June 1999 TOKO, Inc.

Page 7

TK73200

DEFINITION AND EXPLANATION OF TECHNICAL TERMS

OUTPUT VOLTAGE (V

The output voltage is specified with V

and I

DROPOUT VOLTAGE (V

The dropout voltage is the difference between the input

voltage and the output voltage at which point the regulator

starts to fall out of regulation. Below this value, the output

voltage will fall as the input voltage is reduced. It is

dependent upon the load current, the external transistor

and the junction temperature.

BASE CONTROL CURRENT (I

The base control current is the drive current for the base of

the external transistor.

OUTPUT CURRENT (I

The output current depends on the characteristics of the

external transistor and current limit setting.

LINE REGULATION (Line Reg)

Line regulation is the ability of the regulator to maintain a

constant output voltage as the input voltage changes. The

line regulation is specified as the input voltage is changed

from V

LOAD REGULATION (Load Reg)

Load regulation is the ability of the regulator to maintain a

constant output voltage as the load current changes. It is

a pulsed measurement to minimize temperature effects.

Load regulation depends on the external transistor.

QUIESCENT CURRENT (I

The quiescent current is the current which flows through

the ground terminal under no load conditions (I

and excludes the control pin current.

GROUND CURRENT (I

Ground current is the current which flows through the

ground pin(s). It is defined as I

current.

RIPPLE REJECTION RATIO (RR)

Ripple rejection is the ability of the regulator to attenuate

the ripple content of the input voltage at the output. It is

specified with 100 mVrms, 400 Hz superimposed on the

input voltage, where V

decoupling capacitor is set to 10

µF, the noise bypass

capacitor is set to 0.1

µF, and the load current is set to

30 mA. Ripple rejection is the ratio of the ripple content of

the output vs. the input and is expressed in dB.

STANDBY CURRENT (I

Standby current is the current which flows into the regulator

when the output is turned off by the control function

(V

SENSOR CIRCUITS

Overcurrent Sensor

The overcurrent sensor protects the device if the output is

shorted to ground.

Thermal Sensor

The thermal sensor protects the device if the junction

temperature exceeds the safe value (T

temperature rise can be caused by extreme heat, excessive

power dissipation caused by large output voltage drops, or

excessive output current. The regulator will shut off when

the temperature exceeds the safe value. As the junction

temperature decreases, the regulator will begin to operate

again. Under sustained fault conditions, the regulator

output will oscillate as the device turns off then resets.

Damage may occur to the device under extreme fault

conditions.

Reverse Voltage Protection

Reverse voltage protection prevents damage due to the

output voltage being higher than the input voltage. This

fault condition can occur when the output capacitor remains

charged and the input is reduced to zero, or when an

external voltage higher than the input voltage is applied to

the output side.