MICREL MIC5209

MIC5209
Micrel
MIC5209
500mA Low-Noise LDO Regulator
General Description
Features
The MIC5209 is an efficient linear voltage regulator with very
low dropout voltage, typically 10mV at light loads and less
than 500mV at full load, with better than 1% output voltage
accuracy.
• Meets Intel® Slot 1 and Slot 2 requirements
• Guaranteed 500mA output over the full operating
temperature range
• Low 500mV maximum dropout voltage at full load
• Extremely tight load and line regulation
• Thermally-efficient surface-mount package
• Low temperature coefficient
• Current and thermal limiting
• Reversed-battery protection
• No-load stability
• 1% output accuracy
• Ultra-low-noise capability in SO-8 and TO-263-5
Designed especially for hand-held, battery-powered devices,
the MIC5209 features low ground current to help prolong
battery life. An enable/shutdown pin on SO-8 and TO-263-5
versions can further improve battery life with near-zero shutdown current.
Key features include reversed-battery protection, current
limiting, overtemperature shutdown, ultra-low-noise capability (SO-8 and TO-263-5 versions), and availability in thermally efficient packaging. The MIC5209 is available in adjustable or fixed output voltages.
Applications
•
•
•
•
•
•
For space-critical applications where peak currents do not
exceed 500mA, see the MIC5219.
Typical Applications
Ordering Information
Part Number
MIC5209-2.5BS
1
2
VOUT
2.5V ±1%
22µF
tantalum
3.3V Nominal-Input Slot-1
Power Supply
ENABLE
SHUTDOWN
VIN
6V
VOUT
5V
2.2µF
tantalum
Voltage
Junct. Temp. Range
Package
MIC5209-2.5BS
2.5V
–40°C to +125°C
SOT-223
MIC5209-3.0BS
3.0V
–40°C to +125°C
SOT-223
MIC5209-3.3BS
3.3V
–40°C to +125°C
SOT-223
MIC5209-3.6BS
3.6V
–40°C to +125°C
SOT-223
MIC5209-4.2BS
4.2V
–40°C to +125°C
SOT-223
MIC5209-5.0BS
5.0V
–40°C to +125°C
SOT-223
MIC5209-1.8BM
1.8V
0°C to +125°C
SO-8
MIC5209-2.5BM
2.5V
–40°C to +125°C
SO-8
MIC5209-3.0BM
3.0V
–40°C to +125°C
SO-8
MIC5209-3.3BM
3.3V
–40°C to +125°C
SO-8
MIC5209-3.6BM
3.6V
–40°C to +125°C
SO-8
MIC5209-5.0BM
5.0V
–40°C to +125°C
SO-8
3
VIN
≥ 3.0V
0.1µF
Pentium II Slot 1 and Slot 2 support circuits
Laptop, notebook, and palmtop computers
Cellular telephones
Consumer and personal electronics
SMPS post-regulator/dc-to-dc modules
High-efficiency linear power supplies
MIC5209-5.0BM
1
8
2
7
3
6
MIC5209BM
Adj.
–40°C to +125°C
SO-8
4
5
MIC5209-2.5BU
2.5V
–40°C to +125°C
TO-263-5
MIC5209-3.0BU
3.0V
–40°C to +125°C
TO-263-5
MIC5209-3.3BU
3.3V
–40°C to +125°C
TO-263-5
MIC5209-3.6BU
3.6V
–40°C to +125°C
TO-263-5
MIC5209-5.0BU
5.0V
–40°C to +125°C
TO-263-5
MIC5209BU
Adj.
–40°C to +125°C
TO-263-5
470pF
(OPTIONAL)
Ultra-Low-Noise 5V Regulator
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
August 2, 2000
1
MIC5209
MIC5209
Micrel
Pin Configuration
GND
TAB
1
IN
IN 2
7
GND
OUT 3
6
GND
BYP 4
5
GND
MIC5209-x.xBS
SOT-223
Fixed Voltages
TAB
8
GND
3
GND
EN 1
2
GND OUT
5
4
3
2
1
BYP
OUT
GND
IN
EN
MIC5209-x.xBU
TO-263-5
Fixed Voltages
8
GND
IN 2
7
GND
OUT 3
6
GND
ADJ 4
5
GND
TAB
EN 1
GND
MIC5209-x.xBM
SO-8
Fixed Voltages
5
4
3
2
1
ADJ
OUT
GND
IN
EN
MIC5209BU
TO-263-5
Adjustable Voltage
MIC5209BM
SO-8
Adjustable Voltage
Pin Description
Pin No.
SOT-223
Pin No.
SO-8
Pin No.
TO-263-5
Pin Name
Pin Function
1
2
2
IN
Supply Input
2, TAB
5–8
3
GND
Ground: SOT-223 pin 2 and TAB are internally connected. SO-8 pins 5
through 8 are internally connected.
3
3
4
OUT
Regulator Output
1
1
EN
Enable (Input): CMOS compatible control input. Logic high = enable; logic
low or open = shutdown.
4 (fixed)
5 (fixed)
BYP
Reference Bypass: Connect external 470pF capacitor to GND to reduce
output noise. May be left open. For 1.8V or 2.5V operation, see “Applications Information.”
4 (adj.)
5 (adj.)
ADJ
Adjust (Input): Feedback input. Connect to resistive voltage-divider network.
MIC5209
2
August 2, 2000
MIC5209
Micrel
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 2)
Supply Input Voltage (VIN) ............................ –20V to +20V
Power Dissipation (PD) ............... Internally Limited, Note 3
Junction Temperature (TJ)
all except 1.8V ...................................... –40°C to +125°C
1.8V only .................................................. 0°C to +125°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
Storage Temperature (TS) ....................... –65°C to +150°C
Supply Input Voltage (VIN) ........................... +2.5V to +16V
Enable Input Voltage (VEN) .................................. 0V to VIN
Junction Temperature (TJ)
all except 1.8V ...................................... –40°C to +125°C
1.8V only .................................................. 0°C to +125°C
Package Thermal Resistance .................................. Note 3
Electrical Characteristics
VIN = VOUT + 1.0V; COUT = 4.7µF, IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C except
0°C ≤ TJ ≤ +125°C for 1.8V version; unless noted.
Symbol
Parameter
Conditions
VOUT
Output Voltage Accuracy
variation from nominal VOUT
∆VOUT/∆T
Output Voltage
Temperature Coefficient
Note 4
∆VOUT/VOUT
Line Regulation
VIN = VOUT + 1V to 16V
0.009
0.05
0.1
%/V
%/V
∆VOUT/VOUT
Load Regulation
IOUT = 100µA to 500mA, Note 5
0.05
0.5
0.7
%
%
VIN – VOUT
Dropout Voltage, Note 6
IOUT = 100µA
10
60
80
mV
mV
IOUT = 50mA
115
175
250
mV
mV
IOUT = 150mA
165
300
400
mV
mV
IOUT = 500mA
350
500
600
mV
mV
VEN ≥ 3.0V, IOUT = 100µA
80
130
170
µA
µA
VEN ≥ 3.0V, IOUT = 50mA
350
650
900
µA
µA
VEN ≥ 3.0V, IOUT = 150mA
1.8
2.5
3.0
mA
mA
VEN ≥ 3.0V, IOUT = 500mA
8
20
25
mA
mA
VEN ≤ 0.4V (shutdown)
0.05
3
µA
VEN ≤ 0.18V (shutdown)
0.10
8
µA
IGND
IGND
Ground Pin Current, Notes 7, 8
Ground Pin Quiescent Current,
Note 8
Min
Typical
–1
–2
Max
Units
1
2
%
%
40
ppm/°C
PSRR
Ripple Rejection
f = 120Hz
75
ILIMIT
Current Limit
VOUT = 0V
700
∆VOUT/∆PD
Thermal Regulation
Note 9
0.05
%/W
eno
Output Noise
Note 10
VOUT = 2.5V, IOUT = 50mA,
COUT = 2.2µF, CBYP = 0
500
nV/ Hz
IOUT = 50mA, COUT = 2.2µF, CBYP = 470pF
300
nV/ Hz
August 2, 2000
3
dB
900
1000
mA
mA
MIC5209
MIC5209
Micrel
ENABLE Input
VENL
Enable Input Logic-Low Voltage
VEN = logic low (regulator shutdown)
VEN = logic high (regulator enabled)
IENL
Enable Input Current
IENH
0.4
0.18
V
V
2.0
V
VENL ≤ 0.4V
0.01
–1
µA
VENL ≤ 0.18V
0.01
–2
µA
VENH ≥ 2.0V
5
20
25
µA
µA
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:
The maximum allowable power dissipation at any TA (ambient temperature) is calculated using: PD(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. See Table 1
and the “Thermal Considerations” section for details.
Note 4:
Output voltage temperature coefficient is the worst case voltage change divided by the total temperature range.
Note 5:
Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load
range from 100µA to 500mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
Note 6:
Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
differential.
Note 7:
Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of
the load current plus the ground pin current.
Note 8:
VEN is the voltage externally applied to devices with the EN (enable) input pin. [SO-8 (M) and TO-263-5 (U) packages only.]
Note 9:
Thermal regulation is 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 500mA load pulse at VIN = 16V for t = 10ms.
Note 10: CBYP is an optional, external bypass capacitor connected to devices with a BYP (bypass) or ADJ (adjust) pin. [SO-8 (M) and TO-263-5 (U)
packages only].
MIC5209
4
August 2, 2000
MIC5209
Micrel
Block Diagrams
VIN
OUT
IN
VOUT
COUT
Bandgap
Ref.
Current Limit
Thermal Shutdown
MIC5209-x.xBS
GND
Low-Noise Fixed Regulator (SOT-223 version only)
VIN
OUT
IN
VOUT
COUT
BYP
CBYP
(optional)
Bandgap
Ref.
V
REF
EN
Current Limit
Thermal Shutdown
MIC5209-x.xBM/U
GND
Ultra-Low-Noise Fixed Regulator
VIN
OUT
IN
VOUT
COUT
ADJ
R1
R2
Bandgap
Ref.
V
REF
CBYP
(optional)
EN
Current Limit
Thermal Shutdown
MIC5209BM/U [adj.]
GND
Ultra-Low-Noise Adjustable Regulator
August 2, 2000
5
MIC5209
MIC5209
Micrel
Typical Characteristics
Power Supply
Rejection Ratio
-40
-60
-80
-60
-80
0
-60
-40
-60
IOUT = 100µA
COUT = 2.2µF
CBYP = 0.01µF
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
Power Supply Ripple Rejection
vs. Voltage Drop
Power Supply Ripple Rejection
vs. Voltage Drop
1mA
30
10mA
IOUT = 100mA
20
10
COUT = 1µF
0
0.1
0.2
0.3
VOLTAGE DROP (V)
0.4
80
10mA, COUT = 1µF
1
1mA
70
60
IOUT = 100mA
50
40
10mA
30
20
10
0
Noise Performance
COUT = 2.2µF
CBYP = 0.01µF
0
0.1
0.2
0.3
VOLTAGE DROP (V)
10
1
1
500mA Pending
VOUT = 5V
COUT = 10µF
electrolytic
1mA
0.0001
1k 1E+4
10 1E+2
1M 1E+7
10k 1E+5
100k 1E+6
10M
1E+1
100 1E+3
FREQUENCY (Hz)
NOISE (µV/√Hz)
NOISE (µV/√Hz)
100mA
0.01
0.01 500mA Pending
0.001
0.4
VOUT = 5V
0.0001
10 1E+2
1E+1
1k 1E+4
100 1E+3
10k 1E+5
100k 1E+6
1M 1E+7
10M
FREQUENCY (Hz)
Dropout Voltage
vs. Output Current
400
500mA Pending
10mA
0.1
Noise Performance
10
0.1
Noise Performance
10
500mA pending
100mA
0.1
0.01
1mA
VOUT = 5V
COUT = 10µF
0.001 electrolytic
10mA
CBYP = 100pF
0.0001
1k 1E+4
10 1E+2
1M 1E+7
10k 1E+5
100k 1E+6
10M
1E+1
100 1E+3
FREQUENCY (Hz)
6
DROPOUT VOLTAGE (mV)
40
100
90
IOUT = 100mA
COUT = 2.2µF
CBYP = 0.01µF
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
NOISE (µV/√Hz)
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
500mA pending
-60
-80
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
50
-40
IOUT = 1mA
COUT = 2.2µF
CBYP = 0.01µF
-80
60
VIN = 6V
VOUT = 5V
-20
PSRR (dB)
PSRR (dB)
PSRR (dB)
Power Supply
Rejection Ratio
VIN = 6V
VOUT = 5V
-20
-40
MIC5209
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
-80
IOUT = 100mA
COUT = 1µF
Power Supply
Rejection Ratio
VIN = 6V
VOUT = 5V
-20
0.001
-60
-80
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
0
-40
IOUT = 1mA
COUT = 1µF
Power Supply
Rejection Ratio
VIN = 6V
VOUT = 5V
-20
-40
IOUT = 100µA
COUT = 1µF
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
VIN = 6V
VOUT = 5V
-20
PSRR (dB)
-20
PSRR (dB)
0
VIN = 6V
VOUT = 5V
Power Supply
Rejection Ratio
PSRR (dB)
0
Power Supply
Rejection Ratio
300
200
100
0
0
100 200 300 400 500
OUTPUT CURRENT (mA)
August 2, 2000
MIC5209
Micrel
Dropout Characteristics
Ground Current
vs. Output Current
3.0
12
I =100µA
L
GROUND CURRENT (mA)
OUTPUT VOLTAGE (V)
3.5
2.5
2.0
1.5
I =100mA
L
1.0
I =500mA
L
0.5
0
0
1
2 3 4 5 6 7 8
INPUT VOLTAGE (V)
10
8
6
4
2
0
0
9
Ground Current
vs. Supply Voltage
Ground Current
vs. Supply Voltage
3.0
20
GROUND CURRENT (mA)
GROUND CURRENT (mA)
25
15
10
5
0
0
August 2, 2000
100 200 300 400 500
OUTPUT CURRENT (mA)
1
IL=500mA
2 3 4 5 6 7 8
INPUT VOLTAGE (V)
9
2.5
2.0
1.5
1.0
0.5
0
0
7
IL=100 mA
IL=100µA
2
4
6
INPUT VOLTAGE (V)
8
MIC5209
MIC5209
Micrel
Thermal Considerations
The SOT-223 has a ground tab which allows it to dissipate
more power than the SO-8. Refer to “Slot-1 Power Supply” for
details. At 25°C ambient, it will operate reliably at 2W dissipation with “worst-case” mounting (no ground plane, minimum
trace widths, and FR4 printed circuit board).
Applications Information
Enable/Shutdown
Enable is available only on devices in the SO-8 (M) and
TO-263-5 (U) packages.
Forcing EN (enable/shutdown) high (> 2V) enables the regulator. EN is compatible with CMOS logic. If the enable/
shutdown feature is not required, connect EN to IN (supply
input).
Input Capacitor
Thermal resistance values for the SO-8 represent typical
mounting on a 1"-square, copper-clad, FR4 circuit board. For
greater power dissipation, SO-8 versions of the MIC5209
feature a fused internal lead frame and die bonding arrangement that reduces thermal resistance when compared to
standard SO-8 packages.
A 1µF capacitor should be placed from IN to GND 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.
Output Capacitor
An output capacitor is required between OUT and GND to
prevent oscillation. The minimum size of the output capacitor
is dependent upon whether a reference bypass capacitor is
used. 1µF minimum is recommended when CBYP is not used
(see Figure 1). 2.2µF minimum is recommended when CBYP
is 470pF (see Figure 2). Larger values improve the regulator’s
transient response.
The output capacitor should have an ESR (equivalent series
resistance) of about 5Ω and a resonant frequency above
1MHz. Ultra-low-ESR capacitors can cause a low amplitude
oscillation on the output and/or underdamped transient response. Most tantalum or aluminum electrolytic capacitors
are adequate; film types will work, but are more expensive.
Since many aluminum electrolytics have electrolytes that
freeze at about –30°C, solid tantalums are recommended for
operation below –25°C.
At lower values of output current, less output capacitance is
needed for output stability. The capacitor can be reduced to
0.47µF for current below 10mA or 0.33µF for currents below
1mA.
θJC
SOT-223 (S)
50°C/W
8°C/W
SO-8 (M)
50°C/W
25°C/W
—
2°C/W
TO-263-5 (U)
Table 1. MIC5209 Thermal Resistance
Multilayer boards with a ground plane, wide traces near the
pads, and large supply-bus lines will have better thermal
conductivity and will also allow additional power dissipation.
For additional heat sink characteristics, please refer to Micrel
Application Hint 17, “Designing P.C. Board Heat Sinks”,
included in Micrel’s Databook. For a full discussion of heat
sinking and thermal effects on voltage regulators, refer to
Regulator Thermals section of Micrel’s Designing with LowDropout Voltage Regulators handbook.
Low-Voltage Operation
The MIC5209-1.8 and MIC5209-2.5 require special consideration when used in voltage-sensitive systems. They may
momentarily overshoot their nominal output voltages unless
appropriate output and bypass capacitor values are chosen.
During regulator power up, the pass transistor is fully saturated for a short time, while the error amplifier and voltage
reference are being powered up more slowly from the output
(see “Block Diagram”). Selecting larger output and bypass
capacitors allows additional time for the error amplifier and
reference to turn on and prevent overshoot.
To ensure that no overshoot is present when starting up into
a light load (100µA), use a 4.7µF output capacitance and
470pF bypass capacitance. This slows the turn-on enough to
allow the regulator to react and keep the output voltage from
exceeding its nominal value. At heavier loads, use a 10µF
output capacitance and 470pF bypass capacitance. Lower
values of output and bypass capacitance can be used,
depending on the sensitivity of the system.
No-Load Stability
The MIC5209 will remain stable and in regulation with no load
(other than the internal voltage divider) unlike many other
voltage regulators. This is especially important in CMOS
RAM keep-alive applications.
Reference Bypass Capacitor
BYP (reference bypass) is available only on devices in SO-8
and TO-263-5 packages.
BYP is connected to the internal voltage reference. A 470pF
capacitor (CBYP) connected from BYP to GND quiets this
reference, providing a significant reduction in output noise
(ultra-low-noise performance). Because CBYP reduces the
phase margin, the output capacitor should be increased to at
least 2.2µF to maintain stability.
Applications that can withstand some overshoot on the
output of the regulator can reduce the output capacitor and/
or reduce or eliminate the bypass capacitor. Applications that
are not sensitive to overshoot due to power-on reset delays
can use normal output and bypass capacitor configurations.
Please note the junction temperature range of the regulator
at 1.8V output (fixed and adjustable) is 0˚C to +125˚C.
The start-up speed of the MIC5209 is inversely proportional
to the size of the reference bypass capacitor. Applications
requiring a slow ramp-up of output voltage should consider
larger values of CBYP. Likewise, if rapid turn-on is necessary,
consider omitting CBYP.
If output noise is not critical, omit CBYP and leave BYP open.
MIC5209
θJA
Package
8
August 2, 2000
MIC5209
Micrel
Fixed Regulator Circuits
MIC5209-x.xBM
VIN
2
1
IN
OUT
EN
BYP
GND
3
Although ADJ is a high-impedance input, for best performance, R2 should not exceed 470kΩ.
VOUT
VIN
4
MIC5209BM
2
1
1µF
5–8
IN
EN
OUT
ADJ
GND
VOUT
3
4
R1
2.2µF
5–8
470pF
R2
Figure 1. Low-Noise Fixed Voltage Regulator
Figure 1 shows a basic MIC5209-x.xBM (SO-8) fixed-voltage
regulator circuit. See Figure 5 for a similar configuration
using the more thermally-efficient MIC5209-x.xBS (SOT-223).
A 1µF minimum output capacitor is required for basic fixedvoltage applications.
MIC5209-x.xBM
VIN
2
1
IN
OUT
EN
BYP
GND
5–8
Figure 4. Ultra-Low-Noise Adjustable Application.
Figure 4 includes the optional 470pF bypass capacitor from
ADJ to GND to reduce output noise.
Slot-1 Power Supply
Intel’s Pentium II processors have a requirement for a 2.5V
±5% power supply for a clock synthesizer and its associated
loads. The current requirement for the 2.5V supply is dependant upon the clock synthesizer used, the number of clock
outputs, and the type of level shifter (from core logic levels to
2.5V levels). Intel estimates a worst-case load of 320mA.
The MIC5209 was designed to provide the 2.5V power
requirement for Slot-1 applications. Its guaranteed performance of 2.5V ±3% at 500mA allows adequate margin for all
systems, and its dropout voltage of 500mV means that it
operates from a worst-case 3.3V supply where the voltage
can be as low as 3.0V.
VOUT
3
4
2.2µF
470pF
Figure 2. Ultra-Low-Noise Fixed Voltage Regulator
Figure 2 includes the optional 470pF noise bypass capacitor
between BYP and GND to reduce output noise. Note that the
minimum value of COUT must be increased when the bypass
capacitor is used.
Adjustable Regulator Circuits
VIN
VIN
MIC5209BM
2
1
IN
EN
OUT
ADJ
GND
IN
OUT
3
VOUT
VOUT
3
4
MIC5209-x.xBS
1
CIN
0.1µF
R1
1µF
GND
2,TAB
COUT
22µF
5–8
R2
Figure 5. Slot-1 Power Supply
A Slot-1 power supply (Figure 5) is easy to implement. Only
two capacitors are necessary, and their values are not critical.
CIN bypasses the internal circuitry and should be at least
0.1µF. COUT provides output filtering, improves transient
response, and compensates the internal regulator control
loop. Its value should be at least 22µF. CIN and COUT may be
increased as much as desired.
Figure 3. Low-Noise Adjustable Voltage Regulator
The MIC5209BM/U can be adjusted to a specific output
voltage by using two external resistors (Figure 3). The resistors set the output voltage based on the equation:
R2 

VOUT = 1.242V 1 +


R1
Slot-1 Power Supply Power Dissipation
Powered from a 3.3V supply, the Slot-1 power supply of
Figure 5 has a nominal efficiency of 75%. At the maximum
anticipated Slot 1 load (320mA), the nominal power dissipation is only 256mW.
The SOT-223 package has sufficient thermal characteristics
for wide design margins when mounted on a single layer
copper-clad printed circuit board. The power dissipation of
This equation is correct due to the configuration of the
bandgap reference. The bandgap voltage is relative to the
output, as seen in the block diagram. Traditional regulators
normally have the reference voltage relative to ground;
therefore, their equations are different from the equation for
the MIC5209BM/U.
August 2, 2000
9
MIC5209
MIC5209
Micrel
the MIC5209 is calculated using the voltage drop across the
device × output current plus supply voltage × ground current.
Considering worst case tolerances, the power dissipation
could be as high as:
(VIN(max) – VOUT(max)) × IOUT + VIN(max) × IGND
Table 2 and Figure 6 show that the Slot-1 power supply
application can be implemented with a minimum footprint
layout. Figure 6 shows the necessary copper pad area to
obtain specific heat sink thermal resistance (θSA) values. The
θSA values in Table 2 require much less than 500mm2 of
copper, according to Figure 6, and can easily be accomplished with the minimum footprint.
θ JA =
THERMAL RESISTANCE (°C/W)
[(3.6V – 2.375V) × 320mA] + (3.6V × 4mA)
PD = 407mW
Using the maximum junction temperature of 125°C and a θJC
of 8°C/W for the SOT-223, 25°C/W for the SO-8, or 2°C/W for
the TO-263 package, the following worst-case heat-sink
thermal resistance (θSA) requirements are:
TJ(max) − TA
PD
θSA = θ JA − θ JC
40°C
50°C
60°C
75°C
θJA (limit)
209°C/W
184°C/W
160°C/W
123°C/W
θSA SOT-223
201°C/W
176°C/W
152°C/W
115°C/W
θSA SO-8
184°C/W
159°C/W
135°C/W
98°C/W
θSA TO-263-5
207°C/W
182°C/W
158°C/W
121°C/W
TA
70
60
50
40
30
20
10
0
0
2000
4000
6000
COPPER HEAT SINK AREA (mm2)
Figure 6. PCB Heat Sink Thermal Resistance
Table 2. Maximum Allowable Thermal Resistance
MIC5209
10
August 2, 2000
MIC5209
Micrel
Package Information
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
0.038 (0.015)
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)
0.050 (1.27)
TYP
0.064 (1.63)
0.045 (1.14)
0.197 (5.0)
0.189 (4.8)
0.020 (0.51)
0.013 (0.33)
0.0098 (0.249)
0.0040 (0.102)
0°–8°
SEATING
PLANE
45°
0.010 (0.25)
0.007 (0.18)
0.050 (1.27)
0.016 (0.40)
0.244 (6.20)
0.228 (5.79)
8-Pin SOP (M)
August 2, 2000
11
MIC5209
MIC5209
Micrel
0.176 ±0.005
0.405±0.005
0.065 ±0.010
20°±2°
0.060 ±0.005
0.050±0.005
0.360±0.005
0.600±0.025
SEATING PLANE
0.004 +0.004
–0.008
0.067±0.005
0.032 ±0.003
8° MAX
0.100 ±0.01
0.015 ±0.002
DIM. = INCH
TO-263-5 (U)
MIC5209
12
August 2, 2000
MIC5209
Micrel
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
+ 1 (408) 944-0800
FAX
+ 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.
© 2000 Micrel Incorporated
August 2, 2000
13
MIC5209