lm2757tmx National Semiconductor Corporation, lm2757tmx Datasheet

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lm2757tmx

Manufacturer Part Number
lm2757tmx
Description
Switched Capacitor Boost Regulator With High Impedance Output In Shutdown
Manufacturer
National Semiconductor Corporation
Datasheet

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© 2007 National Semiconductor Corporation
LM2757
Switched Capacitor Boost Regulator with High Impedance
Output in Shutdown
General 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 con-
figured 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 op-
tion selection.
The LM2757 presents a high impedance at the V
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 applica-
tions, 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
300337
OUT
pin when
30033701
Features
Applications
Dual gain converter (2x, 3/2x) with up to 93% Efficiency.
Inductorless solution uses only 4 small ceramic
capacitors.
Total solution area < 12mm
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.
USB/USB-OTG 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
2
.
30033723
November 19, 2007
www.national.com

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lm2757tmx Summary of contents

Page 1

... LM2757 requires only 4 small, inexpensive ceramic capacitors. LM2757 is a tiny 1 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 © 2007 National Semiconductor Corporation Features ■ Dual gain converter (2x, 3/2x) with up to 93% Efficiency. ■ ...

Page 2

... Impedance Order Information Order Number LM2757TM LM2757TMX www.national.com 12–Bump Micro SMD Package, 0.4mm Pitch National Semiconductor Package Number TMD12 Flying Capacitor C2 Connection Regulated Output Voltage Flying Capacitor C1 Connection Flying Capacitor C1 Connection Input Voltage Connection Input Voltage Connection Ground Connection ...

Page 3

Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. V Pin: Voltage to GND IN M0, M1 pins: Voltage to GND Continuous Power Dissipation (Note 4) Junction Temperature ...

Page 4

Symbol Parameter V Logic Input Low IL Logic Input Pulldown R PULLDOWN Resistance (M0, M1) I Logic Input High Current IH I Logic Input Low Current IL V Gain Transition Voltage G I Short Circuit Output Current SC V Turn-On ...

Page 5

Block Diagram 5 30033703 www.national.com ...

Page 6

Typical Performance Characteristics 0.47µ 1.0µ OUT Efficiency vs. Input Voltage, 5V Mode Efficiency vs. Input Voltage, 4.1V Mode Output Voltage vs. Output Current, 4.5V Mode ...

Page 7

Output Voltage Ripple vs. Output Current, 5V Mode Output Voltage vs. Input Voltage, 4.5V Mode Output Leakage Current, Device Shutdown Output Voltage vs. Input Voltage, 5V Mode 30033710 Output Voltage vs. Input Voltage, 4.1V Mode 30033712 Current Limit vs. Input ...

Page 8

Oscillator Frequency vs. Input Voltage Shutdown Supply Current vs. Input Voltage Line Step (3.5V to 4V) Load = 200mA Mode OUT CH1 Scale: 1V/Div, DC Coupled IN CH2 Scale: 100mV/Div, AC Coupled OUT ...

Page 9

Load Step with a Li-Ion Battery 200mA to 10mA Mode BATT OUT CH1 Scale: 50mV/Div, AC Coupled OUT CH4 Scale: 100mA/Div, DC Coupled OUT Time scale: 10µs/Div 30033722 9 www.national.com ...

Page 10

Operation Description OVERVIEW The LM2757 is a switched capacitor converter that produces a regulated output voltage of either 5V, 4.5V or 4.1V depend- ing on the mode selected. The core of the part is a highly efficient charge pump that ...

Page 11

Capacitors with a Y5V or Z5U temperature characteristic are generally not recommended for use with the LM2757. These types of capacitors typically have wide capacitance tolerance (+80%, -20%) and vary significantly over temperature (Y5V: +22%, -82% over -30ºC to +85ºC ...

Page 12

The same capacitance value must be used for all the flying capacitors. TABLE 1. LM2757 Performance with Different Capacitor Configurations (Note 12) Typical ...

Page 13

Application Circuits USB OTG POWER SUPPLY The 5V output mode will normally be used for the USB OTG application. Therefore the LM2757 can be enabled/disabled by applying a logic signal on only the M1 pin while grounding the M0 pin. ...

Page 14

LED DRIVER The 5.0V, 4.5V, or the 4.1V mode can be used depending on the forward voltage and load requirements of the LED appli- cation. The LM2757 can be enabled/disabled by applying the appropriate combination of logic signals on the ...

Page 15

Physical Dimensions inches (millimeters) unless otherwise noted NSC Package TMD12AAA Micro SMD Wafer Level Package X1: 1215 µm +/- 30 µm X2: 1615 µm +/- 30 µm X3: 600 µm +/- 75 µm Bump pitch: 0 www.national.com ...

Page 16

... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...

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