43 42 41 40 39 38 37
EN 1
VRHOT# 2
VRRDY1 3
VRRDY 4
VCC 5
SW 6
V12V 7
ALERT# 8
VCLK 9
VDIO 10
PHSSHED 11
IMON_R1 12
IR3531
48 Pin 7 x 7 MLPQ
Top View
49 GND
36 BBR1#
35 PWM4
34 PWM3
33 TSENS
32 ROSC/OVP
31 ADDR
30 ICCP
29 SCLK
28 PWM2
27 PWM1
26 BBR#
25 TRACK
13 14 15 16 17 18 19 20 21 22 23 24
Figure 2: IR3531 Package Top View