LTC1703IG#TR Linear Technology, LTC1703IG#TR Datasheet - Page 7

• Manufacturer Part Number: LTC1703IG#TR
• Description: IC CTLR REG SW DUAL 2PH 28-SSOP
• Manufacturer: Linear Technology

Specifications of LTC1703IG#TR

• Applications: Controller, Mobile Intel Pentium® III
• Voltage - Input: 3 ~ 7 V
• Number Of Outputs: 2
• Voltage - Output: 0.9 ~ 2 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

BLOCK DIAGRA
APPLICATIO S I FOR ATIO
OVERVIEW
The LTC1703 is a dual, step-down (buck), voltage mode
feedback switching regulator controller. It is designed to
be used in a synchronous switching architecture with two
external N-channel MOSFETs per channel. It is intended to
operate from a low voltage input supply (7V maximum)
and provide a high power, high efficiency, precisely regu-
lated output voltage. Several features make it particularly
suited for microprocessor supply regulation. Output regu-
lation is extremely tight, with DC line and load regulation
and initial accuracy better than 1.5%, and total regulation
including transient response inside of 3.5% with a prop-
RUN/SS1,2
COMP1,2
I
MAX1,2
10µA
V
CC
500mV
550kHz
OSC
U
4µA
I
LIM
U
W
THIS CONTROLLER
SHUTDOWN TO
800mV
90% DUTY CYCLE
START
+
SOFT
FB
CONTROLLER
–
W
OTHER
FROM
760mV
MIN
U
840mV
MAX
SHUTDOWN TO
ENTIRE CHIP
BURST
LOGIC
920mV
FLT
erly designed circuit. The 550kHz switching frequency
allows the use of physically small, low value external
components without compromising performance. An
onboard DAC sets the output voltage at channel 1, consis-
tent with the Intel mobile VID specification (Table 1).
The LTC1703’s internal feedback amplifier is a 25MHz
gain-bandwidth op amp, allowing the use of complex
multipole/zero compensation networks. This allows the
feedback loop to maintain acceptable phase margin at
higher frequencies than traditional switching regulator
controllers allow, improving stability and maximizing tran-
sient response. The 800mV internal reference allows
0V
FCB
VID0
VID1
VID2
VID3
VID4
DELAY
25µs
DRIVE
LOGIC
CONTROLLER
V
V
V
V
V
OTHER
FROM
CC
CC
CC
CC
CC
DIS
PV
40k
40k
40k
40k
40k
CC
10µA
CONTROL
SWITCH
LOGIC
BOOST1,2
TG1,2
SW1,2
BG1,2
PGND
SGND
FAULT
FB1,2
R11
10k
R
LTC1703
B1
TO FB1
1703 BD
SENSE
1703fa
7