LM2727_15 Datasheet, PDF (1/32 Pages) Texas Instruments – LM2727/LM2737 N-Channel FET Synchronous Buck Regulator Controller for Low Output Voltages

LM2727, LM2737
www.ti.com
SNVS205D – AUGUST 2002 – REVISED MARCH 2013
LM2727/LM2737 N-Channel FET Synchronous Buck Regulator Controller for Low Output
Voltages
Check for Samples: LM2727, LM2737
FEATURES
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•2 Input Power from 2.2V to 16V
• Output Voltage Adjustable Down to 0.6V
• Power Good flag, Adjustable Soft-Start and
Output Enable for Easy Power Sequencing
• Output Over-Voltage and Under-Voltage Latch-
Off (LM2727)
• Output Over-Voltage and Under-Voltage Flag
(LM2737)
• Reference Accuracy: 1.5% (0°C - 125°C)
• Current Limit Without Sense Resistor
• Soft Start
• Switching Frequency from 50 kHz to 2 MHz
• TSSOP-14 Package
APPLICATIONS
• Cable Modems
• Set-Top Boxes/ Home Gateways
• DDR Core Power
• High-Efficiency Distributed Power
• Local Regulation of Core Power
DESCRIPTION
The LM2727 and LM2737 are high-speed,
synchronous, switching regulator controllers. They
are intended to control currents of 0.7A to 20A with
up to 95% conversion efficiencies. The LM2727
employs output over-voltage and under-voltage latch-
off. For applications where latch-off is not desired, the
LM2737 can be used. Power up and down
sequencing is achieved with the power-good flag,
adjustable soft-start and output enable features. The
LM2737 and LM2737 operate from a low-current 5V
bias and can convert from a 2.2V to 16V power rail.
Both parts utilize a fixed-frequency, voltage-mode,
PWM control architecture and the switching
frequency is adjustable from 50kHz to 2MHz by
adjusting the value of an external resistor. Current
limit is achieved by monitoring the voltage drop
across the on-resistance of the low-side MOSFET,
which enhances low duty-cycle operation. The wide
range of operating frequencies gives the power
supply designer the flexibility to fine-tune component
size, cost, noise and efficiency. The adaptive, non-
overlapping MOSFET gate-drivers and high-side
bootstrap structure helps to further maximize
efficiency. The high-side power FET drain voltage can
be from 2.2V to 16V and the output voltage is
adjustable down to 0.6V.
Typical Application
+5V
D1
RIN
10:
CIN
2.2PF
RFADJ
63.4k
CSS
12n
VCC
SD
PWGD
FREQ
SS
SGND
EAO
HG
LM27x7
BOOT
ISEN
LG
PGND
PGND
FB
CC2
180p
CC1
RC1
2.2p
392k
CBOOT
V_IN = 3.3V
0.1P
RCS
2.2k
Q1 Si4884DY
1.5 PH
6.1 A, 9.6 m:
L1
Q2 Si4884DY
RFB2
10k
CIN1,2
10PF
6.3V
V_O = 1.2V@5A
+
CO1,2
2200PF
6.3V, 2.8A
RFB1
10k
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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