TS9002
300 mA CMOS LDO
Voltage Range 1.5 to 3.8 Volts
SOT-25
General Description
The TS9002 family of positive, linear regulators feature low quiescent current (30µA typ.) with low
dropout voltage, making them ideal for battery applications. The space-saving SOT-23-5 package is
attractive for “Pocket” and “Hand Held” applications.
These rugged devices have both Thermal Shutdown, and Current Fold-back to prevent device failure
under the “Worst” of operating conditions.
An additional feature is a “Power Good” detector, which pulls low when the output is out of regulation.
The TS9002 is stable with an output capacitance of 2.2µF or greater.
Features
Very Low Dropout Voltage
Guaranteed 300mA Output
Accurate to within 1.5%
30µA Quiescent Current
Over-Temperature Shutdown
Current Limiting
Short Circuit Current Fold-back
Power Good Output Function
Power-Saving Shutdown Mode
Space-Saving SOT-25 (SOT-23-5)
Factory Pre-set Output Voltages
Low Temperature Coefficient
PC Peripherals
Battery Powered Widgets
Electronic Scales
Applications
Instrumentation
Portable Electronics
Wireless Devices
Cordless Phones
Functional Block Diagram
IN
OUT
Overcurrent
Shutdown
Typical Application
INPUT
IN
OUT
OUTPUT
TS9002
PG
GND
EN
Thermal
Shutdown
EN
Vref x110%
PG
R1
C1
5V
1µF
C2
2.2µF
AMP
R2
Vref x90%
Vref =1.215V
GND
Note: If output voltage specification is lower than
1.215V, Vref will be trimmed to 1.2V
Detailed Description
The TS9002 family of CMOS regulators contain a PMOS pass transistor, voltage reference, error
amplifier, over-current protection, thermal shutdown, and power good function.
The P-channel pass transistor receives data from the error amplifier, over-current shutdown, 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
o
C, or the current exceeds 300mA. During thermal shutdown,
the output voltage remains low. Normal operation is restored when the junction temperature
drops below 120
o
C.
The TS9002 switches from voltage mode to current mode when the load exceeds the rated output
current. This prevents over-stress. The TS9002 also incorporates current foldback to reduce
power dissipation when the output is short circuited. This feature becomes active when the
output drops below 0.8volts, and reduces the current flow by 65%. Full current is restored when
the voltage exceeds 0.8 volts.
External Capacitors
The TS9002 is stable with an output capacitor to ground of 2.2µF or greater. Ceramic capacitors
have the lowest ESR, and will offer the best AC performance. Conversely, Aluminum Electrolytic
capacitors exhibit the highest ESR, resulting in the poorest AC response. Unfortunately, large
value ceramic capacitors are comparatively expensive. One option is to parallel a 0.1µF ceramic
capacitor with a 10µF Aluminum Electrolytic. The benefit is low ESR, high capacitance, and low
overall cost.
A second capacitor is recommended between the input and ground to stabilize Vin. The input
capacitor should be at least 0.1µF to have a beneficial effect.
All capacitors should be placed in close proximity to the pins. A "Quiet" ground termination is
desirable. This can be achieved with a "Star" connection.
Enable
The Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shuts
off, and all internal circuits are powered down. In this state, the quiescent current is less than
1µA. This pin behaves much like an electronic switch.
Power Good
The TS9002 includes the Power Good feature. When the output is not within ±15% of the speci-
fied voltage, it pulls low. This can occur under the following conditions:
1) Input Voltage too low. 2) During Over-Temperature. 3) During Over-Current. 4) If output is pulled up.
(Note: PG pin is an open-drain output.)
PCB Design
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