Microsemi Corporation LX1669CD Datasheet

LIN DOC #:

LX1669

5V

CPU Core

V

CORE

C2

1500µFx3

Q1

IRL3102

Q2

IRL3303

L1

2.5µH

C1

1500µF x 6

R

SENSE

2.5m

Ω

C8

1µF

TDRV
V

CC12

V

CC5

PWRGD
OVP
VID0
VID1
VID2

PGND

BDRV
AGND
SS/EN

V

FB

V

CORE

VID4
VID3

8

VID3

VID4

VID2
VID1
VID0

C3

1µF

12V

7

6

5

4

3

2

1

11

12

13

14

15

16

9

10

L2,

1µH

Q4*

SCR

2N6504

R3

10k

Ω

C

SS

0.1µF

PWRGD

* Q4 optional OVP crowbar

1669

LX1669

P ROGRAMMABLE DC:DC CONTROLLER

T HE I NFINITE P OWER OF I NNOVATION

DESCRIPTION KEY FEATURES

The LX1669 is a Monolithic Switching
Regulator Controller IC 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. It provides
a programmable switching regulator out­put suitable for powering Pentium

®

II and

other processors.

Programmable Synchronous Recti-

fier Driver for CPU Core. The main

output is adjustable from 1.3 to 3.5V using
a TTL-compatible 5-bit digital code to
meet Intel specifications. The IC can read
the signal from a DIP-switch, hardwired to
Pentium II processor’s pins or from soft­ware. 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

NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.

100mV increments. The device can drive
dual MOSFET’s resulting in typical effi­ciencies of 85 – 90%, even with loads in
excess of 10A.

Short-circuit Current Limiting with-

out Expensive Current Sense Resis­tors. The current sensing mechanism can

use a PCB trace resistance or the parasitic
resistance of the main inductor. For
applications requiring a high degree of
accuracy, a conventional sense resistor
can be used.

Ultra-Fast Transient Response Re-

duces System Cost. The fixed frequency

modulated off-time architecture results in
the fastest transient response for a given
inductor.
Small Package Size. The LX1669 is
available in an economical 16-pin narrow
body SOIC package.

P RODUCTION DATA SHEET

■ 5-Bit Programmable Output For CPU Core

Supply

■ Power Solution For Pentium II Processors

■ No Sense Resistor Required For Short-Circuit

Current Limiting

■ Soft-Start And Hiccup-Mode Current

Limiting Functions

■ Modulated Constant Off-Time Control

Mechanism For Fast Transient Response And
Simple System Design

■ Power Good Flag

■ Over-Voltage Pin Can Drive SCR Crowbar Or

Turn Off Signal Silver-Box Power Supply

■ Digital-Compatible Inputs (Including VID Pins)

APPLICATIONS

■ Socket 7 Processor Supplies

■ Pentium II Processor Supplies

■ Deschutes CPU & L2-Cache Memory

Supplies

■ Voltage Regulator Modules

■ General Purpose And Microprocessor

DC:DC Supplies

Copyright © 1999
Rev. 1.0 4/99

PRODUCT HIGHLIGHT

Note: All surface-mount packages are available in Tape & Reel, append the letter "T" to part number. (i.e. LX1669CDT)

L INF INITY MICROELECTRONICS INC.

11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: [phone]

PACKAGE ORDER INFO

(°C)

T

A

0 to 70 LX1669CD

D

Plastic SOIC
16-pin

1

LX1669

PRODUCT DATABOOK 1996/1997

P ROGRAMMABLE DC:DC CONTROLLER

RODUCTION DATA SHEET

P

ABSOLUTE MAXIMUM RATINGS (Note 1 & 2)

12V Supply Voltage (V
5V Supply Voltage (V

Output Drive Peak Current Source (500ns)....................................................... 1.0A

) .................................................................................. 18V

CC12

) ....................................................................................... 7V

CC5

Output Drive Peak Current Sink (500ns) ........................................................... 1.0A

Input Voltage (SS, VID[0:4]) ................................................................... -0.3V to 6V

Operating Junction Temperature .................................................................... 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

Note 2. V

respect to Ground. Currents are positive into, negative out of the specified
terminal.

supply is used as input to internal low dropout regulator. Voltages above

CC3

3.3V will cause increased thermal dissipation in the package. Power dissipation
should be limited to keep junction temperature below maximum rating.

THERMAL DATA

D PACKAGE:

D

x θ

θθ

θ

θθ

JA

).

JA

120°C/W

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

Junction Temperature Calculation: TJ = TA + (P
The θ

numbers are guidelines for the thermal performance of the device/pc-board

JA

system. All of the above assume no ambient airflow.

PACKAGE PIN OUTS

TDRV

V

CC12

V

PWRGD

OVP
VID0
VID1
VID2

1 16
215
314

CC5

413
512
611
710
89

D PACKAGE

(Top View)

PGND
BDRV
AGND
SS/ENABLE
V

FB

V

CORE

VID4
VID3

2

Copyright © 1999

Rev. 1.0 4/99

PRODUCT DATABOOK 1996/1997

P ROGRAMMABLE DC:DC CONTROLLER

P RODUCTION DATA SHEET

ELECTRICAL CHARACTERISTICS

(

Unless otherwise specified, 4.75V < V

Parameter

Reference & DAC

Initial Accuracy V

Cumulative Regulation Accuracy 1.3V ≤ V

Timing

Off Time OT V

Switching Frequency Freq V

Error Comparator / CS-

Input Bias Current I
E

Delay to Output Overdrive ≤ 5mV

C

Current Sense +

Input Resistance R

Pulse By Pulse Current Limit V

Current Sense Delay To Output Overdrive ≤ 5mV

Output Drivers

Drive Rise Time, Fall Time T

Drive High V
Drive Low V

UVLO and Soft-Start (SS)

V

Start-Up Threshold V

CC5

Hysteresis

SS Resistor R
SS Output Enable V

Hiccup Duty Cycle DC

Supply Current

V

Dynamic Supply Current I

CC12

Static Supply Current 12V I

5V I

Power Good / Over-Voltage Protection (OVP)

Threshold (V

Hysteresis
Power Good Voltage Low I

Over-Voltage Threshold (V
OVP Sourcing Current V

VID Pins

Low Input VILInternally pulled up to V

High Input V

< 5.25V and 10.8V < V

CC5

Symbol

(Less 40mV output adaptive positioning)

CORE

= 2.0V

CORE

= 1.3V to 3.5V

CORE

1.0V < VSS = VFB < 3.5V

FB

0V < VFB = V

CORE

CLP

CL = 3000pF

RF

DHISOURCE

DLISINK

STVCC12

SS

EN

HICCSS

CD

VCC12VSS

VCC5VSS

IH

= 20mA

> 3.9V

= 0.1µF, V

Out Freq = 200kHz, CL = 3000pF, Synch., VSS > 0.5V

< 0.5V

< 0.5V

CORE

(V

CORE

= 4mA

PWRGD

CORE

= 2.0V

OVP

≤ 3.5V

CORE

CORE

= 20mA

/ V

) V

SET

/ V

) V

SET

/ V

), V

SET

< 13.2V, 0°C ≤ TA ≤ 70°C. Test conditions: V

CC12

Test Conditions

< 3.5V

= 2.00V, F

DAC

rising, V

CORE

falling, V

CORE

rising

CORE

= 100Hz

REQ

OUT2

OUT2

thru 30k

CC5

, 1.3V ≤ V

≥ 2.0V

≥ 2.0V

≤ 3.5V, T

CORE

= 25°C

A

LX1669

= 5V, V

CC5

Min. Typ. Max.

-1 +1 %

-1.5 1.5 %

45 60 mV

10 11 V

3.9 4.2 4.6 V

0.4 0.5 V

108 110 111 %

90 91 92 %

110 117 125 %

35 60 mA

2.0 V

= 12V, T = 25°C.

CC12

LX1669

2.4 µs

250 kHz

-0.3 -1 µ A
100 ns

12 kΩ

100 ns

100 ns

0.1 0.2 V

0.10 V

18 kΩ

10 %

24 mA

69mA

13 18 mA

2%

0.5 0.7 V

0.8 V

)

Units

Copyright © 1999
Rev. 1.0 4/99

3

LX1669

PRODUCT DATABOOK 1996/1997

P ROGRAMMABLE DC:DC CONTROLLER

RODUCTION DATA SHEET

P

ELECTRICAL CHARACTERISTICS

Table 1 - Adaptive Transient Voltage Output (Output Voltage Setpoint — Typical)

Processor Pins

0 = Low, 1 = High

VID4 VID3 VID2 VID1 VID0

011111.34V 1.30V

011101.39V 1.35V

011011.44V 1.40V

011001.49V 1.45V

010111.54V 1.50V

010101.59V 1.55V

010011.64V 1.60V

010001.69V 1.65V

001111.74V 1.70V

001101.79V 1.75V

001011.84V 1.80V

001001.89V 1.85V

000111.94V 1.90V

000101.99V 1.95V

000012.04V 2.00V

000002.09V 2.05V

111112.04V 2.00V

111102.14V 2.10V

111012.24V 2.20V

111002.34V 2.30V

110112.44V 2.40V

110102.54V 2.50V

110012.64V 2.60V

110002.74V 2.70V

101112.84V 2.80V

101102.94V 2.90V

101013.04V 3.00V

101003.14V 3.10V

100113.24V 3.20V

100103.34V 3.30V

100013.44V 3.40V

100003.54V 3.50V

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

Output Voltage (V

0.0A

Nominal Output* (V

SET

)

)

SET

Note:

Adaptive Transient Voltage Output

In order to improve transient response a 40mV offset is built into the voltage comparator. At high currents, the
peak output voltage will be lower than the nominal set point , as shown in Figure 4. The actual output voltage
will be a function of the sense resistor, output current and output ripple.

4

Copyright © 1999

Rev. 1.0 4/99

PRODUCT DATABOOK 1996/1997

V

P ROGRAMMABLE DC:DC CONTROLLER

P RODUCTION DATA SHEET

CHARACTERISTICS CURVES

LX1669

100

95

90

85

EFFICIENCY (%)__

80

EFFICIENCY A T 3. 1V
EFFICIENCY A T 2. 8V

75

70

123456 7891011121314

EFFICIENCY A T 1. 8V

I

OUT

(A)

FIGURE 1 — Efficiency Test Results:

V

FB

CS Comp

Error Comp

Hiccup

= 5V

IN

I

PWRGD

OVP

ID[0:4]

Non-Synchronous Operation, V

4

Power Good

& OVP

5

V

REF

6
7
8
9

10

DAC

V

SET

V

CORE

R
20k

12

60mV

40mV

SS

11

100

95

90

85

EFFICIENCY (%)__

80

75

70

BLOCK DIAGRAM

RESET

V

RESET

Hiccup

R

SQ

Set

PWM

Q

Off-Time

Control

EFFICIENCY AT 3.1V
EFFICIENCY A T 2.8V
EFFICIENCY A T 1.8V

1234567891011121314

I

(A)

OUT

FIGURE 2 — Efficiency Test Results:

Synchronous Operation, VIN = 5V

+12V

VIN (5V)

2

V

UVLO

UVLO

15

16

14

1

3

CC12

TDRV

BDRV

PGND

AGND

+5V

V

CC5

C

IN

R

SENSE

L

V

ESR

C

OUT

CORE

SS/ENABLE

Copyright © 1999
Rev. 1.0 4/99

13

C

SS

FIGURE 3 — Block Diagram

5