LTC1702IGN#TR Linear Technology, LTC1702IGN#TR Datasheet - Page 7

• Manufacturer Part Number: LTC1702IGN#TR
• Description: IC REG SW DUAL SYNC 2PH 24SSOP
• Manufacturer: Linear Technology
• Series: PolyPhase®r
• Type: Step-Down (Buck)r

Specifications of LTC1702IGN#TR

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Current - Output: 1A, 25A
• Frequency - Switching: 550kHz
• Voltage - Input: 3 ~ 7 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Output: -
• Power - Output: -

APPLICATIONS
TEST CIRCUIT
OVERVIEW
The LTC1702 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%, and total regulation
including transient response inside of 3% with a properly
designed circuit. The 550kHz switching frequency allows
the use of physically small, low value external components
without compromising performance.
The LTC1702’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
MEASURED
V
f
PGOOD1
OSC
U
V
FB1
10k
5V
INFORMATION
U
C
L
W
2k
0.1µF
C
L
U
I
BOOST1
BOOST1
TG1
BG1
SW1
I
FCB
PGOOD1
RUN/SS1
COMP1
FB1
MAX1
Test Circuit 1
V
GND
CC
I
CC
LTC1702
PGND
controllers allow, improving stability and maximizing tran-
sient response. The 800mV internal reference allows
regulated output voltages as low as 800mV without exter-
nal level shifting amplifiers.
The LTC1702’s synchronous switching logic transitions
automatically into Burst Mode operation, maximizing effi-
ciency with light loads. Onboard power-good and over-
voltage (OV) fault flags indicate when the output is in
regulation or an OV fault has occurred. The OV flag can be
set to latch the device off when an OV fault has occurred,
or to automatically resume operation when the fault is
removed.
The LTC1702 takes a low input voltage and generates two
lower output voltages at very high currents. Its strengths
are small size, unmatched regulation and transient
response and high efficiency. This combination makes it
ideal for providing multiple low voltage logic supplies to
microprocessors or high density ASICs in systems using
a “2-step” regulation architecture, used in portable and
advanced desktop computers.
PV
RUN/SS2
5V
PGOOD2
BOOST2
CC
COMP2
FAULT
I
I
PVCC
MAX2
SW2
TG2
BG2
FB2
I
BOOST2
2k
C
+
L
100µF
C
L
5V
10k
V
V
V
PGOOD2
FAULT
FB2
1702 TC
LTC1702
1702fa
7