SS8014G SSC [Silicon Standard Corp.], SS8014G Datasheet - Page 4

• Manufacturer Part Number: SS8014G
• Description: 150mA Low-Noise LDO Regulator
• Manufacturer: SSC [Silicon Standard Corp.]

1/12/2005 Rev.2.11
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Over Current Protection
The SS8014 use a current mirror to monitor the output
current. A small portion of the PMOS output transis-
tor’s current is mirrored onto a resistor such that the
voltage across this resistor is proportional to the output
current. This voltage is compared against the reference
voltage. Once the output current exceeds the limit, the
PMOS output transistor enters constant current mode.
The current is set to 370mA typically.
Over Temperature Protection
To prevent excessive temperatures from occurring, the
SS8014 has a built-in temperature monitoring circuit.
When it detects the temperature is above 150
output transistor is turned off. When the temperature
drops to below 135
this way, the SS8014 is protected against excessive
junction temperatures during operation.
Shutdown Mode
When the
the SS8014 enters shutdown mode. All the analog cir-
cuits are turned off completely, which reduces the cur-
rent consumption to only the leakage current. The
output is disconnected from the input. When the output
has no load at all, the output voltage will be discharged
to ground through the internal resistor voltage divider.
Operating Region and Power Dissipation
Since the SS8014 is a linear regulator, its power dissipa-
tion is always given by P = I
maximum power dissipation is given by:
P
Where (T
die and the ambient air,
D(MAX)
BATTERY
BATTERY
Figure 2. Adjustable Output Using External
= (T
J
C
C
1µF
1µF
–T
SHDN
IN
IN
J
–T
A
) is the temperature difference the SS8014
A
)/
SHDN
SHDN
IN
IN
Feedback Resistors
SS8014
pin is connected to a logic-low voltage,
JA
o
C, the output is turned on again. In
GND
GND
,=150
OUT
OUT
ADJ
ADJ
o
C-25
JA
, is the thermal resistance
R1
R1
R2
R2
o
C/220
OUT
470pF
470pF
(V
o
www.SiliconStandard.com
C/W= 568mW
C
C
1µF
1µF
IN
OUT
OUT
– V
R
R
OUTPUT
OUTPUT
VOLTAGE
VOLTAGE
L
L
OUT
o
C, the
). The
of the chosen package to the ambient air. In the case
of a SOT23-5 package, the thermal resistance is typi-
cally 220
The die attachment area of the SS8014’s lead frame is
connected to pin 2, which is the GND pin. Therefore,
the GND pin of SS8014 can carry away the heat of the
SS8014 die very effectively. To improve the power dissi-
pation, connect the GND pin to ground using a large
ground plane near the GND pin.
Capacitor Selection and Regulator Stability
Normally, use a 1µF capacitor on the input and a 1µF
capacitor on the output of the SS8014. Larger input ca-
pacitor values and lower ESR provide better sup-
ply-noise rejection and transient response. A higher-
value input capacitor (10µF) may be necessary if large,
fast transients are anticipated and the device is located
several inches from the power source.
Power-Supply Rejection and Operation from
Sources Other than Batteries
The SS8014 is designed to deliver low dropout voltages
and low quiescent currents in battery powered sys-
tems. Power-supply rejection is 42dB at low frequen-
cies.
When operating from sources other than batteries, im-
prove supply-noise rejection and transient response by
increasing the values of the input and output capacitors,
and using passive filtering techniques.
Load Transient Considerations
The SS8014 load-transient response graphs show two
components of the output response: a DC shift of the
output voltage due to the different load currents, and
the transient response. Typical overshoot for step
changes in the load current from 0mA to 100mA is
12mV. Increasing the output capacitor's value and d e-
creasing its ESR attenuates transient spikes.
Input-Output (Dropout) Voltage
A regulator's minimum input-output voltage differential
(or dropout voltage) determines the lowest usable sup-
ply voltage. In battery-powered systems, this will d e-
termine the useful end-of-life battery voltage. Because
the SS8014 use a P-channel MOSFET pass transistor,
the dropout voltage is a function of R
by the load current.
o
C/Watt.
DS(ON)
SS8014G
multiplied
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