SQ2181 Datasheet, PDF (3/5 Pages) SeCoS Halbleitertechnologie GmbH – CMOS Positive Voltage Regula tor

Elektronische Bauelemente
SQ2181
CMOS Positive
Voltage Regulator
Ordering Information(contd.)
Part Number
SQ2181-15
SQ2181-20
SQ2181-27
SQ2181-2H
SQ2181-32
Marking
1L 152
XXXX
1L 202
XXXX
1L 272
XXXX
1L 2H2
XXXX
1L 322
XXXX
Output Voltage
1.5V
2.0V
2.7V
2. 85V
3.2V
Part Number
SQ2181-18
SQ2181-25
SQ2181-28
SQ2181-30
SQ2181-33
Marking
1L 182
XXXX
1L 252
XXXX
1L 282
XXXX
1L 302
XXXX
1L 332
XXXX
Output Voltage
1.8V
2.5V
2.8V
3.0V
3.3V
Detailed Description
The SQ2181 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 exceeds150^oC,or the current exceeds 150mA.During thermal shutdown, the
output voltage remains low. Normal operation is restored when the junction temperature drops below 120^oC.
The SQ2181 switches from voltage mode to current mode when the load exceeds the rated output current. This prevents over-stress.
The SQ2181 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.
External Capacitors
The SQ2181 is stable with an output capacitance to ground of 0.22uF or greater. Ceramic capacitors have the lowest ESR, and will offer
the best AC performance. Conversely, Aluminum Elertrolytic capacitors exhibit the highest ESR, resulting in the poorest AC response.
A second capacitor is recommended between the input and ground to stabilize Vin. The input capacitor should be at least 0.1uF to
have a beneficial effect. 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 . The can be achieved with a "Star" connection.
Shutdown
When actively, pulled low, the PMOS pass transistor shuts off, and all internal circuits are powered down. In the state, the quiescent
current is less than 1uA. This pin behaves much like an electronic switch.
Characteristics Curve
ht tp://www.SeCoSGmbH.com/
01-Jun-2002 Rev. A
Any changing of specification will not be informed individual
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