herunterladen
GND
FB
V
SW
V
IN
SHDN
L
22 PH
LM3501-16
V
OUT
AGND
A1
CNTRL
C3
B1
C1
C2
B3
A2
A3
<0.3V
>1.1V
V
IN
2.7V - 5.5V
Voltage
Control
R2
24:
C
OUT
1PF
Ceramic
C
IN
1PF
Ceramic
LM3501
www.ti.com
SNVS230C –DECEMBER 2003–REVISED MAY 2013
LM3501 Synchronous Step-up DC/DC Converter for White LED Applications
Check for Samples: LM3501
1
FEATURES
APPLICATIONS
2
• Synchronous Rectification, High Efficiency
• LCD Bias Supplies
and no External Schottky Diode required
• White LED Back-Lighting
• Uses Small Surface Mount Components
• Handheld Devices
• Can Drive 2-5 White LEDs in Series (May
• Digital Cameras
Function with More Low V
F
LEDs)
• Portable Applications
• 2.7V to 7V Input Range
• True Shutdown Isolation, no LED Leakage DESCRIPTION
Current
The LM3501 is a fixed-frequency step-up DC/DC
converter that is ideal for driving white LEDs for
• DC Voltage LED Current Control
display backlighting and other lighting functions. With
• Input Undervoltage Lockout
fully integrated synchronous switching (no external
• Internal Output Over-Voltage Protection (OVP)
schottky diode required) and a low feedback voltage
Circuitry, with no External Zener Diode
(515 mV), power efficiency of the LM3501 circuit has
Required LM3501-16: 15.5V OVP; LM3501-21:
been optimized for lighting applications in wireless
phones and other portable products (single cell Li-Ion
20.5V OVP.
or 3-cell NiMH battery supplies). The LM3501
• Requires Only a Small 16V (LM3501-16) or 25V
operates with a fixed 1 MHz switching frequency.
(LM3501-21) Ceramic Capacitor at the Input
When used with ceramic input and output capacitors,
and Output
the LM3501 provides a small, low-noise, low-cost
• Thermal Shutdown
solution.
• 0.1µA shutdown Current
• Small 8-Bump Thin DSBGA Package
Typical Application Circuit
Figure 1. Typical 3 LED Application
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.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2003–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
