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L6911A
5 BIT PROGRAMMABLE POWER SUPPLY CONTROLLER FOR PENTIUM II PROCESSOR
OPERATING SUPPLY VOLTAGE FROM 5V TO 12V TTL-COMPATIBLE 5BIT PROGRAMMABLE OUTPUT FROM: -1.8V TO 2.05V WITH 0.05V BINARY STEPS -2.1V TO 3.5V WITH 0.1V BINARY STEPS VOLTAGE MODE PWM CONTROL EXCELLENT OUTPUT ACCURACY +/-1% OVERLINE, AND TEMPERATURE VARIATIONS HIGH PRECISION INTERNAL REFERENCE DIGITALLY TRIMMED VERY FAST LOAD TRANSIENT 0% TO 100% DUTY CYCLE POWER GOOD OUTPUT OVERVOLTAGE PROTECTION OVERCURRENT PROTECTION REALISED USING THE MOSFET's RDSon OPERATING FREQUENCY FROM 50KHz TO 1MHz MEETS INTEL PENTIUM II SPECIFICATION DISABLE FUNCTION APPLICATION CIRCUIT
Vin 5V/12V VCC 5V/12V
SO20
Applications POWER SUPPLY FOR ADVANCED MICROPROCESSOR SUPPLIES POWER SUPPLY FOR PENTIUM II INTEL PROCESSORS DESCRIPTION The L6911A is a power supply controller specifically designed to provide a high performance DC/DC conversion for Pentium II Microprocessors. A precise 5 bit digital to analog converter
OCSET 18 2 15 14 BOOT UGATE Vo 1.3V to 3.5V 13 17 16 11 1 PHASE LGATE PGND GND VSEN VFB
VCC
OSC OVP VD0 VD1 VD2 VD3 VD4 SS
20
19 4 5 6 7 8 3
10
PGOOD
12
9
COMP
D98IN956B
April 1999
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L6911A
DESCRIPTION (continued) (DAC) allows to adjust the output voltage from 1.8V to 2.05V with 0.05V binary steps and from 2.1V to 3.5V with 0.1V binary steps. The high precision internal reference, digitally trimmed, assures the selected output voltage to within +/-1%. Thanks to the window comparator system, the device provides excellent load transient performance. The high peak current gate drive affords to ABSOLUTE MAXIMUM RATINGS
Symbol VCC VBOOT-VPHASE VCC to PGND Boot Voltage Input, Output or I/O Voltage Parameter Value 15 15 -0.3 to VCC+0.3 Unit V V V
have fast switching to the external power mos, performing an high efficiency. The L6911A assures a fast protection against load overvoltage and load overcurrent. An external SCR is triggered to crowbar the input supply in case of overvoltage. In case of output short circuit the soft start capacitor is discharged and the system works in hiccup mode.
BLOCK DIAGRAM
V CC 12V Vin 5V
PGOOD SS
VCC
OCSET BOOT
MONITOR and PROTECTION OVP RT
UGATE
OSC
PHASE LGATE PGND
Vo 1.8V to 3.5V
VD0 VD1 VD2 VD3 VD4 D/A + E/A + PWM
GND VSEN VFB
D98IN957A
COMP
THERMAL DATA
Symbol Rthj-amb Tmax Tstg Parameter Thermal Resistance Junction to Ambient Maximum Junction Temperature Storage Temperature Range Value 110 150 -65 to 150 Unit C/W C C
RECOMMENDED OPERATING CONDITION
Symbol VCC Tamb TJ VCC to PGND Ambient Temperature Range Junction Temperature Range Parameter Value 5V 10%/12V 10% 0 to 70 0 to 125 Unit V C C
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L6911A
PIN CONNECTION
VSEN OCSET SS VID0 VID1 VID2 VID3 VID4 COMP FB
1 2 3 4 5 6 7 8 9 10
D98IN958
20 19 18 17 16 15 14 13 12 11
RT OVP VCC LGATE PGND BOOT UGATE PHASE PGOOD GND
PIN FUNCTIONS
N 1 2 Name VSEN OCSET Description Connected to the output voltage is able to manage overvoltage conditions and the PGOOD signal. A resistor connected from this pin and the upper Mos Drain sets the current limit protection. The internal 200A current generator sinks a current from the drain through the external resistor. The overcurrent threshold is due to the following equation: IP = 3 SS Iocs Rocs
Rdson
The soft start time is programmed connecting an external capacitor from this pin and GND. The internal current generator forces through the capacitor 10A. This pin can be used to disable the device forcing a voltage lower than 0.4V. Voltage Identification code pins. These input are open collector and TTL compatible. Are used to program the output voltage as specified in Table 1 and to set the overvoltage and powergood thresholds. This pin is connected to the error amplifier output and is used to compensate the voltage control feedback loop. This pin is connected to the error amplifier inverting input and is used to compensate the voltage control feedback loop. All internal voltage reference are referred to this pin. This pin is an open collector output and is pulled low if the output voltage is not within 10% of the programmed voltage. This pin is forced low if the "11111" VID is set. This pin is connected to the source of the upper mosfet and provides the return path for the high side driver. This pin monitors the drop across the upper mosfet for the current limit. High side gate driver output. Bootstrap capacitor pin. Through this pin is supplied the high side driver and the upper mosfet. Power ground pin. This pin has to be connected closely to the low side mosfet source in order to reduce the noise injection into the device. This pin is the lower mosfet gate driver output. Do not connect VIN to 12V if VCC is 5V. Device supply voltage. The operative supply voltage range is 4.5V to 12V. Do not connect VIN to 12V if VCC is 5V. Over voltage protection. If the output voltage reach the 15% above the programmed voltage this pin is driven high and can be used to drive an external SCR that crowbar the supply voltage. 3/7
4-8
VID0 - 4
9 10 11 12 13 14 15 16 17 18 19
COMP FB GND PGOOD PHASE UGATE BOOT PGND LGATE VCC OVP
L6911A
PIN FUNCTION (continued)
N 20 Name RT Description Oscillator Switching frequency pin. Connecting an external resistor from this pin to ground the switching frequency is increased according to the equation: RT(K) Connecting the resistor from this pin and the Vcc the Switching frequency is reduced according to the equation: RT(K) If the pin is not connected the switching frequency is 200kHz. fS = 200kHz - fS = 200kHz +
5 106
4 107
ELECTRICAL CHARACTERISTICS
Symbol ICC POWER-ON Rising VCC Threshold Falling VCC Threshold Rising VOCSET Threshold OSCILLATOR Free Running Frequency Total Variation Vosc Ramp Amplitude DACOUT voltage Accuracy ERROR AMPLIFIER DC Gain GBW SR IUGATE RUGATE ILGATE RLGATE Gain-Bandwidth Product Slew Rate Upper Gate Source Upper Gate Sink Lower Gate Source Lower Gate Sink Overvoltage Trip (VSEN/DACOUT) IOCSET IOVP ISS 4/7 OCSET Current Source OVP Sourcing Current Soft Start Current VOCSET = 4.5VDC VSEN = 5.5V, VOVP = 0V COMP = 10pF VBOOT - Vphase = 12V, VUGATE = 6V ILGATE = 0.3A VCC = 12V, VLGATE = 6V ILGATE = 0.3A 0.6 1.2 170 60 10 88 15 10 1 1.5 2 1 115 200 3 2 120 230 dB MHz V/s A A % A mA A RT = open RT to GND > 6k, RT to VCC = 12V > 200k RT = open VID0, VID1, VID2, VID3 see Table1 185 -15 -1 200 1.9 215 15 1 kHz % V % VOCSET = 4.5V VOCSET = 4.5V 3.6 1.26 4.6 V V V Parameter Supply current Test Condition UGATE and LGATE open Min. Typ. 5 Max. Unit mA VCC SUPPLY CURRENT
REFERENCE and DAC
GATE DRIVERS
PROTECTION
L6911A
ELECTRICAL CHARACTERISTICS (continued)
Symbol Parameter Upper Threshold (VSEN/DACOUT) Upper Threshold (VSEN/DACOUT) Hysteresis (VSEN/DACOUT) VPGOOD PGOOD Voltage Low Test Condition VSEN Rising VSEN Rising Upper and Lower Threshold IPGOOD = -5mA Min. 106 89 Typ. 2 0.5 Max. 111 94 Unit % % % V
Table 1.
VID4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 VID3 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 VID2 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 VID1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 VID0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 OUTPUT VOLTAGE (V) 0 0 0 0 0 0 0 0 0 0 1.8 1.85 1.9 1.95 2 2.05 0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5
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L6911A
DIM. MIN. A A1 B C D E e H h L K 10 0.25 0.4 2.35 0.1 0.33 0.23 12.6 7.4
mm TYP. MAX. 2.65 0.3 0.51 0.32 13 7.6 1.27 10.65 0.75 1.27 0.394 0.010 0.016 MIN. 0.093 0.004 0.013 0.009 0.496 0.291
inch TYP. MAX. 0.104 0.012 0.020 0.013 0.512 0.299 0.050 0.419 0.030 0.050
OUTLINE AND MECHANICAL DATA
SO20
0 (min.)8 (max.)
L
h x 45
A B e K H D A1 C
20
11 E
1
1 0
SO20MEC
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L6911A
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics (c) 1999 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com
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