MIC5256
Micrel
June 2003
1
MIC5256
General Description
The MIC5256 is an efficient, precise CMOS voltage regula-
tor. It offers better than 1% initial accuracy, extremely low-
dropout voltage (typically 135mV at 150mA) and low ground
current (typically 90
A) over load. The MIC5256 features an
error flag that indicates an output fault condition such as
overcurrent, thermal shutdown and dropout.
Designed specifically for handheld and battery-powered de-
vices, the MIC5256 provides a TTL-logic-compatible enable
pin. When disabled, power consumption drops nearly to zero.
The MIC5256 also works with low-ESR ceramic capacitors,
reducing the amount of board space necessary for power
applications, critical in hand-held wireless devices.
Key features include current limit, thermal shutdown, faster
transient response, and an active clamp to speed up device
turnoff. Available in the IttyBittyTM SOT-23-5 package and the
new Thin SOT-23-5, which offers the same footprint as the
standard IttyBittyTM SOT-23-5, but only 1mm tall. The MIC5256
offers a range of output voltages.
Typical Application
1
5
2
3
4
Enable
Shutdown
EN
MIC5256-x.xBM5
EN (pin 3) may be
connected directly
to IN (pin 1).
FLG
V
IN
V
OUT
C
OUT
= 1.0
F
Ceramic
C
IN
= 1.0
F
Ceramic
Low-Noise Regulator Application
MIC5256
150mA
Cap LDO with Error Flag
Final Information
Features
Input voltage range: 2.7V to 6.0V
Thin SOT package: 1mm height
Error flag indicates fault condition
Stable with ceramic output capacitor
Ultralow dropout: 135mV @ 150mA
High output accuracy:
1.0% initial accuracy
2.0% over temperature
Low quiescent current: 90
A
Tight load and line regulation
Thermal shutdown and current limit protection
"Zero" off-mode current
TTL logic-controlled enable input
Applications
Cellular phones and pagers
Cellular accesories
Battery-powered equipment
Laptop, notebook, and palmtop computers
Consumer/personal electronics
Ordering Information
Part Number
Marking
Voltage
Junction Temp. Range
Package
MIC5256-2.6BM5
LX26
2.6V
40
C to +125
C
SOT-23-5
MIC5256-2.7BM5
LX27
2.7V
40
C to +125
C
SOT-23-5
MIC5256-2.8BM5
LX28
2.8V
40
C to +125
C
SOT-23-5
MIC5256-2.85BM5
LX2J
2.85V
40
C to +125
C
SOT-23-5
MIC5256-3.0BM5
LX30
3.0V
40
C to +125
C
SOT-23-5
MIC5256-3.3BM5
LX33
3.3V
40
C to +125
C
SOT-23-5
MIC5256-2.85BD5
NX2J
2.85V
40
C to +125
C
TSOT-23-5
Other voltages available. Contact Micrel for details.
Micrel, Inc. 1849 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 http://www.micrel.com
IttyBitty is a trademark of Micrel, Inc.
MIC5256
Micrel
MIC5256
2
June 2003
Pin Configuration
IN
OUT
FLG
EN
LXxx
1
3
4
5
2
GND
MIC5256-x.xBM5
(SOT-23-5)
Pin Description
Pin Number
Pin Name
Pin Function
1
IN
Supply Input.
2
GND
Ground.
3
EN
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
4
FLG
Error Flag (Output): Open-drain output. Active low indicates an output
undervoltage condition.
5
OUT
Regulator Output.
IN
OUT
BYP
EN
NWxx
1
3
4
5
2
GND
MIC5256-x.xBD5
(TSOT-23-5)
MIC5256
Micrel
June 2003
3
MIC5256
Electrical Characteristics
V
IN
= V
OUT
+ 1V, V
EN
= V
IN;
I
OUT
= 100
A; T
J
= 25
C, bold values indicate 40
C
T
J
+125
C; unless noted.
Symbol
Parameter
Conditions
Min
Typical
Max
Units
V
O
Output Voltage Accuracy
I
OUT
= 100
A
1
+1
%
2
+2
%
V
LNR
Line Regulation
V
IN
= V
OUT
+ 1V to 6V
0.02
0.05
%/V
V
LDR
Load Regulation
I
OUT
= 0.1mA to 150mA, Note 5
1.5
2.5
%
V
IN
V
OUT
Dropout Voltage, Note 6
I
OUT
= 100
A
0.1
5.0
mV
I
OUT
= 100mA
90
150
mV
I
OUT
= 150mA
135
200
mV
250
mV
I
Q
Quiescent Current
V
EN
0.4V (shutdown)
0.2
1
A
I
GND
Ground Pin Current, Note 7
I
OUT
= 0mA
90
150
A
I
OUT
= 150mA
117
A
PSRR
Power Supply Rejection
f = 10Hz, V
IN
= V
OUT
+ 1V; C
OUT
= 1
F
60
dB
f = 100Hz, V
IN
= V
OUT
+ 0.5V; C
OUT
= 1
F
60
dB
f = 10kHz, V
IN
= V
OUT
+ 0.5V
45
dB
I
LIM
Current Limit
V
OUT
= 0V
160
425
mA
e
n
Output Voltage Noise
tbd
V(rms)
Enable Input
V
IL
Enable Input Logic-Low Voltage
V
IN
= 2.7V to 5.5V, regulator shutdown
0.4
V
V
IH
Enable Input Logic-High Voltage
V
IN
= 2.7V to 5.5V, regulator enabled
1.6
V
I
EN
Enable Input Current
V
IL
0.4V, regulator shutdown
0.01
A
V
IH
1.6V, regulator enabled
0.01
A
Shutdown Resistance Discharge
500
Error Flag
V
FLG
Low Threshold
% of V
OUT
(Flag ON)
90
%
High Threshold
% of V
OUT
(Flag OFF)
96
%
V
OL
Output Logic-Low Voltage
I
L
= 100
A, fault condition
0.02
0.1
V
I
FL
Flag Leakage Current
flag off, V
FLG
= 6V
0.01
A
Thermal Protection
Thermal Shutdown Temperature
150
C
Thermal Shutdown Hysteresis
10
C
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
The maximum allowable power dissipation of any T
A
(ambient temperature) is P
D(max)
= T
J(max)
T
A
/
JA
. Exceeding the maximum allowable
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage (V
IN
) .................................. 0V to +7V
Enable Input Voltage (V
EN
) ................................. 0V to +7V
Power Dissipation (P
D
) ............... Internally Limited, Note 3
Junction Temperature (T
J
) ....................... 40
C to +125
C
Storage Temperature ............................... 65
C to +150
C
Lead Temperature (soldering, 5 sec.) ....................... 260
C
ESD, Note 4 .................................................................. 2kV
Operating Ratings
(Note 2)
Input Voltage (V
IN
) ......................................... +2.7V to +6V
Enable Input Voltage (V
EN
) .................................. 0V to V
IN
Junction Temperature (T
J
) ....................... 40
C to +125
C
Thermal Resistance
SOT-23
(
JA
) ..................................................... 235
C/W
MIC5256
Micrel
MIC5256
4
June 2003
power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The
JA
of the MIC5255-x.xBM5 (all
versions) is 235
C/W on a PC board (see "Thermal Considerations" section for further details).
Note 4.
Devices are ESD sensitive. Handling precautions recommended.
Note 5.
Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load
range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
Note 6.
Dropout Voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
differential. For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum
input operating voltage is 2.7V.
Note 7.
Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground
pin current.
MIC5256
Micrel
June 2003
5
MIC5256
Typical Characteristics
0
10
20
30
40
50
60
70
10
100
1000
10000
100000
1000000
PSRR (dB)
FREQUENCY (Hz)
100
A*
50mA*
100mA*
150mA*
Power Supply Rejection Ratio
*I
LOAD
C
OUT
= 1.0
F Ceramic
0
10
20
30
40
50
60
70
10
100
1000
10000
100000
1000000
PSRR (dB)
FREQUENCY (Hz)
100
A*
50mA*
100mA*
150mA*
Power Supply Rejection Ratio
*I
LOAD
C
OUT
= 4.7
F Ceramic
0
10
20
30
40
50
60
70
0
200
400
600
800
1000
PSRR (dB)
VOLTAGE DROP (mV)
PSRR vs. Voltage Drop
I
LOAD
= 150mA
I
LOAD
= 100
A
C
OUT
= 1
F
100
105
110
115
120
125
130
0.1
1
10
100
1000
GROUND CURRENT (
A)
OUTPUT CURRENT (mA)
Ground Pin Current
V
IN
= V
OUT
+ 1V
95
97
99
101
103
105
107
109
111
113
115
-40 -20 0 20 40 60 80 100120140
GROUND CURRENT (
A)
TEMPERATURE (
C)
Ground Pin Current
I
LOAD
= 100
A
95
100
105
110
115
120
125
-40 -20 0 20 40 60 80 100120140
GROUND CURRENT (
A)
TEMPERATURE (
C)
Ground Pin Current
I
LOAD
= 150mA
0
20
40
60
80
100
120
140
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
GROUND CURRENT (
A)
INPUT VOLTAGE (V)
Ground Pin Current
I
LOAD
= 100
A
0
20
40
60
80
100
120
140
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
GROUND CURRENT (
A)
INPUT VOLTAGE (V)
Ground Pin Current
I
LOAD
= 150mA
0
0.5
1
1.5
2
2.5
3
3.5
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Dropout Characteristics
I
LOAD
= 150mA
I
LOAD
= 100
A
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
-40 -20 0 20 40 60 80 100120140
DROPOUT VOLTAGE (mV)
TEMPERATURE (
C)
Dropout Voltage
I
LOAD
= 100
A
0
20
40
60
80
100
120
140
160
180
-40 -20 0 20 40 60 80 100120140
DROPOUT VOLTAGE (mV)
TEMPERATURE (
C)
Dropout Voltage
I
LOAD
= 150mA
0
20
40
60
80
100
120
140
160
180
0
20 40 60 80 100 120 140 160
DROPOUT VOLTAGE (mV)
OUTPUT CURRENT (mA)
Dropout Voltage
T = 40C
T = 25C
T = 125C
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