ISSUED DATE :2006/04/10
REVISED DATE :
Ordering Information ( contd. )
Part Number
GSC2166-15
GSC2166-25
GSC2166-28
GSC2166-29
GSC2166-31
GSC2166-34
GSC2166-36
GSC2166-38
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX
Marking
6F152
6F252
6F282
6F292
6F312
6F342
6F362
6F382
Output Voltage
1.5V
2.5V
2.8V
2.9V
3.1V
3.4V
3.6V
3.8V
Part Number
GSC2166-18
GSC2166-27
GSC2166-2H
GSC2166-30
GSC2166-33
GSC2166-35
GSC2166-37
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX
XXXX
Marking
6F182
6F272
Output Voltage
1.8V
2.7V
2.85V
3.0V
3.3V
3.5V
3.7V
6F2H2
6F302
6F332
6F352
6F372
The GSC2166 series of COMS regulators contain a PMOS pass transistor, voltage reference, error amplifier,
over-current protection, and thermal shutdown.
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 : , or the current exceeds 600mA. During thermal shutdown, the output voltage remains low. Normal
operation is restored when the junction temperature drops below 120 : .
The GSC2166 switches from voltage mode to current mode when the load exceeds the rated output current.
This prevents over-stress. The GSC2166 also incorporates current fold-back to reduce power dissipation when
the output is short circuited. This feature becomes active when the output drops below 0.8 volts, and reduces
the current flow by 65%. Full current is restored when the voltage exceeds 0.8 volts.
Detailed Description
The GSC2166 is stable with an output capacitance to ground of 2.2 F 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 0.1 F ceramic capacitor with a 10 F 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 V
IN
. The input capacitor should
be at least 0.1 F to have a beneficial effect.
A third capacitor can be connected between the BY-PASS pin and GND. This capacitor can be a low cost
Polyester Film variety between the value of 0.001~0.01 F. A large 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. This
can be achieved with a “Star” connection.
External Capacitors
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 1 A. This pin behaves much
like an electronic switch.
Enable
3/5
GTM [ GTM CORPORATION ]
