AP7215 Diodes, Inc., AP7215 Datasheet - Page 8

• Manufacturer Part Number: AP7215
• Description: 600ma Cmos Ldo
• Manufacturer: Diodes, Inc.

Application Note
Input Capacitor
A 1μF ceramic capacitor is recommended to connect between V
and GND pins to decouple input power supply glitch and noise.
The amount of the capacitance may be increased without limit.
A lower ESR (Equivalent Series Resistance) capacitor allows the
use of less capacitance, while higher ESR type requires more
capacitance. This input capacitor must be located as close as
possible to the device to assure input stability and less noise. For
PCB layout, a wide copper trace is required for both V
GND.
Suggested Input Capacitance
Vendor
TAIYO YUDEN
Output Capacitor
The output capacitor is required to stabilize and help the transient
response of the LDO. The AP7215 is designed to have excellent
transient response for most applications with a small amount of
output capacitance. The AP7215 is stable with any small ceramic
output capacitors of 1.0μF or higher value, and the temperature
coefficients of X7R or X5R type. Additional capacitance helps to
reduce undershoot and
PCB layout, the output capacitor must be placed as close as
possible to VR
possible.
Suggested Output Capacitance
Vendor
TAIYO YUDEN
Suggested Resistance
Vendor
YAGEO
AP7215 Rev. 1
OUT
Capacitance
1μF
Capacitance
1μF
Capacitance
SMD
and GND pins, and keep the leads as short as
overshoot during
Type
Ceramic LMK212B
Type
Ceramic LMK212B
Type
FR-SK
Series
Series
transient. For
www.diodes.com
IN
8 of 11
and
IN
ENABLE/SHUTDOWN Operation
The AP7215 is turned on by setting the EN pin high, and is turned
off by pulling it low. If this feature is not used, the EN pin should
be tied to V
ensure proper operation, the signal source used to drive the
EN pin must be able to swing above and below the specified
turn-on/off
Characteristics section under V
Current Limit Protection
When output current at VR
threshold, the current limit protection will be triggered and clamp
the output current to approximately 750mA to prevent
over-current and protect the regulator from damage due to
overheating.
Short circuit protection
When VR
200mV, short circuit protection will be triggered and clamp the
output current to approximately 50mA.
VD
---Open-Drain Active-Low reset output---
In general, VD
AP7215 microprocessor (μP) supervisory circuitry asserts a
guaranteed logic-low reset during power-up and power-down.
Reset is asserted when V
remain asserted for at least t
threshold.
As long as V
logic "0". When V
asserted after a 20ms time delay defined by t
EN=0
EN=1
OUT
(reset output)
OUT
VR
IN
3.3V
IN
voltage
pin is shorted to GND or VR
0V
pin to keep the regulator output on at all time. To
OUT
is lower than the reset threshold, VD
OUT
is pulled up by a resistor (100KΩ) to V
IN
becomes higher than V
thresholds
VD
Φ
Φ
IN
OUT
OUT
is below the reset threshold and
RP
EH
pin is higher than current limit
after V
and V
600mA CMOS LDO
listed
EL
IN
.
OUT
FEBRUARY 2009
rises above the reset
©
AP7215
in
RP
voltage is less than
Diodes Incorporated
HYS
, a logic "1" is
the
OUT
remains at
Electrical
IN
. The