5-Bit VID-Controlled High Current 4-Phase Application (Simplified Block Diagram) 4.5V TO 22V LTC1629 TG1 SW1 BG1 PGND TG2 SW2 BG2 4.

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1 -Bit Desktop VID Voltage Programmer FEATRES Programs Regulator Output Voltage Range from.v to.v in mv Steps and from.v to.v in mv Steps (VRM 8.) Programs a Wide Range of Linear Technology DC/DC Converters with a.8v Reference Fully Compliant with the Intel Pentium Processor Desktop VID Specification ±.% Accurate Output Voltage Built-In k Pull-p Resistors on VID Inputs Available in MSOP- Package APPLICATIO S Intel Pentium II and III Processor Power Supply AMD Athlon TM Processor Power Supply Workstations and Servers Large Memory Array Supply DESCRIPTIO The LTC -8 is a precision, digitally programmed, resistive ladder which adjusts the output of any.8v referenced regulator. Depending on the state of the five VID inputs, an output voltage between.v and.v is programmed in mv and mv increments. The LTC-8 is designed specifically to program an entire family of Linear Technology DC/DC converters in full compliance with the Intel Desktop (VRM 8.) VID specification. The LTC-8 programs the following Linear Technology DC/DC converter products: LTC, LTC8, LTC, LTC, LTC, LTC-, LTC and LTC. (Consult factory for future compatible DC/DC converter products.), 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. TYPICAL APPLICATION -Bit VID-Controlled High Current -Phase Application (Simplified Block Diagram).V TO V FROM µp VID VID VID VID VID SENSE LTC-8 FB LTC INT V DIFFOT S EAIN TG SW BG P TG SW BG.V TO V L L R SENSE R SENSE C OT V OT.V TO.V P TO A LTC TG SW L R SENSE S EAIN BG P TG SW L R SENSE BG -8 TA

2 ABSOLTE MAXIMM RATINGS W W W (Note ) (Voltages Referred to Pin) Input Supply Voltage ( )....V to V VID Input Pins....V to V SENSE Pin....V to V FB Pin....V to V Operating Temperature Range (Note ).. C to 8 C Junction Temperature... C Storage Temperature Range... C to C Lead Temperature (Soldering, sec)... C PACKAGE/ORDER INFORMATION VID VID VID VID TOP VIEW T JMAX = C, θ JA = C/ W Consult factory for Industrial and Military grade parts. 8 MS PACKAGE -LEAD PLASTIC MSOP FB NC VID SENSE W ORDER PART NMBER LTCEMS-8 MS PART MARKING LTLR ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are T A = C..V.V, VID = VID = VID = VID = VID = NC unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX NITS Operating Supply Voltage Range.. V I VCC Supply Current (Note ). µa R FB-SENSE Resistance Between SENSE and FB 8 kω V OT Error % Output Voltage Accuracy Programmed from.v to.v (VID = ).. % Programmed from.v to.v (VID = ).. % R PLLP VID Input Pull-p Resistance V DIODE =.V (Note ) kω VID TH VID Input Voltage Threshold V IL (.V.V). V V IH (.V.V). V I VID-LEAK VID Input Leakage Current < VID < V (Note ). ± µa V PLLP VID Pull-p Voltage =.V.8 V = V. V Note : Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note : The LTC-8 is guaranteed to meet performance specifications from C to C. Specifications over the C to 8 C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note : With all five VID inputs floating, the supply current is simply the device leakage current. However, the supply current will rise and be approximately equal to the number of grounded VID input pins times (.V)/k. (See the VID Input Characteristics section for more details.) Note : Each built-in pull-up resistor attached to the VID inputs also has a series diode connected to to allow input voltages higher than the supply without damage or clamping. (See Operation section for further details.)

3 TYPICAL PERFORMANCE CHARACTERISTICS W. Typical Error % vs Output Voltage T A = C. Typical Error % vs Temperature ERROR (%) VID = ERROR (%) V OT =.V V OT =.V V OT = V VID = OTPT VOLTAGE (V) V OT =.V. TEMPERATRE ( C) -8 G -8 G R FB vs Temperature I VID-PLLP vs Temperature RFB (kω) VID PLL-P CRRENT (µa) 8 = V VID = V VID = VID = VID = VID = OPEN TEMPERATRE ( C) TEMPERATRE ( C) -8 G -8 G SPPLY CRRENT (µa) Supply Current vs Temperature. ALL VID INPTS OPEN.. = V =.V =.V. SPPLY CRRENT (µa) Supply Current vs Supply Voltage ALL VID INPTS OPEN T A = C TEMPERATRE ( C) 8 SPPLY VOLTAGE (V) -8 G -8 G

4 PIN FNCTIONS VID (Pin ): LSB Programming Input. Low =, High = or Float. Grounding VID adds mv (VID = LOW) or mv (VID = HIGH) to the output sense voltage. VID (Pin ): rd MSB Programming Input. Low =, High = or Float. Grounding VID adds mv (VID = LOW) or mv (VID = HIGH) to the output sense voltage. VID (Pin ): nd MSB Programming Input. Low =, High = or Float. Grounding VID adds mv (VID = LOW) or mv (VID = HIGH) to the output sense voltage. VID (Pin ): MSB Programming Input. Low =, High = or Float. Grounding VID adds mv (VID = LOW) or 8mV (VID = HIGH) to the output sense voltage. (Pin ): Power Supply Voltage. Range from.v to.v. SENSE (Pin ): Regulator Output Voltage. Connect directly to regulator output sense node or, when used with the LTC and LTC to V DIFFOT. VID (Pin ): High-Low Output Range Programming Input. VID = Low puts the output voltage in the lower range of.v to.v in mv steps. VID = HIGH puts the output voltage in the upper range of.v to.v in mv steps. NC (Pin 8): No Connect. (Pin ): Ground. Connect to regulator signal ground. FB (Pin ): Feedback Input. Connect to the.8v feedback pin of a compatible regulator or the EAIN pin of the LTC and LTC. NOMINAL (V) ABSOLTE MAX (V) PIN NAME DESCRIPTION MIN TYP MAX MIN MAX VID LSB Programmable Input. VID rd MSB Programmable Input. VID nd MSB Programmable Input. VID st MSB Programmable Input. Power Supply... SENSE Regulator Output Voltage... VID Output Range Programmable Input. 8 NC Ground. FB.8V Feedback Input.8..

5 BLOCK DIAGRA W k VID k SENSE VID R FB k SWITCH CONTROL LOGIC R FB FB VID -8 BD k k VID VID OPERATIO The LTC-8 is a precision resistive divider designed specifically for use with an entire family of Linear Technology Corporation DC/DC switching regulators with.8v internal reference and feedback voltage. The LTC-8 produces an output voltage ranging from.v to.v in mv steps and from.v to.v in mv steps by closing the loop between the output voltage sense and the feedback input of the regulator with the appropriate resistive divider network. The top feedback resistor, R FB, connected between SENSE and FB, is typically k and is not modified by the state of the VID program inputs. The bottom feedback resistor, R FB, however, is modified by the five VID inputs and is precisely ratioed to R FB. VID Programming A list of programmed inputs and their corresponding output voltages is shown in Table. Programming is accomplished by applying the proper voltage (or float condition) on the five digital VID inputs. VID is the range bit that puts the output voltage in either the.v to.v range or the.v to.v range. In either range, VID is the most significant bit (MSB) and VID is the least significant bit (LSB). In the lower range (VID = ), when the four VID inputs are low or grounded, the regulator output voltage is set to.v. Each increasing binary count is equivalent to a decrease of mv in the output voltage. Therefore, to obtain a.v output, the four VID inputs should be floating, or high.

6 OPERATIO Table. VID Inputs and Corresponding Output Voltage CODE VID VID VID VID VID OTPT Float.V Float Float.V Float Float.V Float Float Float.V Float Float.V Float Float Float.V Float Float Float.V Float Float Float Float.8V Float Float.V Float Float Float.V Float Float Float.V Float Float Float Float.V Float Float Float.V Float Float Float Float.V Float Float Float Float.V Float Float Float Float Float *.V Float.V Float.V Float Float.V Float.8V Float Float.8V Float Float.V Float Float Float.V Float.V Float Float.V Float Float.V Float Float Float.V Float Float.V Float Float Float.V Float Float Float.V Float Float Float Float.V * Represents codes without a defined output voltage as specified in Intel specifications. The LTC-8 interprets these codes as a valid input and produces an output voltage as follows: () = V To program output voltages higher than.v, the range bit should be set high (VID = High). In this range, when the four VID inputs are low, the output is.v. Each increasing binary count is equivalent to a decrease of mv in the output voltage. When all five VID inputs are high or floating, such as when no CP is present in a system, a regulated V output is generated at V SENSE. Each VID input pin is pulled up by a k resistor in series with a diode connected to. Therefore, it should be grounded (or driven low) to produce a digital low input. It can either be floated or connected to 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. 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 LTC or LTC, the LTC-8 s FB, SENSE, and pins should be connected, respectively, with the EAIN, V DIFFOT, INT and S pins of the LTC and LTC. 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 V IL of.v and a minimum V IH of.v. However, the VID input range is not limited to values less than. Because of the internal diode between and the pull-up resistor, the inputs can go higher than without being clamped to or damaging the input. This allows the LTC-8 to be fully logic compatible and operational over a higher input voltage range (less than the V absolute maximum rating).

7 APPLICATIONS INFORMATION W When a VID input is grounded, there will be a higher quiescent current flow from because of a resistor from through a series diode to each one of the inputs. This increase in quiescent current is calculated from: I Q = N( V DIODE )/R PLLP N is the number of grounded VID inputs. V DIODE is typically.v while R PLLP has a typical pull-up resistance of kω. In other words, each VID input has a typical pull-up current of 8µA for a.v system. Besides the LTC, the LTC-8 also programs a whole family of LTC DC/DC converters that have an onboard.8v reference. The LTC8, LTC, LTC, LTC and LTC are just a few of the high efficiency step-down switching regulators that will work equally well with the LTC-8. PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. MS Package -Lead Plastic MSOP (LTC DWG # -8-).8 ±.* (. ±.) 8. ±. (. ±.).8 ±.** (. ±.). (.8). ±. (. ±.) TYP SEATING PLANE. ±. (. ±.). (.8) REF. (.) BSC. ±. (.8 ±.) * DIMENSION DOES NOT INCLDE MOLD FLASH, PROTRSIONS OR GATE BRRS. MOLD FLASH, PROTRSIONS OR GATE BRRS SHALL NOT EXCEED." (.mm) PER SIDE ** DIMENSION DOES NOT INCLDE INTERLEAD FLASH OR PROTRSIONS. INTERLEAD FLASH OR PROTRSIONS SHALL NOT EXCEED." (.mm) PER SIDE. ±. (. ±.) MSOP (MS) 8 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.

8 TYPICAL APPLICATION VID Controlled High Current A -Phase Application OPTIONAL SYNC CLOCK IN FROM µp VID VID VID VID VID LTC-8 SENSE FB.µF.µF pf k pf 8pF 8 pf RN/SS SENSE SENSE EAIN PLLFLTR PLLIN PHASMD I LTC TH S V DIFFOT V OS V OS SENSE SENSE CLKOT TG SW BOOST BG EXT INT P BG BOOST SW TG AMPMD 8 8 V.µF D D8.µF µf µf V Ω µf.v M µf, V M M M L M M.Ω D MBRS T C OT µf,.v D MBRS T.Ω V OT.V TO.V A L k k M TO M: FDSA L TO L: µh SMIDA CEPH-IROMC D TO D: CENTROI CMDSH-TR C OT : KEMET TXMAS f SW : khz pf.µf k pf k 8pF pf 8 NC pf 8 RN/SS CLKOT SENSE TG SENSE SW EAIN BOOST PLLFLTR PLLIN BG PHASMD EXT LTC I TH INT S P V DIFFOT BG V 8 OS BOOST V OS SW SENSE TG SENSE AMPMD V.µF D D.µF µf µf V Ω µf.v M µf, V M M8 M L M M L.Ω D MBRS T C OT µf,.v D MBRS T.Ω V -8 TA RELATED PARTS PART NMBER DESCRIPTION COMMENTS LTC Low Voltage Step-Down Controller 8-Pin MSOP, V V, khz, Burst Mode TM Operation LTC8 Dual High Efficiency, -Phase Synchronous Step-Down Controller Constant, Standby, V and.v LDOs,.V V LTC PolyPhase TM High Efficiency Step-Down DC/DC Controller Expandable p to Phases, p to A, Remote Sense Diff Amp LTC/LTC Dual High Efficiency, -Phase Synchronous Step-Down Controller 8 Linear Technology Corporation McCarthy Blvd., Milpitas, CA - (8)- FAX: (8) - khz, MHz GBW, No R SENSE TM,.V V LTC -Phase Synchronous Step-Down Controller with -Bit VID V V, PLL, -Pin SSOP, Current Mode Operation LTC High Efficiency Synchronous Step-Down Controller Burst Mode Operation, -Pin Narrow SSOP, Fault Protection,.V V LTC High Efficiency Synchronous Step-Down Controller with -Bit VID GN-, Power Good, Output Fault Protection,.V V LTC SOT- Low Voltage Step-Down Controller -Pin SOT-, V V, khz, Burst Mode Operation LTC -Phase Synchronous Step-Down Controller Current Mode Operation, I OT p to A,.V V Burst Mode, PolyPhase and No R SENSE are trademarks of Linear Technology Corporation. 8f LT/TP K PRINTED IN SA LINEAR TECHNOLOGY CORPORATION

VID Controlled High Current 4-Phase DC/DC Converter (Simplified Block Diagram) 4.5V TO 22V TG1 SW1 LTC1629 BG1 PGND TG2 SW2 BG2 4.

VID Controlled High Current 4-Phase DC/DC Converter (Simplified Block Diagram) 4.5V TO 22V TG1 SW1 LTC1629 BG1 PGND TG2 SW2 BG2 4. FEATRES Fully Compliant with the Intel VRM./. VID Specification Programs Regulator Output Voltage from.v to.8v in mv Steps Programs an Entire Family of Linear Technology DC/DC Converters ±.% Accurate Voltage