TS9001 series

3-5

2003/12 rev. A

Detail Description

Description

The TS9001 series of CMOS regulators contain a P-MOS pass transistor, voltage reference, error amplifier, over

current protection, thermal shutdown and short circuit protection.

The TS9001 series switches from voltage mode to current mode when the load exceeds the rated output current. This

prevents over stress. The TS9000 also incorporates current fold-back to reduce power dissipation when the output is

short circuit. This feature becomes active when the output drops below 1.05V, and reduces the current flow by 65%.

Full current is restored when the voltage exceeds 0.95V.

The internal P-channel pass transistor receives data from the error amplifier, over current shutdown, short output

protection and thermal protection circuits. During normal operation, the error amplifier compares the output voltage to a

precision reference. Over current and thermal shutdown circuits become active when the junction temperature exceeds

150

restored when the junction temperature drops below 120

Enable

The Chip Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shut off, and all internal

circuits are powered down. In this state, the quiescent current is less than 5uA. This pin behaves much like an

electronic switch.

External Capacitor

The TS9001 series is stable with an output capacitor to ground of 2.2uF or greater. It can keep stable even with higher

or poor ESR capacitors.

A second capacitor is recommended between the input and ground to stabilize Vin. The input capacitor should be

larger than 0.1uF to have a beneficial effect.

A third capacitor can be connected between the Bypass pin and Ground. This capacitor can be a low cost polyester

film variety between the value of 1~10nF. A larger capacitor improves the AC ripple rejection, but also makes the

output come up slowly. This “soft” turn-on is desirable in some applications to limit turn-on surges.

All capacitors should be placed in close proximity to the pins. A “quiet” ground termination is desirable.