TC120 is a 300kHz PFM/PWM step-down (Buck) DC/
DC regulator/controller combination for use in systems
operating from two or more cells, or in line-powered
applications. It uses PWM as the primary modulation
scheme, but automatically converts to PFM at low
output loads for greater efficiency. It requires only an
external inductor, Schottky diode, and two capacitors to
implement a step-down converter having a maximum
output current of 600mA (VIN = 5V, VOUT = 3.3V). An
external switching transistor (P-channel MOSFET) can
be added to increase output current capability to
support output loads of 2A or more.
The TC120 consumes only 55μA (max) of supply
current (VOUT = 3.3V) and can be placed in shutdown
mode by bringing the shutdown input (SHDN) low.
During shutdown, the regulator is disabled, supply
current is reduced to 2.5μA (max), and VOUT is
internally pulled to ground, discharging the output
capacitor. Normal operation resumes when SHDN is
brought high. Other features include a built-in undervoltage
lockout (UVLO), an externally programmable
soft start time, and output short circuit protection. The
TC120 operates from a maximum input voltage of 10V
and is available in a low-profile 8-Pin SOP package.