LMR70503_15 Datasheet, PDF (1/24 Pages) Texas Instruments – SIMPLE SWITCHER Buck-Boost Converter For Negative Output Voltage in

LMR70503
www.ti.com
SNVS850A – JUNE 2012 – REVISED APRIL 2013
LMR70503 SIMPLE SWITCHER^® Buck-Boost Converter For Negative Output Voltage in
µSMD
Check for Samples: LMR70503
FEATURES
1
•23 Tiny 8-Bump Thin DSBGA Package: 0.84 mm ×
1.615 mm × 0.6 mm
• 2.8 V to 5.5 V Input Voltage Range
• Adjustable Output Voltage: -0.9 V to -5.5 V
• 320 mA Switch Current Limit
• 500 kHz Minimum Switching Frequency
• Ground Referred Enable Input
• Under Voltage Lock Out (UVLO)
• No External Compensation
• Internal Soft Start
• 1 µA Shutdown Supply Current
• Small Output Voltage Ripple
• WEBENCH^® Enabled
APPLICATIONS
• General Purpose Negative Voltage Supply
• Negative Rail / Bias Supply For Op-amp And
Data Converters
• LCD Biasing
PERFORMANCE BENEFITS
• Easy To Use
• Tiny Overall Solution Size Reduces System
Cost
System Performance
80
70
60
50
VIN = 2.8V
VIN = 3.3V
40
VIN = 4.0V
VIN = 5.0V
VIN = 5.5V
30
0 10 20 30 40 50 60 70 80 90 100
LOAD (mA)
Figure 1. Efficiency, V_OUT= -5.0 V
80
70
60
50
40
30
0
VIN = 2.8V
VIN = 3.3V
VIN = 4.0V
VIN = 5.0V
VIN = 5.5V
30 60 90 120 150 180
LOAD (mA)
DESCRIPTION
The LMR70503 is a buck-boost converter with
adjustable negative output voltage in a tiny 8-bump
thin DSBGA package. Its unique control method is
designed to provide fast transient response, low
output noise, high efficiency, and tight regulation in
the smallest possible PCB area. The LMR70503 has
built in soft start, peak current limit, minimum
switching frequency, and Under Voltage Lock Out
(UVLO), with no external compensation required. For
ease of use, the Enable pin is referred to the IC
ground, instead of the lowest potential of the IC: the
negative output voltage.
Figure 2. Efficiency, V_OUT= -2.5 V
Typical Application Circuit
VIN (2.8V to 5.5V)
Cin
1.8V
0V
Refer to GND
VIN
SW
VOUT
LMR70503
EN
FB
GND
VREF
D
Rb
Rt
L
Cout
VOUT
Cff
(-0.9V to -5.5V)
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SIMPLE SWITCHER, WEBENCH are registered trademarks of Texas Instruments.
2
All other trademarks are the property of their respective owners.
3
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 © 2012–2013, Texas Instruments Incorporated