2A Ultra Low Dropout Linear Regulator
TJ4220
Output Adjustment (Adjustable Version)
An adjustable output device has output voltage range of 0.8V to 5.0V. The operating condition of VIN and
the operating characteristics of VOUT depend on the dropout voltage performance in accordance with
output load current presented at Fig. 7. To obtain a desired output voltage, the following equation can be
used with R1 resistor range of 100Ω to 50kΩ.
VIN
VIN
VOUT
VOUT
TJ4220
Cff
R2
R1
CIN
10uF
COUT
10uF
EN
EN
ADJ
GND
V
OUT
R2 R1
1
0.8
Fig. 4. Application for Adjustable Output Voltage
To enhance output stability, a feed-forward capacitor of 10nF to 1uF can be placed in series with VOUT and
ADJ.(Refer to "Component Selection" Section)
SENSE Pin
In applications where the regulator output is not very close to the load, the TJ4220 can provide better
remote load regulation characteristics using the SENSE pin. TJ4220 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 VOUT pin. Connecting the sense pin to the remote load will provide regulation
at the remote load because the TJ4220 regulates the voltage at the sense pin when the sense option pin
is used.
Fig. 5. Conventional Linear Regulator Application
Fig.6. Remote Load Sense Application
Maximum Output Current Capability
The TJ4220 can deliver a continuous current of 2A over the full operating junction temperature range.
However, the output current is limited by the restriction of power dissipation which differs from packages.
A heat sink may be required depending on the maximum power dissipation and maximum ambient
temperature of application. With respect to the applied package, the maximum output current of 2A may
be still undeliverable due to the restriction of the power dissipation of TJ4220. Under all possible
conditions, the junction temperature must be within the range specified under operating conditions.
The temperatures over the device are given by:
TC = TA + PD X θCA
TJ = TC + PD X θJC
TJ = TA + PD X θJA
Jun. 2011 – R1.0.6
7/14
HTC
HTC [ HTC KOREA TAEJIN TECHNOLOGY CO. ]
