Data Sheet No. PD94148 revA IRU3034 & (PbF) 8-PIN PWM SWITCHER CONTROLLER IC WITH CURRENT LIMITING FEATURES DESCRIPTION 8-Pin SOIC switching controller with The IRU3034 IC provides a low cost switching controller HICCUP current limiting reduces diode power with true short circuit protection all in a compact 8-pin dissipation to less than 1% of normal operation surface mount package, providing a low cost switching Soft-Start capacitor allows for smooth output solution for dual supply processor applications that re- voltage ramp up quire switching regulator for the 3.3V supply such as On-Board MOSFET Driver the applications with AGP on-board. Typically in these Fastest transient response of any controller applications, a dual supply regulator converts 5V to 3.3V method. (0 to 100% Duty Cycle in 100ns) for I/O supply and a jumper programmable supply of 1% Internal Voltage Reference 1.25V to 3.5V for Core supply. The IC uses an internal Internal Under-Voltage Lockout protects MOSFET regulator generated from the 12V supply to power the during start-up controller as well as the 12V supply to drive the power MOSFET, allowing a low cost N-channel MOSFET to be APPLICATIONS used. The IC also includes an error comparator for fast Dual supply low voltage processor applications, transient response, a precise voltage reference for set- such as: P55C, CYRIX M2, POWER PC ting the output voltage as well as a direct drive of the and AMD K6 MOSFET for the minimum part count. Simple 5V to 3.3V switcher for Pentium with AGP or Pentium II applications TYPICAL APPLICATION C6 SS CS+ CS- C8 Drv IRU3034 Gnd V12 VFB VHYST R8 R7 12V C3 R3 C5 L2 R1 R6 VOUT C7 L1 D1 C4 Q2 R4 5V R2 C1 C2 R5 Figure 1 - Typical application of IRU3034. Notes: P55C, Pentium II are trademarks of Intel Corp. K5 & K6 are trademarks of AMD corp. Cyrix 6X86L, M1, M2 are trademarks of Cyrix Corp. Power PC is trademark of IBM Corp. PACKAGE ORDER INFORMATION TA (C) Basic Device Leadfree Device Package Parts per Parts per T & R Tube Reel Orientation 0 To 70 IRU3034CS IRU3034CS(PbF) 8-Pin Plastic SOIC(S) 95 2500 see Fig. A www.irf.com 1IRU3034 & (PbF) ABSOLUTE MAXIMUM RATINGS V12 Supply Voltages .................................................. 20V Fb Pin Voltages ......................................................... -0.3V To 5V Storage Temperature Range ....................................... -65 To 150C Operating Junction Temperature ................................. 0 To 150C PACKAGE INFORMATION 8-PIN PLASTIC SOIC (S) TOP VIEW 1 8 Drv SS 2 7 V12 CS+ VFB 3 6 CS- 4 5 VHYST Gnd JA =160 C/W ELECTRICAL SPECIFICATIONS Unless otherwise specified, the following specification applies over V12=12V and TA=0 to 70 C. Low duty cycle pulse testing is used which keeps junction and case temperatures equal to the ambient temperature. PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS Fb Voltage Initial Accuracy VFB TJ=25 C 1.237 1.250 1.262 V Fb Voltage Total Variation 1.225 1.250 1.275 V Fb Voltage Line Regulation 0.2 % Fb Input Bias Current IFB VFB=1.25V -1 +1 A Minimum On Time VFB is sq wave with 300ns on 800 ns time and 2s off time Minimum Off Time VFB is sq wave with 300ns off 800 ns time and 2s on time VHYST Pin Output-HI ISOURCE=500A, VFB=1.5V 11 V VHYST Pin Output-LO ISINK=500A, VFB=1V 1 V Supply Current I12(SW) VFB=1V 10 mA Maximum Duty Cycle DMAX VFB=1V 100 % Minimum Duty Cycle DMIN VFB=1.5V 0 % Gate Drive Rise/Fall Time VGATE Load=IRL3303 70 ns CL Threshold Current ICL CS+, CS- from 1.3V to 3.7V 20 A CS Comp Common Mode VCS+=VCS- 0 4.5 V Soft-Start Current 10 A www.irf.com 2