1A Ultra Low Dropout Linear Regulator
APPLICATION INFORMATION
TJ3964
Output Adjustment (Adjustable Version)
An adjustable output device has output voltage range of 1.145V to 5.0V. To obtain a desired output
voltage, the following equation can be used with R1 resistor. The sum of R1 and R2 should be in range
of 1kΩ to 100kΩ.
INPUT
C
IN
68uF
V
IN
V
OUT
OUTPUT
R2
ADJ
R1
+
-
EN
EN
TJ3964
GND
+
C
OUT
68uF
-
⎛
V
⎞
R2
=
R1
⎜
OUT
−
1
⎟
⎝
1.145
⎠
To enhance output stability, a capacitor of 68pF to 100pF can be placed in series with V
OUT
and ADJ.
SENSE Pin
In applications where the regulator output is not very close to the load, the TJ3964 can provide better
remote load regulation characteristics using the SENSE pin. TJ3964 regulates the voltage at the output
pin. Hence, the voltage at the remote load will be lower than the voltage at the output pin as a value of
the voltage drop across the trace series resistance. If the sense option pin is not required, the sense pin
must be connected to the V
OUT
pin. Connecting the sense pin to the remote load will provide regulation
at the remote load because the TJ3964 regulates the voltage at the sense pin when the sense option pin
is used.
Dec. 2009 – Rev. 1.1
-8-
HTC