TS39154 Datasheet, PDF (4/7 Pages) Taiwan Semiconductor Company, Ltd – 1.5A Ultra Low LDO with Enable

TS39154
1.5A Ultra Low LDO with Enable
Application Information (Continue)
Input Capacitor Requirement
An input capacitor of 1uF or greater is recommended when the device is more than 4” away from the bulk AC supply
capacitance or when the supply is a battery. Small, surface mount, ceramic chip capacitors can be used for bypassing.
Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity
of the output voltage.
Minimum Load Current

The TS39154 is specified between finite loads. If the output current is too small leakage currents dominate and the
output voltage rises. A 10mA minimum load current is necessary for proper regulation.
Adjustable Regulator Design
The TS39154 is allowed to programming the output voltage anywhere between 1.25 and the 16V maximum operating
rating of the family.
Two resistors are used. Resistors can be quite large up to 1MΩ, because of the very high input impedance and low
bias current of the sense comparator, the resistor values are calculated by:
Table 1: Resistor select for output voltage setting
V_OUT
R1
R2
5V
470kΩ
155kΩ
3.3V
470kΩ
290kΩ
2.5V
470kΩ
460kΩ
1.8V
210kΩ
470kΩ
1.5V
100kΩ
470kΩ
Where V_OUT is the desired output voltage. Above application circuit shows component definition. Applications with
widely varying load currents may scale the resistors to draw the minimum load current required for proper operation.
Enable Input
TS39154 feature an active-high enable (EN) input that allows ON/OFF control of the regulator. Current drain reduces
to “zero” when the device is shutdown, with only micro-amperes of leakage current. The EN input has TTL/CMOS
compatible thresholds for simple interfacing with logic interfacing. EN may be directly tied to V_IN and pulled up to the
maximum supply voltage.
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Version: D08