LTC1699 Series

1

, LTC and LT are registered trademarks of Linear Technology Corporation.

s

Fully Compliant with Intel 5-Bit Mobile

(LTC1699-80) and Desktop VRM8.4 (LTC1699-81)

and VRM9.0 (LTC1699-82) VID Specifications

s

Precision

±0.35% Programmable Resistor Divider

for Use with 0.8V Referenced DC/DC Converters

s

Two Different Divider Settings Can Be Stored Using a

2-Wire SMBus Serial Interface (Rev 1.1)

s

Built-In Safeguards Minimize Misprogramming Due

to Bus Conflicts

s

Three Open-Drain Pins (CPU_ON, IO_ON, CLK_ON)

and a Global Control Pin (VRON)to Shutdown or

Soft-Start 3 DC/DC Converters Simultaneously

s

PGOOD Pin and 50

µs PGOOD Timer

s

Available in MSOP-8 and SSOP-16 Package

AMD Athlon is a trademark of Advanced Micro Devices, Inc.

Pentium is a registered trademark of Intel Corporation.

Intel SpeedStep is a trademark of Intel Corporation.

The LTC

cision (

±0.35% max), digitally programmed resistor di-

viders that comply with Intel 5-bit mobile (LTC1699-80),

desktop VRM8.4 (LTC1699-81) and VRM9.0 (LTC1699-82)

VID specifications. Each IC can switch the output of a

DC/DC converter between two set voltages. A digital input

pin, SEL, selects one of two divider settings stored into

registers via a 2-wire SMBus interface.

The SMBus interface uses Write Word protocol to setup

the registers and to turn the DC/DC converters on or off.

Read Word protocol is used to verify register contents and

to return the On/Off status of the converters. The

LTC1699-80, LTC1699-81 and LTC1699-82 incorporate

safeguards against errors due to bus conflicts.

Three open-drain N-channel outputs (CPU_ON, IO_ON

and CLK_ON) are provided to turn DC/DC converter sup-

plies on or off via their RUN/SS inputs. A global control pin,

VRON is used to turn the converters on or off simulta-

neously. An internal timer pulls the PGOOD pin low for

50

µs if the divider setting changes or the converters are

turned on via the SMBus and the VRON pin.

s

Intel Desktop Pentium

s

Intel Mobile Pentium

SpeedStep

s

Desktop AMD Athlon

s

Software Programmable Remote Power Supply

s

Power Supplies with Voltage Margining

SMBus VID

Voltage Programmers

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

CPU_ON

IO_ON

CLK_ON

PGOOD

FB

VRON

SCL

SEL

SDA

VRON

SCL

SEL

SDA

SENSE

U1

LTC1699-81

M1

M2

L1, 1

µH

C1

10

µF

25V

C1, C2, C3, C4, C9: TAIYO YUDAN

C5: SANYO

C10, C11: PANASONIC, SPCL. POLY.

D1: CMDSH-3

D2: DIODES INC., B340A

L1: TOKO, 919AS-1RON

M1: Si4884DY

M2: Si4874DY

C2

10

µF

25V

C3

10

µF

25V

C9

22

µF

6.3V

C4

10

µF

25V

C5

10

µF

35V

ALUM

D2

D1

5VDC

5

3

4

1

NC

2

NC

7

NC

11

GND

14

GND

15

8

13

9

10

6

12

16

RUN/SS

PGOOD

FCB

SGND

BOOST

TG

SW

PGND

BG

U2

LTC1778

1699 TA05

5V

TO 20V

R4

10k

R3

1

Ω

R5

715k, 1%

R2, 11k

C7

0.22

µF

C15

220pF

C12

0.1

µF

C19, 0.01

µF

C6

0.01

µF

+

C11

180

µF

4V

GND

GND

5V

2.5V

AT 10A

+

C10

180

µF

4V

+

C18

2200pF

C14, 0.1

µF

C8, 0.01

µF

R1

39k

R9

100k

PGOOD

C13

4.7

µF

6.3V

SMBus Controlled High Efficiency DC/DC Converter

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO