SE5318 Datasheet, PDF (5/6 Pages) Seaward Electronics Inc. – 300mA CMOS LDO with PGOOD

Detailed Description
Enable
SE5318 is a CMOS regulator containing a PMOS pass
The EN Pin is an enable control Pin, When The
transistor, voltage reference, error amplifier, over-current Enable pin pulled High, IC is enabled; when pulled
protection, thermal shutdown, and Power Good low, the PMOS pass transistor shuts off, and all
detection circuitry.
internal circuits are powered down. In this state, the
quiescent current is less than 1µA. This pin
The P-channel pass transistor receives data from the
behaves much like an electronic switch.
error amplifier, over-current shutdown, and thermal pro-
tection circuits. During normal operation, the error am-
plifier compares the output voltage to an internal
precision voltage reference. Over Temperature
Protection (OTP) and Over Current Protection (OCP)
circuits become active when the junction temperature
exceeds 150℃, or the current exceeds 550mA,
respectively. During OTP, the output voltage remains
low. Normal operation is restored when the junction
temperature drops below 120℃.
Power Good
SE5318 includes the Power Good feature.
Normally, Pin 4 is "Floating", however, when the
output is not within ±10% of the specified voltage, it
pulls low. This can occur under the following con-
ditions:
1) Input Voltage too low.
External Capacitors
SE5318 is stable with an output capacitor to ground of
2) During Over-Temperature Protection.
3) If output is pulled up.
1.0µF 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 com-
paratively 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.
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..
Revision 12/30/2011
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 5