LTC1706-81 5-Bit Desktop VID Voltage Programmer U FEATURES ■ ■ ■ ■ ■ ■ DESCRIPTIO The LTC®1706-81 is a precision, digitally programmed, resistive ladder which adjusts the output of any 0.8V referenced regulator. Depending on the state of the five VID inputs, an output voltage between 1.3V and 3.5V is programmed in 50mV and 100mV increments. Programs Regulator Output Voltage Range from 1.3V to 2.05V in 50mV Steps and from 2.1V to 3.5V in 100mV Steps (VRM 8.4) Programs a Wide Range of Linear Technology DC/DC Converters with a 0.8V Reference Fully Compliant with the Intel Pentium® Processor Desktop VID Specification ±0.25% Accurate Output Voltage Built-In 40k Pull-Up Resistors on VID Inputs Available in MSOP-10 Package The LTC1706-81 is designed specifically to program an entire family of Linear Technology DC/DC converters in full compliance with the Intel Desktop (VRM 8.4) VID specification. The LTC1706-81 programs the following Linear Technology DC/DC converter products: LTC1622, LTC1628, LTC1629, LTC1702, LTC1735, LTC1735-1, LTC1772 and LTC1929. (Consult factory for future compatible DC/DC converter products.) U APPLICATIO S ■ ■ ■ Intel Pentium II and III Processor Power Supply AMD AthlonTM Processor Power Supply Workstations and Servers Large Memory Array Supply , LTC and LT are registered trademarks of Linear Technology Corporation. Pentium is a registered trademark of Intel Corporation. AMD Athlon is a trademark of Advanced Micro Devices, Inc. U ■ TYPICAL APPLICATION 5-Bit VID-Controlled High Current 4-Phase Application (Simplified Block Diagram) VIN 4.5V TO 22V VIN LTC1629 VID0 FROM µP INTVCC SENSE VID2 LTC1706-81 VID3 VID4 L1 RSENSE1 SW1 VCC VID1 TG1 VDIFFOUT + BG1 VOUT 1.3V TO 3.5V UP TO 70A COUT VIN PGND SGND FB TG2 EAIN L2 RSENSE2 L3 RSENSE3 L4 RSENSE4 SW2 GND BG2 VIN 4.5V TO 22V VIN LTC1629 TG1 SW1 BG1 PGND VIN SGND EAIN TG2 SW2 BG2 1706-81 TA01 1 LTC1706-81 W U PACKAGE/ORDER INFORMATION U W W W (Note 1) (Voltages Referred to GND Pin) Input Supply Voltage (VCC) ..........................– 0.3V to 7V VID Input Pins .............................................– 0.3V to 7V SENSE Pin ...................................................– 0.3V to 7V FB Pin ..........................................................– 0.3V to 7V Operating Temperature Range (Note 2) .. – 40°C to 85°C Junction Temperature ........................................... 110°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C U ABSOLUTE MAXIMUM RATINGS ORDER PART NUMBER TOP VIEW VID0 VID1 VID2 VID3 VCC 1 2 3 4 5 10 9 8 7 6 FB GND NC VID4 SENSE LTC1706EMS-81 MS10 PART MARKING MS10 PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 110°C, θJA = 120°C/ W LTLR Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. 2.7V ≤ VCC ≤ 5.5V, VID0 = VID1 = VID2 = VID3 = VID4 = NC unless otherwise specified. SYMBOL VCC IVCC RFB-SENSE VOUT Error % RPULLUP VIDTH IVID-LEAK VPULLUP PARAMETER CONDITIONS Operating Supply Voltage Range Supply Current (Note 3) Resistance Between SENSE and FB Output Voltage Accuracy Programmed from 1.3V to 2.05V (VID4 = 0) Programmed from 2.1V to 3.5V (VID4 = 1) VID Input Pull-Up Resistance VDIODE = 0.6V (Note 4) VID Input Voltage Threshold VIL (2.7V ≤ VCC ≤ 5.5V) VIH (2.7V ≤ VCC ≤ 5.5V) VID Input Leakage Current VCC < VID < 7V (Note 4) VID Pull-Up Voltage VCC = 3.3V VCC = 5V Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC1706-81 is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the – 40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. 2 MIN 2.7 ● ● ● 12 – 0.25 – 0.35 TYP 0.1 20 MAX 5.5 5 28 + 0.25 + 0.25 40 0.4 1.6 0.01 2.8 4.5 ±1 UNITS V µA kΩ % % kΩ V V µA V V Note 3: With all five VID inputs floating, the VCC supply current is simply the device leakage current. However, the VCC supply current will rise and be approximately equal to the number of grounded VID input pins times (VCC – 0.6V)/40k. (See the VID Input Characteristics section for more details.) Note 4: Each built-in pull-up resistor attached to the VID inputs also has a series diode connected to VCC to allow input voltages higher than the VCC supply without damage or clamping. (See Operation section for further details.) LTC1706-81 U W TYPICAL PERFORMANCE CHARACTERISTICS Typical Error % vs Output Voltage Typical Error % vs Temperature 0.25 0.25 ERROR (%) ERROR (%) TA = 25°C 0 VID4 = 0 VOUT = 1.3V 0 VOUT = 1.7V VOUT = 2V VID4 = 1 –0.25 –50 –0.25 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 3.3 3.5 OUTPUT VOLTAGE (V) VOUT = 3.5V 0 50 TEMPERATURE (°C) 100 1706-81 G02 1706-81 G01 RFB1 vs Temperature IVID-PULLUP vs Temperature 30 VID PULL-UP CURRENT (µA) 120 RFB1 (kΩ) 20 10 VCC = 5V VID4 = 0V VID0 = VID1 = VID2 = VID3 = OPEN 100 80 60 40 20 0 –50 0 50 TEMPERATURE (°C) 0 –50 100 0 50 TEMPERATURE (°C) 1706-81 G03 100 1706-81 G04 Supply Current vs Temperature Supply Current vs Supply Voltage 5 2.0 ALL VID INPUTS OPEN TA = 25°C ALL VID INPUTS OPEN SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 4 1.5 1.0 VCC = 5V VCC = 3.3V 0.5 0 –50 VCC = 2.7V 3 2 1 0 0 50 TEMPERATURE (°C) 100 1706-81 G05 0 2 4 6 SUPPLY VOLTAGE (V) 8 1706-81 G06 3 LTC1706-81 U U U PIN FUNCTIONS VID0 (Pin 1): LSB Programming Input. Low = GND, High = VCC or Float. Grounding VID0 adds 50mV (VID4 = LOW) or 100mV (VID4 = HIGH) to the output sense voltage. VID1 (Pin 2): 3rd MSB Programming Input. Low = GND, High = VCC or Float. Grounding VID1 adds 100mV (VID4 = LOW) or 200mV (VID4 = HIGH) to the output sense voltage. VID2 (Pin 3): 2nd MSB Programming Input. Low = GND, High = VCC or Float. Grounding VID2 adds 200mV (VID4 = LOW) or 400mV (VID4 = HIGH) to the output sense voltage. VID3 (Pin 4): MSB Programming Input. Low = GND, High = VCC or Float. Grounding VID3 adds 400mV (VID4 = LOW) or 800mV (VID4 = HIGH) to the output sense voltage. VCC (Pin 5): Power Supply Voltage. Range from 2.7V to 5.5V. SENSE (Pin 6): Regulator Output Voltage. Connect directly to regulator output sense node or, when used with the LTC1629 and LTC1929 to VDIFFOUT. VID4 (Pin 7): High-Low Output Range Programming Input. VID4 = Low puts the output voltage in the lower range of 1.3V to 2.05V in 50mV steps. VID4 = HIGH puts the output voltage in the upper range of 2.1V to 3.5V in 100mV steps. NC (Pin 8): No Connect. GND (Pin 9): Ground. Connect to regulator signal ground. FB (Pin 10): Feedback Input. Connect to the 0.8V feedback pin of a compatible regulator or the EAIN pin of the LTC1629 and LTC1929. ABSOLUTE MAX (V) MIN MAX NAME DESCRIPTION 1 VID0 LSB Programmable Input 0 VCC – 0.3 7 2 VID1 3rd MSB Programmable Input 0 VCC – 0.3 7 3 VID2 2nd MSB Programmable Input 0 VCC – 0.3 7 4 VID3 1st MSB Programmable Input 0 VCC – 0.3 7 5 VCC Power Supply 2.7 5.5 – 0.3 7 1.3 3.5 – 0.3 7 0 VCC – 0.3 7 – 0.3 7 – 0.3 7 6 SENSE Regulator Output Voltage 7 VID4 Output Range Programmable Input 8 NC 9 GND Ground 10 FB 0.8V Feedback Input 4 MIN NOMINAL (V) TYP MAX PIN 0 0 0.8 1.5 LTC1706-81 W BLOCK DIAGRA VCC 40k VID0 1 VCC VCC 5 6 40k VID1 2 SENSE RFB1 VCC 10 FB SWITCH CONTROL LOGIC RFB2 9 40k GND VID2 3 1706-81 BD VCC VCC 40k VID3 4 40k VID4 7 U OPERATIO The LTC1706-81 is a precision resistive divider designed specifically for use with an entire family of Linear Technology Corporation DC/DC switching regulators with 0.8V internal reference and feedback voltage. The LTC1706-81 produces an output voltage ranging from 1.3V to 2.05V in 50mV steps and from 2.1V to 3.5V in 100mV steps by closing the loop between the output voltage sense and the feedback input of the regulator with the appropriate resistive divider network. VID Programming The “top” feedback resistor, RFB1, connected between SENSE and FB, is typically 20k and is not modified by the state of the VID program inputs. In the lower range (VID4 = 0), when the four VID inputs are low or grounded, the regulator output voltage is set to 2.05V. Each increasing binary count is equivalent to a decrease of 50mV in the output voltage. Therefore, to obtain a 1.3V output, the four VID inputs should be floating, or high. The “bottom” feedback resistor, RFB2, however, is modified by the five VID inputs and is precisely ratioed to RFB1. A list of programmed inputs and their corresponding output voltages is shown in Table 1. Programming is accomplished by applying the proper voltage (or float condition) on the five digital VID inputs. VID4 is the range bit that puts the output voltage in either the 1.3V to 2.05V range or the 2.1V to 3.5V range. In either range, VID3 is the most significant bit (MSB) and VID0 is the least significant bit (LSB). 5 LTC1706-81 U OPERATIO Table 1. VID Inputs and Corresponding Output Voltage CODE VID4 VID3 VID2 VID1 VID0 OUTPUT 10000 Float GND GND GND GND 3.5V 10001 Float GND GND GND Float 3.4V 10010 Float GND GND Float GND 3.3V 10011 Float GND GND Float Float 3.2V 10100 Float GND Float GND GND 3.1V 10101 Float GND Float GND Float 3.0V 10110 Float GND Float Float GND 2.9V 10111 Float GND Float Float Float 2.8V 11000 Float Float GND GND GND 2.7V 11001 Float Float GND GND Float 2.6V 11010 Float Float GND Float GND 2.5V 11011 Float Float GND Float Float 2.4V 11100 Float Float Float GND GND 2.3V 11101 Float Float Float GND Float 2.2V 11110 Float Float Float Float GND 2.1V 11111 Float Float Float Float Float * 00000 GND GND GND GND GND 2.05V 00001 GND GND GND GND Float 2.00V 00010 GND GND GND Float GND 1.95V 00011 GND GND GND Float Float 1.90V 00100 GND GND Float GND GND 1.85V 00101 GND GND Float GND Float 1.80V 00110 GND GND Float Float GND 1.75V 00111 GND GND Float Float Float 1.70V 01000 GND Float GND GND GND 1.65V 01001 GND Float GND GND Float 1.60V 01010 GND Float GND Float GND 1.55V 01011 GND Float GND Float Float 1.50V 01100 GND Float Float GND GND 1.45V 01101 GND Float Float GND Float 1.40V 01110 GND Float Float Float GND 1.35V 01111 GND Float Float Float Float 1.30V * Represents codes without a defined output voltage as specified in Intel specifications. The LTC1706-81 interprets these codes as a valid input and produces an output voltage as follows: (11111) = 2V To program output voltages higher than 2.05V, the range bit should be set high (VID4 = High). In this range, when the four VID inputs are low, the output is 3.5V. Each increasing binary count is equivalent to a decrease of 100mV in the output voltage. When all five VID inputs are high or floating, such as when no CPU is present in a system, a regulated 2V output is generated at VSENSE. Each VID input pin is pulled up by a 40k resistor in series with a diode connected to VCC. Therefore, it should be grounded (or driven low) to produce a digital low input. It can either be floated or connected to VCC to get a digital high input. The series diode is included to prevent the input from being damaged or clamped when it is driven higher than VCC. Voltage Sensing and Feedback Pins The FB pin is a high impedance node that requires minimum layout distance to reduce extra loading and unwanted stray pickup. When used with the LTC1629 or LTC1929, the LTC1706-81’s FB, SENSE, VCC and GND pins should be connected, respectively, with the EAIN, VDIFFOUT, INTVCC and SGND pins of the LTC1629 and LTC1929. The result of this application is a precisely controlled, multiphase, variable output voltage supply to any low voltage, high current system such as a powerful personal computer, workstation or network server. True remote sense capability is retained in this case. VID Input Characteristics The VID inputs should be driven with a maximum VIL of 0.4V and a minimum VIH of 1.6V. However, the VID input range is not limited to values less than VCC. Because of the internal diode between VCC and the pull-up resistor, the inputs can go higher than VCC without being clamped to VCC or damaging the input. This allows the LTC1706-81 to be fully logic compatible and operational over a higher input voltage range (less than the 7V absolute maximum rating). 6 LTC1706-81 U U W U APPLICATIONS INFORMATION When a VID input is grounded, there will be a higher quiescent current flow from VCC because of a resistor from VCC through a series diode to each one of the inputs. This increase in quiescent current is calculated from: IQ = N(VCC – VDIODE)/RPULLUP N is the number of grounded VID inputs. VDIODE is typically 0.6V while RPULLUP has a typical pull-up resistance of 40kΩ. U PACKAGE DESCRIPTION In other words, each VID input has a typical pull-up current of 68µA for a 3.3V system. Besides the LTC1629, the LTC1706-81 also programs a whole family of LTC DC/DC converters that have an onboard 0.8V reference. The LTC1628, LTC1735, LTC1622, LTC1772 and LTC1929 are just a few of the high efficiency step-down switching regulators that will work equally well with the LTC1706-81. Dimensions in inches (millimeters) unless otherwise noted. MS10 Package 10-Lead Plastic MSOP (LTC DWG # 05-08-1661) 0.118 ± 0.004* (3.00 ± 0.102) 10 9 8 7 6 0.118 ± 0.004** (3.00 ± 0.102) 0.193 ± 0.006 (4.90 ± 0.15) 1 2 3 4 5 0.040 ± 0.006 (1.02 ± 0.15) 0.007 (0.18) 0.034 ± 0.004 (0.86 ± 0.102) 0° – 6° TYP 0.021 ± 0.006 (0.53 ± 0.015) SEATING PLANE 0.009 (0.228) REF 0.0197 (0.50) BSC 0.006 ± 0.004 (0.15 ± 0.102) MSOP (MS10) 1098 * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 7 LTC1706-81 U TYPICAL APPLICATION VID Controlled High Current 70A 4-Phase Application OPTIONAL SYNC CLOCK IN 0.33µF 1 SENSE1+ TG1 SENSE1– SW1 2 3 FROM µP 4 7 5 VCC 6 VID0 SENSE VID1 VID2 0.33µF 6 7 100pF 8 6800pF 47k LTC1706-81 9 10 VID3 FB 10 VID4 GND EAIN BOOST1 PLLFLTR VIN PLLIN BG1 PHASMD ITH LTC1629 SGND EXTVCC INTVCC PGND VDIFFOUT BG2 11 VOS– BOOST2 12 VOS+ SW2 SENSE2– TG2 SENSE2+ AMPMD 1000pF 13 9 CLKOUT 3 1000pF 4 5 RUN/SS 2 14 L1 28 27 5V 0.003Ω 26 0.47µF 25 M1 10Ω 24 M2 1µF 23 22 21 D7 20 D8 1µF 25V + 1 22µF 6.3V M3 150µF, 16V ×2 + + COUT 470µF, 6.3V ×3 GND 19 18 M4 0.47µF 17 D1 MBRS 340T3 M5 16 M6 15 VOUT 1.3V TO 3.5V 70A D2 MBRS 340T3 0.003Ω L2 75k 1 2 3 47pF 1000pF 4 10k 5 0.01µF 6 7 6800pF 47k 100pF 8 9 NC 10 11 12 M1 TO M12: FDS7760A L1 TO L4: 1µH SUMIDA CEPH149-IROMC D7 TO D10: CENTROI CMDSH-3TR COUT: KEMET T510X477M006AS fSW: 200kHz 1000pF 13 14 CLKOUT RUN/SS SENSE1+ TG1 SENSE1– SW1 BOOST1 EAIN VIN PLLFLTR BG1 PLLIN EXTVCC PHASMD LTC1629 ITH INTVCC PGND SGND VDIFFOUT BG2 VOS– BOOST2 VOS+ SW2 SENSE2– TG2 + AMPMD SENSE2 L3 28 27 5V 0.003Ω 26 25 0.47µF 10Ω 24 M7 22 21 D9 20 D10 1µF 25V M9 M8 1µF 23 + 24k COUT 470µF, 6.3V ×3 150µF, 16V ×2 22µF 6.3V + D3 MBRS 340T3 + GND VIN 12V 19 18 17 0.47µF M10 M12 M11 16 15 D4 MBRS 340T3 0.003Ω L4 1706-81 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1622 Low Voltage Step-Down Controller 8-Pin MSOP, 2V ≤ VIN ≤ 10V, 550kHz, Burst ModeTM Operation LTC1628 Dual High Efficiency, 2-Phase Synchronous Step-Down Controller Constant, Standby, 5V and 3.3V LDOs, 3.5V ≤ VIN ≤ 36V LTC1629 PolyPhaseTM High Efficiency Step-Down DC/DC Controller Expandable Up to 12 Phases, Up to 120A, Remote Sense Diff Amp LTC1702/LTC1703 Dual High Efficiency, 2-Phase Synchronous Step-Down Controller 550kHz, 25MHz GBW, No RSENSETM, 2.7V ≤ VIN ≤ 7V LTC1709 2-Phase Synchronous Step-Down Controller with 5-Bit VID 4V ≤ VIN ≤ 36V, PLL, 36-Pin SSOP, Current Mode Operation LTC1735 High Efficiency Synchronous Step-Down Controller Burst Mode Operation, 16-Pin Narrow SSOP, Fault Protection, 3.5V ≤ VIN ≤ 36V LTC1736 High Efficiency Synchronous Step-Down Controller with 5-Bit VID GN-24, Power Good, Output Fault Protection, 3.5V ≤ VIN ≤ 36V LTC1772 SOT-23 Low Voltage Step-Down Controller 6-Pin SOT-23, 2V ≤ VIN ≤ 10V, 550kHz, Burst Mode Operation LTC1929 2-Phase Synchronous Step-Down Controller Current Mode Operation, IOUT Up to 40A, 3.5V ≤ VIN ≤ 36V Burst Mode, PolyPhase and No RSENSE are trademarks of Linear Technology Corporation. 8 Linear Technology Corporation 170681f LT/TP 0400 4K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1999