TS29100 Datasheet, PDF (6/8 Pages) Taiwan Semiconductor Company, Ltd – 1.0A Ultra Low Dropout Positive Voltage Regulator

Application Information
Application Information
The TS29100/1/2 series are high performance with low
dropout voltage regulator suitable for moderate to high
current and voltage regulator application. Its
4000mA(typ) dropout voltage at full load and over
temperature makes it especially valuable in battery
power systems and as high efficiency noise filters in
post regulator applications. Unlike normal NPN
transistor design, where the base to emitter voltage
drop and collector to emitter saturation voltage limit the
minimum dropout voltage, dropout performance of the
PNP output of these devices is limited only by low Vce
saturation voltage.
The TS29100/1/2 series is fully protected from damage
due to fault conditions. Linear current limiting is
provided. Output current during overload conditions is
constant. Thermal shutdown the device when the die
temperature exceeds the maximum safe operating
temperature. Transient protection allows device survival
even when the input voltage spikes above and below
nominal. The output structure of these regulators allows
voltages in excess of the desired output voltage to be
applied without reverse current flow.
Capacitor Requirement
The TS29100/1/2 series requires an output capacitor to
maintain stability and improve transient response is
necessary. The value of this capacitor is dependent
upon the output current, lower currents allow smaller
capacitors. TS29100/1/2 series regulators are stable
with the 10uF minimum capacitor value at full load.
Where the regulator is powered from a source with high
AC impedance, a 0.1uF capacitor connected between
input and ground is recommended. The capacitor
should have good characteristics to above 250KHz. The
capacitance values will be help to improved transient
response, ripple rejection and output noise.
Minimum Load Current
The TS29100/1/2 series is specified between finite
loads. If the output current is too small leakage currents
dominate and the output voltage rises. A 10mA
minimum load current swamps any expected leakage
current across the operating temperature range.
Adjustable Regulator Design
The adjustable regulator versions (TS29102) is allow
to programming the output voltage anywhere between
1.25 and the 26V maximum operating rating of the
family.
Two resistors are used. Resistors can be quite large
up to 1MΩ, because of the very high input impedance
and low bias current of the sense comparator, the
resistor values are calculated by:
R1 = R2 * [(Vout / 1.24) – 1]
Where is Vout the desired output voltage. Above
application circuit shows component definition.
Applications with widely varying load currents may
scale the resistors to draw the minimum load current
required for proper operation.
Error Flag
TS29101 versions feature an Error Flag, which looks at
the output voltage and signals an error condition when
this voltage drops 5% below its expected value. The
error flag is an open-collector output that pulls low
under fault conditions. It may sink 10mA. Low output
voltage signifies a number of possible problems,
including an over-current fault (the device is in current
limit) and low input voltage. The flag output is
inoperative during over temperature shutdown
conditions.
Enable Input
TS29101 and TS29102 versions feature an enable
(EN) input that allows ON/OFF control of the device.
Special design allows “zero” current drain when the
device is disabled–only microamperes of leakage
current flow. The EN input has TTL/CMOS compatible
thresholds for simple interfacing with logic, or may be
directly tied to ≤30V. Enabling the regulator requires
approximately 20uA of current.
TS29100/1/2
6-6
2003/12 rev. A