MIC2920A/29201/29202/29204
Micrel
MIC2920A/29201/29202/29204
400mA Low-Dropout Voltage Regulator
General Description
Features
The MIC2920A family are “bulletproof,” efficient voltage
regulators with very low dropout voltage (typically 40mV at
light loads and 370mV at 250mA), and very low quiescent
current (140µA typical). The quiescent current of the MIC2920A
increases only slightly in dropout, prolonging battery life. Key
MIC2920A features include protection against reversed battery,
fold-back current limiting, and automotive “load dump”
protection (60V positive transient).
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•
•
•
•
The MIC2920 is available in several configurations. The
MIC2920A-x.x devices are three pin fixed voltage regulators
available in 3.3V, 4.85V, 5V, and 12V outputs. The MIC29201
is a fixed regulator offering a logic compatible ON/OFF
(shutdown) input and an error flag output. This flag may also
be used as a power-on reset signal. A logic-compatible
shutdown input is provided on the adjustable MIC29202
which allows the regulator to be switched on and off. The
MIC29204 8-pin SOIC adjustable regulator includes both
shutdown and error flag pins and may be pin-strapped for 5V
output or programmed from 1.24V to 26V using two external
resistors.
•
•
•
•
High output voltage accuracy
Guaranteed 400mA output
Low quiescent current
Low dropout voltage
Extremely tight load and line regulation
Very low temperature coefficient
Current and thermal limiting
Input withstands –20V reverse battery and
60V positive transients
Error flag warns of output dropout
Logic-controlled electronic shutdown
Output programmable from 1.24V to 26V
(MIC29202/MIC29204)
Available in TO-220, TO-220-5, and surface-mount
TO-263-5, SOT-223, and SO-8 packages.
Applications
•
•
•
•
•
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Battery-powered equipment
Cellular telephones
Laptop, notebook, and palmtop computers
PCMCIA VCC and VPP regulation/switching
Bar code scanners
Automotive electronics
SMPS post-regulators
Voltage reference
High-efficiency linear power supplies
Pin Configuration
TAB
OUTPUT 1
8
INPUT
SENSE 2
7
NC
SHUTDOWN 3
6
NC
GROUND 4
5
ERROR
MIC29201-3.3BM (SO-8)
OUTPUT 1
8
INPUT
SENSE 2
7
ADJUST
SHUTDOWN 3
6
5V TAP
GROUND 4
5
ERROR
1
2
3
INPUT
OUTPUT
GROUND
MIC2920A-x.xBS
(SOT-223)
MIC29204BM (SO-8)
5-Lead Package Pinouts
MIC29201 MIC29202
1) Error
Adjust
2) Input
Shutdown
3) Ground
Ground
4) Output
Input
5) Shutdown
Output
1
2
3
1 2 3 4 5
INPUT OUTPUT
GROUND
1 2 3 4 5
MIC29201/29202BU
(TO-263-5)
MIC2920A-xxBT
(TO-220)
MIC29201/29202BT
(TO-220-5)
Tab is Ground on SOT-223, TO-220, and TO-263 packages.
January 1998
3-9
3
MIC2920A/29201/29202/29204
Micrel
Absolute Maximum Ratings
Ordering Information
Part Number
Voltage
Temperature Range*
Package
MIC2920A-3.3BS
3.3V
–40°C to +125°C
SOT-223
MIC2920A-3.3BT
3.3V
–40°C to +125°C
TO-220
MIC2920A-4.8BS
4.85V
–40°C to +125°C
SOT-223
MIC2920A-4.8BT
4.85V
–40°C to +125°C
TO-220
MIC2920A-5.0BS
5.0V
–40°C to +125°C
SOT-223
MIC2920A-5.0BT
5.0V
–40°C to +125°C
TO-220
MIC2920A-12BS
12V
–40°C to +125°C
SOT-223
MIC2920A-12BT
12V
–40°C to +125°C
TO-220
MIC29201-3.3BM
3.3V
–40°C to +125°C
SO-8
MIC29201-3.3BT
3.3V
–40°C to +125°C
TO-220-5
MIC29201-3.3BU
3.3V
–40°C to +125°C
TO-263-5
MIC29201-4.8BT
4.85V
–40°C to +125°C
TO-220-5
MIC29201-4.8BU
4.85V
–40°C to +125°C
TO-263-5
MIC29201-5.0BT
5.0V
–40°C to +125°C
TO-220-5
MIC29201-5.0BU
5.0V
–40°C to +125°C
TO-263-5
MIC29201-12BT
12V
–40°C to +125°C
TO-220-5
MIC29201-12BU
12V
–40°C to +125°C
TO-263-5
MIC29202BT
Adj
–40°C to +125°C
TO-220-5
MIC29202BU
Adj
–40°C to +125°C
TO-263-5
MIC29204BM
5V and Adj
–40°C to +125°C
SO-8
MIC29204BN
5V and Adj
–40°C to +125°C
8-pin PDIP
3-10
If Military/Aerospace specified devices
are required, contact your local Micrel
representative/distributor for availability
and specifications.
Power Dissipation ................ Internally Limited, Note 1
Lead Temperature (Soldering, 5 seconds) ........ 260°C
Storage Temperature Range ............ –65°C to +150°C
Operating Junction Temperature Range
................................................. –40°C to +125°C
Thermal Characteristics:
SOT−223 θJC .................................................... 15°C/W
TO-220 θJC ......................................................... 3°C/W
TO-263 θJC ......................................................... 3°C/W
8-Pin SOIC θJA ................................................... Note 1
Input Supply Voltage ............................... –20V to +60V
Operating Input Supply Voltage ................... 2V† to 26V
Adjust Input Voltage (Notes 9 and 10)
...................................................... –1.5V to +26V
Shutdown Input Voltage ......................... –0.3V to +30V
Error Comparator Output Voltage .......... –0.3V to +30V
†
Across the full operating temperature, the minimum
input voltage range for full output current is 4.3V to 26V.
Output will remain in-regulation at lower output voltages
and low current loads down to an input of 2V at 25°C.
* Junction temperatures
January 1998
MIC2920A/29201/29202/29204
Micrel
Electrical Characteristics
Limits in standard typeface are for TJ = 25°C and limits in boldface apply over the full operating temperature range. Unless
otherwise specified, VIN = VOUT + 1V, IL = 1mA, CL = 10µF. Adjustable version are set for an output of 5V. The MIC29202 VSHUTDOWN
≤ 0.7V. The eight pin MIC29204 is configured with the Adjust pin tied to the 5V Tap, the Output is tied to Output Sense (VOUT
= 5V), and VSHUTDOWN ≤ 0.7V.
Symbol
VO
Parameter
Output Voltage
Accuracy
Conditions
Variation from factory trimmed VOUT
1mA ≤ IL ≤ 400mA, across temp. range
MIC2920A-12 and 29201-12 only
∆VO
∆T
∆VO
VO
∆VO
VO
Output Voltage
Temperature Coef.
Line Regulation
1mA ≤ IL ≤ 400mA, across temp. range
(Note 2)
VOUT > 10V only
VIN = VOUT + 1V to 26V
Load Regulation
IL = 1 to 250mA (Note 3)
VIN – VO
Dropout Voltage
(Note 4)
IL = 1mA
20
80
0.03
0.04
Max
1
2
2.5
1.5
3
4
100
350
0.10
0.40
0.16
0.30
150
180
IL = 400mA
250
350
370
500
450
IL = 1mA
140
IL = 100mA
1.3
IL = 250mA
5
IL = 400mA
13
200
300
2
2.5
9
12
15
VOUT > 10V only
IL = 250mA
VOUT > 10V only
Ground Pin Current
(Note 5)
Typical
100
IL = 100mA
IGND
Min
–1
–2
–2.5
–1.5
–3
–4
Units
%
ppm/°C
%
%
3
mV
600
750
µA
mA
IGNDDO
Ground Pin
Current at Dropout
(Note 5)
VIN = 0.5V less than designed VOUT
(VOUT ≥ 3.3V)
IO = 1mA
180
400
µA
ILIMIT
Current Limit
VOUT = 0V
(Note 6)
425
1000
1200
mA
∆VO
∆PD
Thermal Regulation (Note 7)
0.05
0.2
%/W
en
Output Noise
Voltage
(10Hz to 100kHz)
IL = 100mA
CL = 10µF
400
CL = 100µF
260
January 1998
3-11
µV RMS
MIC2920A/29201/29202/29204
Micrel
Electrical Characteristics (Continued)
MIC29202, MIC29204
Parameter
Conditions
Min
Typ
Max
Units
1.235
1.247
1.260
V
1.266
V
1.260
1.270
V
1.285
V
40
60
nA
Reference Voltage
MIC29202
1.223
1.210
Reference Voltage
MIC29202 (Note 8)
1.204
Reference Voltage
MIC29204
1.210
1.200
Reference Voltage
MIC29204 (Note 8)
1.185
Adjust Pin
Bias Current
Reference Voltage
Temperature
Coefficient
1.235
20
(Note 7)
Adjust Pin Bias
Current Temperature
Coefficient
20
ppm/°C
0.1
nA/°C
Error Comparator
MIC29201, MIC29204
Output Leakage
Current
VOH = 26V
0.01
1.00
2.00
µA
Output Low
Voltage
VIN = 4.5V
IOL = 250µA
150
250
400
mV
Upper Threshold
Voltage
(Note 9)
Lower Threshold
Voltage
(Note 9)
75
Hysteresis
(Note 9)
15
Shutdown Input
MIC29201, MIC29202, MIC29204
40
25
Input Logic Voltage
Regulator Output
Current in Shutdown
mV
95
140
mV
mV
1.3
Low (ON)
High (OFF)
Shutdown Pin
Input Current
60
V
0.7
2.0
VSHUTDOWN = 2.4V
30
50
100
µA
VSHUTDOWN = 26V
450
600
750
µA
3
10
20
µA
(Note 10)
3-12
January 1998
MIC2920A/29201/29202/29204
Micrel
General Note: Devices are ESD protected; however, handling precautions are recommended.
Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not
apply when operating the device outside of its rated operating conditions. The maximum allowable power dissipation is a function of the
maximum junction temperature, TJ (MAX), the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. The maximum
allowable power dissipation at any ambient temperature is calculated using: P(MAX) = (TJ(MAX) – TA) / θJA. Exceeding the maximum allowable
power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The junction to ambient thermal
resistance of the MIC29204BM is 160°C/W mounted on a PC board.
Note 2: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 3: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Changes in output voltage due to
heating effects are covered by the thermal regulation specification.
Note 4: Dropout Voltage is defined as the input to output differential at which the output voltage drops 100mV below its nominal value
measured at 1V differential. At low values of programmed output voltage, the minimum input supply voltage of 4.3V over temperature must
be taken into account. The MIC2920A operates down to 2V of input at reduced output current at 25°C.
Note 5: 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.
Note 6: The MIC2920A features fold-back current limiting. The short circuit (VOUT = 0V) current limit is less than the maximum current with
normal output voltage.
Note 7: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding
load or line regulation effects. Specifications are for a 200mA load pulse at VIN = 20V (a 4W pulse) for T = 10ms.
Note 8: VREF ≤ VOUT ≤ (VIN – 1 V), 4.3V ≤ VIN ≤ 26V, 1 mA < IL ≤400 mA, TJ ≤ TJ MAX.
Note 9: Comparator thresholds are expressed in terms of a voltage differential at the Adjust terminal below the nominal reference voltage
measured at 6V input. To express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT /VREF =
(R1 + R2)/R2. For example, at a programmed output voltage of 5V, the Error output is guaranteed to go low when the output drops by 95
mV x 5V/1.235 V = 384 mV. Thresholds remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at typically
5% below nominal, 7.7% guaranteed.
Note 10: VSHUTDOWN ≥ 2V, VIN ≤ 26V,VOUT = 0, with Adjust pin tied to 5V Tap or to the R1, R2 junction (see Figure 3) with R1 ≥ 150kΩ.
Note 11: When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode
clamped to ground.
Note 12: Maximum positive supply voltage of 60V must be of limited duration (< 100ms) and duty cycle ( ≤ 1%). The maximum continuous
supply voltage is 26V.
Schematic Diagram
ADJUST
IN
R18
20kΩ
Q15A
Q15B
Q24
Q26
Q25
OUT
Q9
Q3
R11
18
kΩ
Q4
Q7
Q6
R11
20.6
kΩ
Q1
10
R2
50 kΩ
Q17
Q16
R27
R17
12 kΩ
Q14
V TAP
R28
Q2
Q20
R1
20 kΩ
Q42
SENSE
Q8
Q5
C1
20
pF
R5
180
kΩ
Q40
R6
140
kΩ
Q13
Q22
R10
150
kΩ
R8
31.4 kΩ
Q21
R9
27.8 kΩ
R12
110
kΩ
Q12
Q41
Q23
C2
40 pF
R13
100
kΩ
R15
100 kΩ
R14
350
kΩ
R16
30 kΩ
Q11
R17
10 Ω
Q29
R30
30
kΩ
Q18
Q19
Q28
R3
50 kΩ
R4
13 kΩ
R21 8 Ω
50 kΩ
Q30 Q31
Q37
10 kΩ
R22
150 kΩ
Q36
R23 60 kΩ
ERROR
Q38
Q34
R26
60 kΩ
DENOTES CONNECTION ON
MIC2920A-xx AND MIC29201-xx
VERSIONS ONLY
R25
2.8 kΩ
GND
Q39
January 1998
SHDN
R24
50 kΩ
3-13
3
MIC2920A/29201/29202/29204
Micrel
Typical Characteristics
Dropout Voltage
vs. Temperature
DROPOUT VOLTAGE (mV)
400
300
200
100
0
6
600
5
500
400
ILOAD = 400mA
300
200
100
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
100
200
300
400
OUTPUT CURRENT (mA)
Ground Current
vs. Output Current
1
150
100
VOUT = 5V
IOUT = 1mA
50
0
10
100
400
OUTPUT CURRENT (mA)
GROUND CURRENT (mA)
GROUND CURRENT (mA)
0.15
0.10
IOUT = 1mA
2
0
3.38
3.36
650
20
15
10
VOUT = 5V
IOUT = 400mA
5
0
2
4
6
8
INPUT VOLTAGE (V)
10
Ground Current
vs. Temperature
ILOAD = 100mA
VOUT = VNOMINAL – 0.5V
VOUT = 3.3V
550
3 SAMPLES
(HI/AVG/LO)
450
400
350
6
25
600
500
1
2
3
4
5
INPUT VOLTAGE (V)
25
0
8
VOUT = 0V
300
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3-14
20
ILOAD = 400mA
15
10
5
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
Short Circuit and Maximum
Current vs. Temperature
700
CURRENT (mA)
OUTPUT VOLTAGE (V)
Fixed 3.3V Output Voltage
vs. Temperature
3.22
3.20
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
2 3 4 5 6 7
SUPPLY VOLTAGE (V)
1
3.40
3.26
3.24
1
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
0.00
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3.30
3.28
0
3
0.20
3.34
3.32
ILOAD = 400mA
1
Ground Current
vs. Temperature
Ground Current
vs. Temperature
0.05
2
30
GROUND CURRENT (mA)
GROUND CURRENT (µA)
GROUND CURRENT (mA)
0.1
3
Ground Current
vs. Supply Voltage
200
1
ILOAD = 1mA
Ground Current
vs. Supply Voltage
20
10
4
0
GROUND CURRENT (mA)
0
Dropout
Characteristics
700
Ground Current
vs. Supply Voltage
GROUND CURRENT (µA)
DROPOUT VOLTAGE (mV)
500
OUTPUT VOLTAGE (V)
Dropout Voltage
vs. Output Current
1000
900 R
LOAD = 100Ω
800
700
600
500
400
300
200
100
0
-100
-30 -20 -10 0
10 20
INPUT VOLTAGE (V)
30
January 1998
MIC2920A/29201/29202/29204
Micrel
MIC29201/2 Shutdown Current
vs. Temperaure
50
VEN = 2V
25
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
COUT = 10µF
100
0
-100
600
-200
400
1mA
200
0
-200
-5
0
5
10 15
TIME (ms)
MIC29202 Adjust Pin
Current vs. Temperature
30
20
10
ILOAD = 1mA
25
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
40
COUT = 10 µF
IL = 10mA
20
0
-20
10
-40
8
6
4
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
TIME (ms)
1
0.1
1x106
100x103
10x103
10
1x103
1x100
1
100x100
ILOAD = 10mA
10x100
OUTPUT IMPEDANCE (Ω)
10
0.01
100 1k 10k 100k 1M
FREQUENCY (Hz)
Ripple Rejection
0
CL = 10µF
REJECTION (dB)
-20
IL = 100mA
-40
1mA
-60
-80
-100
1E+1
10 1E+2
1k 1E+4
10k 1E+5
100k 1E+6
1M
100 1E+3
FREQUENCY (Hz)
3-15
COUT = 100µF
0
-50
600
-100
400
1mA
200
0
-200
-5
0
5
10 15
TIME (ms)
20
25
Line Transient
Output Impedance
vs. Frequency
January 1998
50
INPUT (V)
∆ OUTPUT (mV)
40
20
100
Line Transient
INPUT (V)
ADJUST PIN CURRENT (nA)
50
OUTPUT (mA) ∆ OUTPUT (mV)
VEN = 5V
75
Load Transient
200
∆ OUTPUT (mV)
100
Load Transient
OUTPUT (mA) ∆ OUTPUT (mV)
ENABLE CURRENT (µA)
125
20
10
COUT = 100 µF
IL = 10mA
0
-10
10
-20
8
6
4
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
TIME (ms)
3
MIC2920A/29201/29202/29204
Micrel
Applications Information
External Capacitors
A 10µF (or greater) capacitor is required between the
MIC2920A output and ground to prevent oscillations due to
instability. Most types of tantalum or aluminum electrolytics
will be adequate; film types will work, but are costly and
therefore not recommended. Many aluminum electrolytics
have electrolytes that freeze at about –30°C, so solid tantalums
are recommended for operation below –25°C. The important
parameters of the capacitor are an effective series resistance
of about 5Ω or less and a resonant frequency above 500kHz.
The value of this capacitor may be increased without limit.
At lower values of output current, less output capacitance is
required for output stability. The capacitor can be reduced to
2.2µF for current below 10mA or 1µF for currents below
1mA. Adjusting the MIC29202/29204 to voltages below 5V
runs the error amplifier at lower gains so that more output
capacitance is needed. For the worst-case situation of a
500mA load at 1.23V output (Output shorted to Adjust) a 47µF
(or greater) capacitor should be used.
The MIC2920A/29201 will remain in regulation with a minimum
load of 1mA. When setting the output voltage of the MIC29202/
29204 versions with external resistors, the current through
these resistors may be included as a portion of the minimum
load.
A 0.1µF capacitor should be placed from the MIC2920A input
to ground if there is more than 10 inches of wire between the
input and the AC filter capacitor or if a battery is used as the
input.
system requirements, this resistor may be returned to the 5V
output or some other supply voltage. In determining a value
for this resistor, note that while the output is rated to sink
250µA, this sink current adds to battery drain in a low battery
condition. Suggested values range from 100k to 1MΩ. The
resistor is not required if this output is unused.
Programming the Output Voltage (MIC29202/29204)
The MIC29202/29204 may be programmed for any output
voltage between its 1.235V reference and its 26V maximum
rating, using an external pair of resistors, as shown in
Figure 3.
The complete equation for the output voltage is
VOUT = VREF × { 1 + R1/R2 } – |IFB| R1
where VREF is the nominal 1.235 reference voltage and IFB is
the Adjust pin bias current, nominally 20nA. The minimum
recommended load current of 1µA forces an upper limit of
1.2MΩ on the value of R2, if the regulator must work with no
load (a condition often found in CMOS in standby), IFB will
produce a –2% typical error in VOUT which may be eliminated
at room temperature by trimming R1. For better accuracy,
choosing R2 = 100k reduces this error to 0.17% while
increasing the resistor program current to 12µA. Since the
MIC29202/29204 typically draws 110µA at no load with
SHUTDOWN open-circuited, this is a negligible addition. The
MIC29204 may be pin-strapped for 5V using the internal
voltage divider by tying Pin 1 (output) to Pin 2 (sense) and Pin
7 (Adjust) to Pin 6 (V Tap).
Configuring the MIC29201-3.3BM
For the MIC29201-3.3BM, the output (Pin 1) and sense pin
(pin 2), must be connected to ensure proper operation. They
are not connected internally.
Error Detection Comparator Output
(MIC29201/MIC29204)
A logic low output will be produced by the comparator whenever
the MIC29201/29204 output falls out of regulation by more
than approximately 5%. This figure is the comparator’s builtin offset of about 75mV divided by the 1.235V reference
voltage. (Refer to the block diagram on Page 1). This trip level
remains “5% below normal” regardless of the programmed
output voltage of the MIC29201/29204. For example, the
error flag trip level is typically 4.75V for a 5V output or 11.4V
for a 12V output. The out of regulation condition may be due
either to low input voltage, extremely high input voltage,
current limiting, or thermal limiting.
Figure 1 is a timing diagram depicting the ERROR signal and
the regulated output voltage as the MIC29201/29204 input is
ramped up and down. The ERROR signal becomes valid (low)
at about 1.3V input. It goes high at about 5V input (the input
voltage at which VOUT = 4.75). Since the MIC29201/29204’s
dropout voltage is load-dependent (see curve in Typical
Performance Characteristics), the input voltage trip point
(about 5V) will vary with the load current. The output voltage
trip point (approximately 4.75V) does not vary with load.
Reducing Output Noise
In reference applications it may be advantageous to reduce
the AC noise present at the output. One method is to reduce
the regulator bandwidth by increasing the size of the output
4.75V
OUTPUT
VOLTAGE
ERROR
NOT
VALID
*
NOT
VALID
INPUT
VOLTAGE
*
5V
1.3V
* SEE APPLICATIONS INFORMATION
Figure 1. ERROR Output Timing
The error comparator has an NPN open-collector output
which requires an external pull-up resistor. Depending on
3-16
January 1998
MIC2920A/29201/29202/29204
Micrel
capacitor. This is relatively inefficient, as increasing the
capacitor from 1µF to 220µF only decreases the noise from
430µV to 160µVRMS for a 100kHz bandwidth at 5V output.
Noise can be reduced fourfold by a bypass capacitor across
R1, since it reduces the high frequency gain from 4 to unity.
Pick
1
CBYPASS ≅
2 π R1 • 200 Hz
or about 0.01µF. When doing this, the output capacitor must
be increased to 10µF to maintain stability. These changes
reduce the output noise from 430µV to 100µV rms for a
100kHz bandwidth at 5V output. With the bypass capacitor
added, noise no longer scales with output voltage so that
improvements are more dramatic at higher output voltages.
Automotive Applications
The MIC2920A is ideally suited for automotive applications for
a variety of reasons. It will operate over a wide range of input
voltages with very low dropout voltages (40mV at light loads),
and very low quiescent currents (100µA typical). These features
are necessary for use in battery powered systems, such as
automobiles. It is a “bulletproof” device with the ability to
survive both reverse battery (negative transients up to 20V
below ground), and load dump (positive transients up to 60V)
conditions. A wide operating temperature range with low
temperature coefficients is yet another reason to use these
versatile regulators in automotive designs.
Typical Applications
+VIN
V IN
100kΩ
+VIN
*V OUT ≈5V
VOUT
+
5 ERROR
ERROR
OUTPUT
VOUT = 5V
8
VIN
VOUT
1
SHUTDOWN 3
SHUTDOWN
INPUT
10µF
870 25
10µF
OFF
GND
GND ADJUST
7
4
1.23V
ON
VOUT = VREF x (1 +
R1
)
R2
VOUT
1.2 26V
V REF
R1 100
pF
R2
NOTE: PINS 2 AND 6 ARE LEFT OPEN
Figure 2. MIC2920A-5.0 Fixed +5V Regulator
Figure 3. MIC29202/29204 Adjustable Regulator. Pinout is for
MIC29204.
≥ 5.3V
+VIN
8
+VIN
8
+VIN
ERROR
OUTPUT
5 ERROR
SHUTDOWN
INPUT
*VOUT ≈VIN
VOUT 1
3
HIGH = OFF
VCC OUT
VOUT 1
SHUTDOWN
+
MIC2951
SHUTDOWN
INPUT
3
OFF
ON
GND
4
SD
GND
4
ADJUST
7
ADJUST
FB
HIGH = 5V OUT
7
LOW = 3.3V OUT
*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV TO 400mV,
DEPENDING ON LOAD CURRENT.
470 kΩ
220kΩ
1%
300kΩ
1%
10µF
180kΩ
1%
2N2222
PIN 3 LOW= ENABLE OUTPUT. Q1 ON = 3.3V, Q1 OFF = 5.0V.
Figure 4. MIC29204 Wide Input Voltage Range Current Limiter
January 1998
100pF
LOW = ON
Figure 5. MIC29202/29204 5.0V or 3.3V Selectable Regulator
with Shutdown. Pinout is for MIC29204.
3-17
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