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US2075
PWM SWITCHER CONTROLLER & 7.5A LOW DROPOUT REGULATOR COMBO
PATENT PENDING
FEATURES
The US2075 eliminates the need for a seperate switching controller IC Minimum part count allows lower system cost Fixed 3.30V/7.5A LDO on board On board MOSFET driver Fastest transient response of any controller method. ( 0 to 100% Duty Cycle in 100 nS ) 1% internal voltage reference Internal Thermal shutdown Internal Under Voltage Lockout protects MOSFET during start-up
DESCRIPTION
The US2075 is a dual function IC combining a switching controller and a 7.5A low dropout regulator all in a compact 7 pin TO220 and TO263 surface mount packages providing a total solution for dual supply processor applications such as an Intel P55C TM, AMD K6TM, as well as Cyrix 6X86LTM and the M2TMprocessors. Typically in these applications a dual supply regulator converts 5V to 3.3V for I/O supply and a jumper programmable supply of 2.8V to 3.5V for CORE supply .The linear regulator portion in the US2075 is a fixed 3.30V output and has a minimum of 7.5A current capability designed to provide ample current for most applications while the switching regulator controller uses the 5V supply to power the controller and the 12V supply to drive the power MOSFET, allowing a low cost N- MOS switch to be used. The IC also includes an error comparator for fastest transient response, a precise voltage reference for setting the output voltage as well as a direct drive of the MOSFET for the minimum part count.
APPLICATIONS
Dual supply low voltage processor applications, such as: P55CTM,CYRIX M2TM, POWER PCTM and AMD
TYPICAL APPLICATION
5V
V5 Vout Vhyst
7 6 5 4 3 2 1 2.8V / 10A 3.30V / 7.5A
US2075
Gnd Vfb V12 Drv
2075ap1a-1.0
12V
Typical application of US2075 in a flexible mother board designed for Intel P55TM,P54TM AMD K5,K6TM as well as Cyrix M1TM and M2TM applications.
Notes: P54C,P55C are trade marks of Intel Corp. K5 & K6 are trade marks of AMD corp. Cyrix 6X86L,M1,M2 are trade marks of Cyrix Corp. Power PC is trade mark of IBM Corp.
PACKAGE ORDER INFORMATION
Tj (C) 0 TO 125 7 PIN PLASTIC TO220 (T) US2075CT 7 PIN PLASTIC TO263 (M) US2075CM
Rev. 1.2 4/26/98
4-1
US2075
ABSOLUTE MAXIMUM RATINGS
12V Supply Voltage ............................................................. 14V 5V Supply Voltage .............................................................. 7V LDO Power Dissipation .................................... Internally Limited FB Pin Voltage........................................................ -0.3V to 5V Storage Temperature Range ................................. -65 TO 150C Operating Junction Temperature ............................... O TO 150C
PACKAGE INFORMATION
7 PIN PLASTIC TO220 (T)
FRONT VIEW 7 6 5 4 3 2 1
7 PIN PLASTIC TO263 (M)
FRONT VIEW 7 6 5 4 3 2 1
V5 Vout Vhyst Gnd Vfb V12 Drv
V5 Vout Vhyst Gnd Vfb V12 Drv
JT=2.7C/W JA=60C/W
JA=35C/W for 1" Square pad
ELECTRICAL SPECIFICATIONS
Unless otherwise specified the following specification applies over,V5=5V,V12=12V,and Tj=0 to 125C.Low duty cycle pulse testing are used which keeps junction and case temperatures equal to the ambient temperature.
LDO Section
PARAMETER Output Voltage Line Regulation Load Regulation (note 1) Maximum Output Current Thermal Regulation Ripple Rejection SYM TEST CONDITION VOUT Io=0mA Io=0mA, 4.75Switching Controller Section
PARAMETER F.B Voltage Initial Accuracy F.B Voltage Total Variation F.B Input Bias Current Min On Time Min Off Time Vhyst pin output-HI Vhyst pin output-LO Supply Current Maximum Duty Cycle Minimum Duty Cycle Gate Drive Rise/Fall Time SYM Vfb Vfb Ifb TEST CONDITION TJ =25C Includes Temp & line,4.75 to 5.25V Vfb=1.25V Vfb is sq wave with 300 ns on time and 2 uS off time Vfb is sq wave with 300 ns off time and 2 uS on time Isource=500uA,Vfb=1.5V Isink=500uA,Vfb=1V Icc Vfb=1V Dmax Vfb=1V Dmin Vfb=1.5V Vgate Load=IRL3303 MIN 1.237 1.225 -2 400 400 11 1 10 100 0 70 TYP 1.250 1.250 600 600 MAX 1.262 1.275 +2 800 800 UNITS V V uA nS nS V V mA % % nS
4-2
Rev. 1.2 4/26/98
US2075
Note 1 : Low duty cycle pulse testing with Kelvin connections are required in order to maintain accurate data.
PIN DESCRIPTIONS
PIN # 3 6 7 PIN SYMBOL Vfb Vout V5 PIN DESCRIPTION A resistor divider from this pin to the output of the switching regulator and ground sets the core supply voltage. The output of the linear regulator. A minimum of a 10uF capacitor must be connected from this pin to ground to insure stability. This voltage is set at 3.30V typ. The input pin of the regulator. Typically a large storage capacitor is connected from this pin to ground to insure that the input voltage does not sag below the minimum drop out voltage during the load transient response. This pin must always be 1.3V higher than Vout in order for the device to regulate properly. This pin is connected to the IC substrate and must be connected to the lowest potential in the system. It is also connected to the Tab of the package. A high frequency capacitor must be connected from V12 to this pin to insure proper operation. The PWM output of the switching controller. This pin is a totem pole drive that is connected to the gate of the power MOSFET. A resistor may be placed from this pin to the gate in order to reduce switching noise. A resistor is connected from this pin to the Vfb pin to set the output ripple voltage. See application note for more details. This pin is connected to the 12V supply voltage A high frequency cap must be connected from this pin to the GND pin of the IC.
4
Gnd
1
Drv
5 2
Vhyst V12
BLOCK DIAGRAM
V12 2 Vhyst 5 Vfb 3 V5 7 Vout 6
Vref PWM Control
Drv 1
UVLO
Gnd 4
1.25V
7.5A LDO
2075blk1-1.0
Figure 1 - Simplified block diagram of the US2075
Rev. 1.2 4/26/98
4-3
US2075
TYPICAL APPLICATION
5V
C7 V5 7 Vo 6 Vhyst 5 C5 C8 R6A L2 R3 Q2 R8B R8C C4 JP7
1 2 3
L1
Cache & Chip Set CPU I / O Core Supply
C6
U1
Gnd 4 Vfb 3 V12 2 Drv 1
2050ta3d
12V
C1
JP2
C3 R5 D2 R7A R7B R7C R7D R7E
JP3 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1
JP4 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1
JP5 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
JP2
JP3
JP4
JP5
Figure2- Typical application of US2075 in a flexible motherboard with the 4 bit VID output voltage selection. This circuit uses a single jumper that programs the output voltage in 16 steps with 0.1V steps from 2V to 3.5V, designed for Intel P55TM,P54TM, AMD K5 & K6TM as well as Cyrix M1TM and M2TM applications. The jumper JP7 selects between single supply and dual supply processors.
0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
Output Voltage 3.5 3.4 3.3 3.2 3.1 3.0 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0
Ref Desig U1 Q2 D2 L2 L1 R3 R5 R8C R8B R7A R7B R7C R7D R7E R6A C8 C1 C7 C3 C4 C5 C6 HS1 HS2 HS3
Description LDO/Switcher IC MOSFET Schottky Diode Inductor Inductor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Capacitor Capacitor Capacitor Capacitor Capacitor Capacitor Heat Sink Heat Sink Heat Sink
Qty 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 4 1 1 1
Part # US2075CT (TO220) US2075CM (TO263) (note 1) IRL3303 (TO220) IRL3103S (TO263) (note 1) MBR1045CT (TO220) MBRB1545CT (TO263) (note1) Core:T50-18,L=4 uH Turns: 10T, 18 AWG L=2 uH 22 ohm,5%, SMT 1206 size 10 ohm, 5%, SMT 1206 size 806 ohm,1%, SMT 0805 size 90.9 kohm,1%, SMT 0805 size 1.24 kohm,1%, SMT 0805 size 2.49 kohm,1%, SMT 0805 size 4.99 kohm,1%, SMT 0805 size 10 kohm,1%, SMT 0805 size 1.30 kohm,1%, SMT 0805 size 324 kohm,1%, SMT 0805 size 10pF,Ceramic, SMT 0805 size 1 uF,Ceramic, SMT 0805 size, Z5U EEUFA1A681L, 680uF,10V, Elect 470pF,Ceramic, SMT 0805 size 6MV1500GX, 1500uF,6.3V, Elect EEUFA1A681L, 680uF,10V, Elect 6MV1500GX, 1500uF,6.3V, Elect For MOSFET , 577002 For Schottky Diode , 577002 For US2075 , 507222 (I/O Load Current<5A) 576602 (I/O Load Current< 3.5A)
Manufacturer Unisem International Rectifier Motorola Micro Metal (core)
Panasonic Sanyo Panasonic Sanyo Aavid Aavid Aavid
Note 1: For the applications where it is desirable to eliminate the heat sink, the US2075CM for U1 when load current is less than 1.5A, the IRL3103S for Q2 and MBR1545CT for D1 in TO263 packages with minimum of 1" square copper pad can be used.
4-4
Rev. 1.2 4/26/98

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