MICREL MIC49150

MIC49150
Micrel
MIC49150
1.5A Low Voltage LDO Regulator w/Dual Input Voltages
Final Information
General Description
Features
The MIC49150 is a high-bandwidth, low-dropout, 1.5A voltage regulator ideal for powering core voltages of low-power
microprocessors. The MIC49150 implements a dual supply
configuration allowing for very low output impedance and
very fast transient response.
The MIC49150 requires a bias input supply and a main input
supply, allowing for ultra-low input voltages on the main
supply rail. The input supply operates from 1.4V to 6.5V and
the bias supply requires between 3V and 6.5V for proper
operation. The MIC49150 offers fixed output voltages from
0.9V to 1.8V and adjustable output voltages down to 0.9V.
The MIC49150 requires a minimum of output capacitance for
stability, working optimally with small ceramic capacitors.
The MIC49150 is available in an 8-pin power MSOP package
and a 5-pin S-Pak. Its operating temperature range is –40°C
to +125°C.
• Input Voltage Range:
VIN: 1.4V to 6.5V
VBIAS: 3.0V to 6.5V
• Stable with 1µF ceramic capacitor
• ±1% initial tolerance
• Maximum dropout voltage (VIN-VOUT) of 500mV over
temperature
• Adjustable output voltage down to 0.9V
• Ultra fast transient response (Up to 10MHz bandwidth)
• Excellent line and load regulation specifications
• Logic controlled shutdown option
• Thermal shutdown and current limit protection
• Power MSO-8 and S-Pak packages
• Junction temperature range: –40°C to 125°C
Applications
•
•
•
•
•
•
Graphics processors
PC Add-In Cards
Microprocessor core voltage supply
Low voltage digital ICs
High Efficiency Linear power supplies
SMPS post regulators
Typical Application
Load Transient Response
MIC49150BR
IN
OUT
BIAS
ADJ
VOUT = 1.0V
VOUT
50mV/div
VIN = 1.8V
R1
VBIAS = 3.3V
CBIAS = 1µF
Ceramic
GND
VBIAS = 3.3V
VIN = 1.8V
VOUT = 1V
COUT = 1µF
R2 COUT = 1µF
Ceramic
IOUT
1A/div
CIN = 1µF
Ceramic
Low Voltage,
Fast Transient Response Regulator
TIME (10µs/div.)
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
January 2002
1
MIC49150
MIC49150
Micrel
Ordering Information
Part Number
Output Current
Voltage
Temperature Range
Package
MIC49150-0.9BMM
1.5A
0.9V
–40°C to +125°C
Power MSOP-8
MIC49150-1.5BMM
1.5A
1.5V
–40°C to +125°C
Power MSOP-8
MIC49150BMM
1.5A
ADJ.
–40°C to +125°C
Power MSOP-8
MIC49150-0.9BR
1.5A
0.9V
–40°C to +125°C
S-Pak-5
MIC49150-1.5BR
1.5A
1.5V
–40°C to +125°C
S-Pak-5
MIC49150BR
1.5A
ADJ.
–40°C to +125°C
S-Pak-5
Other voltages available. Contact Micrel for details.
Pin Configuration
1
8
GND
VBIAS
2
7
GND
VIN
3
6
GND
VOUT
4
5
GND
5
4
3
2
1
TAB
EN/ADJ.
VOUT
VIN
GND
VBIAS
EN/ADJ.
5-Lead S-Pak (R)
Power MSOP-8 (MM)
Pin Description
MIC49150
MSOP8
MIC49150
S-Pak
Pin Name
1
1
Enable
Pin Function
Enable (Input): CMOS compatible input. Logic high = enable, logic low =
shutdown
ADJ.
Adjustable regulator feedback input. Connect to resistor voltage divider.
Input voltage which supplies current to the output power device.
3
4
VIN
4
5
VOUT
Regulator Output
2
2
VBIAS
Input Bias Voltage for powering all circuitry on the regulator with the exception of the output power device.
5/6/7/8
3
GND
MIC49150
Ground (TAB is connected to ground on S-Pak)
2
January 2002
MIC49150
Micrel
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 2)
Supply Voltage (VIN) ....................................................... 8V
Bias Supply Voltage (VBIAS) ............................................ 8V
Enable Input Voltage (VEN) ............................................. 8V
Power Dissipation .................................... Internally Limited
ESD Rating, Note 3 ...................................................... 2kV
Supply Voltage (VIN) ....................................... 1.4V to 6.5V
Bias Supply Voltage (VBIAS) ............................... 3V to 6.5V
Enable Input Voltage (VEN) .................................. 0V to VIN
Junction Temperature Range ............. –40°C ≤TJ ≤ +125°C
Package Thermal Resistance
MSOP-8 (θJA) ...................................................... 80°C/W
S-PAK(θJC) ............................................................ 2°C/W
Electrical Characteristics
TA = 25°C with VBIAS = VOUT +2.1V; VIN = VOUT + 1V; bold values indicate –40°C < TJ < +125°C, Note 4; unless otherwise specified.
Parameter
Conditions
Output Voltage Accuracy
At 25°C
Over temperature range
Line Regulation
VIN = 3.0V to 6.5V
Load Regulation
Dropout Voltage (VIN - VOUT)
Max
Units
+1
+2
%
%
0.01
+0.1
%/V
IL = 0mA to 1.5A
0.2
1
1.5
%
%
IL = 750mA
130
IL = 1.5A
280
200
300
400
500
mV
mV
mV
mV
Dropout Voltage (VBIAS - VOUT)
Note 4
IL = 750mA
IL = 1.5A
1.3
1.65
1.9
2.1
V
V
V
Ground Pin Current, Note 5
IL = 0mA
IL = 1.5A
15
15
25
30
mA
mA
mA
Ground Pin Current in Shutdown
VEN ≤ 0.6V, (IBIAS + ICC), Note 6
0.5
1
2
µA
µA
Current thru VBIAS
IL = 0mA
9
15
25
IL = 1.5A
32
mA
mA
mA
3.5
4
A
A
0.6
V
V
0.1
1
µA
0.9
0.909
0.918
V
V
Current Limit
Min
Typ
–1
–2
–0.1
MIC49150
1.6
Enable Input Threshold
(Fixed Voltage only)
Regulator enable
Regulator shutdown
1.6
Enable Pin Input Current
Independent of state
2.3
Enable Input, Note 6
Reference
Reference Voltage
0.891
0.882
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.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 4.
For VOUT ≤1V, VBIAS dropout specification does not apply due to a minimum 3V VBIAS input.
Note 5.
IGND = IBIAS + (IIN – IOUT). At high loads, input current on VIN will be less than the output current, due to drive current being supplied by VBIAS.
Note 6.
Fixed output voltage versions only.
January 2002
3
MIC49150
MIC49150
Micrel
Functional Diagram
VBIAS
VIN
Ilimit
VEN/ADJ
Fixed
Enable
Bandgap
Adj.
VIN Open
Circuit
Fixed
MIC49150
4
VOUT
R1
R2
January 2002
MIC49150
Micrel
Power Supply Rejection Ratio
(Input Supply)
Power Supply Rejection Ratio
(Bias Supply)
80
80
70
70
60
60
0.1
1
10
100
FREQUENCY (kHz)
0
1000
1600
0
0.01
1000
VBIAS = 5V
VOUT = 1.0V
50
1400
0.1
1
10
100
FREQUENCY (kHz)
100
1200
10
150
800
0
0.01
20
VBIAS = 3.3V
VIN = 1.8V
VOUT = 1.0V
IOUT = 1.5A
COUT = 1µF ceramic
1000
10
30
600
20
40
400
VBIAS = 3.3V
VIN = 1.8V
VOUT = 1.0V
IOUT = 1.5A
COUT = 1µF ceramic
30
200
0
40
50
250
200
50
Dropout Voltage
(Input Supply)
300
DROPOUT VOLTAGE (mV)
PSRR (dB)
PSRR (dB)
Typical Characteristics
OUTPUT CURRENT (mA)
Dropout Voltage
vs. Temperature
(Input Supply)
Dropout Voltage
(Bias Supply)
1.4
1.2
1.0
0.8
0.6
0.4
2.0
350
1.8
1.6
300
250
200
150
VBIAS = 5V
IOUT = 1.5A
VOUT = 1.5V
100
50
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE(°C)
1600
1400
1200
800
200
0
0
600
0.2
1000
VIN = 2.5V
VOUT = 1.5V
400
DROPOUT VOLTAGE (V)
DROPOUT VOLTAGE (mV)
1.6
400
DROPOUT VOLTAGE (V)
1.8
Dropout Voltage
vs. Temperature
(Bias Supply)
1.4
1.2
1.0
0.8
0.6
0.4
VIN = 2.5V
IOUT = 1.5A
VOUT = 1.5V
0.2
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE(°C)
OUTPUT CURRENT (mA)
Dropout Characteristics
(Bias Voltage)
0.4
VBIAS = 5V
0.2 V
OUT = 1.5V
0
0
0.5
1
1.5
2
INPUT VOLTAGE (V)
0.8
0.4
VIN = 2.5V
VOUT = 1.5V
0.2
0
0
2.5
IOUT = 1.5A
0.6
1
2
3
4
5
6
BIAS VOLTAGE (V)
7
1.500
1.499
1.498
1.497
1.496
1.495
VBIAS = 5V
VIN = 2.5V
1600
0.6
1.502
1.501
1400
0.8
IOUT = 10mA
1.0
1200
IOUT = 1.5A
1.2
1000
1.0
1.504
1.503
800
1.2
1.4
600
= 10mA
400
OUT
1.505
0
I
Load Regulation
1.6
OUTPUT VOLTAGE (V)
1.4
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
1.6
200
Dropout Characteristics
(Input Voltage)
OUTPUT CURRENT (mA)
Maximum Bias Current
vs. Bias Voltage
Maximum Bias Current
vs. Temperature
300
300
250
250
45
Bias Current
vs. Temperature
VIN = 2.5V
VOUT = 1.5V
VBIAS = 5V
VADJ = 0V
IOUT = 1.5A
VIN = 2.5V
200
150
100
50
0
3
*Note: Maximum bias current is bias
current with input in dropout
3.5
January 2002
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
6.5
200
VBIAS = 5V
VADJ = 0V
VIN = 2.5V
150
100
50
BIAS CURRENT (mA)
BIAS CURRENT (mA)
BIAS CURRENT (mA)
40
35
30 I
= 750mA
OUT
25
20
15
IOUT = 1500mA
IOUT = 100mA
10
5
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE(°C)
5
IOUT = 10mA
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
MIC49150
MIC49150
Micrel
Bias Current
vs. Output Current
Ground Current
vs. Bias Voltage
50
IBIAS
20
12
10
8
6
IOUT = 0mA
VIN = 2.5V
VOUT = 1.5V
4
2
0
1600
1400
1200
800
1000
600
400
0
200
10
GROUND CURRENT (mA)
CURRENT (mA)
30
GROUND CURRENT (mA)
VBIAS = 5V
VIN = 2.5V
VOUT = 1.5V
40
0
Bias Current
vs. Bias Voltage
14
14
3
3.5
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
12
10
8
6
IOUT = 100mA
VIN = 2.5V
VOUT = 1.5V
4
2
0
6.5
IBIAS
3
3.5
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
6.5
OUTPUT CURRENT (mA)
Bias Current
vs. Bias Voltage
Bias Current
vs. Bias Voltage
3.5
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
Bias Current
vs. Input Voltage
VBIAS = 5V
250 VOUT = 1.5V
750mA
100
50
0
0
1.55
0.5
1
1.5
2
INPUT VOLTAGE (V)
2.5
1.52
1.51
1.50
1.49
1.48
1.47
1.46
1.45
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
IOUT = 1500mA
VIN = 2.5V
VOUT = 1.5V
10
3
3.5
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
Reference Voltage
vs. Input Voltage
3.0
2.4
3.4
4.4
5.4
INPUT VOLTAGE (V)
6.4
2.0
1.5
1.0
VBIAS = 5V
VIN = 2.5V
VOUT = 0V
0.5
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
6
OUT
= 100mA
8
6
IOUT = 0mA
4
2
0.5
1
1.5
2
INPUT VOLTAGE (V)
2.5
Reference Voltage
vs. Bias Voltage
VIN = 2.5V
0.900
0.899
3
Short Circuit Current
vs. Temperature
2.5
I
12
10
0.901
0.900
0.899
1.4
20
18 VBIAS = 5V
VOUT = 1.5V
16
14
0
0
6.5
VBIAS = 5V
Output Voltage
vs. Temperature
VBIAS = 5V
1.54
VIN = 2.5V
1.53
MIC49150
20
0.901
1500mA
200
150
30
0
6.5
REFERENCE VOLTAGE (V)
3
BIAS CURRENT (mA)
10
IBIAS
REFERENCE VOLTAGE (V)
20
300
BIAS CURRENT (mA)
IBIAS
40
1.6
ENABLE THRESHOLD (V)
30
GROUND CURRENT (mA)
40
0
OUTPUT VOLTAGE (V)
50
IOUT = 750mA
VIN = 2.5V
VOUT = 1.5V
SHORT CIRCUIT CURRENT (A)
GROUND CURRENT (mA)
50
Bias Current
vs. Input Voltage
3.5
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
6.5
Enable Threshold
vs. Bias Voltage
1.4
ON
1.2
1.0
OFF
0.8
0.6
0.4
VIN = 2.5V
0.2
0
3
3.5
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
6.5
January 2002
MIC49150
Micrel
Enable Threshold
vs. Temperature
ENABLE THRESHOLD (V)
1.6
1.4
ON
1.2
1.0
OFF
0.8
0.6
0.4
0.2
VBIAS = 5V
VIN = 2.5V
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Functional Characteristics
Bias Voltage
Line Transient Response
OUTPUT VOLTAGE
20mV/div
OUTPUT VOLTAGE
50mV/div
Load Transient Response
OUTPUT CURRENT
1A/div
BIAS VOLTAGE
2V/div
VBIAS = 3.3V
VIN = 1.8V
VOUT = 1V
COUT = 1µF ceramic
TIME (10µs/div.)
VBIAS = 6.5V
VBIAS = 3.3V
VIN = 1.8V
VOUT = 1V
COUT = 1µF ceramic
IOUT = 1.5A
TIME (400µs/div.)
INPUT VOLTAGE
2V/div
OUTPUT VOLTAGE
20mV/div
Input Voltage
Line Transient Response
VIN = 6.5V
VIN = 1.8V
VBIAS = 3.3V
VOUT = 1V
COUT = 1µF ceramic
IOUT = 1.5A
TIME (400µs/div.)
January 2002
7
MIC49150
MIC49150
Micrel
Input Capacitor
An input capacitor of 1µF or greater is recommended when
the device is more than 4 inches away from the bulk supply
capacitance, or when the supply is a battery. Small, surfacemount, ceramic chip capacitors can be used for the bypassing. The capacitor should be placed within 1" of the device for
optimal performance. Larger values will help to improve
ripple rejection by bypassing the input to the regulator, further
improving the integrity of the output voltage.
Thermal Design
Linear regulators are simple to use. The most complicated
design parameters to consider are thermal characteristics.
Thermal design requires the following application-specific
parameters:
• Maximum ambient temperature (TA)
• Output Current (IOUT)
• Output Voltage (VOUT)
• Input Voltage (VIN)
• Ground Current (IGND)
First, calculate the power dissipation of the regulator from
these numbers and the device parameters from this datasheet.
PD = VIN × IIN + VBIAS × IBIAS – VOUT × IOUT
The input current will be less than the output current at high
output currents as the load increases. The bias current is a
sum of base drive and ground current. Ground current is
constant over load current. Then the heat sink thermal
resistance is determined with this formula:
Applications Information
The MIC49150 is an ultra-high performance, low dropout
linear regulator designed for high current applications requiring fast transient response. The MIC49150 utilizes two input
supplies, significantly reducing dropout voltage, perfect for
low-voltage, DC-to-DC conversion. The MIC49150 requires
a minimum of external components and obtains a bandwidth
of up to 10MHz. As a µCap regulator, the output is tolerant of
virtually any type of capacitor including ceramic type and
tantalum type capacitors.
The MIC49150 regulator is fully protected from damage due
to fault conditions, offering linear current limiting and thermal
shutdown.
Bias Supply Voltage
VBIAS, requiring relatively light current, provides power to the
control portion of the MIC49150. VBIAS requires approximately 33mA for a 1.5A load current. Dropout conditions
require higher currents. Most of the biasing current is used to
supply the base current to the pass transistor. This allows the
pass element to be driven into saturation, reducing the
dropout to 300mVat a 1.5A load current. Bypassing on the
bias pin is recommended to improve performance of the
regulator during line and load transients. Small ceramic
capacitors from VBIAS to ground help reduce high frequency
noise from being injected into the control circuitry from the
bias rail and are good design practice. Good bypass techniques typically include one larger capacitor such as a 1µF
ceramic and smaller valued capacitors such as 0.01µF or
0.001µF in parallel with that larger capacitor to decouple the
bias supply. The VBIAS input voltage must be 1.6V above the
output voltage with a minimum VBIAS input voltage of 3 volts.
Input Supply Voltage
VIN provides the high current to the collector of the pass
transistor. The minimum input voltage is 1.4V, allowing
conversion from low voltage supplies.
Output Capacitor
The MIC49150 requires a minimum of output capacitance to
maintain stability. However, proper capacitor selection is
important to ensure desired transient response. The MIC49150
is specifically designed to be stable with virtually any capacitance value and ESR. A 1µF ceramic chip capacitor should
satisfy most applications. Output capacitance can be increased without bound. See typical characteristics for examples of load transient response.
X7R dielectric ceramic capacitors are recommended because of their temperature performance. X7R-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic
capacitors. Z5U and Y5V dielectric capacitors change value
by as much as 50% and 60% respectively over their operating
temperature ranges. To use a ceramic chip capacitor with
Y5V dielectric, the value must be much higher than an X7R
ceramic or a tantalum capacitor to ensure the same capacitance value over the operating temperature range. Tantalum
capacitors have a very stable dielectric (10% over their
operating temperature range) and can also be used with this
device.
MIC49150
 TJ(MAX) – TA 
θSA = 

 PD – θ JC + θCS 
(
)
The heat sink may be significantly reduced in applications
where the maximum input voltage is known and large compared with the dropout voltage. Use a series input resistor to
drop excessive voltage and distribute the heat between this
resistor and the regulator. The low dropout properties of the
MIC49150 allow significant reductions in regulator power
dissipation and the associated heat sink without compromising performance. When this technique is employed, a capacitor of at least 1µF is needed directly between the input and
regulator ground. Refer to Application Note 9 for further
details and examples on thermal design and heat sink specification.
Minimum Load Current
The MIC49150, unlike most other high current regulators,
does not require a minimum load to maintain output voltage
regulation.
Power MSOP-8 Thermal Characteristics
One of the secrets of the MIC49150’s performance is its
power MSOP-8 package featuring half the thermal resistance
of a standard MSOP-8 package. Lower thermal resistance
means more output current or higher input voltage for a given
package size.
8
January 2002
MIC49150
Micrel
Lower thermal resistance is achieved by joining the four
ground leads with the die attach paddle to create a singlepiece electrical and thermal conductor. This concept has
been used by MOSFET manufacturers for years, proving
very reliable and cost effective for the user.
Thermal resistance consists of two main elements, θJC
(junction-to-case thermal resistance) and θCA (case-to-ambient thermal resistance). See Figure 1. θJC is the resistance
from the die to the leads of the package. θCA is the resistance
from the leads to the ambient air and it includes θCS (case-tosink thermal resistance) and θSA (sink-to-ambient thermal
resistance).
Using the power MSOP-8 reduces the θJC dramatically and
allows the user to reduce θCA. The total thermal resistance,
θJA (junction-to-ambient thermal resistance) is the limiting
factor in calculating the maximum power dissipation capability of the device. Typically, the power MSOP-8 has a θJA of
80°C/W, this is significantly lower than the standard MSOP-8
which is typically 160°C/W. θCA is reduced because pins 5
through 8 can now be soldered directly to a ground plane
which significantly reduces the case-to-sink thermal resistance and sink to ambient thermal resistance.
Low-dropout linear regulators from Micrel are rated to a
maximum junction temperature of 125°C. It is important not
to exceed this maximum junction temperature during operation of the device. To prevent this maximum junction temperature from being exceeded, the appropriate ground plane heat
sink must be used.
400
300
200
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Figure 2. Copper Area vs. Power-MSOP
Power Dissipation (∆TJA)
900
COPPER AREA (mm2)
800
700
T = 125°C
J
85°C
50°C 25°C
600
500
400
300
200
100
0
0
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Figure 3. Copper Area vs. Power-MSOP
Power Dissipation (TA)
∆T = TJ(max) – TA(max)
TJ(max) = 125°C
TA(max) = maximum ambient operating temperature
For example, the maximum ambient temperature is 50°C, the
∆T is determined as follows:
∆T = 125°C – 50°C
∆T = 75°C
Using Figure 2, the minimum amount of required copper can
be determined based on the required power dissipation.
Power dissipation in a linear regulator is calculated as follows:
PD = VIN × IIN + VBIAS × IBIAS – VOUT × IOUT
Using a typical application of 750mA output current, 1.2V
output voltage, 1.8V input voltage and 3.3V bias voltage, the
power dissipation is as follows:
PD = (1.8V) × (730mA) + 3.3V(30mA) – 1.2V(750mA)
At full current, a small percentage of the output current is
supplied from the bias supply, therefore the input current is
less than the output current.
PD = 513mW
From Figure 2, the minimum current of copper required to
operate this application at a ∆T of 75°C is less than 100mm2.
ground plane
heat sink area
AMBIENT
printed circuit board
Figure 1. Thermal Resistance
Figure 2 shows copper area versus power dissipation with
each trace corresponding to a different temperature rise
above ambient.
From these curves, the minimum area of copper necessary
for the part to operate safely can be determined. The maximum allowable temperature rise must be calculated to determine operation along which curve.
January 2002
500
0
0
θJA
θCA
600
100
MSOP-8
θJC
700
100°C
COPPER AREA (mm2)
800
40°C
50°C
55°C
65°C
75°C
85°C
900
9
MIC49150
MIC49150
Micrel
Quick Method
Enable
The fixed output voltage versions of the MIC49150 feature an
active high enable input (EN) that allows on-off control of the
regulator. Current drain reduces to “zero” when the device is
shutdown, with only microamperes of leakage current. The
EN input has TTL/CMOS compatible thresholds for simple
logic interfacing. EN may be directly tied to VIN and pulled up
to the maximum supply voltage
Determine the power dissipation requirements for the design
along with the maximum ambient temperature at which the
device will be operated. Refer to Figure 3, which shows safe
operating curves for three different ambient temperatures:
25°C, 50°C and 85°C. From these curves, the minimum
amount of copper can be determined by knowing the maximum power dissipation required. If the maximum ambient
temperature is 50°C and the power dissipation is as above,
513mW, the curve in Figure 3 shows that the required area of
copper is less than 100mm2.
The θJA of this package is ideally 80°C/W, but it will vary
depending upon the availability of copper ground plane to
which it is attached.
Adjustable Regulator Design
The MIC49150 adjustable version allows programming the
output voltage anywhere between 0.9Vand 5V. Two resistors
are used. The resistor value between VOUT and the adjust pin
should not exceed 10kΩ. Larger values can cause instability.
The resistor values are calculated by:
V

R1 = R2 ×  OUT – 1
 0.9

Where VOUT is the desired output voltage.
MIC49150
10
January 2002
MIC49150
Micrel
Package Information
0.122 (3.10)
0.112 (2.84)
0.199 (5.05)
0.187 (4.74)
DIMENSIONS:
INCH (MM)
0.120 (3.05)
0.116 (2.95)
0.036 (0.90)
0.032 (0.81)
0.043 (1.09)
0.038 (0.97)
0.007 (0.18)
0.005 (0.13)
0.012 (0.30) R
0.012 (0.3)
0.0256 (0.65) TYP
0.008 (0.20)
0.004 (0.10)
5° MAX
0° MIN
0.012 (0.03) R
0.039 (0.99)
0.035 (0.89)
0.021 (0.53)
8-Lead MSOP (MM)
0.370±0.005
9.395±0.125
0.040±0.010
1.015±0.255
0.315±0.005
8.000±0.130
0.067
1.700
0.355±0.005
9.015±0.125
0.075±0.005
1.905±0.125
0.256
6.50
0.010
0.250
0.040±0.005
1.015±0.125
0.415±0.005
10.54±0.130
0.003±0.002
0.080±0.050
0.010
0.250
0.028±0.003
0.710±0.080
INCHES
MILLIMETER
0.036±0.005
0.915±0.125
0° min
6° max
5-Lead S-Pak (R)
January 2002
11
MIC49150
MIC49150
Micrel
MICREL INC. 1849 FORTUNE DRIVE
TEL
+ 1 (408) 944-0800
FAX
SAN JOSE, CA 95131
+ 1 (408) 944-0970
WEB
USA
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
© 2002 Micrel Incorporated
MIC49150
12
January 2002