LTC1699 Series
SMBus VID
Voltage Programmers
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DESCRIPTIO
FEATURES
The LTC®1699-80, LTC1699-81 and LTC1699-82 are pre-
cision (±0.35% max), digitally programmed resistor di-
viders that comply with Intel 5-bit mobile (LTC1699-80),
desktopVRM8.4(LTC1699-81)andVRM9.0(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.
■
Fully Compliant with Intel 5-Bit Mobile
(LTC1699-80) and Desktop VRM8.4 (LTC1699-81)
and VRM9.0 (LTC1699-82) VID Specifications
■
Precision ±0.35% Programmable Resistor Divider
for Use with 0.8V Referenced DC/DC Converters
■
Two Different Divider Settings Can Be Stored Using a
2-Wire SMBus Serial Interface (Rev 1.1)
■
Built-In Safeguards Minimize Misprogramming Due
to Bus Conflicts
The SMBus interface uses Write Word protocol to setup
the registers and to turn the DC/DC converters on or off.
ReadWordprotocolisusedtoverifyregistercontentsand
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 Pins (CPU_ON, IO_ON, CLK_ON)
and a Global Control Pin (VRON)to Shutdown or
Soft-Start 3 DC/DC Converters Simultaneously
■
PGOOD Pin and 50µs PGOOD Timer
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Available in MSOP-8 and SSOP-16 Package
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Three open-drain N-channel outputs (CPU_ON, IO_ON
and CLK_ON) are provided to turn DC/DC converter sup-
pliesonoroffviatheirRUN/SSinputs.Aglobalcontrolpin,
VRON is used to turn the converters on or off simulta-
neously. An internal timer pulls the PGOOD pin low for
50µs if the divider setting changes or the converters are
turned on via the SMBus and the VRON pin.
APPLICATIO S
Intel Desktop Pentium® III Power Supply
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Intel Mobile Pentium® Power Supply with Intel
■
SpeedStepTM Technology
Desktop AMD AthlonTM Power Supply
■
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Software Programmable Remote Power Supply
Power Supplies with Voltage Margining
, LTC and LT are registered trademarks of Linear Technology Corporation.
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.
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TYPICAL APPLICATIO
SMBus Controlled High Efficiency DC/DC Converter
V
IN
5V
V
IN
R9
100k
5V
C1
10µF
25V
C2
10µF
25V
C3
10µF
25V
C4
10µF
25V
C5
10µF
35V
+
+
D1
TO 20V
C6
0.01µF
M1
R1
PGOOD
U1
U2
39k
ALUM
GND
LTC1699-81
LTC1778
C7
0.22µF
5
3
4
1
2
8
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VRON
SDA
SCL
VRON CPU_ON
RUN/SS BOOST
PGOOD
L1, 1µH
13
9
10
6
12
16
V
OUT
C8, 0.01µF
SDA
SCL
SEL
NC
FB
IO_ON
CLK_ON
PGOOD
TG
SW
2.5V
AT 10A
V
RNG
FCB
C9
22µF
6.3V
+
C10
180µF
4V
C11
R2, 11k
SEL
PGND
BG
180µF
4V
M2
D2
I
TH
SGND
7
C15
R4
10k
C13
4.7µF
6.3V
NC
INTV
CC
SENSE
GND
11
14
15
220pF
NC
I
V
V
ON
IN
C1, C2, C3, C4, C9: TAIYO YUDAN
C5: SANYO
CC
C12
0.1µF
GND
GND
V
EXTV
FB
CC
R3
1Ω
C18
2200pF
C10, C11: PANASONIC, SPCL. POLY.
D1: CMDSH-3
R5
715k, 1%
5VDC
D2: DIODES INC., B340A
L1: TOKO, 919AS-1RON
M1: Si4884DY
C19, 0.01µF
M2: Si4874DY
1699 TA05
C14, 0.1µF
1