TK71541SCL_41 データシートの表示（PDF） - Toko America Inc

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TK71541SCL_41

LOW DROPOUT VOLTAGE REGULATOR

Toko America Inc  

TK715xx

DEFINITION AND EXPLANATION OF TECHNICAL TERMS

OUTPUT VOLTAGE (VOUT)

The output voltage is specified with VIN = (VOUT(TYP) + 1 V)

and IOUT = 30 mA.

DROPOUT VOLTAGE (VDROP)

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 and the junction

temperature.

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 200 mVrms, 100 Hz superimposed on the

input voltage, where VIN = VOUT(TYP) + 2.0 V. The output

decoupling capacitor is set to 4.7 µF and the load current

is set to 5 mA. Ripple rejection is the ratio of the ripple

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

REVERSE VOLTAGE PROTECTION

CONTINUOUS OUTPUT CURRENT (IOUT)

Normal operating output current. This is limited by package

power dissipation.

PULSE OUTPUT CURRENT (IOUT(PULSE))

Maximum pulse width 5 ms at VOUT above 2.0 V, duty cycle

12.5%: pulse load only.

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 VIN = VOUT(TYP) + 1 V to VIN = VOUT(TYP) + 6 V or VIN =

max 14 V.

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.

REDUCTION OF OUTPUT NOISE

Although the architecture of the Toko regulators are

designed to minimize semiconductor noise, further

reduction can be achieved by the selection of external

components. The obvious solution is to increase the size

of the output capacitor. Please note that several parameters

are affected by the value of the capacitors and bench

testing is recommended when deviating from standard

values.

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

with the input voltage set to VIN = VOUT(TYP) +1 V. The load

regulation is specified under two output current step

conditions of 1 mA to 60 mA and 1 mA to 100 mA.

QUIESCENT CURRENT (IQ)

The quiescent current is the current which flows through

the ground terminal under no load conditions (IOUT = 0 mA).

GROUND CURRENT (IGND)

Ground current is the current which flows through the

ground pin(s). It is defined as IIN - IOUT, excluding control

PACKAGE POWER DISSIPATION (PD)

This is the power dissipation level at which the thermal

sensor is activated. The IC contains an internal thermal

sensor which monitors the junction temperature. When the

junction temperature exceeds the monitor threshold of

150 °C, the IC is shut down. The junction temperature

rises as the difference between the input power (VIN x IIN)

and the output power (VOUT x IOUT) increases. The rate of

temperature rise is greatly affected by the mounting pad

configuration on the PCB, the board material, and the

ambient temperature. When the IC mounting has good

thermal conductivity, the junction temperature will be low

even if the power dissipation is great. When mounted on

the recommended mounting pad, the power dissipation of

the SOT-23-3 is increased to 350 mW. For operation at

ambient temperatures over 25 °C, the power dissipation of

the SOT-23-3 device should be derated at 2.8 mW/°C. To

Page 8

January 1999 TOKO, Inc.

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