MIC39100-2.5BS [MICREL]
1A Low-Voltage Low-Dropout Regulator; 1A低压低压降稳压器型号: | MIC39100-2.5BS |
厂家: | MICREL SEMICONDUCTOR |
描述: | 1A Low-Voltage Low-Dropout Regulator |
文件: | 总12页 (文件大小:104K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
MIC39100/39101/39102
1A Low-Voltage Low-Dropout Regulator
General Description
Features
The MIC39100, MIC39101, and MIC39102 are 1A low-
dropout linear voltage regulators that provide low-voltage,
high-current output from an extremely small package. Utiliz-
ing Micrel’s proprietary Super βeta PNP™ pass element, the
MIC39100/1/2 offers extremely low dropout (typically 410mV
at 1A) and low ground current (typically 11mA at 1A).
• Fixed and adjustable output voltages to 1.24V
• 410mV typical dropout at 1A
Ideal for 3.0V to 2.5V conversion
Ideal for 2.5V to 1.8V conversion
• 1A minimum guaranteed output current
• 1% initial accuracy
• Low ground current
The MIC39100 is a fixed output regulator offered in the
SOT-223 package. The MIC39101 and MIC39102 are fixed
and adjustable regulators, respectively, in a thermally en-
hanced power 8-lead SOP (small outline package).
• Current limiting and thermal shutdown
• Reversed-battery protection
• Reversed-leakage protection
• Fast transient response
• Low-profile SOT-223 package
• Power SO-8 package
The MIC39100/1/2 is ideal for PC add-in cards that need to
convert from standard 5V to 3.3V, 3.3V to 2.5V or 2.5V to
1.8V.Aguaranteedmaximumdropoutvoltageof630mVover
all operating conditions allows the MIC39100/1/2 to provide
2.5V from a supply as low as 3.13V and 1.8V from a supply
as low as 2.43V.
Applications
• LDO linear regulator for PC add-in cards
• PowerPC™ power supplies
• High-efficiency linear power supplies
• SMPS post regulator
• Multimedia and PC processor supplies
• Battery chargers
The MIC39100/1/2 is fully protected with overcurrent limiting,
thermal shutdown, and reversed-battery protection. Fixed
voltages of 5.0V, 3.3V, 2.5V, and 1.8V are available on
MIC39100/1 with adjustable output voltages to 1.24V on
MIC39102.
• Low-voltage microcontrollers and digital logic
For other voltages, contact Micrel.
Ordering Information
Part Number
Voltage Junction Temp. Range
Package
MIC39100-1.8BS
MIC39100-2.5BS
MIC39100-3.3BS
MIC39100-5.0BS
MIC39101-1.8BM
MIC39101-2.5BM
MIC39101-3.3BM
MIC39101-5.0BM
MIC39102BM
1.8V
2.5V
3.3V
5.0V
1.8V
2.5V
3.3V
5.0V
Adj.
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
SOT-223
SOT-223
SOT-223
SOT-223
SOP-8
SOP-8
SOP-8
SOP-8
SOP-8
Typical Applications
100k
Error
Flag
Output
MIC39100
MIC39101
MIC39102
VIN
3.3V
VIN
3.3V
VIN
2.5V
IN
OUT
2.5V
IN
OUT
2.5V
IN
OUT
1.5V
R1
R1
ENABLE
SHUTDOWN
ENABLE
SHUTDOWN
EN
FLG
EN
ADJ
10µF
tantalum
10µF
tantalum
10µF
tantalum
GND
R2
GND
GND
2.5V/1A Regulator
2.5V/1A Regulator with Error Flag
1.5V/1A Adjustable Regulator
Super βeta PNP is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
June 2000
1
MIC39100/39101/39102
MIC39100/39101/39102
Micrel
Pin Configuration
GND
TAB
1
2
3
IN GND OUT
MIC39100-x.x
Fixed
SOT-223 (S)
EN
IN
1
2
3
4
8
7
6
5
GND
GND
GND
GND
EN
IN
1
2
3
4
8
7
6
5
GND
GND
GND
GND
OUT
FLG
OUT
ADJ
MIC39101-x.x
Fixed
SOP-8 (M)
MIC39102
Adjustable
SOP-8 (M)
Pin Description
Pin No.
Pin No.
Pin No.
Pin Name
Pin Function
MIC39100 MIC39101 MIC39102
1
1
1
EN
Enable (Input): CMOS-compatible control input. Logic high = enable, logic
low or open = shutdown.
2
3
4
2
3
IN
Supply (Input)
3
OUT
FLG
Regulator Output
Flag (Output): Open-collector error flag output. Active low = output under-
voltage.
4
ADJ
Adjustment Input: Feedback input. Connect to resitive voltage-divider
network.
2, TAB
5–8
5–8
GND
Ground
MIC39100/39101/39102
2
June 2000
MIC39100/39101/39102
Micrel
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 2)
Supply Voltage (V ) ..................................... –20V to +20V
Supply Voltage (V ) .................................. +2.25V to +16V
IN
IN
Enable Voltage (V ) ..................................................+20V
Enable Voltage (V ) ..................................................+16V
EN
EN
Storage Temperature (T ) ....................... –65°C to +150°C
Maximum Power Dissipation (P
)..................... Note 4
S
D(max)
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD, Note 3
Junction Temperature (T ) ....................... –40°C to +125°C
J
Package Thermal Resistance
SOT-223 (θ ) .....................................................15°C/W
JC
SOP-8 (θ ).........................................................20°C/W
JC
Electrical Characteristics
VIN = VOUT + 1V; VEN = 2.25V; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted
Symbol
Parameter
Condition
Min
Typ
Max
Units
VOUT
Output Voltage
10mA
–1
–2
1
2
%
%
10mA ≤ IOUT ≤ 1A, VOUT + 1V ≤ VIN ≤ 8V
Line Regulation
Load Regulation
IOUT = 10mA, VOUT + 1V ≤ VIN ≤ 16V
VIN = VOUT + 1V, 10mA ≤ IOUT ≤ 1A,
0.06
0.2
40
0.5
1
%
%
∆VOUT/∆T
Output Voltage Temp. Coefficient,
100 ppm/°C
Note 5
VDO
Dropout Voltage, Note 6
IOUT = 100mA, ∆VOUT = –1%
140
200
250
mV
mV
IOUT = 500mA, ∆VOUT = –1%
IOUT = 750mA, ∆VOUT = –1%
IOUT = 1A, ∆VOUT = –1%
275
330
mV
mV
500
550
630
mV
mV
410
400
4
IGND
Ground Current, Note 7
IOUT = 100mA, VIN = VOUT + 1V
IOUT = 500mA, VIN = VOUT + 1V
IOUT = 750mA, VIN = VOUT + 1V
IOUT = 1A, VIN = VOUT + 1V
µA
mA
mA
mA
A
6.5
11
20
IOUT(lim)
Enable Input
VEN
Current Limit
VOUT = 0V, VIN = VOUT + 1V
1.8
2.5
Enable Input Voltage
Enable Input Current
logic low (off)
logic high (on)
VEN = 2.25V
0.8
V
V
2.25
IEN
1
15
30
75
µA
µA
VEN = 0.8V
2
4
µA
µA
Flag Output
IFLG(leak)
Output Leakage Current
Output Low Voltage
VOH = 16V
0.01
210
1
2
µA
µA
VFLG(do)
VFLG
VIN = 2.250V, IOL, = 250µA, Note 9
300
400
mV
mV
Low Threshold
High Threshold
Hysteresis
% of VOUT
% of VOUT
93
%
%
%
99.2
1
June 2000
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MIC39100/39101/39102
MIC39100/39101/39102
Micrel
Symbol
Parameter
Condition
Min
Typ
Max
Units
MIC39102 Only
Reference Voltage
1.228 1.240 1.252
V
V
V
1.215
1.203
1.265
1.277
Note 10
Note 7
Adjust Pin Bias Current
40
20
80
120
nA
nA
Reference Voltage
Temp. Coefficient
ppm/°C
Adjust Pin Bias Current
Temp. Coefficient
0.1
nA/°C
Note 1. Exceeding the absolute maximum ratings 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.
Note 4.
P
= (T
– T ) ÷ θ , where θ depends upon the printed circuit layout. See “Applications Information.”
J(max) A JA JA
D(max)
Note 5. Output voltage temperature coefficient is ∆V
÷ (T
– T
) where T
is +125°C and T is –40°C.
J(min)
OUT(worst case)
J(max)
J(min)
J(max)
Note 6.
V
= V – V
when V
decreases to 98% of its nominal output voltage with V = V
+ 1V. For output voltages below 2.25V, dropout
OUT
DO
IN
OUT
OUT
IN
voltage is the input-to-output voltage differential with the minimum input voltage being 2.25V. Minimum input operating voltage is 2.25V.
Note 7.
Note 8.
I
is the quiescent current. I = I + I
.
OUT
GND
IN
GND
V
≤ 0.8V, V ≤ 8V, and V
= 0V.
EN
IN
OUT
Note 9. For a 2.5V device, V = 2.250V (device is in dropout).
IN
Note 10. V
≤ V
≤ (V – 1V), 2.25V ≤ V ≤ 16V, 10mA ≤ I ≤ 1A, T = T
.
REF
OUT
IN
IN
L
J
MAX
Note 11. 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 V = 16V for t = 10ms.
IN
MIC39100/39101/39102
4
June 2000
MIC39100/39101/39102
Micrel
Typical Characteristics
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
80
80
60
40
20
0
80
60
40
20
0
VIN = 5V
VOUT = 3.3V
VIN = 5V
VOUT = 3.3V
VIN = 3.3V
VOUT = 2.5V
60
40
IOUT = 1A
20
IOUT = 1A
COUT = 47µF
CIN = 0
IOUT = 1A
COUT = 10µF
CIN = 0
COUT = 10µF
CIN = 0
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
1k
10k 1M
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
1k
10k 1M
1k
10k
1M
10
100
100k
10
100
100k
10
100
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
Dropout Voltage
vs. Output Current
Dropout Voltage
vs. Temperature
80
600
500
VIN = 3.3V
VOUT = 2.5V
450
400
350
300
250
200
150
100
50
ILOAD = 1A
550
500
450
400
350
300
2.5V
60
40
20
0
1.8V
3.3V
3.3V
1.8V
TA = 25°C
2.5V
IOUT = 1A
COUT = 47µF
CIN = 0
0
1E+1 1E+2 1E+3 1E+4 1E+5 1E+6
1k
10k
-40 -20
0
20 40 60 80 100 120
1M
3.5
8
0
250 500 750 1000 1250
OUTPUT CURRENT (mA)
10
100
100k
FREQUENCY (Hz)
TEMPERATURE (°C)
Dropout Characteristics
(2.5V)
Dropout Characteristics
(3.3V)
Ground Current
vs. Output Current
2.8
3.6
3.4
3.2
3.0
2.8
2.6
2.4
14
2.6
2.4
2.2
2.0
1.8
1.6
1.4
12
10
8
I
=100mA
I
=100mA
LOAD
LOAD
1.8V
2.5V
I
LOAD
=750mA
3.3V
I
LOAD
=750mA
6
I
=1A
LOAD
4
I
=1A
LOAD
2
0
0
200 400 600 800 1000
OUTPUT CURRENT (mA)
2
2.3
2.6
2.9
3.2
2.8
3.2
3.6
4.0
4.4
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Ground Current
vs. Supply Voltage (2.5V)
Ground Current
vs. Supply Voltage (2.5V)
Ground Current
vs. Supply Voltage (3.3V)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
35
30
25
20
15
10
5
ILOAD =100mA
I
=100mA
=10mA
LOAD
I
=1A
LOAD
I
LOAD
ILOAD =10mA
0
0
2
4
6
8
0
2
4
6
0
2
4
6
8
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
June 2000
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MIC39100/39101/39102
MIC39100/39101/39102
Micrel
Ground Current
vs. Supply Voltage (3.3V)
Ground Current
vs. Temperature
Ground Current
vs. Temperature
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
50
40
30
20
10
0
1.0
0.8
0.6
0.4
0.2
0
2.5V
3.3V
ILOAD =10mA
I
=1A
LOAD
1.8V
3.3V
2.5V
1.8V
ILOAD = 500mA
-40 -20
0
20 40 60 80 100 120
0
2
4
6
8
-40 -20
0
20 40 60 80 100 120
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
Output Voltage
vs. Temperature
Ground Current
vs. Temperature
Short Circuit
vs. Temperature
20
15
10
5
3.40
3.35
3.30
3.25
3.20
2.5
2.0
1.5
1.0
0.5
0
ILOAD = 1A
3.3V
Typical 3.3V
Device
1.8V
2.5V
2.5V
1.8V
3.3V
0
-40 -20
0
20 40 60 80 100 120
-40 -20
0
20 40 60 80 100 120
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
Error Flag
Pull-Up Resistor
Enable Current
vs. Temperature
Flag-Low Voltage
vs. Temperature
12
10
8
250
200
150
100
50
6
5
4
3
2
1
VIN = 5V
VIN = VOUT + 1V
FLAG-LOW
VOLTAGE
VEN = 2.4V
FLAG HIGH
(OK)
6
VIN = 2.25V
RPULL-UP = 22kΩ
4
FLAG LOW
(FAULT)
2
0
0
0
0.01 0.1
1
10 100 100010000
-40 -20
0
20 40 60 80 100120140
-40 -20
0
20 40 60 80 100120140
RESISTANCE (kΩ)
TEMPERATURE (°C)
TEMPERATURE (°C)
MIC39100/39101/39102
6
June 2000
MIC39100/39101/39102
Micrel
Functional Characteristics
Load Transient Response
Load Transient Response
VOUT = 2.5V
COUT = 10µF
VOUT = 2.5V
COUT = 47µF
1A
1A
100mA
10mA
TIME (250µs/div.)
TIME (500µs/div.)
Line Transient Response
TIME (25µs/div.)
June 2000
7
MIC39100/39101/39102
MIC39100/39101/39102
Micrel
Functional Diagrams
IN
OUT
OV ILIMIT
18V
1.240V
Ref.
Thermal
Shut-
down
MIC39100
GND
MIC39100 Fixed Regulator Block Diagram
OUT
IN
O.V.
ILIMIT
18V
1.180V
1.240V
Ref.
FLAG
EN
Thermal
Shut-
down
GND
MIC39101
MIC39101 Fixed Regulator with Flag and Enable Block Diagram
OUT
IN
O.V.
ILIMIT
18V
1.240V
Ref.
ADJ
EN
Thermal
Shut-
down
GND
MIC39102
MIC39102 Adjustable Regulator Block Diagram
MIC39100/39101/39102
8
June 2000
MIC39100/39101/39102
Micrel
Input Capacitor
Applications Information
An input capacitor of 1µF or greater is recommended when
thedeviceismorethan4inchesawayfromthebulkacsupply
capacitance or when the supply is a battery. Small, surface
mount, ceramic chip capacitors can be used for bypassing.
Larger values will help to improve ripple rejection by bypass-
ing the input to the regulator, further improving the integrity of
the output voltage.
The MIC39100/1/2 is a high-performance low-dropout volt-
age regulator suitable for moderate to high-current voltage
regulator applications. Its 630mV dropout voltage at full load
and overtemperature makes it especially valuable in battery-
powered systems and as high-efficiency noise filters in post-
regulator applications. Unlike older NPN-pass transistor de-
signs, where the minimum dropout voltage is limited by the
base-to-emitter voltage drop and collector-to-emitter satura-
tion voltage, dropout performance of the PNP output of these
Error Flag
The MIC39101 features an error flag (FLG), which monitors
the output voltage and signals an error condition when this
voltage drops 5% below its expected value. The error flag is
an open-collector output that pulls low under fault conditions
and may sink up to 10mA. Low output voltage signifies a
number of possible problems, including an overcurrent fault
(the device is in current limit) or low input voltage. The flag
output is inoperative during overtemperature conditions. A
devices is limited only by the low V saturation voltage.
CE
A trade-off for the low dropout voltage is a varying base drive
requirement. Micrel’s Super βeta PNP™ process reduces
this drive requirement to only 2% of the load current.
The MIC39100/1/2 regulator is fully protected from damage
due to fault conditions. Linear current limiting is provided.
Output current during overload conditions is constant. Ther-
mal shutdown disables the device when the die temperature
exceeds the maximum safe operating temperature. Tran-
sient protection allows device (and load) survival even when
the input voltage spikes above and below nominal. The
outputstructureoftheseregulatorsallowsvoltagesinexcess
of the desired output voltage to be applied without reverse
current flow.
pull-up resistor from FLG to either V or V
is required for
IN
OUT
properoperation.Forinformationregardingtheminimumand
maximum values of pull-up resistance, refer to the graph in
the typical characteristics section of the data sheet.
Enable Input
The MIC39101 and MIC39102 versions 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
MIC39100-x.x
VIN
VOUT
IN
OUT
GND
logic interfacing. EN may be directly tied to V and pulled up
CIN
COUT
IN
to the maximum supply voltage
Transient Response and 3.3V to 2.5V or 2.5V to 1.8V
Conversion
Figure 1. Capacitor Requirements
Output Capacitor
The MIC39100/1/2 has excellent transient response to varia-
tions in input voltage and load current. The device has been
designed to respond quickly to load current variations and
input voltage variations. Large output capacitors are not
required to obtain this performance. A standard 10µF output
capacitor, preferably tantalum, is all that is required. Larger
values help to improve performance even further.
The MIC39100/1/2 requires an output capacitor to maintain
stability and improve transient response. Proper capacitor
selection is important to ensure proper operation. The
MIC39100/1/2 output capacitor selection is dependent upon
theESR(equivalentseriesresistance)oftheoutputcapacitor
to maintain stability. When the output capacitor is 10µF or
greater, the output capacitor should have an ESR less than
2Ω. This will improve transient response as well as promote
stability. Ultra-low-ESR capacitors (<100mΩ), such as ce-
ramic chip capacitors, may promote instability. These very
low ESR levels may cause an oscillation and/or underdamp-
ed transient response. A low-ESR solid tantalum capacitor
works extremely well and provides good transient response
and stability over temperature. Aluminum electrolytics can
also be used, as long as the ESR of the capacitor is <2Ω.
By virtue of its low-dropout voltage, this device does not
saturate into dropout as readily as similar NPN-based de-
signs. Whenconvertingfrom3.3Vto2.5Vor2.5Vto1.8V, the
NPN based regulators are already operating in dropout, with
typical dropout requirements of 1.2V or greater. To convert
down to 2.5V or 1.8V without operating in dropout, NPN-
based regulators require an input voltage of 3.7V at the very
least. The MIC39100 regulator will provide excellent perfor-
mance with an input as low as 3.0V or 2.5V respectively. This
gives the PNP based regulators a distinct advantage over
older, NPN based linear regulators.
The value of the output capacitor can be increased without
limit. Higher capacitance values help to improve transient
response and ripple rejection and reduce output noise.
Minimum Load Current
TheMIC39100/1/2regulatorisspecifiedbetweenfiniteloads.
If the output current is too small, leakage currents dominate
and the output voltage rises. A 10mA minimum load current
is necessary for proper regulation.
June 2000
9
MIC39100/39101/39102
MIC39100/39101/39102
Micrel
Adjustable Regulator Design
sink thermal resistance) and θ
(sink-to-ambient thermal
SA
resistance).
Using the power SOP-8 reduces the θ dramatically and
JC
MIC39102
allows the user to reduce θ . The total thermal resistance,
VIN
IN
OUT
VOUT
COUT
CA
R1
R2
θ
(junction-to-ambient thermal resistance) is the limiting
JA
ENABLE
SHUTDOWN
EN
ADJ
factor in calculating the maximum power dissipation capabil-
GND
ity of the device. Typically, the power SOP-8 has a θ of
JC
20°C/W, this is significantly lower than the standard SOP-8
R1
R2
which is typically 75°C/W. θ
is reduced because pins 5
V
= 1.240V 1+
CA
OUT
through 8 can now be soldered directly to a ground plane
which significantly reduces the case-to-sink thermal resis-
tance and sink to ambient thermal resistance.
Figure 2. Adjustable Regulator with Resistors
The MIC39102 allows programming the output voltage any-
wherebetween1.24Vandthe16Vmaximumoperatingrating
of the family. Two resistors are used. Resistors can be quite
large, up to 1MΩ, because of the very high input impedance
and low bias current of the sense comparator: The resistor
values are calculated by:
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 opera-
tionofthedevice.Topreventthismaximumjunctiontempera-
ture from being exceeded, the appropriate ground plane heat
sink must be used.
VOUT
R1= R2
−1
1.240
Where V is the desired output voltage. Figure 2 shows
O
SOP-8
component definition. Applications with widely varying load
currents may scale the resistors to draw the minimum load
current required for proper operation (see above).
Power SOP-8 Thermal Characteristics
θJA
One of the secrets of the MIC39101/2’s performance is its
power SO-8 package featuring half the thermal resistance of
a standard SO-8 package. Lower thermal resistance means
more output current or higher input voltage for a given
package size.
ground plane
heat sink area
θJC
θCA
AMBIENT
printed circuit board
Lower thermal resistance is achieved by joining the four
ground leads with the die attach paddle to create a single-
piece electrical and thermal conductor. This concept has
been used by MOSFET manufacturers for years, proving
very reliable and cost effective for the user.
Figure 3. Thermal Resistance
Figure 4 shows copper area versus power dissipation with
each trace corresponding to a different temperature rise
above ambient.
Thermal resistance consists of two main elements, θ
From these curves, the minimum area of copper necessary
for the part to operate safely can be determined. The maxi-
mum allowable temperature rise must be calculated to deter-
mine operation along which curve.
JC
(junction-to-casethermalresistance)andθ (case-to-ambi-
CA
ent thermal resistance). See Figure 3. θ is the resistance
JC
from the die to the leads of the package. θ is the resistance
CA
from the leads to the ambient air and it includes θ (case-to-
CS
900
800
900
T
= 125°C
800
700
600
500
400
300
200
100
0
J
∆TJA
=
700
600
500
400
300
200
100
0
TA = 85°C
50°C 25°C
0
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
0
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Figure 4. Copper Area vs. Power-SOP
Power Dissipation
Figure 5. Copper Area vs. Power-SOP
Power Dissipation
MIC39100/39101/39102
10
June 2000
MIC39100/39101/39102
Micrel
Quick Method
∆T = T
– T
A(max)
J(max)
Determine the power dissipation requirements for the design
along with the maximum ambient temperature at which the
device will be operated. Refer to Figure 5, 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 maxi-
mum power dissipation required. If the maximum ambient
temperature is 50°C and the power dissipation is as above,
836mW, the curve in Figure 5 shows that the required area of
T
= 125°C
J(max)
T
= maximum ambient operating temperature
A(max)
Forexample, themaximumambienttemperatureis50°C, the
∆T is determined as follows:
∆T = 125°C – 50°C
∆T = 75°C
Using Figure 4, the minimum amount of required copper can
be determined based on the required power dissipation.
Power dissipation in a linear regulator is calculated as fol-
lows:
2
copper is 160mm .
The θ of this package is ideally 63°C/W, but it will vary
JA
depending upon the availability of copper ground plane to
which it is attached.
P = (V – V
) I
+ V · I
D
IN
OUT OUT IN GND
If we use a 2.5V output device and a 3.3V input at an output
current of 1A, then our power dissipation is as follows:
P = (3.3V – 2.5V) × 1A + 3.3V × 11mA
D
P = 800mW + 36mW
D
P = 836mW
D
From Figure 4, the minimum amount of copper required to
2
operate this application at a ∆T of 75°C is 160mm .
June 2000
11
MIC39100/39101/39102
MIC39100/39101/39102
Micrel
Package Information
3.15 (0.124)
2.90 (0.114)
C
L
7.49 (0.295)
6.71 (0.264)
3.71 (0.146)
3.30 (0.130)
C
L
2.41 (0.095)
2.21 (0.087)
1.04 (0.041)
0.85 (0.033)
4.7 (0.185)
4.5 (0.177)
DIMENSIONS:
MM (INCH)
1.70 (0.067)
1.52 (0.060)
16°
10°
6.70 (0.264)
6.30 (0.248)
0.10 (0.004)
0.38 (0.015)
10°
MAX
0.02 (0.0008)
0.25 (0.010)
0.84 (0.033)
0.64 (0.025)
0.91 (0.036) MIN
SOT-223 (S)
0.026 (0.65)
MAX)
PIN 1
0.157 (3.99)
0.150 (3.81)
DIMENSIONS:
INCHES (MM)
0.020 (0.51)
0.013 (0.33)
0.050 (1.27)
TYP
45°
0.0098 (0.249)
0.0040 (0.102)
0.010 (0.25)
0.007 (0.18)
0°–8°
0.197 (5.0)
0.189 (4.8)
0.050 (1.27)
0.016 (0.40)
SEATING
PLANE
0.064 (1.63)
0.045 (1.14)
0.244 (6.20)
0.228 (5.79)
8-Lead SOP (M)
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB 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.
© 2000 Micrel Incorporated
MIC39100/39101/39102
12
June 2000
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