LM2757_14 Datasheet, PDF (1/20 Pages) Texas Instruments – Switched Capacitor Boost Regulator with High Impedance Output in Shutdown

LM2757
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SNVS536D – OCTOBER 2007 – REVISED AUGUST 2009
LM2757 Switched Capacitor Boost Regulator with High Impedance Output in Shutdown
Check for Samples: LM2757
FEATURES
1
•2 Dual gain converter (2x, 3/2x) with up to 93%
Efficiency.
• Inductorless solution uses only 4 small
ceramic capacitors.
• Total solution area < 12mm².
• True input-output and output-input disconnect.
• Up to 180 mA output current capability (5V).
• Selectable 4.1V, 4.5V or 5.0V output.
• Pre-regulation minimizes input current ripple.
• 1.24 MHz switching frequency for a low-noise,
low-ripple output voltage.
• Integrated Over Current and Thermal
Shutdown Protection.
• Tiny 1.2 mm X 1.6 mm X 0.4 mm pitch,
12–bump micro SMD package.
APPLICATIONS
• USB/USB-OTG/HDMI Power
• Supercapacitor Charger
• Keypad LED Drive
• Audio amplifier power supply
• Low-current Camera Flash
• General Purpose Li-Ion-to-5V Conversion
• Cellular Phone SIM cards
DESCRIPTION
The LM2757 is a constant frequency pre-regulated switched-capacitor charge pump that operates at 1.25 MHz to
produce a low-noise regulated output voltage. The device can be configured to provide up to 100 mA at 4.1V,
110 mA at 4.5V, or 180 mA at 5V. Excellent efficiency is achieved without the use of an inductor by operating the
charge pump in a gain of either 3/2 or 2 according to the input voltage and output voltage option selection.
The LM2757 presents a high impedance at the V_OUT pin when shut down. This allows for use in applications that
require the regulated output bus to be driven by another supply while the LM2757 is shut down.
A perfect fit for space-constrained, battery-operated applications, the LM2757 requires only 4 small, inexpensive
ceramic capacitors. LM2757 is a tiny 1.2 mm X 1.6 mm 12–bump micro SMD device. Built in soft-start, over-
current protection, and thermal shutdown features are also included in this device.
Typical Application Circuit
VIN = 3.0V - 5.5V
CIN
1 µF
C1
0.47 µF
C2
0.47 µF
B2,B3 ^VIN
A3 ^C1+
B1
C1-
A1 ^C2+
C3
C2-
VOUT
VOUT = 4.1V (100 mA), 4.5V (110 mA)
5.0V (180 mA)
A2
1.0 µF
COUT
LM2757
M0
M1
GND
D3
D2
C1,C2
*Bump D1 is (NC) No Connect
1
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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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.
Copyright © 2007–2009, Texas Instruments Incorporated