IRU3038 Datasheet, PDF (1/18 Pages) International Rectifier – SYNCHRONOUS PWM CONTROLLER FOR TERMINATION POWER SUPPLY APPLICATIONS

Data Sheet No. PD94250
IRU3038
SYNCHRONOUS PWM CONTROLLER
FOR TERMINATION POWER SUPPLY APPLICATIONS
PRELIMINARY DATA SHEET
FEATURES
DESCRIPTION
Synchronous Controller in 14-Pin Package
Operating with single 5V or 12V supply voltage
200KHz to 400KHz operation set by an external
resistor
Soft-Start Function
Fixed Frequency Voltage Mode
500mA Peak Output Drive Capability
Uncommitted Error Amplifier available for DDR
voltage tracking application
1.25V Reference Voltage
Protects the output when control FET is shorted
APPLICATIONS
DDR memory source sink Vtt application
Low cost on-board DC to DC such as
5V to 3.3V, 2.5V or 1.8V
Graphic Card
Hard Disk Drive
The IRU3038 controller IC is designed to provide a low
cost synchronous Buck regulator for voltage tracking
applications such DDR memory and general purpose
on-board DC to DC converter. Modern micro processors
combined with DDR memory, need high-speed bandwidth
data bus which requires a particular bus termination volt-
age. This voltage will be tightly regulated to track the
half of chipset voltage for best performance. The IRU3038
together with dual N-channel MOSFETs such as IRF7313,
provide a low cost solution for such applications. This
device features a programmable frequency set from
200KHz to 400KHz, under-voltage lockout for both Vcc
and Vc supplies, an external programmable soft-start
function as well as output under-voltage detection that
latches off the device when an output short is detected.
TYPICAL APPLICATION
VDDQ
(2.5V)
DDR
Memory
C1
0.1uF
R1
1K
R2
1K _C5
0.1uF
C7
2200pF
R3
33K
Vcc Vc
VREF
HDrv
VP
SS U1
IRU3038
LDrv
Rt
Comp
PGnd
Fb
Gnd
12V
C2
1uF
C3
10TPB100M,
100uF, 55mV
L1
1uH
D1
BAT54
or 1N4148
Q1
1/2 of IRF7313 _L2
D03316P-103, 10uH, 3.9A
Q2
1/2 of IRF7313
5V
C4
47uF
Vtt
1.25V @ 3A
C6
2x 6TPB150M,
150uF, 55mV
Figure 1 - Typical application of IRU3038 when Vtt tracks the VDDQ.
PACKAGE ORDER INFORMATION
TA (°C)
0 To 70
0 To 70
DEVICE
IRU3038CF
IRU3038CS
PACKAGE
14-Pin Plastic TSSOP (F)
14-Pin Plastic SOIC NB (S)
Rev. 2.0
09/12/02
www.irf.com
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