Datasheet MIC39501-2.5BU, MIC39501-2.5BT, MIC39500-2.5BT, MIC39500-2.5BU Datasheet (MICREL)
Page 1
MIC39500/39501 Micrel
MIC39500/39501
5A Low-Voltage Low-Dropout Regulator
Advance Information
General Description
The MIC39500 and MIC39501 is a 5A low-dropout linear
voltage regulator that provides a low-voltage, high-current
output with a minimum of external components. Utilizing
Micrel’s proprietary Super βeta PNP™ pass element, the
MIC39500 offers extremely low dropout (typically 400mV at
5A) and low ground current (typically 70mA at 5A).
The MIC39500 is ideal for PC Add-In cards that need to
convert from standard 5V or 3.3V, down to new, lower core
voltages. A guaranteed maximum dropout voltage of 500mV
over all operating conditions allows the MIC39500 to provide
2.5V from a supply as low as 3V. The MIC39500 also has fast
transient response, for heavy switching applications. The
device requires only 47µF of output capacitance to maintain
stability and achieve fast transient response
The MIC39500 is fully protected with overcurrent limiting,
thermal shutdown, reversed-battery and reversed-lead insertion protection. The MIC39501 offers a TTL-logic-compatible enable pin and an error flag that indicates undervoltage
and overcurrent conditions. The MIC39500 comes in the TO220 and TO-263 packages and is an ideal upgrade to older,
NPN-based linear voltage regulators.
Features
• 5A minimum guaranteed output current
• 500mV maximum dropout voltage over temperature
• 1% initial accuracy
• Low ground current
• Current limiting and thermal shutdown
• Reversed-battery and reversed-lead insertion protection
• Fast transient response
• TO-263 and TO-220 packages
• TTL/CMOS compatible enable pin (MIC39501 only)
• Error flag output (MIC39501 only)
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
• Low-voltage microcontrollers
• StrongARM™ processor supply
For applications requiring input voltage
greater than 16V, see the
MIC29500/1/2/3 family.
Typical Application
V
IN
3.3V
1.0µF 47µF
MIC39500-2.5
IN OUT
GND
Ordering Information
Part Number Voltage Junction Temp. Range Package
MIC39500-2.5BT 2.5V –40°C to +125°C 3-lead TO-220
MIC39500-2.5BU 2.5V –40°C to +125°C 3-lead TO-263
MIC39501-2.5BT 2.5V –40°C to +125°C 5-lead TO-220
MIC39501-2.5BU 2.5V –40°C to +125°C 5-lead TO-263
100KΩ
V
OUT
2.5V
Enable
Shutdown
V
IN
3.3V
1.0µF
MIC39501-2.5
EN
IN
FLG
OUT
GND
ERROR
FLAG OUTPUT
47µF
V
OUT
2.5V
MIC39500
MIC39501
StrongARM is a trademark of Advanced RISC Machines, Ltd.
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 1999 1 MIC39500/39501
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MIC39500/39501 Micrel
Pin Configuration
TAB
TAB
MIC39500-x.xBT
TO-220 (T)
MIC39501-x.xBT
TO-220-5 (T)
3 OUT
2 GND
1IN
5 FLG
4 OUT
3 GND
2IN
1EN
TAB
MIC39500-x.xBU
TO-263 (U)
TAB
MIC39501-x.xBU
TO-263-5 (U)
3 OUT
2 GND
1IN
5 FLG
4 OUT
3 GND
2IN
1EN
Pin Description
Pin Number Pin Number Pin Name Pin Function
MIC39500 MIC39501
1 EN Enable (Input): TTL/CMOS compatible input. Logic high = enable; logic low
or open = shutdown
1 2 IN Unregulated Input: +16V maximum supply.
2, TAB 3, TAB GND Ground: Ground pin and TAB are internally connected.
3 4 OUT Regulator Output
5 FLG Error Flag (Ouput): Open collector output. Active low indicates an output
fault condition.
MIC39500/39501 2 June 1999
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MIC39500/39501 Micrel
Absolute Maximum Ratings (Note 1)
Supply Voltage (VIN) ..................................... –20V to +20V
Enable Voltage (VEN) ..................................................+20V
Storage Temperature (TS) ....................... –65°C to +150°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD, Note 3
Operating Ratings (Note 2)
Supply Voltage (VIN) .................................. +2.25V to +16V
Enable Voltage (VEN) ..................................................+16V
Maximum Power Dissipation (P
Junction Temperature (TJ) ....................... –40°C to +125°C
Package Thermal Resistance
)..................... Note 4
D(max)
TO-263 (θJC) .........................................................2°C/W
TO-220 (θJC) .........................................................2°C/W
Electrical Characteristics
TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted
Symbol Parameter Condition Min Typ Max Units
V
OUT
Output Voltage 10mA ≤ I
Line Regulation I
= 10mA, V
OUT
Load Regulation VIN = V
∆V
/∆T Output Voltage Temp. Coefficient, 20 100 ppm/°C
OUT
Note 5
V
DO
I
GND
I
GND(do)
I
OUT(lim)
e
n
Dropout Voltage, Note 6 I
Ground Current, Note 7 I
= 250mA, ∆V
OUT
I
= 2.5A, ∆V
OUT
I
= 5A, ∆V
OUT
= 2.5A, VIN = V
OUT
I
= 5A, VIN = V
OUT
Dropout Ground Pin Current VIN ≤ V
Current Limit V
Output Noise Voltage C
OUT
OUT
Enable Input (MIC39501)
V
EN
Enable Input Voltage logic low (off) 0.8 V
logic high (on) 2.4 V
I
IN
I
OUT(shdn)
Enable Input Current VEN = V
= 0.8V 2 µA
V
EN
Shutdown Output Current Note 8 10 20 µA
Flag Output (MIC39501)
I
FLG(leak)
V
FLG(do)
Output Leakage Current VOH = 16V 0.01 1 µA
Output Low Voltage VIN = 2.250V, IOL, = 250µA, Note 9 125 150 mV
≤ 5A, V
OUT
OUT
+ 1V, 10mA ≤ I
OUT
OUT
OUT
OUT(nominal)
= 0V, VIN = V
= 47µF, I
OUT
IN
+ 1V ≤ VIN ≤ 16V –11%
OUT
–2 2 %
+ 1V ≤ VIN ≤ 16V 0.06 0.5 %
≤ 5A 0.2 1 %
OUT
= –2% 125 250 mV
OUT
= –2% 320 mV
= –2% 400 500 mV
+ 1V 15 50 mA
OUT
+ 1V 70 mA
OUT
– 0.5V, I
+ 1V 7.5 A
OUT
= 100mA, 10Hz to 100kHz 260
= 10mA 2.1 mA
OUT
µV(rms)
30 35 µA
75 µA
4 µA
2 µA
200 mV
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
Note 5. Output voltage temperature coefficient is ∆V
Note 6. VDO = VIN – V
Note 7. I
Note 8. VEN ≤ 0.8V, VIN ≤ 8V, and V
Note 9. For a 2.5V device, VIN = 2.250V (device is in dropout).
= (T
D(max)
is the quiescent current. IIN = I
GND
– TA) ÷ θJA, where θJA depends upon the printed circuit layout. See “Applications Information.”
J(max)
when V
OUT
decreases to 98% of its nominal output voltage with VIN = V
OUT
GND
= 0V
OUT
OUT(worst case)
+ I
OUT
.
÷ (T
J(max)
– T
J(min)
) where T
is +125°C and T
J(max)
+ 1V.
OUT
J(min)
is 0°C.
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MIC39500/39501 Micrel
Functional Diagram
FLAG*
EN*
IN
O.V.
I
LIMIT
Ref.
1.240V1.180V
Thermal
Shutdown
* MIC39501 only
18V
OUT
GND
MIC39500/39501 4 June 1999
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MIC39500/39501 Micrel
Applications Information
The MIC39500/1 is a high-performance low-dropout voltage
regulator suitable for moderate to high-current voltage regulator applications. Its 500mV dropout voltage at full load
makes it especially valuable in battery-powered systems and
as a high-efficiency noise filter in post-regulator applications.
Unlike older NPN-pass transistor designs, where the minimum dropout voltage is limited by the base-to-emitter voltage
drop and collector-to-emitter saturation voltage, dropout performance of the PNP output of these devices is limited only
by the low VCE saturation voltage.
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% to 5% of the load current.
The MIC39500/1 regulator is fully protected from damage
due to fault conditions. Current limiting is provided. This
limiting is linear; output current during overload conditions is
constant. Thermal shutdown disables the device when the
die temperature exceeds the maximum safe operating temperature. Transient protection allows device (and load) survival even when the input voltage spikes above and below
nominal. The output structure of these regulators allows
voltages in excess of the desired output voltage to be applied
without reverse current flow.
IN
C
IN
OUT
−
P
D
MIC39500-x.x
IN OUT
GND
)
OUT
)
OUT
)
GND
) × I
+ V
OUT
−+
()
JC CS
IN
× I
V
C
OUT
GND
OUT
V
Figure 1. Capacitor Requirements
Thermal Design
Linear regulators are simple to use. The most complicated
design parameters to consider are thermal characteristics.
Thermal design requires four application-specific parameters:
• Maximum ambient temperature (TA)
• Output Current (I
• Output Voltage (V
• Input Voltage (VIN)
• Ground Current (I
Calculate the power dissipation of the regulator from these
numbers and the device parameters from this datasheet,
where the ground current is taken from data sheet.
PD = (V
IN
– V
The heat sink thermal resistance is determined by:
TT
SA
J(max) A
=
θθθ
where:
T
≤ 125°C and θCS is between 0° and 2°C/W.
J (max)
The heat sink may be significantly reduced in applications
where the minimum input voltage is known and is 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 Micrel Super βeta PNP regulators 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.
Output capacitor
The MIC39500/1 requires an output capacitor to maintain
stability and improve transient response. Proper capacitor
selection is important to ensure proper operation. The
MIC39500/1 output capacitor selection is dependent upon
the ESR (equivalent series resistance) of the output capacitor
to maintain stability. When the output capacitor is 47µF or
greater, the output capacitor should have less than 1Ω of
ESR. This will improve transient response as well as promote
stability. Ultra-low-ESR capacitors, such as ceramic chip
capacitors may promote instability. These very low ESR
levels may cause an oscillation and/or underdamped 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 < 1Ω.
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.
Input capacitor
An input capacitor of 1µF or greater is recommended when
the device is more than 4 inches away from the bulk ac supply
capacitance, or when the supply is a battery. Small surfacemount ceramic chip capacitors can be used for bypassing.
Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of
the output voltage.
Transient Response
The MIC39500/1 has excellent transient response to variations 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 47µF output
capacitor, preferably tantalum, is all that is required. Larger
values improve performance even further.
3.3V to 2.5V Conversion
By virtue of its low-dropout voltage, this device does not
saturate into dropout as readily as similar NPN-based designs. When converting from 3.3V to 2.5V, the NPN-based
regulators are already operating in dropout, with typical
dropout requirements of 1.2V or greater. To convert down to
2.5V without operating in dropout, NPN-based regulators
require an input voltage of 3.7V at the very least. The
MIC39500/1 regulator provides excellent performance with
June 1999 5 MIC39500/39501
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MIC39500/39501 Micrel
an input as low as 3.0V. This gives PNP-based regulators a
distinct advantage over older, NPN-based linear regulators.
A typical NPN regulator does not have the headroom to do
this conversion.
Minimum Load Current
The MIC39500/1 regulator is specified between finite loads.
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.
Error Flag
The MIC39501 version features an error flag circuit which
monitors the output voltage and signals an error condition
when the voltage 5% below the nominal output voltage. The
error flag is an open-collector output that can sink 10mA
during a fault condition.
Low output voltage can be caused by a number of problems,
including an overcurrent fault (device in current limit) or low
input voltage. The flag is inoperative during overtemperature
shutdown.
Enable Input
The MIC39501 version features an enable input for on/off
control of the device. Its shutdown state draws “zero” current
(only microamperes of leakage). The enable input is TTL/
CMOS compatible for simple logic interface, but can be
connected to up to 20V.
MIC39500/39501 6 June 1999
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MIC39500/39501 Micrel
Package Information
0.151 D ±0.005
0.108 ±0.005
(2.74 ±0.13)
0.818 ±0.005
(20.78 ±0.13)
(3.84 D ±0.13)
0.410 ±0.010
(10.41 ±0.25)
0.356 ±0.005
(9.04 ±0.13)
0.176 ±0.005
(4.47 ±0.13)
0.590 ±0.005
(14.99 ±0.13)
0.050 ±0.005
(1.27 ±0.13)
7°
0.050 ±0.003
(1.27 ±.08)
0.100 ±0.005
(2.54 ±0.13)
0.108 ±0.005
(2.74 ±0.13)
0.400 ±0.015
(10.16 ±0.38)
0.030 ±0.003
(0.76 ±0.08)
TO-220 (T)
0.150 D ±0.005
(3.81 D ±0.13)
0.241 ±0.017
(6.12 ±0.43)
0.578 ±0.018
(14.68 ±0.46)
1.140 ±0.010
(28.96 ±0.25)
0.018 ±0.008
(0.46 ±0.020)
7°
3°
0.100 ±0.020
DIMENSIONS:
0.177 ±0.008
(4.50 ±0.20)
0.050 ±0.005
(1.27 ±0.13)
SEATING
PLANE
(2.54 ±0.51)
INCH
(MM)
7°
Typ.
0.550 ±0.010
(13.97 ±0.25)
0.067 ±0.005
(1.70 ±0.127)
0.268 REF
(6.81 REF)
0.032 ±0.005
(0.81 ±0.13)
0.018 ±0.008
(0.46 ±0.20)
Dimensions:
0.103 ±0.013
(2.62±0.33)
inch
(mm)
TO-220-5 (T)
June 1999 7 MIC39500/39501
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MIC39500/39501 Micrel
0.405±0.005
0.065±0.010
20°±2°
0.100 BSC 0.050
DIM. = INCH
0.405±0.005
0.065±0.010
20°±2°
0.050±0.005
0.360±0.005
0.600±0.025
TO-263 (U)
0.050±0.005
0.360±0.005
8° MAX
0.015 ±0.002
0.176±0.005
0.050±0.005
SEATING PLANE
+0.004
0.004
–0.008
0.100±0.01
0.176±0.005
0.060±0.005
0.600±0.025
SEATING PLANE
+0.004
0.004
–0.008
0.067±0.005 0.032 ±0.003
DIM. = INCH
8° MAX
0.015 ±0.002
0.100±0.01
TO-263-5 (U)
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.
© 1999 Micrel Incorporated
MIC39500/39501 8 June 1999
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