MIC2920A/29201/29202/29204
Micrel, Inc.
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).
•
•
•
•
•
•
•
•
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-220-3, 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 VPP regulation/switching
Bar code scanners
Automotive electronics
SMPS post-regulators
Voltage reference
High-efficiency linear power supplies
Pin Configuration
TAB
TAB
OUTPUT 1
8 INPUT
SENSE 2
7 NC
SHUTDOWN 3
6 NC
GROUND 4
5 ERROR
MIC29201-3.3BM (SOIC-8)
OUTPUT 1
SENSE 2
8 INPUT
7 A D JUST
SHUTDOWN 3
6 5V TAP
GROUND 4
5 ERROR
1
2
3
INPUT
OUTPUT
GROUND
MIC2920A-x.xBS
(SOT-223)
TAB
MIC29204BM (SOIC-8)
5-Lead Package Pinouts
MIC29201 MIC29202
1) Error
Adjust
2) Input
Shutdown
3) Ground
Ground
4) Output
Input
5) Shutdown
Output
TAB
1
IN
1 2 3 4 5
MIC29201/29202BU
(TO-263-5)
3
OU T
GND
2
MIC2920A-xxBT
(TO-220)
1 2 3 4 5
MIC29201/29202BT
(TO-220-5)
Tab is Ground on SOT-223, TO-220, and TO-263 packages.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2005
1
M9999-021505
MIC2920A/29201/29202/29204
Micrel, Inc.
Ordering Information
Part Number
Voltage
Junction Temp. Range
Package
Standard
Pb-Free
MIC2920A-3.3BS
MIC2920A-3.3WS*
3.3V
-40°C to +125°C
SOT-223
MIC2920A-3.3BT
MIC2920A-3.3WT*
3.3V
-40°C to +125°C
TO-220-3
MIC2920A-4.8BS
MIC2920A-4.8WS*
4.85V
-40°C to +125°C
SOT-223
MIC2920A-4.8BT
MIC2920A-4.8WT*
4.85V
-40°C to +125°C
TO-220-3
MIC2920A-5.0BS
MIC2920A-5.0WS*
5.0V
-40°C to +125°C
SOT-223
MIC2920A-5.0BT
MIC2920A-5.0WT*
5.0V
-40°C to +125°C
TO-220-3
MIC2920A-12BS
MIC2920A-12WS*
12V
-40°C to +125°C
SOT-223
MIC2920A-12BT
MIC2920A-12WT*
12V
-40°C to +125°C
TO-220-3
MIC29201-3.3BM
MIC29201-3.3YM
3.3V
-40°C to +125°C
SO-8
MIC29201-3.3BT
MIC29201-3.3WT*
3.3V
-40°C to +125°C
TO-220-5
MIC29201-3.3BU
MIC29201-3.3WU*
3.3V
-40°C to +125°C
TO-263-5
MIC29201-4.8BT
MIC29201-4.8WT*
4.85V
-40°C to +125°C
TO-220-5
MIC29201-4.8BU
MIC29201-4.8WU*
4.85V
-40°C to +125°C
TO-263-5
MIC29201-5.0BT
MIC29201-5.0WT*
5.0V
-40°C to +125°C
TO-220-5
MIC29201-5.0BU
MIC29201-5.0WU*
5.0V
-40°C to +125°C
TO-263-5
MIC29201-12BT
MIC29201-12WT*
12V
-40°C to +125°C
TO-220-5
MIC29201-12BU
MIC29201-12WU*
12V
-40°C to +125°C
TO-263-5
MIC29202BT
MIC29202WT*
Adj
-40°C to +125°C
TO-220-5
MIC29202BU
MIC29202WU*
Adj
-40°C to +125°C
TO-263-5
MIC29204BM
MIC29204YM
5V and Adj
-40°C to +125°C
SO-8
MIC29204BN
MIC29204YN
5V and Adj
-40°C to +125°C
8-pin PDIP
* Pb-Free RoHS compliant with high-melting solder exemption.
M9999-021505
2
February 2005
MIC2920A/29201/29202/29204
Micrel, Inc.
Absolute Maximum Ratings
Operating Ratings
Input Supply Voltage .................................................–20V to +60V
Adjust Input Voltage (Notes 9 and 10) ......................–1.5V to +26V
Power Dissipation ................................... Internally Limited, Note 1
Operating Junction Temperature Range ............. –40°C to +125°C
Lead Temperature (Soldering, 5 seconds) ............................260°C
Storage Temperature Range ............................... –65°C to +150°C
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 +30VOperating
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
If Military/Aerospace specified devices are required, contact your local
Micrel representative/distributor for availability and specifications.
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.
†
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 versions are set for an ouptu 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
Conditions
Min
Output Voltage
Accuracy
Variation from factory trimmed VOUT
Max
Units
-1
-2
1
2
%
1mA ≤ IL ≤ 400mA, across temp. range
-2.5
2.5
MIC2920A-12 and 29201-12 only
-1.5
-3
1.5
3
-4
4
1mA ≤ IL ≤ 400mA, across temp. range
Typ
Output Voltage
Temperature Coef.
(Note 2)
80
350
∆VO
VO
Line Regulation
VIN = VOUT + 1V to 26V
0.03
0.10
0.40
%
∆VO
VO
Load Regulation
IL = 1 to 250mA (Note 3)
0.04
0.16
0.30
%
VIN - VO
Dropout Voltage
(Note 4)
IL = 1mA
100
150
180
mV
VOUT > 10V only
IL = 100mA
IL = 250mA
IL = 400mA
IGND
VOUT > 10V only
VOUT > 10V only
250
350
370
500
400
IL = 400mA
13
VIN = 0.5V less than designed VOUT
(VOUT = 3.3V)
IO = 1mA
180
400
µA
ILIMIT
Current Limit
VOUT = 0V
(Note 6)
425
100
1200
mA
∆VO
∆PD
Thermal Regulation
(Note 7)
0.05
0.2
%/W
Output Noise Voltage
(10Hz to 100kHz)
IL = 100mA
CL = 10µF
CL = 100µF
400
260
February 2005
140
IL = 100mA
1.3
IL = 250mA
5
600
750
Ground Pin Current
at Dropout
(Note 5)
en
IL = 1mA
ppm/°C
200
300
2
2.5
9
12
15
IGNDDO
Ground Pin Current
(Note 5)
20
100
∆VO
∆T
3
µA
mA
µV RMS
M9999-021505
MIC2920A/29201/29202/29204
Parameter
Micrel, Inc.
Conditions
Min
Typ
Max
Units
1.235
1.247
1.260
V
1.266
V
1.260
1.270
V
MIC29202, MIC29204
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
Bia Current
Reference Voltage
Temperature
Coefficient
1.235
20
(Note 7)
Adjust Pin Bias
Current Temperature
Coefficient
1.285
V
40
60
nA
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
Input Logic Voltage
Shutdown Pin
Input Current
Regulator Output
Current in Shutdown
M9999-021505
40
25
60
1.3
Low (ON)
High (OFF)
2.0
mV
95
140
mV
mV
0.7
V
VSHUTDOWN = 2.4V
30
50
100
µA
VSHUTDOWN = 26V
450
600
750
µA
3
10
20
µA
(Note 10)
4
February 2005
MIC2920A/29201/29202/29204
Notes:
General:
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
Micrel, Inc.
Devices are ESD protected; however, handling precautions are recommended.
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.
Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
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.
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.
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.
The MIC2920A features fold-back current limiting. The short circuit (VOUT = 0V) current limit is less than the maximum current with normal
output voltage.
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.
VREF ≤ VOUT ≤ (VIN – 1 V), 4.3V ≤ VIN ≤ 26V, 1 mA < IL ≤400 mA, TJ ≤ TJ MAX.
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.
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.
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.
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
Q7
Q4
Q6
R11
20.6
kΩ
Q1
10
R2
50 kΩ
Q40
Q17
Q16
R27
R17
12 kΩ
Q14
V TAP
R28
Q2
Q20
R1
20 kΩ
Q42
SENSE
Q8
Q5
C1
20
pF
R6
140
kΩ
R5
180
kΩ
Q13
Q41
Q21
Q23
C2
40 pF
R9
27.8 kΩ
Q12
Q22
R10
150
kΩ
R8
31.4 kΩ
R12
110
kΩ
R13
100
kΩ
R15
100 kΩ
R14
350
kΩ
R16
30 kΩ
Q11
R17
10 Ω
Q29
R30
30
kΩ
Q19
Q18
R3
50 kΩ
Q28
R4
13 kΩ
R21 8 Ω
50 kΩ
Q30 Q31
Q37
10 kΩ
R22
150 kΩ
Q36
R23 60 kΩ
ERROR
Q34
Q38
R26
60 kΩ
D E NO T E S CO NNE CT I O N O N
MIC2920A-xx AND MIC29201-xx
VERSIONS ONLY
R25
2.8 kΩ
GND
Q39
February 2005
SHDN
R24
50 kΩ
5
M9999-021505
MIC2920A/29201/29202/29204
Micrel, Inc.
Typical Characteristics
Dropout V oltage
vs . Output C urrent
700
200
100
0
0
100
200
300
OUTPUT CURRENT (mA)
400
I LOAD = 400mA
300
200
100
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
400
G round C urrent
vs . Output C urrent
20
5
500
OUTPUT VOLTAGE (V)
300
G round C urrent
vs . S upply V oltage
200
3
2
I LOAD = 400mA
1
0
1
2
3
4
INPUT VOLTAGE (V)
5
6
G round C urrent
vs . S upply V oltage
30
1
100
10
OUTPUT CURRENT (mA)
0
G round C urrent
vs . T emperature
3
GROUND CURRENT (mA)
0.15
0.10
I OUT = 1mA
0.05
F ixed 3.3V Output V oltage
vs . T emperature
M9999-021505
2
0
1
2 3 4 5 6
SUPPLY VOLTAGE (V)
7
G round C urrent
vs . T emperature
650
I LOAD = 100mA
CURRENT (mA)
550
500
3 S AMP LE S
(HI/AV G /LO)
450
400
350
V OUT = 0V
300
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
6
V OUT = 5V
I OUT = 400mA
5
0
2
4
6
8
INPUT VOLTAGE (V)
10
G round C urrent
vs . T emperature
20
I LOAD = 400mA
15
10
5
G round C urrent
vs . S upply V oltage
V OUT = V NOMINAL – 0.5V
V OUT = 3.3V
10
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
S hort C irc uit and Maximum
C urrent vs . T emperature
600
15
25
1
700
20
0
8
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
0.00
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3.40
3.38
3.36
3.34
3.32
3.30
3.28
3.26
3.24
3.22
3.20
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
V OUT = 5V
I OUT = 1mA
50
400
GROUND CURRENT (mA)
100
GROUND CURRENT (µA)
1
150
GROUND CURRENT (mA)
GROUND CURRENT (µA)
GROUND CURRENT (mA)
GROUND CURRENT (mA)
I LOAD = 1mA
25
0.20
OUTPUT VOLTAGE (V)
4
0
10
0.1
Dropout
C harac teris tic s
6
600
400
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
500
Dropout V oltage
vs . T emperature
1000
900 R
LOAD = 100Ω
800
700
600
500
400
300
200
100
0
-100
-30 -20 -10
0
10
INPUT VOLTAGE (V)
20
30
February 2005
MIC2920A/29201/29202/29204
Micrel, Inc.
5
10 15
TIME (ms)
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
20
25
0
-50
600
-100
400
0
-200
0
-5
20
C OUT = 10 µF
I L = 10mA
20
1mA
200
L ine T rans ient
-20
-40
10
INPUT (V)
8
6
4
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
TIME (ms)
10
0
0
5
10 15
TIME (ms)
20
25
L ine T rans ient
C OUT = 100 µF
I L = 10mA
-10
-20
10
8
6
4
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
TIME (ms)
Output Impedanc e
vs . F requenc y
10
1
0.1
I LOAD = 10mA
0.01
1x10 0
OUTPUT IMPEDANCE (Ω)
50
C OUT = 100µF
1
10
1x10 6
10
0
40
20
I LOAD = 1mA
-5
100x10 3
30
∆ OUTPUT (mV)
0
-200
MIC 29202 A djus t P in
C urrent vs . T emperature
40
1mA
200
∆ OUTPUT (mV)
ADJUST PIN CURRENT (nA)
50
400
10x10 3
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
600
-200
1x10 3
25
-100
100x10 0
V E N = 2V
0
10x10 0
50
∆ OUTPUT (mV)
75
OUTPUT (mA)
V E N = 5V
L oad T rans ient
100
C OUT = 10µF
100
INPUT (V)
ENABLE CURRENT (µA)
100
L oad T rans ient
200
OUTPUT (mA)
125
∆ OUTPUT (mV)
MIC 29201/2 S hutdown C urrent
vs . T emperaure
100 1k 10k 100k 1M
FREQUENCY (Hz)
R ipple R ejec tion
0
C L = 10µF
REJECTION (dB)
-20
I L = 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)
February 2005
7
M9999-021505
MIC2920A/29201/29202/29204
Micrel, Inc.
Applications Information
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.
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.
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
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.
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).
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.
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)
Reducing Output Noise
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
built-in 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.
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
capacitor. This is relatively inefficient, as increasing the capaci4.75V
OUTPUT
VOLTAGE
ERROR
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.
INPUT
VOLTAGE
NOT *
VALID
NOT *
VALID
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 system
requirements, this resistor may be returned to the 5V output
M9999-021505
8
February 2005
MIC2920A/29201/29202/29204
Micrel, Inc.
Automotive Applications
tor 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
C BYPASS =
2 πR1 • 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.
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
+V IN
V IN
100kΩ
+V IN
V OUT = 5V
V OUT
+ 10µF
ERROR
O U T PU T
5 ERROR
SHUTDOWN
INPUT
3
V OUT
VOUT
1
SHUTDOWN
OFF
GND ADJU ST
7
4
1.23V
ON
GND
8
VIN
R1
V OUT = V R E F x (1 +
)
R2
26V
1.2
R 1 100
pF
10µF
R2
VREF
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
+V IN
8
+VIN
ERROR
OUTPUT
5 ERROR
SHUTDOWN
INPUT
3
*V OUT = V IN
VOUT 1
SHUTDOWN
INPUT
3
HIGH = OFF
OFF
ON
8
+V IN
1
SHUTDOWN
+
100pF
LOW = ON
SD
V CC OUT
VOUT
GND
4
GND ADJ U ST
4
7
HIGH = 5V OUT
* Minimum Input-Output Voltage ranges from 40mV to 400mV, depending on load current
LOW = 3.3V OUT
ADJUST
7
470 kΩ
220kΩ
1%
300kΩ
1%
10µF
180kΩ
1%
2N2222
PIN 3 LOW= ENABLE OUTPUT. Q1 ON = 3.3V, Q1 OFF = 5.0V.
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
February 2005
9
M9999-021505
MIC2920A/29201/29202/29204
Micrel, Inc.
Package Information
8-Pin SOIC (M)
3.15 (0.124)
2.90 (0.114)
CL
3.71 (0.146) 7.49 (0.295)
3.30 (0.130) 6.71 (0.264)
CL
2.41 (0.095)
2.21 (0.087)
1.04 (0.041)
0.85 (0.033)
4.7 (0.185)
4.5 (0.177)
0.10 (0.004)
0.02 (0.0008)
DIMENSIONS:
MM (INCH)
6.70 (0.264)
6.30 (0.248)
1.70 (0.067)
16°
1.52 (0.060)
10°
10°
MAX
0.38 (0.015)
0.25 (0.010)
0.84 (0.033)
0.64 (0.025)
0.91 (0.036) MIN
SOT-223 (S)
M9999-021505
10
February 2005
MIC2920A/29201/29202/29204
Micrel, Inc.
3-Lead TO-220 (T)
5-Lead TO-220 (T)
February 2005
11
M9999-021505
MIC2920A/29201/29202/29204
Micrel, Inc.
θ4
θ1
θ2
θ1
θ1
θ2
θ3
θ4
θ1
θ3
5-Lead TO-263 (U)
MICREL INC.
TEL
2180 FORTUNE DRIVE
+ 1 (408) 944-0800
FAX
SAN JOSE, CA 95131
+ 1 (408) 474-1000
WEB
USA
http://www.micrel.com
This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's
use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 1998 Micrel Incorporated
M9999-021505
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February 2005