YB1231 – HV600mA
Low-Noise LDO Regulator
designs using a PNP pass transistor,
including low operating power and longer
battery life. The YB1231 consumes only
100µA of quiescent current under most
up, the output capacitor and output load are
charged with a reduced output current.
Shortly after the initial power up, the
soft-start feature is terminated and normal
operation is resumed.
Output Short-Circuit Current Limit
The YB1231 includes a current limiter,
which monitors and controls the pass
transistor’s gate voltage, limiting the output
current to about 420mA, for example, in a
short-circuit output situation.
The YB1231 also features a low-power
active shutdown mode. It has a switch that
turns off the device when disabled. This
allows the output capacitor and load to
discharge and de-energize the load. In the
shutdown mode, the internal functional
blocks, such as voltage reference and the
error amplifier, are turned off completely,
and the quiescent current is less than 1µA.
Thermal Protection Shutdown
The thermal protection shutdown function
protects the device from operating in over
temperature condition. When the junction
temperature exceeds +160°C, the thermal
sensor signals the shutdown logic, turning
off the pass transistor and allowing the IC
to cool down. The thermal sensor turns the
pass transistor on again after the IC’s
junction temperature drops to +140°C.
The YB1231 comes with an active-high
enable pin that allows the regulator to be
enabled. Forcing the enable pin low
disables the regulator and puts it into the
shutdown mode. This pin cannot be left
floating as it may cause an undetermined
It is recommended to use a 2.2µF capacitor
on the YB1231 input and a 2.2µF capacitor
on the output. For high regulation
performance, larger input capacitor values
and lower ESRs provide better noise
rejection and line-transient response. The
output noise, load-transient response,
stability, and power-supply rejection can be
improved by using large output capacitors.
Low ESR ceramic capacitors provide
optimal performance and save space.
The YB1231 includes a soft-start circuitry to
limit inrush current at turn-on. During power
YB1231 MRev. 1.4