Micrel MIC37501-1.5BR 5a, low voltage ucap ldo regulator Datasheet

MIC37500/37501/37502
Micrel
MIC37500/37501/37502
5A, Low Voltage µCap LDO Regulator
Advance Information
General Description
Features
The Micrel MIC37500/01/02 is a 5A low-dropout linear voltage regulator that provides a low voltage, high current output
with a minimum of external components. It offers high precision, ultra low dropout (500mV), and low ground current.
The MIC37500/01/02 operates from an input of 2.3V to 6.0V.
It is designed to drive digital circuits requiring low voltage at
high currents (i.e. PLDs, DSP, microcontroller, etc.). It is
available in fixed and adjustable output voltages. Fixed
voltages include 1.5V. The adjustable version is capable of
1.24V to 5.5V.
Features of the MIC37500/01/02 LDO include thermal and
current limit protection, and reverse current & reverse battery
protection. Logic enable and error flag pins are available.
Junction temperature range of the MIC37500/01/02 is from
–40°C to 125°C.
For applications requiring input voltage greater than 6.0V,
see MIC3910x, MIC3915x, MIC3930x, and MIC3950x LDOs.
• 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
• Excellent line and load regulation specifications
• Logic controlled shutdown
• Thermal shutdown and current limit protection
• Reverse-leakage protection
• Low profile S-Pak package
Applications
•
•
•
•
•
LDO linear regulator for low-voltage digital IC
PC add-in cards
High efficiency linear power supplies
SMPS post regulator
Battery charger
Typical Application
VIN = 3.0V
CIN
MIC37500
VIN
VOUT
VIN
VOUT
VEN
FLG
VIN
VOUT = 2.5V
100k
CIN
COUT
100µF, Ceramic
MIC37502
VIN
VOUT
VIN
VOUT
VEN
1.3V
R1
COUT
100µF, Ceramic
ADJ
GND
R2
GND
Fixed 2.5V Regulator with Error Flag
Adjustable Regulator
SuperSwitcher 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
January 2002
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MIC37500/37501/37502
MIC37500/37501/37502
Micrel
Ordering Information
Part Number
Output
Current
Voltage*
Junction Temp. Range
Package
MIC37502BR
5A
ADJ.
–40°C to +125°C
S-Pak-7
MIC37501-1.5BR
5A
1.5V
–40°C to +125°C
S-Pak-7
*For other voltages contact Micrel.
Pin Configuration
TAB
7
6
5
4
3
2
1
FLG/ADJ
VOUT
VOUT
GND
VIN
VIN
EN
S-PAK7
Pin Description
Pin Number
Pin Name
1
EN
Enable (Input): CMOS compatible input. Logic high = enable, logic
low = shutdown
2, 3
VIN
Input voltage which supplies current to the output power device. Connect
pins 2 and 3 together externally.
4
GND
Ground (TAB is connected to ground on S-Pak)
5, 6
VOUT
Regulator Output. Connect pins 5 and 6 together externally.
7
FLG.
Error Flag (Output): Open collector output. Active low indicates an output
fault condition.
ADJ.
Adjustable regulator feedback input. Connect to resistor voltage divider.
MIC37500/37501/37502
Pin Function
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January 2002
MIC37500/37501/37502
Micrel
Absolute Maximum Rating (Note 1)
Operating Maximum Rating (Note 2)
Supply Voltage (VIN) .................................................... 6.5V
Enable Input Voltage (VEN) .......................................... 6.5V
Power Dissipation .................................... Internally Limited
Junction Temperature ........................ –40°C ≤ TJ ≤ +125°C
Storage Temperature ......................... –65°C ≤ TJ ≤ +150°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD, Note 3
Supply Voltage (VIN) ....................................... 2.3V to 6.0V
Enable Input Voltage (VEN) ................................ 0V to 6.0V
Junction Temperature Range ............. –40°C ≤ TJ ≤ +125°C
Maximum Power Dissipation …………….. ............... Note 4
Package Thermal Resistance
S-Pak(θJC) …………………… ............. …………2°C/W
Electrical Characteristics
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
10mA < IOUT < IL(max), VOUT + 1 ≤ VIN ≤ 6V
Typ
Max
Units
-1
+1
%
-2
+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
%
VIN – VOUT; Dropout Voltage ;
IL = 2.5A
350
mV
Note 5
IL = 5A
330
500
mV
Ground Pin Current, Note 6
IL = 5A
57
mA
Ground Pin Current in Shutdown
VIL < 0.5V, VIN = VOUT + 1V
1.0
µA
Current Limit
VOUT = 0
7.5
A
Start-up Time
VEN = VIN, IOUT = 10mA, COUT = 22µF
170
500
µs
Enable Input
Enable Input Threshold
Regulator enable
2.25
V
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
µA
75
µA
1
µA
2
µA
Flag Output
IFLG(LEAK)
VFLG(LO)
VOH = 6V
VIN = 2.25V, IOL = 250uA, Note 7
210
mV
mV
VFLG
Low Threshold, % of Vout below nominal
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
Reference Voltage
1.228
1.215
Adjust Pin Bias Current
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MIC37500/37501/37502
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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.
Device is ESD sensitive. Handling precautions recommended.
Note 4.
PD(MAX) = (TJ(MAX) – TA) / θJA, where θJA, depends upon the printed icurcuit layout. See “Applications Information.”
Note 5.
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 due to a minimum input operating voltage of 2.3V.
Note 6.
IGND is the quiescent current. IIN = IGND + IOUT.
Note 7.
For a 2.5V device, VIN = 2.3V (device is in dropout).
MIC37500/37501/37502
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Output Capacitor
The MIC37500/01/02 requires an output capacitor for stable
operation. As a µCap LDO, the MIC37500/01/02 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 MIC37500/01/02 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. The
MIC37500/01/02 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 that is required. Larger values help to improve
performance even further.
Input Capacitor
An input capacitor of 1.0µF or greater is recommended when
the device is more than 4 inches away from the bulk ad supply
capacitance, or when the supply is a battery. Small, surfacemount chip capacitors can be used for the bypassing. The
capacitor should be place 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.
Transient Response and 3.3V to 2.5V, 2.5V to 1.8V or
1.65V, or 2.5V to 1.5V Conversions
The MIC37500/01/02 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 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 NPN-based designs. When converting from 3.3V to 2.5V, 2.5V to 1.8V or
1.65V, or 2.5V to 1.5V, 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 MIC37500/01/02 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.
Applications Information
The MIC37500/01/02 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 battery-powered systems and
as high-efficiency noise filters in post-regulator applications.
Unlike older NPN-pass transistor designs, there the minimum
dropout voltage is limited by the based-to-emiiter 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 Beta PNP™ process reduces
this drive requirement to only 2% to 5% of the load current.
The MIC37500/01/02 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. 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.
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 – VOUT) IOUT + VIN IGND
where the ground current is approximated by using numbers
from the “Electrical Characteristics” or “Typical Characteristics.” Then the heat sink thermal resistance is determined
with this formula:
θSA = ((TJ(MAX) – TA)/ PD) – (θJC + θCS)
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 votlage 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 Beta 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.
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MIC37500/37501/37502
MIC37500/37501/37502
Micrel
Minimum Load Current
The MIC37500/01/02 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.
Error Flag
The MIC37501 features an error flag circuit that 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 MIC37501/37502 also feature an enable input for on/off
control of the device. Its shutdown state draws “zero” current
(only micoamperes of leakage). The enable input is TTL/
CMOS compatible for simple logic interface, but can be
connected to up to VIN. When enabled, it draws approximately 15µA.
MIC37500/37501/37502
Adjustable Regulator Design
VIN
MIC37502
OUT
IN
VOUT
R1
ENABLE
SHUTDOWN
EN
ADJ
GND
R2
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:

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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January 2002
MIC37500/37501/37502
Micrel
Package Information
DIMENSIONS:
INCH (MM)
0.375 (9.52)
0.365 (9.27)
0.360 (9.14)
0.350 (8.89)
0.050 (1.27)
0.030 (0.76)
0.320 (8.13)
0.310 (7.87)
0.050 BSC
(1.27 BSC)
0.080 (2.03)
0.070 (1.78)
0.256 BSC
(6.50 BSC)
0.010 BSC
(0.25 BSC)
0.316 BSC
(8.03 BSC)
0.420 (10.67)
0.410 (10.41)
0.045 (1.14)
0.035 (0.89)
0.031 (0.79)
0.025 (0.63)
0.005 (0.13)
0.001 (0.03)
0.010 BSC
(0.25 BSC)
6°
0°
SCALE 20:1
7-Lead S-PAK (R)
January 2002
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MIC37500/37501/37502
MIC37500/37501/37502
Micrel
MICREL INC.
TEL
1849 FORTUNE DRIVE SAN JOSE, CA 95131
+ 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.
© 2002 Micrel Incorporated
MIC37500/37501/37502
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January 2002
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