MIC5281
120VIN, 25mA, Ultra-Low IQ, High-PSRR
Linear Regulator
General Descr i ption
The MIC5281 high-performance linear regulator offers a
very-wide input operating voltage range, up to 120V DC,
and supplies an output current of up to 25mA.
Ideal for high input voltage applications such as industrial
and telecom, the MIC5281 offers ±3% initial accuracy,
extremely high-power supply rejection ratio (>90db) and
ultra-low quiescent current of 6µA. The MIC5281 is
optimized for high-voltage line transients, making it ideal
for harsh environment applications.
The MIC5281 is offered in both fixed output voltage
(3.3V/5.0V) and adjustable output voltage (1.27V to 5.5V)
options.
The MIC5281 operates over a −40ºC to +125ºC
temperature range and is available in lead-free, RoHS-
compliant, 8-pin ePad MSOP, and 8-pin MSO P packages
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• Wide input voltage range: 6V to 120V DC
• Ultra-low quiescent current: 6µA
• 25mA guaranteed output current
• Adjustable output from 1.27V to 5.5V
• Withstands up to +120V DC at the input
• Stable with ceramic capacitors
• Ultra-high PSRR >90dB
• Ultra-high line rejection (load dump)
• High output accuracy:
− ±3% initial accuracy
• Thermal-shutdow n and current-limit prot ection:
− Thermally-efficient, 8-pin MSOP, and 8-pin ePad
MSOP packages
Applications
• Industrial applicati ons
• Remote keyless ent ry power supply
• Telecom applicat i ons
• Off-line power supplie s
Typical Applicatio n
Quiescent Supply Current
vs. Input Voltage
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
020 40 60 80 100 120
I NPUT VOLTAG E (V)
Q UIESCENT CURRE NT (µA)
VOUT = 5V
IOUT = 0
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 2, 2014 Revision 3.0
Micrel, Inc.
MIC5281
Ordering I nfor m ati on
Part Number
Output Voltage
Top Mark
Temperatur e Range
Package
Lead Finish
MIC5281YMME Adjustable 781A –40°C to +125°C 8-Pin ePad MSOP Pb-Free
MIC5281-3.3YMME 3.3V 781S –40°C to +125°C 8-Pin ePad MSOP Pb-Free
MIC5281-5.0YMME 5.0V 7815 –40°C to +125°C 8-Pin ePad MSOP Pb-Free
MIC5281YMM Adjustable 5281
YMM –40°C to +125°C 8-Pin MSOP Pb-Free
MIC5281-3.3YMM 3.3V 5281
3.3Y –40°C to +125°C 8-Pin MSOP Pb-Free
MIC5281-5.0YMM 5.0V 5281
5.0Y –40°C to +125°C 8-Pin MSOP Pb-Free
Pin Configuration
8-Pin ePAD MSOP
MIC5281-x.xYMME
(TOP VIEW)
8-Pin MSOP
MIC5281-x.xYMM
(TOP VIEW)
8-Pin ePAD MSOP
MIC5281YMME
(TOP VIEW)
8-Pin MSOP
MIC5281YMM
(TOP VIEW)
October 2, 2014 2 Revision 3.0
Micrel, Inc.
MIC5281
Pin Description
Pin
Name Function
MIC5281YMME MIC5281-x.xYMME MIC5281YMM MIC5281-x.xYMM
1 1 1 1 VIN Supply Volta ge Input. Conn ec t 1µF
capacitor from VIN to GND.
2, 3, 7 2, 3, 7 2, 3, 7 2, 3, 7 NC Not intern al ly connected. Connect
NC to GND or leave u nc onnected.
4 4 4 4 CPSRR Bypass Capacitor Connection.
Connect 0.1µF capacitor from
CPSRR to GND.
5 5 5 5 GND Ground.
6 − 6 − FB Feedback Connec tion. For external
resistor divider to set V OUT.
− 6 − 6 SNS Sense input. Connect SNS to
VOUT.
8 8 8 8 VOUT Regulator Output. Connect 10µF
capacitor from VOUT to G ND .
EP EP − − EP Exposed Pad ( eP ad) for Therm al
Relief. Connect EP to GND.
October 2, 2014 3 Revision 3.0
Micrel, Inc.
MIC5281
Absolute Ma xi mu m Ratings(1)
VIN to GND ................................................... –0.3V to +125V
VCPSRR to GND .................................................. –0.3 to +14V
VFB, VSNS, VOUT to GND ................................... –0.3V to +6V
Lead Temperat ure (soldering, 10s) .......................... +260°C
Junction Temperature ......................... –40°C ≤ TJ ≤ +125°C
Storage Temperature ......................... –65°C ≤ TA ≤ +150°C
ESD Ratings(4)
HBM ......................................................................... 2kV
MM ......................................................................... 200V
Operating Ratings(2)
VIN ................................................................. +6V to +120V
VOUT Adjust Range ..................................... +1.27V to +5.5V
Junction Temperature ......................... –40°C ≤ TJ ≤ +125°C
Power Dissipat i on (P D) ........................... Internally Limited(3)
Junction Thermal Resistance (θJA)
8-pin ePad MSOP .............................................. 64°C/W
8-pin MSOP ..................................................... 160°C/W
Electric al Characteristics(5)
VIN = 12V, CIN = 1.0µF, CPSRR = 0.1µF, COUT = 10µF, VOUT = 5. 0V or 3.3V, IOUT = 100µA, TA = 25°C, bold values ind icate
–40°C ≤ TJ ≤ +125°C, unless noted.
Parameter Condition Min. Typ. Max. Units
Power Supply Input
Input Voltage Range(6) 6 120 V
Quiescent Supply Current IOUT = 0 6
11
µA
Output Voltage
Output Voltage
Adjustable 1.27 5.5
V
Fixed 3.3V 3.2 3.3 3.4
3.13 3.3 3.47
Fixed 5.0V 4.85 5.0 5.15
4.75
5.0
5.25
Output Voltage Accuracy Variation from nominal VOUT −3 +3 %
−5
+5 %
Load Regulati on IOUT = 100µA to 25mA
−
1.0 0.2 +1.0 %
Line Regulat ion(7) VIN = 10V to 120V
−
0.5 0.04 +0.5 %
Feedback Input (Adjustable)
FB Voltage 1.232 1.270 1.308 V
1.206 1.270 1.333
FB Current VFB = 1.27V 3.2 nA
Current Limit
Current Limit VOUT = 0V 30 65 130 mA
Ripple Rejection
Power Supply R ejection Rati o f = 20kHz t o 2MHz 90 dB
Notes:
1. Exceeding an absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation at any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA. Exceeding the maximum allowable power
dissipation results in excessive die temperature, and causes the regulator to enter thermal shutdown.
4. Devices are ESD sensitive; use proper handling precautions. Human body model, 1.5kΩ in series with 100pF.
5. Specifications are for packaged products only.
6. Assure that VIN ≥ (VOUT + 3V) and VIN ≥ 6V.
7. Line regulation is a percentage of VOUT.
October 2, 2014 4 Revision 3.0
Micrel, Inc.
MIC5281
Electric al Characteristics(5) (Continued)
VIN = 12V, CIN = 1.0µF, CPSRR = 0.1µF, COUT = 10µF, VOUT = 5. 0V or 3.3V, IOUT = 100µA, TA = 25°C, bold values ind icate
–40°C ≤ TJ ≤ +125°C, unless noted.
Parameter
Condition
Min.
Typ.
Max.
Units
Power Dropout Voltage
Dropout Voltage IOUT = 25mA 2 3 V
Thermal Protection
Thermal-Shut down Temperature TJ rising 157 °C
Thermal-Shut down Hysteresis 15 °C
October 2, 2014 5 Revision 3.0
Micrel, Inc.
MIC5281
Typical Characteristics
Quiescent Supply Current
vs. Input Voltage
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
020 40 60 80 100 120
I NPUT VOLTA GE (V)
Q UIESCENT CURRE NT (µA)
V
OUT
= 5V
I
OUT
= 0
Quiescent Supply Current
vs. Temperature
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
Q UIESCENT CURRE NT (µA)
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 0m A
Output Voltage
vs. Input Voltage
4.85
4.90
4.95
5.00
5.05
5.10
5.15
020 40 60 80 100 120
I NPUT VOLTA GE (V)
O UTPUT VOLTAG E ( V)
VIN = 12V
VOUT = 5V
IOUT = 5m A
Output Voltage
vs. Output C urrent
4.75
4.80
4.85
4.90
4.95
5.00
5.05
5.10
5.15
5.20
5.25
0 5 10 15 20 25
O UT PUT CURRE NT (mA)
O UTPUT VOLTAG E ( V)
V
IN
= 12V
V
OUT
= 5V
Output Voltage
vs. Temperature
4.75
4.80
4.85
4.90
4.95
5.00
5.05
5.10
5.15
5.20
5.25
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
O UTPUT VOLTAG E ( V)
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 5m A
Dropout Voltage
vs. Output C urrent
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 5 10 15 20 25
O UT PUT CURRE NT (mA)
DROPOUT VOLTAGE (V)
V
OUT
= 5V
ADJUSTABLE OPTION
Dropout Voltage
vs. Temperature
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
DROPOUT VOLTAGE (V)
V
OUT
= 5V
I
OUT
= 25m A
FB Voltage
vs. Input Voltage
1.23
1.24
1.25
1.26
1.27
1.28
1.29
1.30
1.31
020 40 60 80 100 120
I NPUT VO L TAG E ( V)
FB VOLTAG E ( V)
V
OUT
= 5V
I
OUT
= 5m A
FB Current
vs. Input Voltage
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
020 40 60 80 100 120
I NPUT VOLTA GE (V)
FB CURRENT (nA)
V
OUT
= 5V
V
FB
= 1. 267V
October 2, 2014 6 Revision 3.0
Micrel, Inc.
MIC5281
Typical Characteristics (Continued)
FB Voltage
vs. Temperature
1.24
1.25
1.26
1.27
1.28
1.29
1.30
1.31
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
FB VOLTAG E ( V)
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 5m A
FB Current
vs. Temperature
0.0
0.5
1.0
1.5
2.0
2.5
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
FB CURRENT (nA)
V
IN
= 12V
V
FB
= 1. 267V
I
OUT
= 0
FB Voltage
vs. Output C urrent
1.266
1.268
1.270
1.272
1.274
1.276
0 5 10 15 20 25
O UT PUT CURRE NT (mA)
FB VOLTAG E ( V)
V
IN
= 12V
V
OUT
= 5. 0V
Current Limi t
vs. Temperature
50
55
60
65
70
75
80
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
CURRENT LIM IT ( mA)
V
IN
= 12V
V
OUT
= 0V
Li ne Regul ation
vs. Temperature
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
LINE REGULATION (%/V)
V
IN
= 10V to 120V
V
OUT
= 5V
I
OUT
= 100µA
Load Regulation
vs. Temperature
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
0.26
0.28
0.30
-50 -25 025 50 75 100 125
TEM PERATURE (° C)
LOAD REG ULAT IO N ( %)
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 100µA t o 25mA
Power Dissipation
vs. Output C urrent
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
0 5 10 15 20 25
O UT PUT CURRE NT (mA)
POWER DISSIPATION (W)
V
IN
= 12V
V
OUT
= 4. 5V
Case Temperat ure (MME)
vs. Output C urrent
24
26
28
30
32
34
36
38
40
0 5 10 15 20 25
O UT PUT CURRE NT (mA)
CASE TE M P ERATURE ( °C)
V
IN
= 12V
V
OUT
= 4. 5V
PSRR vs. Frequency
-130
-110
-90
-70
-50
-30
-10
10
30
0.01 0.1 110 100 1000 10000
FREQUENCY ( kHz)
PSRR (dB)
V
IN
= 12V
V
OUT
= 5V
I
OUT
= 5m A
C
IN
= None
C
PSRR
= 0. 1µF
C
OUT
= 10µF
October 2, 2014 7 Revision 3.0
Micrel, Inc.
MIC5281
Functional Characteristics
October 2, 2014 8 Revision 3.0
Micrel, Inc.
MIC5281
Functional Characteristics (Continued)
October 2, 2014 9 Revision 3.0
Micrel, Inc.
MIC5281
Functional Diagram
MIC5281 Adjustable Version
MIC5281 Fixed Version
October 2, 2014 10 Revision 3.0
Micrel, Inc.
MIC5281
Functional Descript ion
The MIC5281 voltage regulator accepts a 6V to 120V
input and has an ultra-low 6µA typical quiescent current
while offering an excellent line transient response and
PSRR. These features make it ideal for harsh, noisy
environments. All options of the device offer 25mA of
output current. The MIC5281YMM and MIC5281YMME
offer an adjustable output voltage from 1.27V to 5.5V.
The MIC5281-3.3YMME and MIC5281-3.3YMM offer
fixed 3.3V outputs and the MIC5281-5.0YMME and
MIC5281-5.0YMM offer fixed 5.0V outputs. The YMME
packaged devices feature a heat slug to more effectively
remove heat from the die.
Applications Inform ation
Thermal Protection
MIC5281 has internal thermal shutdown to protect it from
excessive heating of the die. When the junction
temperature exceeds approximately +155°C, the output is
disabled and the device begins to cool down. The device
turns back on when the junction temperature cools by
15°C. This will result in a cycled output during continuous
thermal-overload conditions.
Current Limit
MIC5281 features output current-limit protection. The
output sustains a continuous short circuit to GND without
damage to the device, but thermal shutdown often
results.
Input Capacitor
Connect a 1.0µF capacitor from VIN to GND. Micrel
recommends the C5750X7R2E105M, 1.0µF, 250V
capacitor made by TDK. When using a different
capacitor, assure that the voltage rating of the capacitor
exceeds any potenti al transient.
CPSRR Capac itor
Connect a 0.1µF capacitor from CPSRR to GND to
maintain high power supply rejection. The voltage rating
of the capacitor must be at least 14V.
Output Capacitor
Connect a 10µF capacitor from VOUT to GND. Assure
that the voltage rating of the capacitor exceeds the
designed output voltage of the MIC5281.
Output Voltage Setting
For the MIC5281YMME and MIC5281YMM, VOUT is
programmed from 1.27V to 5.5V using E quat i on 1:
+×= 1
R2
R1
VV
REFOUT
Eq. 1
where VREF = 1.267V, and R1 and R2 are shown in the
Typical Applications circuit.
Thermal Measurements
It is always wise to measure an IC’s case temperature to
make sure that it is within operating limits, but it is easy to
get erroneous results. The standard thermal couple that
comes with many voltage meters uses a large wire gauge
that behaves like a heat-sink, resulting in artificially low
case temperature measurements. Use a thermocouple of
36-gauge wire or smaller, such as the Omega (5SC-TT-
K-36-36), to minimize the heat-sinking effect. Also, apply
thermal compound to maximize heat transfer between the
IC and the thermocouple.
An infrared thermometer is a recommended alternative.
The IR thermometer from Optris has a 1mm spot size,
ideal for monitoring small surface mount packages. Also,
the optional stand makes it easy to keep the beam on the
IC for long periods of t i m e.
October 2, 2014 11 Revision 3.0
Micrel, Inc.
MIC5281
MIC5281 Ev aluat i o n Board Schematic
Bill of Materials
Item
Part Number
Manufacturer
Description
Qty.
C1 C5750X7R2E105M TDK(8) 1.0µF, 250V, 20%, X7R capaci tor (2220) 1
C2 08053C104KAT2A AVX
(9)
0.1µF 25V 20%, X5R capac itor (0805) 1
C3 0805ZD106KAT2A AVX 10µF, 10V, 20%, X5R, capacitor (0805) 1
C4 OPEN Panasonic(10) 100µF, 160V, 20% capacit or (ALU, 0.492"diameter can 0.197" lead
spacing - Part # ECA-2CM101) 0
C5 OPEN ANY Capacitor 0
R1 CRCW06030000F Vishay/Dale(11) 0Ω, 1% resistor, 0603 1
R2 CRCW06032942F Vishay/Dale 29.4kΩ, 1% resistor, 0603 1
R3 CRCW06031002F Vishay/Dale 10.0kΩ, 1% resistor, 0603 1
R4 CRCW06031822F Vishay/Dale 18.2kΩ, 1%, resistor, 0603 1
R5 CRCW06033012F Vishay/Dale 30.1kΩ, 1% resistor chip, 0603 1
R6 CRCW06036982F Vishay/Dale 69.8kΩ, 1%, resistor, 0603 1
U1 MIC5281YMME Micrel
(12)
120VIN, 25mA, Ultra-Low IQ, High-PSRR Linear Regulator 1
Notes:
8. TDK: www.tdk.com.
9. AVX: www.avx.com.
10. Panasonic: www.panasonic.com.
11. Vishay: www.vishay.com.
12. Micrel, Inc.: www.micrel.com.
October 2, 2014 12 Revision 3.0
Micrel, Inc.
MIC5281
PCB Layout Recommendations
Top Layer Silk Screen
Top Layer Traces
October 2, 2014 13 Revision 3.0
Micrel, Inc.
MIC5281
PCB Layout Recommendations (Continued)
Bottom Layer Traces
Bottom Layer S ilk Screen
October 2, 2014 14 Revision 3.0
Micrel, Inc.
MIC5281
PCB Layout Recommendations (Continued)
Evaluation Board Dimensions
October 2, 2014 15 Revision 3.0
Micrel, Inc.
MIC5281
Package I nformation and Recommended Landing Pattern(13) (Continued)
8-Pin Exposed Pad (ePad) MSOP
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liabili ty or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
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 reason
ably 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 a
nd Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2011 Micrel, Incorporated.
October 2, 2014 17 Revision 3.0
