Datasheet MIC2920A-4.8BS, MIC2920A-4.8BT, MIC2920A-5.0BS, MIC2920A-3.3BT, MIC2920A-12BT Datasheet (MICREL)

MIC2920A/29201/29202/29204 Micrel

January 1998 3-9

3

12 3

MIC2920A/29201/29202/29204

400mA Low-Dropout Voltage Regulator

Features

• 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

• Battery-powered equipment

• Cellular telephones

• Laptop, notebook, and palmtop computers

• PCMCIA VCC and V

PP

regulation/switching

• Bar code scanners

• Automotive electronics

• SMPS post-regulators

• Voltage reference

• High-efficiency linear power supplies

General Description

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).

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.

MIC2920A-xxBT

(TO-220)

MIC29201/29202BT

(TO-220-5)

12345

MIC29201/29202BU

(TO-263-5)

5-Lead Package Pinouts

MIC29201 MIC29202

1) Error Adjust

2) Input Shutdown

3) Ground Ground

4) Output Input

5) Shutdown Output

Tab is Ground on SOT-223, TO-220, and TO-263 packages.

132

TAB

INPUT OUTPUT

GROUND

MIC2920A-x.xBS

(SOT-223)

Pin Configuration

12345

INPUT OUTPUT

GROUND

1
2
3
4

8
7
6
5

INPUT
NC
NC
ERROR

OUTPUT

SENSE

SHUTDOWN

GROUND

MIC29201-3.3BM (SO-8)

1
2
3
4

8
7
6
5

INPUT
ADJUST
5V TAP
ERROR

OUTPUT

SENSE

SHUTDOWN

GROUND

MIC29204BM (SO-8)

MIC2920A/29201/29202/29204 Micrel

3-10 January 1998

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

Absolute Maximum Ratings

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

MIC2920A/29201/29202/29204 Micrel

January 1998 3-11

3

Limits in standard typeface are for TJ = 25°C and limits in boldface apply over the full operating temperature range. Unless
otherwise specified, VIN = V

OUT

+ 1V, IL = 1mA, CL = 10µF. Adjustable version are set for an output of 5V. The MIC29202 V

SHUTDOWN

≤ 0.7V. The eight pin MIC29204 is configured with the Adjust pin tied to the 5V Tap, the Output is tied to Output Sense (V

OUT

= 5V), and V

SHUTDOWN

≤ 0.7V.

Symbol Parameter Conditions Min Typical Max Units

V

O

Output Voltage Variation from factory trimmed V

OUT

–1 1 %

Accuracy –2 2

1mA ≤ IL ≤ 400mA, across temp. range –2.5 2.5
MIC2920A-12 and 29201-12 only –1.5 1.5

–3 3

1mA ≤ IL ≤ 400mA, across temp. range –4 4

∆V

O

Output Voltage (Note 2) 20 100 ppm/°C

∆T Temperature Coef. V

OUT

> 10V only 80 350

∆V

O

Line Regulation VIN = V

OUT

+ 1V to 26V 0.03 0.10 %

V

O

0.40

∆V

O

Load Regulation IL = 1 to 250mA (Note 3) 0.04 0.16 %

V

O

0.30

VIN – V

O

Dropout Voltage IL = 1mA 100 150 mV
(Note 4) 180

IL = 100mA 250

V

OUT

> 10V only 350

IL = 250mA 370

V

OUT

> 10V only 500

IL = 400mA 450 600

750

I

GND

Ground Pin Current IL = 1mA 140 200 µA
(Note 5) 300

IL = 100mA 1.3 2 mA

2.5

IL = 250mA 5 9

12

IL = 400mA 13 15

I

GNDDO

Ground Pin VIN = 0.5V less than designed V

OUT

180 400 µA

Current at Dropout (V

OUT

≥ 3.3V)

(Note 5) IO = 1mA

I

LIMIT

Current Limit V

OUT

= 0V 425 1000 mA

(Note 6) 1200

∆V

O

Thermal Regulation (Note 7) 0.05 0.2 %/W

∆P

D

e

n

Output Noise CL = 10µF 400 µV RMS
Voltage
(10Hz to 100kHz) CL = 100µF 260
IL = 100mA

Electrical Characteristics

MIC2920A/29201/29202/29204 Micrel

3-12 January 1998

Parameter Conditions Min Typ Max Units

Reference Voltage MIC29202 1.223 1.235 1.247 V

1.210 1.260

Reference Voltage MIC29202 (Note 8) 1.204 1.266 V
Reference Voltage MIC29204 1.210 1.235 1.260 V

1.200 1.270

Reference Voltage MIC29204 (Note 8) 1.185 1.285 V
Adjust Pin 20 40 nA

Bias Current 60
Reference Voltage (Note 7) 20 ppm/°C

Temperature
Coefficient

Adjust Pin Bias 0.1 nA/°C
Current Temperature
Coefficient

Error Comparator MIC29201, MIC29204

Output Leakage V

OH

= 26V 0.01 1.00 µA

Current 2.00
Output Low V

IN

= 4.5V 150 250 mV

Voltage I

OL

= 250µA 400

Upper Threshold (Note 9) 40 60 mV
Voltage 25

Lower Threshold (Note 9) 75 95 mV
Voltage 140

Hysteresis (Note 9) 15 mV

Shutdown Input MIC29201, MIC29202, MIC29204

Input Logic Voltage 1.3 V

Low (ON) 0.7
High (OFF) 2.0

Shutdown Pin V

SHUTDOWN

= 2.4V 30 50 µA

Input Current 100

V

SHUTDOWN

= 26V 450 600 µA

750

Regulator Output (Note 10) 310µA
Current in Shutdown 20

Electrical Characteristics (Continued)

MIC29202, MIC29204

MIC2920A/29201/29202/29204 Micrel

January 1998 3-13

3

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, T

J (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)

= (T

J(MAX)

– TA) / θ

JA.

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 (V

OUT

= 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: V

REF

≤ V

OUT

≤ (VIN – 1 V), 4.3V ≤ VIN ≤ 26V, 1 mA < I

L

≤400 mA, T

J

≤ T

J 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 = V

OUT

/V

REF

=
(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 V

OUT as VOUT is varied, with the dropout warning occurring at typically

5% below nominal, 7.7% guaranteed.
Note 10: V

SHUTDOWN

≥ 2V, VIN ≤ 26V,V

OUT

= 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.

ADJUST

SENSE

Q15A

OUT

Q24

Q26

R27

V TAP

R28

R18
20kΩ

Q25

Q23

Q22

R15
100 kΩ

R16
30 kΩ

Q29

Q28

R17

10 Ω

R21 8 Ω

R17

12 kΩ

Q31

Q30

R23 60 kΩ

SHDN

R24
50 kΩ

R22
150 kΩ

Q21

Q19

C2
40 pF

R14
350
kΩ

Q14

R13
100

kΩ

Q18

R12
110

kΩ

Q20

Q9

Q15B

Q8

Q7

R11

20.6
kΩ

Q5

R8

31.4 kΩ

R10
150

kΩ

R9

27.8 kΩ

Q11

Q12

Q13

R6

140

kΩ

R5

180

kΩ

R4

13 kΩ

R3

50 kΩ

Q2

C1
20
pF

Q4Q3

R11
18
kΩ

Q6

Q1

10

R1

20 kΩ

R2

50 kΩ

Q41

R30

30
kΩ

Q40

Q34

GND

Q36

Q37

R25

2.8 kΩ

Q38

ERROR

R26
60 kΩ

Q39

Q42

Q16

Q17

50 kΩ

10 kΩ

IN

DENOTES CONNECTION ON
MIC2920A-xx AND MIC29201-xx
VERSIONS ONLY

Schematic Diagram

MIC2920A/29201/29202/29204 Micrel

3-14 January 1998

Typical Characteristics

0

100

200

300

400

500

0 100 200 300 400

DROPOUT VOLTAGE (mV)

OUTPUT CURRENT (mA)

Dropout Voltage

vs. Output Current

0

100

200

300

400

500

600

700

-60 -30 0 30 60 90 120 150

DROPOUT VOLTAGE (mV)

TEMPERATURE (°C)

Dropout Voltage
vs. Temperature

I

LOAD

= 400mA

0

1

2

3

4

5

6

0123456

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout

Characteristics

I

LOAD

= 1mA

I

LOAD

= 400mA

0.1

1

10

20

1 10 100 400

GROUND CURRENT (mA)

OUTPUT CURRENT (mA)

Ground Current

vs. Output Current

0

50

100

150

200

012345678

GROUND CURRENT (µA)

SUPPLY VOLTAGE (V)

Ground Current

vs. Supply Voltage

V

OUT

= 5V

I

OUT

= 1mA

0

5

10

15

20

25

30

0246810

GROUND CURRENT (mA)

INPUT VOLTAGE (V)

Ground Current

vs. Supply Voltage

V

OUT

= 5V

I

OUT

= 400mA

0.00

0.05

0.10

0.15

0.20

-60 -30 0 30 60 90 120 150

GROUND CURRENT (mA)

TEMPERATURE (°C)

Ground Current

vs. Temperature

I

OUT

= 1mA

0

1

2

3

-60 -30 0 30 60 90 120 150

GROUND CURRENT (mA)

TEMPERATURE (°C)

Ground Current

vs. Temperature

I

LOAD

= 100mA

0

5

10

15

20

25

-60 -30 0 30 60 90 120 150

GROUND CURRENT (mA)

TEMPERATURE (°C)

Ground Current

vs. Temperature

I

LOAD

= 400mA

3.20

3.22

3.24

3.26

3.28

3.30

3.32

3.34

3.36

3.38

3.40

-60 -30 0 30 60 90 120 150

OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

Fixed 3.3V Output Voltage

vs. Temperature

300

350

400

450

500

550

600

650

700

-60 -30 0 30 60 90 120 150

CURRENT (mA)

TEMPERATURE (°C)

Short Circuit and Maximum

Current vs. Temperature

V

OUT

= V

NOMINAL

– 0.5V

V

OUT

= 0V

3 SAMPLES
(HI/AVG/LO)

V

OUT

= 3.3V

-100

0

100

200

300

400

500

600

700

800

900

1000

-30 -20 -10 0 10 20 30

GROUND CURRENT (µA)

INPUT VOLTAGE (V)

Ground Current

vs. Supply Voltage

R

LOAD

= 100Ω

MIC2920A/29201/29202/29204 Micrel

January 1998 3-15

3

-200

0

200

400

600

-5 0 5 10 15 20 25

OUTPUT (mA)

TIME (ms)

Load Transient

-200

-100

0

100

200

∆ OUTPUT (mV)

C

OUT

= 10µF

1mA

-200

0

200

400

600

-5 0 5 10 15 20 25

OUTPUT (mA)

TIME (ms)

Load Transient

-100

-50

0

50

100

∆ OUTPUT (mV)

C

OUT

= 100µF

1mA

0

10

20

30

40

50

-60 -30 0 30 60 90 120 150

ADJUST PIN CURRENT (nA)

TEMPERATURE (°C)

MIC29202 Adjust Pin

Current vs. Temperature

I

LOAD

= 1mA

-40

-20

0

20

40

∆ OUTPUT (mV)

4

6

8

10

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

INPUT (V)

TIME (ms)

Line Transient

C

OUT

= 10 µF

I

L

= 10mA

-20

-10

0

10

20

∆ OUTPUT (mV)

4

6

8

10

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

INPUT (V)

TIME (ms)

Line Transient

C

OUT

= 100 µF

I

L

= 10mA

0.01

0.1

1

10

1x10

0

10x10

0

100x10

0

1x10

3

10x10

3

100x10

3

1x10

6

OUTPUT IMPEDANCE (Ω)

FREQUENCY (Hz)

Output Impedance

vs. Frequency

I

LOAD

= 10mA

10

10011k

10k

100k

1M

0

25

50

75

100

125

-60 -30 0 30 60 90 120 150

ENABLE CURRENT (µA)

TEMPERATURE (°C)

MIC29201/2 Shutdown Current

vs. Temperaure

VEN = 5V

VEN = 2V

-100

-80

-60

-40

-20

0

1E+1 1E+2 1E+3 1E+4 1E+5 1E+6

REJECTION (dB)

FREQUENCY (Hz)

Ripple Rejection

10

1M

1k

100

10k 100k

IL = 100mA

1mA

CL = 10µF

MIC2920A/29201/29202/29204 Micrel

3-16 January 1998

OUTPUT

VOLTAGE

INPUT

VOLTAGE

ERROR

NOT

VALID

NOT

VALID

5V

1.3V

4.75V

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
V

OUT

= V

REF

× { 1 + R1/R2 } – |I

FB

| R

1

where V

REF

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 V

OUT

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.

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

Figure 1. ERROR Output Timing

*

*

* SEE APPLICATIONS INFORMATION

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.

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 V

OUT

= 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.

The error comparator has an NPN open-collector output
which requires an external pull-up resistor. Depending on

MIC2920A/29201/29202/29204 Micrel

January 1998 3-17

3

SHUT­DOWN

V

GND

4

7

8

OUT

+V

IN

ADJUST

1

3

SHUTDOWN
INPUT

100pF

2N2222

1%

300kΩ

≥ 5.3V

1%

180kΩ

+

10µF

470 kΩ

HIGH = OFF

LOW = ON

LOW = 3.3V OUT

220kΩ
1%

VCC OUT

HIGH = 5V OUT

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.

capacitor. This is relatively inefficient, as increasing the
capacitor from 1µF to 220µF only decreases the noise from
430µV to 160µV

RMS

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

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.

*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV TO 400mV,
DEPENDING ON LOAD CURRENT.

870 25

NOTE: PINS 2 AND 6 ARE LEFT OPEN

IN

OUT

GND ADJUST

ERROR

5

3

4

1

8

SHUTDOWN

V

V

ERROR
OUTPUT

SHUTDOWN
INPUT

IN

+V

100kΩ

OUT

V

1.2

26V

1

R 100

pF

10µF

2

R

1.23V

REF

V

7

V

OUT

= V

REF

x (1 + )

1

R

2

R

OFF

ON

OUT

GND

+V

IN

*V

≈5V

OUT

V

V

10µF

+

IN

V

OUT

= 5V

Figure 2. MIC2920A-5.0 Fixed +5V Regulator Figure 3. MIC29202/29204 Adjustable Regulator. Pinout is for

MIC29204.

T ypical Applications

Figure 5. MIC29202/29204 5.0V or 3.3V Selectable Regulator
with Shutdown. Pinout is for MIC29204.

Figure 4. MIC29204 Wide Input Voltage Range Current Limiter

PIN 3 LOW= ENABLE OUTPUT. Q1 ON = 3.3V, Q1 OFF = 5.0V.

MIC2951

OUT

FB

SD

ERROR

5

1

3

7

GND

4

+V

IN

8

+V

IN

*V ≈V

IN

OUT

V

ERROR
OUTPUT

SHUTDOWN
INPUT

OFF

ON

C

BYPASS

≅

1

2R

1

• 200 Hzπ

ADJUST