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Data Sheet No. PD94173
IRU3037 / IRU3037A
8-PIN SYNCHRONOUS PWM CONTROLLER FEATURES
Synchronous Controller in 8-Pin Package Operating with single 5V or 12V supply voltage Internal 200KHz Oscillator (400KHz for IRU3037A) Soft-Start Function Fixed Frequency Voltage Mode 500mA Peak Output Drive Capability Protects the output when control FET is shorted
DESCRIPTION
The IRU3037 controller IC is designed to provide a low cost synchronous Buck regulator for on-board DC to DC converter applications. With the migration of today’s ASIC products requiring low supply voltages such as 1.8V and lower, together with currents in excess of 3A, traditional linear regulators are simply too lossy to be used when input supply is 5V or even in some cases with 3.3V input supply. The IRU3037 together with dual N-channel MOSFETs such as IRF7313, provide a low cost solution for such applications. This device features an internal 200KHz oscillator (400KHz for "A" version), 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.
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
TYPICAL APPLICATION
5V 12V C3 1uF C4 1uF C2 10TPB100M, 100uF, 55mV L1 1uH C1 47uF
Vcc
Vc HDrv Q1 1/2 of IRF7313 L2 1.5V/5A C7 2x 6TPC150M, 150uF, 40mV
C8 0.1uF
SS/SD U1
IRU3037
LDrv
D05022P-562, 5.6uH, 5.3A Q2 1/2 of IRF7313 R3
C9 2200pF R4 24k
Comp Fb Gnd R5 1.24K, 1%
249, 1%
Figure 1 - Typical application of IRU3037 or IRU3037A.
PACKAGE ORDER INFORMATION
TA (°C) 0 To 70 0 To 70 0 To 70 0 To 70 DEVICE IRU3037CF IRU3037CS IRU3037ACF IRU3037ACS PACKAGE 8-Pin Plastic TSSOP (F) 8-Pin Plastic SOIC NB (S) 8-Pin Plastic TSSOP (F) 8-Pin Plastic SOIC NB (S) FREQUENCY 200KHz 200KHz 400KHz 400KHz
Rev. 2.8 03/10/03
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IRU3037 / IRU3037A
ABSOLUTE MAXIMUM RATINGS
Vcc Supply Voltage .................................................. Vc Supply Voltage ...................................................... Storage Temperature Range ...................................... Operating Junction Temperature Range ..................... 25V 30V (not rated for inductive load) -65°C To 150°C 0°C To 125°C
CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device.
PACKAGE INFORMATION
8-PIN PLASTIC TSSOP (F) 8-PIN PLASTIC SOIC (S)
Fb 1 Vcc 2 LDrv 3 Gnd 4
8 SS/SD 7 Comp 6 Vc 5 HDrv
Fb 1 Vcc 2 LDrv 3 Gnd 4
8 SS/SD 7 Comp 6 Vc 5 HDrv
θJA=124°C/W
θJA=160°C/W
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over Vcc=5V, Vc=12V and TA=0 to 70°C. Typical values refer to TA=25°C. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient temperature. PARAMETER Reference Voltage Fb Voltage Fb Voltage Line Regulation UVLO UVLO Threshold - Vcc UVLO Hysteresis - Vcc UVLO Threshold - Vc UVLO Hysteresis - Vc UVLO Threshold - Fb UVLO Hysteresis - Fb Supply Current Vcc Dynamic Supply Current Vc Dynamic Supply Current Vcc Static Supply Current Vc Static Supply Current Soft-Start Section Charge Current SYM
V FB LREG
TEST CONDITION IRU3037 IRU3037A 5