amc7635 ADDtek Corp, amc7635 Datasheet - Page 7

• Manufacturer Part Number: amc7635
• Description: 300ma Cmos Dropout Regulator
• Manufacturer: ADDtek Corp

Copyright © 2007 ADDtek Corp.
External Capacitors
EN
Detailed Description
amplifier, over-current protection, and thermal shutdown circuit.
protection circuits. During normal operation, the error amplifier compares the output voltage to a precision
reference. T hermal shutdown and over-current circuits become active when the junction temperature exceeds
150℃, or the current exceeds 300mA. During thermal shutdown, the output voltage remains low. Normal operation
is restored when the junction temperature drops below 120℃.
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 over-all cost.
at least 0.1µF to have a beneficial effect.
Film variety between the value of 0.001 ~ 0.01µF. A larger 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.
can be achieved with a "Star" connection.
all internal circuits are powered down. In this state, the quiescent current is less than 1µA. This pin behaves much
like an electronic switch.
The AMC7635 CMOS low dropout regulator contains a PMOS pass transistor, a voltage reference, an error
The P-channel pass transistor receives data from the error amplifier, over-current shutdown, and thermal
The AMC7635 is stable with an output capacitor to ground of 2.2µF or greater. Ceramic capacitors have the
A second capacitor is recommended between the input and ground to stabilize V
A third capacitor can be connected between the BP pin and GND. This capacitor can be a low cost Polyester
All capacitors should be placed in close proximity to the pins. A "Quiet" ground termination is desirable. This
The EN pin is normally pulled to high. When shutdown, pulled low, the PMOS pass transistor shuts off, and
GND
V
IN
1uF
C
IN
APPLICATION INFORMATION
1000pF
C
BP
BP
V
IN
AMC7635
GND
7
V
EN
OUT
C
2.2uF
OUT
IN
. The input capacitor should be
V
DD078_A -- SEPTEMBER 2007
OUT
AMC7635