Microsemi Corporation LX1665CN, LX1665CDW, LX1665ACN, LX1665ACDW, LX1664CN Datasheet

		LX1664/64A, LX1665/65A
		DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC
T H E I N F I N I T E P O W E R O F I N N O V A T I O N		P R O D U C T I O N D A T A S H E E T

D E S C R I P T I O N

The LX1664/64A and LX1665/65A are monolithic switching regulator controller IC’s designed to provide a low cost, high performance adjustable power supply for advanced microprocessors and other applications requiring a very fast transient response and a high degree of accuracy.

Short-circuit Current Limiting without Expensive Current Sense Resistors.

Current-sensing mechanism can use PCB trace resistance or the parasitic resistance of the main inductor. The LX1664A and LX1665A have reduced current sense comparator threshold for optimum performance using a sense resistor. For applications requiring a high degree of accuracy, a conventional sense resistor can be used to sense current.

Programmable Synchronous Rectifier Driver for CPU Core. The main output is adjustable from 1.3V to 3.5V using a 5-bit code. The IC can read a VID signal

set by a DIP switch on the motherboard, or hardwired into the processor’s package (as in the case of Pentium® Pro and Pentium II processors). The 5-bit code adjusts the output voltage between 1.30 and 2.05V in 50mV increments and between 2.0 and 3.5V in 100mV increments, conforming to the Intel Corporation specification. The device can drive dual MOSFET’s resulting in typical efficiencies of 85 - 90% even with loads in excess of 10 amperes. For cost sensitive applications, the bottom MOSFET can be replaced with a Schottky diode (non-syn- chronous operation).

Linear Regulator Driver. The LX1664/ 65 family of devices have a secondary regulator output. This can drive a MOSFET or bipolar transistor as a pass element to construct a low-cost adjustable linear regulator suitable for powering a 1.5V GTL+ bus or 2.5V clock supply.

(continued next page)

IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.

K E Y F E AT U R E S

■5-bit Programmable Output For CPU Core

Supply

■Adjustable Linear Regulator Driver Output

■No Sense Resistor Required For Short-

Circuit Current Limiting

■Designed To Drive Either Synchronous Or

Non-Synchronous Output Stages

■Soft-Start Capability

■Modulated, Constant Off-Time Architecture

For Fast Transient Response And Simple

System Design

■Available Over-Voltage Protection (OVP) Crowbar Driver And Power Good Flag

(LX1665 only)

A P P L I C AT I O N S

■Socket 7 (Pentium Class) Microprocessor

Supplies (including Intel Pentium Processor, AMD-K6TM And Cyrix® 6x86TM, Gx86TM and M2TM Processors)

■Pentium II and Deschutes Processor & L2-

Cache Supplies

■Voltage Regulator Modules

P R O D U C T H I G H L I G H T

LX1665 I N A

PE N T I U M

II SI N G L E -CH I P PO W E R

SU P P LY

SO L U T I O N

12V

F1 20A

5V

C3

L2

1µH

6.3V

0.1µF

U1

C5

1500µF x3

LX1665

1µF

1

18

Q1

C2

R1

SS

VC1

Supply Voltage

2

INV

TDRV

17

IRL3102

L1

0.0025

for CPU Core VOUT

3

16

2.5µH

4

VCC_CORE

GND

15

Q2

C

VID0

VID0

BDRV

IRL3303

1

VID1

5

VID1

VCC

14

6.3V, 1500µF x 3**

6

13

C9

** Three capacitors for Pentium

VID2

VID2

CT

Four capacitors for Pentium II

C8

330µF

VID3

7

VID3

OV 12

Q4

VID4

8

VID4

LDRV

11

680pF

Supply Voltage

IRLZ44

For I/O Chipset or GTL+ Bus

9

LFB

PWRGD 10

R5

C7

18-pin

OV

330µF

Wide-Body SOIC

PWRGD

R6

PA C K A G E O R D E R I N F O R M AT I O N

Guide

TA (°C)

N

Plastic DIP

N

Plastic DIP

D Plastic SOIC

DW Plastic SOIC Wide

page

16-pin

18-pin

16-pin

18-pin

See next for

Selection

0 to 70

LX1664CN

LX1665CN

LX1664CD

LX1665CDW

LX1664ACN

LX1665ACN

LX1664ACD

LX1665ACDW

Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (e.g. LX1664CDT)

	Copyright © 1999	L I N F I N I T Y M I C R O E L E C T R O N I C S I N C .	1
		11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: [phone]
	Rev. 1.2 11/99

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

LX1664/64A, LX1665/65A

DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC

P R O D U C T I O N D A T A S H E E T

D E S C R I P T I O N (con't.)

Smallest Package Size. The LX1664 is available in a narrow body 16-pin surface mount IC package for space sensitive applications. The LX1665 provides the additional functions of Over Voltage Protection (OVP) and Power Good (PWRGD) output drives for applications requiring output voltage monitoring and protection functions.

Ultra-Fast Transient Response reduces system cost. The modulated offtime architecture results in the fastest tran-

sient response for a given inductor, reducing output capacitor requirements, and reducing the total regulator system cost.

Over-Voltage Protection and Power Good Flag. The OVP output in the LX1665 & LX1665A can be used to drive an SCR crowbar circuit to protect the load in the event of a short-circuit of the main MOSFET. The LX1665 & LX1665A also have a logiclevel Power Good Flag to signal when the output voltage is out of specified limits.

D E V I C E S E L E C T I O N G U I D E

					OVP and		Current-Sense
	DEVICE		Packages		Power Good		Comp. Thresh. (mV)		Optimal Load
	LX1664		16-pin SOIC		No		100		Pentium-class (<10A)
	LX1664A		& DIP				60		Pentium II (> 10A)
	LX1665		18-pin SOIC		Yes		100		Pentium-class (<10A)
	LX1665A		& DIP				60		Pentium II (> 10A)
			ABSOLUTE MAXIMUM RATINGS (Note 1)

Supply Voltage (VC1) ....................................................................................................	25V
Supply Voltage (VCC) ....................................................................................................	15V
Output Drive Peak Current Source (500ns)...............................................................	1.5A
Output Drive Peak Current Sink (500ns) ...................................................................	1.5A
Input Voltage (SS, INV, VCC_CORE, CT, VID0-VID4) ...........................................	-0.3V to 6V
Operating Junction Temperature
Plastic (N, D & DW Packages) .............................................................................	150°C
Storage Temperature Range ....................................................................	-65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) .............................................................	300°C

Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal. Pin numbers refer to DIL packages only.

THERMAL DATA

N (16-PIN DIP) PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA	65°C/W
N (18-PIN DIP) PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA	60°C/W
D PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA	120°C/W
DW PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA	90°C/W

PACKAGE PIN OUTS

SS		1	16		VC1
INV		2	15		TDRV
VCC_CORE		3	14		GND
VID0		4	13		BDRV
VID1		5	12		VCC
VID2		6	11		CT
VID3		7	10		LDRV
VID4		8	9		LFB

N PACKAGE — 16-Pin

LX1664/1664A (Top View)

SS		1	18		VC1
INV		2	17		TDRV
VCC_CORE		3	16		GND
VID0		4	15		BDRV
VID1		5	14		VCC
VID2		6	13		CT
VID3		7	12		OV
VID4		8	11		LDRV
LFB		9	10		PWRGD

N PACKAGE — 18-Pin

LX1665/1665A (Top View)

SS				1	16			VC1
INV				2	15			TDRV
VCC_CORE				3	14			GND
VID0				4	13			BDRV
VID1				5	12			VCC
VID2				6	11			CT
VID3				7	10			LDRV
VID4				8	9			LFB

D PACKAGE — 16-Pin

LX1664/1664A (Top View)

SS				1	18			VC1
INV				2	17			TDRV
VCC_CORE				3	16			GND
VID0				4	15			BDRV
VID1				5	14			VCC
VID2				6	13			CT
VID3				7	12			OV
VID4				8	11			LDRV
LFB				9	10			PWRGD

DW PACKAGE — 18-Pin

LX1665/1665A (Top View)

Junction Temperature Calculation: TJ = TA + (PD x θJA).

The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow

2		Copyright © 1999
		Rev. 1.2 11/99

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

LX1664/1664A, LX1665/65A

DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC

P R O D U C T I O N D A T A S H E E T

E L E C T R I C A L C H A R A C T E R I S T I C S

(Unless otherwise specified, 10.8 < VCC < 13.2, 0°C ≤ TA ≤ 70°C. Test conditions: VCC = 12V, T = 25°C. Use Application Circuit.)

	Parameter			Symbol	Test Conditions	LX1664/1665 (A)			Units
						Min.	Typ.	Max.
	Reference & DAC Section (See Table 1 - Next Page)
	Regulation Accuracy (See Table 1)				(Less 40mV output adaptive positioning), VCC = 12V, ILOAD = 6A	-30		30	mV
	Regulation Accuracy				1.8V ≤ VOUT ≤ 2.8V	-1		1	%
	Timing Section
	Off Time Initial			OT	VCC_CORE = 1.3V, CT = 390pF		2		µs
					VCC_CORE = 3.5V, CT = 390pF		1		µs
	Off Time Temp Stability				VCC_CORE = 1.3V to 3.5V		40		ppm
	Discharging Current			IDIS	VCC_CORE = 1.3V, VCT = 1.5V	180	210	240	µA
	Ramp Peak			VP			2		V
	Ramp Peak-Valley			VRPP	VCC_CORE = 1.3V	0.9	1	1.1	V
					VCC_CORE = 3.5V	0.37	0.42	0.47	V
	Ramp Valley Delay to Output				10% Overdrive		100		ns
	Error Comparator Section
	Input Bias Current			IB	1.3V < VSS = VINV < 3.5V		0.8	2	µA
	Input Offset Voltage			VIO		36	41	46	mV
	EC Delay to Output				10% Overdrive		200		ns
	Current Sense Section
	Input Bias Current (VCC_CORE Pin)			IB	1.3V < VINV = VCC_CORE < 3.5V		27	35	µA
	Pulse By Pulse CL		LX1664/1665	VCLP	Initial Accuracy	85	100	115	mV
			LX1664A/1665A		Initial Accuracy	50	60	70	mV
	CS Delay to Output				10% Overdrive		200		ns
	Output Drivers Section
	Drive Rise Time			TR	VC1 = VCC = 12V, CL = 3000pF		70		ns
	Drive Fall Time			TF	VC1 = VCC = 12V, CL = 3000pF		70		ns
	Drive High			VDH	VCC = VCC = 12V, ISOURCE = 20mA		11		V
					VCC = VCC = 12V, ISINK = 200mA		10		V
	Drive Low			VDL	VCC = VCC = 12V, ISOURCE = 20mA		0.06	0.1	V
					VCC = VCC = 12V, ISINK = 200mA		0.8	1.2	V
	Output Pull Down			VPD	VCC = VC = 0, IPULL UP = 2mA		0.8	1.4	V
	UVLO and S.S. Section
	Start-Up Threshold			VST		9.9	10.1	10.4	V
	Hysteresis			VHYST			0.31		V
	SS Sink Current			ISD	VC1 = 10.1V	2	5.5		mA
	SS Sat Voltage			VOL	VC1 = 9V, ISD = 200µA		0.15	0.6	V
	Supply Current Section
	Dynamic Operating Current			ICD	VCC = VC1 = 12V, Out Freq = 200kHz, CL = 0			27	mA
	Power Good / Over-Voltage Protection Section (LX1665 Only)
	Lower Threshold				(VCC_CORE / DACOUT)	88	90	92	%
	Hysteresis						1		%
	Power Good Voltage Low				IPWRGD = 5mA		0.5	0.7	V
	Over-Voltage Threshold				(VCC_CORE / VDAC)	110	117	125	%
	OVP Sourcing Current				VOV = 5V	30	45		mA
	Linear Regulator Section
	Output Voltage				Set by external resistors	1.5		3.6	V
	Setpoint Accuracy				IL = 0.5A using 0.5% resistors	-1.5		1.5	%
	Output Temperature Drift						40		ppm
	Load Regulation							1.5	%
	Cummulative Accuracy							3	%
	Op-Amp Output Current				Open Loop	50	70		mA

Copyright © 1999	3
Rev. 1.2 11/99

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

LX1664/64A, LX1665/65A

DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC

P R O D U C T I O N D A T A S H E E T

E L E C T R I C A L C H A R A C T E R I S T I C S

	Table 1 - Adaptive Transient Voltage Output										(Output Voltage Setpoint — Typical)
			Processor Pins							Output Voltage (VCC_CORE)
		0 = Ground, 1 = Open (Floating)
	VID4		VID3		VID2		VID1		VID0		0.0A		Nominal Output*
	0		1		1		1		1		1.34V		1.30V
	0		1		1		1		0		1.39V		1.35V
	0		1		1		0		1		1.44V		1.40V
	0		1		1		0		0		1.49V		1.45V
	0		1		0		1		1		1.54V		1.50V
	0		1		0		1		0		1.59V		1.55V
	0		1		0		0		1		1.64V		1.60V
	0		1		0		0		0		1.69V		1.65V
	0		0		1		1		1		1.74V		1.70V
	0		0		1		1		0		1.79V		1.75V
	0		0		1		0		1		1.84V		1.80V
	0		0		1		0		0		1.89V		1.85V
	0		0		0		1		1		1.94V		1.90V
	0		0		0		1		0		1.99V		1.95V
	0		0		0		0		1		2.04V		2.00V
	0		0		0		0		0		2.09V		2.05V
	1		1		1		1		1		2.04V		2.00V
	1		1		1		1		0		2.14V		2.10V
	1		1		1		0		1		2.24V		2.20V
	1		1		1		0		0		2.34V		2.30V
	1		1		0		1		1		2.44V		2.40V
	1		1		0		1		0		2.54V		2.50V
	1		1		0		0		1		2.64V		2.60V
	1		1		0		0		0		2.74V		2.70V
	1		0		1		1		1		2.84V		2.80V
	1		0		1		1		0		2.94V		2.90V
	1		0		1		0		1		3.04V		3.00V
	1		0		1		0		0		3.14V		3.10V
	1		0		0		1		1		3.24V		3.20V
	1		0		0		1		0		3.34V		3.30V
	1		0		0		0		1		3.44V		3.40V
1			0		0		0		0		3.54V		3.50V

* Nominal = DAC setpoint voltage with no adaptive output voltage positioning.

Note:

Adaptive Transient Voltage Output

In order to improve transient response a 40mV offset is built into the Current Sense comparator. At high currents, the peak output voltage will be lower than the nominal set point, as shown in Figure 1. The actual output voltage will be a function of the sense resistor, the output current and output ripple.

	5A/Div.				Output Load 0 to 14A
0A
2.8V	100mV/Div.				Output Voltage

Time - 100µs/Div.

FIGURE 1 — Output Transient Response (using 5mΩ sense resistor and 5µH output inductor)

4		Copyright © 1999
		Rev. 1.2 11/99

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

LX1664/1664A, LX1665/65A

DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC

P R O D U C T I O N D A T A S H E E T

C H A R A C T E R I S T I C S C U RV E S

	95
	90
(%)	85
EFFICIENCY	80
			Output Set Point
				EFFICIENCY AT 3.1V
	75			EFFICIENCY AT 2.8V
				EFFICIENCY AT 1.8V
	70
	1	2	3	4	5	6	7	8	9	10	11	12	13	14

IOUT (A)

FIGURE 2 — Efficiency Test Results:

Non-Synchronous Operation, VIN = 5V

	100
	95
	90
(%)
EFFICIENCY	85
	80
			Output Set Point
				EFFICIENCY AT 3.1V
	75			EFFICIENCY AT 2.8V
				EFFICIENCY AT 1.8V
	70
	1	2	3	4	5	6	7	8	9	10	11	12	13	14

IOUT (A)

FIGURE 3 — Efficiency Test Results:

Synchronous Operation, VIN = 5V

90
85
80
75
70
				Output Set Point
					1.8V EFFICIENCY
65					2.8V EFFICIENCY
					3.3V EFFICIENCY
60
1	2	3	4	5	6	7	8	9	10	11	12	13	14

IOUT (A)

FIGURE 4 — Efficiency Test Results: Synchronous Operation, VIN = 12V.

Note: Non-synchronous operation not recommended for 12V operation, due to power loss in Schottky diode.

Copyright © 1999	5
Rev. 1.2 11/99

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

LX1664/64A, LX1665/65A

DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC

		P R O D U C T I O N D A T A S H E E T
			B L O C K D I A G R A M
		VCC						18	VC1
SS	1					PWM Latch
			Trimmed
			2V Out			S	Q
			2V REF
			UVLO		R DOM			17	TDRV
			10.6/10.1			R	Q
			Internal
			VCC	VREG				16	GND
		40mV			Break			15	BDRV
					Before
					Make
INV	2	Error Comp		Off-Time				0.7V
					SYNC EN
				Controller				14	VCC
						Comp
VCC_CORE	3	100mV **
		CS Comp				OV Comp
CT	13							12	OV*
						UV Comp		10	PWRGD*
		10k
		DAC OUT
								LX1665/1665A ONLY

DAC	1.5V					Linear Op Amp

11 LDRV

9 LFB

		4			5			6			7			8
																Note: Pin numbers are correct for LX1665/1665A, 18-pin package.
	VID0			VID1			VID2			VID3			VID4
																* Not connected on LX1664/1664A.

** 60mV in LX1664A/1665A.

FIGURE 5 — LX1664/1665 Block Diagram

6		Copyright © 1999
		Rev. 1.2 11/99