LM3501 Datasheet, PDF (2/18 Pages) National Semiconductor (TI) – Synchronous Step-up DC/DC Converter for White LED Applications

Connection Diagram
Top View
20065302
8-bump micro SMD
Ordering Information
Order Number
LM3501TL-16
LM3501TLX-16
LM3501TL-21
LM3501TLX-21
Package Type
micro SMD
micro SMD
micro SMD
micro SMD
NSC Package Drawing
TL08SSA
TL08SSA
TL08SSA
TL08SSA
Top Mark
19
19
30
30
Supplied As
250 Units, Tape and Reel
3000 Units, Tape and Reel
250 Units, Tape and Reel
3000 Units, Tape and Reel
Pin Description/Functions
Pin
Name
Function
A1
AGND
Analog ground.
B1
V_IN
Analog and Power supply input.
C1
V_OUT
PMOS source connection for synchronous rectification.
C2
V_SW
Switch pin. Drain connections of both NMOS and PMOS power devices.
C3
GND
Power Ground.
B3
FB
Output voltage feedback connection.
A3
CNTRL
Analog LED current control.
A2
SHDN
Shutdown control pin.
AGND (pin A1): Analog ground pin. The analog ground pin
should tie directly to the GND pin.
V_IN (pin B1):Analog and Power supply pin. Bypass this pin
with a capacitor, as close to the device as possible, con-
nected between the V_IN and GND pins.
V_OUT (pin C1):Source connection of internal PMOS power
device. Connect the output capacitor between the V_OUT and
GND pins as close as possible to the device.
V_SW (pin C2):Drain connection of internal NMOS and PMOS
switch devices. Keep the inductor connection close to this
pin to minimize EMI radiation.
GND (pin C3):Power ground pin. Tie directly to ground
plane.
FB (pin B3):Output voltage feedback connection. Set the
primary White LED network current with a resistor from the
FB pin to GND. Keep the current setting resistor close to the
device and connected between the FB and GND pins.
CNTRL (pin A3): Analog control of LED current. A voltage
above 125 mV will begin to regulate the LED current. De-
creasing the voltage below 75 mV will turn off the LEDs.
SHDN (pin A2):Shutdown control pin. Disable the device
with a voltage less than 0.3V and enable the device with a
voltage greater than 1.1V. The white LED current can be
controlled using a PWM signal at this pin. There is an
internal pull down on the SHDN pin, the device is in a
normally off state.
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