Micrel MIC37501-2.5WR 5a, low voltage î¼cap ldo regulator Datasheet

MIC37501/37502
5A, Low Voltage µCap LDO Regulator
General Description
Features
The MIC37501 and MIC37502 are 5A, low dropout
linear voltage regulator that provide low voltage, high
current outputs with a minimum of external components.
They offer high precision, ultra-low dropout (500mV),
and low ground current.
The MIC37501and MIC37502 operate from an input of
2.3V to 6.0V. They are designed to drive digital circuits
requiring low voltage at high currents (i.e., PLDs, DSPs,
microcontrollers, etc.). They are available in fixed and
adjustable output voltages. Fixed voltages include 1.5V,
1.65V, 1.8V, 2.5V, and 3.3V. The adjustable version is
capable of 1.24V to 5.5V.
MIC37501 and MIC37502 LDOs feature thermal and
currentlimit protection and reverse current protection.
Logic enable and error flag pins are available.
Junction temperature range of the MIC37501/02 is from
–40°C to 125°C.
For applications requiring input voltage greater than
6.0V, see MIC3910x, MIC3915x, MIC3930x, and
MIC3950x LDOs.
All support documentation can be found on Micrel’s web
site at www.micrel.com.
• 5A minimum guaranteed output current
• 500mV maximum dropout voltage
– Ideal for 3.0V to 2.5V conversion
– Ideal for 2.5V to 1.8V, 1.65V, or 1.5V
conversion
• Stable with ceramic or tantalum capacitor
• Wide input voltage range:
- VIN: 2.3V to 6.0V
• ±1.0% initial output tolerance
• Fixed and adjustable output voltages:
– MIC37501—7 terminal fixed voltage
– MIC37502—5 (TO-263) and 7 (SPAK) terminal
adjustable voltage
• Excellent line and load regulation specifications
• Logic controlled shutdown
• Thermal shutdown and current-limit protection
• Reverse-leakage protection
• Low profile S-Pak and TO-263 packages
Applications
•
•
•
•
•
LDO linear regulator for low-voltage digital IC
PC add-in cards
High efficiency linear power supplies
SMPS post regulator
Battery charger
Typical Applications
VIN = 3.0V
CIN
MIC37501
VIN
VOUT
VIN
VOUT
VEN
VOUT = 2.5V
100k
COUT
100F, Ceramic
FLG
450
400
DROPOUT (mV)
GND
Fixed 2.5V Regulator with Error Flag
V IN
CIN
MIC37502
VIN
VOUT
VIN
VOUT
VEN
1.3V
R1
ADJ
GND
Dropout
vs. Output Current
COUT
100F, Ceramic
350
300
2.5VOUT
250
200
150
100
50
0
R2
0
1
2
3
4
OUTPUT CURRENT (A)
5
Adjustable Regulator
Super βeta is a registered trademark of Micrel Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2007
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Micrel, Inc.
MIC37501/37502
Ordering Information
Part Number
RoHS Compliant(1)
Standard
Output
Current
Voltage(2)
Junction Temp. Range
Package
–40°C to +125°C
S-Pak-7
MIC37501-1.5BR
MIC37501-1.5WR
5A
1.5V
MIC37501-1.65BR
MIC37501-1.65WR
5A
1.65V
–40°C to +125°C
S-Pak-7
MIC37501-1.8BR
MIC37501-1.8WR
5A
1.8V
–40°C to +125°C
S-Pak-7
MIC37501-2.5BR
MIC37501-2.5WR
5A
2.5V
–40°C to +125°C
S-Pak-7
MIC37501-3.3BR
MIC37501-3.3WR
5A
3.3V
–40°C to +125°C
S-Pak-7
MIC37502BR
MIC37502WR
5A
Adj.
–40°C to +125°C
S-Pak-7
MIC37502BU
MIC37502WU
5A
Adj.
–40°C to +125°C
To-263-5
Note:
1.
RoHS compliant with “high-melting solder” exemption.
2.
Other Voltage available. Contact Micrel for detail.
Pin Configuration
ADJ
VOUT
GND
VIN
EN
7
6
5
4
3
2
1
TAB
TAB
5
4
3
2
1
TO-263-5
FLG/ADJ
VOUT
VOUT
GND
VIN
VIN
EN
S-PAK-7
Pin Description
Pin Number
TO-263-5
Pin Number
S-PAK-7
Pin Name
1
1
EN
Enable (input): CMOS-compatible input. Logic high = enable, logic
low = shutdown.
2
2, 3
VIN
Input voltage which supplies current to the output power device.
Connect pins 2 and 3 together externally.
3
4
GND
Ground (TAB is connected to ground on S-Pak).
4
5, 6
VOUT
Pin Name
Regulator Output: Connect pins 5 and 6 together externally.
—
7
FLG
Error Flag (output): Open collector output. Active low indicates an
output fault condition.
5
7
ADJ
Adjustable regulator feedback input. Connect to resistor voltage
divider.
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MIC37501/37502
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) ................................................. 6.5V
Enable Input Voltage (VEN) ....................................... 6.5V
Power Dissipation(PD) .......................... Internally Limited
Junction Temperature(TJ) ............... –40°C ≤ TJ ≤ +125°C
Storage Temperature(TS) ............... –65°C ≤ TJ ≤ +150°C
Lead Temperature (soldering, 5 sec.) ....................260°C
ESD Rating(3) ...............................................................2kV
Supply Voltage (VIN) ......................................... 2.3V to 6.0V
Enable Input Voltage (VEN) .................................. 0V to 6.0V
Junction Temperature Range(TJ) ....... –40°C ≤ TJ ≤ +125°C
Maximum Power Dissipation .....................................Note 4
Package Thermal Resistance
S-Pak (θJC) .......................................................... 2°C/W
TO-263 (θJC) ....................................................... 2°C/W
Electrical Characteristics(5)
TA = 25°C with VIN = VOUT + 1V; VEN = VIN; bold values indicate –40°C < TJ < +125°C; unless otherwise noted.
Parameter
Condition
Min
Output Voltage Accuracy
IL = 10mA
–1
10mA < IOUT < IL(max), VOUT + 1 ≤ VIN ≤ 6V
–2
Typ
Max
Units
+1
%
+2
%
Output Voltage Line Regulation
VIN = VOUT +1.0V to 6.0V
0.06
0.5
%
Output Voltage Load Regulation
IL = 10mA to 5A
0.2
1
%
350
mV
(6)
VIN – VOUT, Dropout Voltage
Ground Pin Current
(7)
Ground Pin Current in Shutdown
IL = 2.5A
IL = 5A
330
500
mV
IL = 5A
57
100
mA
VIL < 0.5V, VIN = VOUT + 1V
1.0
Current Limit
VOUT = 0
Start-up Time
VEN = VIN, IOUT = 10mA, COUT = 100µF
5
µA
7.5
11
A
170
500
µs
Enable Input
Enable Input Threshold
Regulator enable
V
2.25
Regulator shutdown
Enable Pin Input Current
VIL < 0.8V (Regulator shutdown)
VIH > 2.25V (Regulator enabled)
1
15
0.8
V
2
4
µA
µA
30
75
µA
µA
1
2
µA
µA
400
500
mV
mV
Flag Output
IFLG(LEAK)
VOH = 6V
VFLG(LO)
VIN = 2.25V, IOL = 250µA
VFLG
Low threshold, % of VOUT below nominal
(8)
210
93
Hysteresis
%
2
High threshold, % of VOUT below nominal
%
99.2
%
1.240
1.252
1.265
V
V
40
80
120
nA
nA
MIC37502 Only
1.228
1.215
Reference Voltage
Adjust Pin Bias Current
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MIC37501/37502
Notes:
1. Exceeding the ratings in the “Absolute Maximum Ratings” section may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
4. PD(max) = (TJ(max) – TA) / θJC, where θJC depends upon the printed circuit layout. See “Applications Information” section.
5. Specification for packaged product only
6. VDO = VIN – VOUT when VOUT decreased to 98% of its nominal output voltage with VIN = VOUT + 1V. For output voltages below 1.75V,
dropout voltage specification does not apply dut to a minimum input operating voltage of 2.3V.
7. IGND is the quiescent current. IIN = IGND + IOUT.
8. For a 2.5V device, VIN = 2.3V (device is in dropout).
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MIC37501/37502
Typical Characteristics
500
400
300
DROPOUT (mV)
DROPOUT (mV)
350
2.5VOUT
250
200
150
100
1.6
2.5VOUT
450
400
350
300
50
5
5A load
1.7 1.9 2.1 2.3 2.5
INPUT VOLTAGE (V)
GROUND CURRENT (mA)
30
25
20
15
10
5
0
Ground Current
vs. Suppl (1.8V)
0.7
0.5
0.4
100mA
0.3
0.2
0.1
0
1
2
3
4
INPUT VOLTAGE (V)
February 2007
5
5A load
0.5
0.4
0.2
2.0
0.2
0.1
1
2
3
4
INPUT VOLTAGE (V)
1.0
0.5
0
70
60
2.5A
40
30
20
5A
10
0
1
2
3
4
INPUT VOLTAGE (V)
5
60
50
5
2.5A
40
30
20
5A
10
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
INPUT VOLTAGE (V)
Ground Current
vs. Suppl (2.5V)
1.8
80
Ground Current
vs. Suppl (1.5V)
70
0
5
Ground Current
vs. Suppl (1.8V)
50
5A load
1.5
80
100mA
0
10mA load
INPUT VOLTAGE (V)
0.5
0.3
2.5
2.5
3.5
10mA
0.4
1.7
1.9
2.1
2.3
INPUT VOLTAGE (V)
Dropout Characteristics
(3.3V)
3.0
Ground Current
vs. Suppl (1.5V)
0.6
0
0
10mA load
2.0
2.5
3.0
INPUT VOLTAGE (V)
5A load
0.6
3.5
1.0
90
10mA
0.6
1.5
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
OUTPUT CURRENT (A)
Dropout Characteristics
(2.5V)
2.0
0.7
2.5VOUT
45
40
35
2.5
0
1.5
2.7
Ground Current
vs. Output Current
50
GROUND CURRENT (mA)
OUTPUT VOLTAGE (V)
1.2
1
0.8
0.6
0.4
0.2
0
1.5
GROUND CURRENT (mA)
3.0
GROUND CURRENT (mA)
OUTPUT VOLTAGE (V)
Dropout Characteristics
(1.8V)
2
10mA load
1.8
1.6
1.4
1
0.8
0
1.5
OUTPUT VOLTAGE (V)
1
2
3
4
OUTPUT CURRENT (A)
1.2
GROUND CURRENT (mA)
0
10mA load
1.4
250
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
GROUND CURRENT (mA)
0
Dropout Characteristics
(1.5V)
1.5
1.8
2.0
2.3
2.5
2.8
3.0
3.3
3.5
3.8
4.0
4.3
450
Dropout
vs. Temperature
OUTPUT VOLTAGE (V)
Dropout
vs. Output Current
1.6
1.4
1.2
1.0
0.8
100mA
0.6
0.4
10mA
0.2
0
0
1
2
3
4
INPUT VOLTAGE (V)
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M9999-020507
Micrel, Inc.
MIC37501/37502
Ground Current
vs. Supply (2.5V)
Ground Current
vs. Supply (3.3V)
0.06
5A
0.04
2.5A
0.02
1
2
3
4
INPUT VOLTAGE (V)
1.40
1.20
1.00
0.80
0.20
0
5
60
100mA
0.5
0.4
10mA
0.3
0.2
0.1
10mA
0.40
Ground Current
vs. Temperature
0.7
0.6
100mA
0.60
GROUND CURRENT (mA)
0
1
2
3
4
INPUT VOLTAGE (V)
5A
40
30
20
2.5A
10
1A
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Short Circuit Current
vs. Suppl Voltage
Short Circuit Current
vs. Temperature
10
9
8
7
6
5
4
3
2
1
0
2.25
3
3.75 4.5 5.25
SUPPLY VOLTAGE (V)
6
10
9
8
80
60
2.5A
40
20
0
5
Ground Current
vs. Temperature
50
5A
100
0
2.60
2.58
2.56
1
2
3
4
INPUT VOLTAGE (V)
Output Voltage
vs. Temperature
2.50
2.48
2.46
2.44
2.42
2.40
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Error Flag Pull-Up Resistor
6
5
7
6
5
4
3
2
1
Flag High (OK )
VIN = 5V
4
3
2
Flag Low (FAULT)
1
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
5
2.54
2.52
ERROR FLAG (V)
GROUND CURRENT (mA)
SHORT CIRCUIT CURRENT (A)
1
0.9
0.8
12
ENABLE CURRENT(µA)
0
GROUND CURRENT (mA)
0.08
1.60
OUTPUT VOLTAGE (V)
GROUND CURRENT (mA)
0.10
0
120
1.80
OUTPUT VOLTAGE (V)
GROUND CURRENT (mA)
0.12
Ground Current
vs. Supply (3.3V)
0
0.01 0.1
1
10
100
)
1k
10k
Enable Current
vs. Temperature
10
8
6
4
2
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
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MIC37501/37502
Functional Characteristics
Enable Transient Response
Line Transient Response
VIN = 3.3V
VOUT = 2.5V
COUT = 100µF Ceramic
IOUT = 5A
5V
3.3V
VIN = 3.3V
VOUT = 2.5V
COUT = 100µF Ceramic
Load Transient Response
Load Transient Response
VIN = 3.3V
VOUT = 2.5V
COUT = 100µF Ceramic
VIN = 3.3V
VOUT = 2.5V
COUT = 100µF Ceramic
5A
5A
1A
100mA
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Micrel, Inc.
MIC37501/37502
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 1.0µF 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
applications.
Application Information
The MIC37501/02 is a high-performance, low dropout
voltage regulator suitable for moderate to high-current
regulator applications. Its 500mV dropout voltage at
full load makes it especially valuable in batterypowered 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 based-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 MIC37501/02 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.
The output structure of these regulators allows
voltages in excess of the desired output voltage to be
applied without reverse current flow.
Output Capacitor
The MIC37501/02 requires an output capacitor for
stable operation. As a µCap LDO, the MIC37501/02
can operate with ceramic output capacitors as long as
the amount of capacitance is 100µF or greater. For
values of output capacitance lower than 100µF, the
recommended ESR range is 200mΩ to 2Ω. The
minimum value of output capacitance recommended
for the MIC37501/02 is 47µF.
For 100µF or greater, the ESR range recommended is
less than 1Ω. Ultra-low ESR ceramic capacitors are
recommended for output capacitance of 100µF or
greater to help improve transient response and noise
reduction at high frequency. X7R/X5R dielectric-type
ceramic capacitors are recommended because of
their temperature performance. X7Rtype 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
capacitor to ensure the same minimum capacitance
over the equivalent operating temperature range.
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 data sheet.
Input Capacitor
An input capacitor of 1.0µF 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 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.
PD = (VIN – VOUT) IOUT + VIN IGND
where the ground current is approximated by using
numbers from the “Electrical Characteristics” or
“Typical Characteristics” sections. The heat sink
thermal resistance is then determined with this
formula:
θSA = ((TJ(max) – TA)/ PD) – (θJC + θCS)
Transient Response and 3.3V to 2.5V, 2.5V to 1.8V
or 1.65V, or 2.5V to 1.5V Conversions
The MIC37501/02 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 is all
Where TJ(max) ≤125°C and θCS is between 0°C and
2°C/W. 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
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Micrel, Inc.
MIC37501/37502
that is required. Larger values help to improve
performance even further.
By virtue of its low dropout voltage, this device does
not saturate into dropout as readily as similar NPNbased designs. When converting from 3.3V to 2.5V,
2.5V to 1.8V or 1.65V, or 2.5V to 1.5V, the NPNbased 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 at
least 3.7V. The MIC37501/02 regulator will provide
excellent performance with an input as low as 3.0V or
2.25V, respectively. This gives the PNP-based
regulators a distinct advantage over older, NPN-based
linear regulators.
Enable Input
The MIC37501/02 also 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 up to VIN. When
enabled, it draws approximately 15µA.
Adjustable Regulator Design
MIC37502
VIN
ENABLE
SHUTDOWN
Minimum Load Current
The MIC37501/02 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
operation.
R1
EN
ADJ
GND
R2
VOUT
COUT
R1⎞
⎛
VOUT = 1.240V ⎜ 1 +
⎟
⎝ R2 ⎠
Figure 2. Adjustable Regulator with Resistors
The MIC37502 allows programming the output voltage
anywhere between 1.24V and the 5.5V maximum
operating rating 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:
Error Flag
The MIC37501 features an error flag circuit that
monitors the output voltage and signals an error
condition when the voltage drops 5% below the
nominal output voltage. The error flag is an opencollector 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.
February 2007
OUT
IN
⎛V
⎞
R1 = R2⎜⎜ OUT − 1⎟⎟
⎝ 1.240
⎠
Where VOUT is the desired output voltage. Figure 2
shows component definition. Applications with widely
varying load currents may scale the resistors to draw
the minimum load current required for proper
operation (see above).
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MIC37501/37502
Package Information
7-Pin S-PAK (R)
θ4
θ1
θ2
θ1
θ1
θ2
θ3
θ4
θ1
θ3
5-Pin TO-263 (U)
February 2007
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Micrel, Inc.
MIC37501/37502
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
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for
its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
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 reasonably 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
and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.
© 2004 Micrel, Incorporated.
February 2007
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