MIC5231
Micropower µCap LDO Regulator
General Description
The MIC5231 µCap low dropout voltage regulator is
intended for low output current biasing applications. It
features extremely low ground current, not greater than
4µA under all load and temperature conditions, making it
efficient and ideal for keep-alive applications in devices
such as notebook computers.
The MIC5231 offers better than 2% initial accuracy and
low dropout (typically 150mV at 10mA output current). An
output capacitor is not required for stable operation,
decreasing cost and board space. Tiny ceramic chip
capacitors may be used to improve transient response.
The MIC5231 also features a control pin which allows the
regulator to be shut down when not required. Its shutdown-
state draws zero current, benefiting battery-powered appli-
cations.
The MIC5231 is available in fixed output voltages of 2.75V,
3.0V, 3.3V and 5V in the small SOT-23-5 IttyBitty
®
package. Contact Micrel for other voltage options.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
Extremely low quiescent current—only
0.65µA
No output capacitor requirement
Stable with ceramic or tantalum capacitors
IttyBitty
®
SOT-23-5 surface-mount package
10mA output drive
Low 150mV at 10mA dropout voltage
Tight load and line regulation
Low temperature coefficient
Logic-level enable input
Applications
•
•
•
•
•
•
•
Real-time clocks
SRAM backup
Cellular telephones
Laptop, notebook and palmtop computers
Battery-powered equipment
Bar code scanners
SMPS post-regulator and DC-to-DC modules
_________________________________________________________________________________________________________
Typical Application
V
IN
6V
MIC5231-5.0YM5
IN
OUT
V
OU T
5V
EN
GND
5V Linear Regulator Application
IttyBitty is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
November 2008
M9999-110408-B
Micrel, Inc.
MIC5231
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ...................................... –0.6V to +14V
Lead Temperature (soldering, 5sec.)......................... 260°C
Storage Temperature (T
s
) .........................–60°C to +150°C
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)........................................ 3.5VV to 12V
Ambient Temperature (T
A
) .......................... –40°C to +85°C
Junction Temperature (T
J
) ........................ –40°C to +125°C
Thermal Resistance
(4)
Electrical Characteristics
V
IN
= V
OUT
+ 1V; I
L
= 100µA; C
L
= 0.47µF; T
J
= 25°C,
bold
values indicate –40°C≤ T
J
≤
+125°C, unless noted.
Symbol
V
OUT
∆V
OUT
/∆
T
∆V
OUT
/V
OUT
V
DO
I
Q
PSRR
Enable Input
V
ENL
I
ENL
I
ENH
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. The maximum allowable power dissipation at any T
A
(ambient temperature) is P
D(max)
= (T
J(max)
– T
A
) ÷
θ
JA
. The
θ
JC
of the MIC5231 is 130°C/W.
Mounted to a standard PC board, the
θ
JA
is approximately 235°C/W.
5. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
6. Regulation is measured at constant junction temperature using low duty cycle pulse testing.
7. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1Vdifferential.
For outputs below 3.5V, dropout voltage is the input-to-output differential with the minimum input voltage 3.5V. Minimum input operating voltage is
3.5V.
Parameter
Output Voltage Accuracy
Output Voltage
Temperature Coefficient
Line Regulation
Load Regulation
Dropout Voltage,
Note 7
Ground Pin Current
Ripple Rejection
Enable Input Voltage
Enable Input Current
Enable Input Current
Condition
variation from nominal V
OUT
Note 5
V
IN
= 6V to 12V
I
L
= 10µA to 10mA,
Note 6
I
L
= 1mA
I
L
= 10mA
V
IN
= 6V, I
L
= 10mA
V
IN
= 12V, I
L
= 10mA
f = 100Hz, I
L
= 100µA
V
EN
= logic low (regulator off)
V
EN
= logic high (regulator on)
V
ENL
≤
0.18V (regulator off)
V
ENH
≥
1.4V (regulator on)
Min
–2
–3
Typ
Max
+2
+3
Units
%
%
ppm/°C
250
0.2
0.2
15
150
0.65
1.1
50
0.4
1.4
1
1
0.18
300
3
4
0.25
1
%
%
mV
mV
µA
µA
dB
V
V
nA
nA
November 2008
3
M9999-110408-B
单片机
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