MIC29751-5.0BWT [ROCHESTER]
5V FIXED POSITIVE LDO REGULATOR, 0.75V DROPOUT, SFM5, TO-247, 5 PIN;
| 型号： | MIC29751-5.0BWT |
| 厂家： | 
Rochester Electronics |
| 描述： | 5V FIXED POSITIVE LDO REGULATOR, 0.75V DROPOUT, SFM5, TO-247, 5 PIN 局域网 输出元件 调节器 |
| 文件： | 总26页 (文件大小：1615K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC29150/29300/29500/29750
High-Current Low-Dropout Regulators
General Description
Features
The MIC29150/29300/29500/29750 are high current, high
accuracy, low-dropout voltage regulators. Using Micrel's
proprietary Super βeta PNP® process with a PNP pass
element, these regulators feature 350mV to 425mV (full
load) typical dropout voltages and very low ground current.
Designed for high current loads, these devices also find
applications in lower current, extremely low dropout-critical
systems, where their tiny dropout voltage and ground
current values are important attributes.
• High current capability:
− MIC29150/29151/29152/29153..............................1.5A
− MIC29300/29301/29302/29303.................................3A
− MIC29500/29501/29502/29503.................................5A
− MIC29750/29751/29752.........................................7.5A
• Low-dropout voltage
• Low ground current
• Accurate 1% guaranteed tolerance
• Extremely fast transient response
• Reverse-battery and “Load Dump” protection
The MIC29150/29300/29500/29750 are fully protected
against overcurrent faults, reversed input polarity, reversed
lead insertion, overtemperature operation, and positive
and negative transient voltage spikes. Five pin fixed
voltage versions feature logic level ON/OFF control and an
error flag which signals whenever the output falls out of
regulation. Flagged states include low input voltage
(dropout), output current limit, overtemperature shutdown,
and extremely high voltage spikes on the input.
• Zero-current shutdown mode
(5-pin versions)
• Error flag signals output out-of-regulation
(5-pin versions)
• Also characterized for smaller loads with industry-
leading performance specifications
• Fixed voltage and adjustable versions
On the MIC29xx1 and MIC29xx2, the ENABLE pin may be
tied to VIN if it is not required for ON/OFF control. The
MIC29150/29300/29500 are available in 3-pin and 5-pin
TO-220 and surface mount TO-263 (D2Pak) packages.
The MIC29750 7.5A regulators are available in 3-pin and
5-pin TO-247 packages. The 1.5A, adjustable output
MIC29152 is available in a 5-pin power D-Pak (TO-252)
package.
Applications
• Battery-powered equipment
• High-efficiency “Green” computer systems
• Automotive electronics
• High-efficiency linear lower supplies
• High-efficiency lost-regulator for switching supply
For applications with input voltage 6V or below, see
MIC37xxx LDOs.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
_________________________________________________________________________________________________________________________
Typical Application**
Adjustable Output Voltage
Fixed Output Voltage
(*See Minimum Load Current Section)
**See Thermal Design Section
Super βeta PNP 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
M9999-122012-B
December 2012
Micrel, Inc.
MIC29150/29300/29500/29750
Ordering Information
Part Number
Junction Temperature
Range(1)
Voltage
Current
Package
Standard
RoHS Compliant(2)
MIC29150-3.3BT
MIC29150-3.3BU
MIC29150-5.0BT
MIC29150-5.0BU
MIC29150-12BT
MIC29150-12BU
MIC29151-3.3BT
MIC29151-3.3BU
MIC29151-5.0BT
MIC29151-5.0BU
MIC29151-12BT
MIC29151-12BU
MIC29152BT
MIC29150-3.3WT(2)
MIC29150-3.3WU(2)
MIC29150-5.0WT(2)
MIC29150-5.0WU(2)
MIC29150-12WT(2)
MIC29150-12WU(2)
MIC29151-3.3WT(2)
MIC29151-3.3WU(2)
MIC29151-5.0WT(2)
MIC29151-5.0WU(2)
MIC29151-12WT(2)
MIC29151-12WU(2)
MIC29152WT(2)
–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
–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
–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
–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
3.3
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
1.5A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
3.0A
5.0A
3-Pin TO-220
3-Pin TO-263
3-Pin TO-220
3-Pin TO-263
3-Pin TO-220
3-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-252
5-Pin TO-220
5-Pin TO-263
3-Pin TO-220
3-Pin TO-263
3-Pin TO-220
3-Pin TO-263
3-Pin TO-220
3-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
3-Pin TO-220
3.3
5
5
12
12
3.3
3.3
5
5
12
12
Adjustable
MIC29152BU
MIC29152WU(2)
MIC29152WD(2)
Adjustable
—
Adjustable
MIC29153BT(3)
MIC29153BU(3)
MIC29300-3.3BT
MIC29300-3.3BU
MIC29300-5.0BT
MIC29300-5.0BU
MIC29300-12BT
MIC29300-12BU
MIC29301-3.3BT
MIC29301-3.3BU
MIC29301-5.0BT
MIC29301-5.0BU
MIC29301-12BT
MIC29301-12BU
MIC29302BT
Contact Factory
Adjustable
Contact Factory
Adjustable
MIC29300-3.3WT(2)
MIC29300-3.3WU(2)
MIC29300-5.0WT(2)
MIC29300-5.0WU(2)
MIC29300-12WT(2)
MIC29300-12WU(2)
MIC29301-3.3WT(2)
MIC29301-3.3WU(2)
MIC29301-5.0WT(2)
MIC29301-5.0WU(2)
MIC29301-12WT(2)
MIC29301-12WU(2)
MIC29302WT(2)
3.3
3.3
5
5
12
12
3.3
3.3
5
5
12
12
Adjustable
Adjustable
Adjustable
Adjustable
3.3
MIC29302BU
MIC29302WU(2)
MIC29303WT(2)
MIC29303WU(2)
MIC29500-3.3WT(2)
MIC29303BT
MIC29303BU
MIC29500-3.3BT
Notes:
1. Junction temperature.
2. RoHS compliant with ‘high-melting solder’ exemption.
3. Special Order; please contact factory for availability.
M9999-122012-B
December 2012
2
Micrel, Inc.
MIC29150/29300/29500/29750
Ordering Information (Continued)
Part Number
Junction Temperature
Range(1)
Voltage
Current
Package
Standard
RoHS Compliant(2)
MIC29500-5.0WT(2)
MIC29501-3.3WT(2)
MIC29501-3.3WU(2)
MIC29501-5.0WT(2)
MIC29501-5.0WU(2)
MIC29502WT(2)
MIC29500-5.0BT
MIC29501-3.3BT
MIC29501-3.3BU
MIC29501-5.0BT
MIC29501-5.0BU
MIC29502BT
–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
–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
5
5.0A
5.0A
5.0A
5.0A
5.0A
5.0A
5.0A
5.0A
5.0A
7.5A
7.5A
7.5A
7.5A
7.5A
3-Pin TO-220
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
5-Pin TO-220
5-Pin TO-263
3-Pin TO-247
3-Pin TO-247
5-Pin TO-247
5-Pin TO-247
5-Pin TO-247
3.3
3.3
5
5
Adj.
Adj.
Adj.
Adj.
3.3
MIC29502BU
MIC29502WU(2)
MIC29503WT(2)
MIC29503WU(2)
MIC29503BT
MIC29503BU
MIC29750-3.3BWT(4)
MIC29750-5.0BWT(4)
MIC29751-3.3BWT(4)
MIC29751-5.0BWT(4)
MIC29752BWT(4)
Contact Factory(4)
Contact Factory(4)
Contact Factory(4)
Contact Factory(4)
MIC29752WWT(2, 4)
5
3.3
5
Adjustable
Note:
4. Not recommended for design.
M9999-122012-B
December 2012
3
Micrel, Inc.
MIC29150/29300/29500/29750
Pin Configuration
3-Pin TO-220 (T)
5-Pin TO-220 Fixed Voltage (T)
MIC29150/29300/29500
MIC29151/29301/29501/29751
5-Pin TO-220 Adjustable Voltage (T)
MIC29152/29302/29502
5-Pin TO-220 Adjustable with Flag (T)
MIC29153/29303/29503
3-Pin TO-247 (WT)
MIC29750
5-Pin TO-247 Fixed Voltage (WT)
MIC29751
M9999-122012-B
December 2012
4
Micrel, Inc.
MIC29150/29300/29500/29750
Pin Configuration (Continued)
5-Pin TO-247 Adjustable Voltage (WT)
MIC29752
3-Pin TO-263 (D2Pak) (UT)
MIC29150/29300
5-Pin TO-263 (D2Pak) Fixed Voltage (U)
MIC29151/29301/29501
5-Pin TO-263 (D2Pak) Adjustable Voltage (U)
MIC29302/29502
5-Pin TO-263 (D2Pak) Adjustable with Flag (U)
MIC29153/29303/29503
5-Pin TO-252 (D-Pak) Adjustable Voltage (D)
MIC29152
M9999-122012-B
December 2012
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Micrel, Inc.
MIC29150/29300/29500/29750
Pin Description
Pin Number
TO-220
TO-247
TO-263
Pin Name
1
2
3
INPUT: Supplies the current to the output power device.
GND: TAB is also connected internally to the IC’s ground on D-PAK.
OUTPUT: The regulator output voltage.
Pin Description
Pin Number
Adjustable
TO-220
TO-247
TO-252
Pin Number
Fixed
TO-220
TO-247
TO-263
Pin Number
Adj. with Flag
TO-220
Pin Name
TO-247
TO-263
TO-263
ENABLE: CMOS compatible control input. Logic high = enable, logic low =
shutdown.
1
1
—
2
3, TAB
4
2
3, TAB
4
2
3, TAB
4
INPUT: Supplies the current to the output power device
GND: TAB is also connected internally to the IC’s ground on D-PAK.
OUTPUT: The regulator output voltage
ADJUST: Adjustable regulator feedback input that connects to the resistor
voltage divider that is placed from OUTPUT to GND in order to set the output
voltage.
—
5
5
5
1
—
FLAG: Active low error flag output signal that indicates an output fault condition
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December 2012
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Micrel, Inc.
MIC29150/29300/29500/29750
Absolute Maximum Ratings(1)
Operating Ratings(2)
Input Supply Voltage (VIN)(1) ........................... –20V to +60V
Enable Input Voltage (VEN)................................–0.3V to VIN
Lead Temperature (soldering, 5sec.)......................... 260°C
Power Dissipation .....................................Internally Limited
Storage Temperature Range ....................–65°C to +150°C
ESD Rating.................................................................Note 3
Operating Junction Temperature ..............–40°C to +125°C
Maximum Operating Input Voltage ................................26V
Package Thermal Resistance
TO-220 (θJC).........................................................2°C/W
TO-263 (θJC).........................................................2°C/W
TO-247 (θJC) .....................................................1.5°C/W
TO-252 (θJC).........................................................3°C/W
TO-252 (θJA) ......................................................56°C/W
Electrical Characteristics(4, 13)
VIN = VOUT + 1V; IOUT = 10mA; TJ = 25°C. Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Parameter
Condition
Min.
–1
Typ.
Max.
1
Units
IOUT = 10mA
Output Voltage
%
10mA ≤ IOUT ≤ IFL, (VOUT + 1V) ≤ VIN ≤26V (5)
IOUT = 10mA, (VOUT + 1V) ≤ VIN ≤26V
VIN = VOUT + 1V, 10mA ≤ IOUT ≤ 1.5A (5,9)
–2
2
Line Regulation
Load Regulation
0.06
0.2
0.5
1
%
%
∆VO
∆T
Output Voltage(9)
Temperature Coefficient.
20
100
ppm/°C
∆VOUT = −1%(6)
200
IOUT = 100mA
MIC29150
80
IOUT = 750mA
IOUT = 1.5A
220
350
80
250
370
125
250
370
80
600
175
IOUT = 100mA
IOUT = 1.5A
IOUT = 3A
IOUT = 250mA
IOUT = 2.5A
IOUT = 5A
IOUT = 250mA
IOUT = 4A
IOUT = 7.5A
MIC29300
Dropout Voltage
mV
600
250
MIC29500
600
200
MIC29750
270
425
750
Notes:
1. Maximum positive supply voltage of 60V must be of limited duration (<100msec) and duty cycle (≤1%). The maximum continuous supply voltage is
26V. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. Specification for packaged product only.
5. Full load current (IFL) is defined as 1.5A for the MIC29150, 3A for the MIC29300, 5A for the MIC29500, and 7.5A for the MIC29750 families.
6. Dropout voltage is defined as the input-to-output differential when the output voltage drops to 99% of its normal value with VOUT + 1V applied to VIN.
7.
V
IN = VOUT (nominal) + 1V. For example, use VIN = 4.3V for a 3.3V regulator or use 6V for a 5V regulator. Employ pulse-testing procedures to pin
current.
8. Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus the ground pin
current.
9. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
10. 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 a200mA load pulse at VIN = 20V (a 4W pulse) for T = 10ms.
11. Comparator thresholds are expressed in terms of a voltage differential at the Adjust terminal below the nominal reference voltage measured at 6V
input. To express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For example,
at a programmed output voltage of 5V, the Error output is guaranteed to go low when the output drops by 95mV x 5V/1.240V = 384mV. Thresholds
remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.7% guaranteed.
12.
VEN ≤ 0.8V and VIN ≤ 26V, VOUT = 0.
13. When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode clamped to ground.
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Micrel, Inc.
MIC29150/29300/29500/29750
Electrical Characteristics(4, 13) (Continued)
VIN = VOUT + 1V; IOUT = 10mA; TJ = 25°C. Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Parameter
Condition
Min.
Typ.
Max.
Units
MIC29150
IOUT = 750mA, VIN = VOUT + 1V
IOUT = 1.5A
IOUT = 1.5A, VIN = VOUT + 1V
IOUT = 3A
IOUT = 2.5A, VIN = VOUT + 1V
IOUT = 5A
IOUT = 4A, VIN = VOUT + 1V
IOUT = 7.5A
8
22
10
37
15
70
35
120
20
35
50
75
MIC29300
MIC29500
Ground Current
mA
MIC29750
Note 8
VIN = 0.5V less than specified VOUT × IOUT = 10mA
MIC29150
MIC29300
MIC29500
MIC29750
0.9
1.7
2.1
3.1
IGRNDDOGround Pin
Current at Dropout
mA
A
VOUT = 0V(7)
VOUT = 0V(7)
VOUT = 0V(7)
VOUT = 0V(7)
2.1
4.5
7.5
9.5
3.5
5.0
10.0
15
MIC29150
MIC29300
MIC29500
MIC29750
Current Limit
en, Output Noise Voltage
(10Hz to 100kHz)
IL = 100mA
CL = 10µF
CL = 33µF
400
260
µV (rms)
µA
2
Ground Current in
Shutdown
MIC29150/1/2/3 only
VEN = 0.4V
10
30
Reference − MIC29xx2/MIC29xx3
Reference Voltage
1.228
1.215
1.252
1.265
1.240
V
V
1.203
1.277
Reference Voltage
80
120
Adjust Pin Bias Current
40
20
nA
Reference Voltage
Note 10
ppm/°C
Temperature Coefficient
Adjust Pin Bias Current
Temperature Coefficient
0.1
nA/°C
Flag Output (Error Comparator) − MIC29xx1/29xx3
1.00
2.00
Output Leakage Current
Output Low Voltage
VOH = 26V
0.01
220
µA
mV
mV
Device set for 5V, VIN = 4.5V
IOL = 250µA
300
400
40
25
Upper Threshold Voltage Device set for 5V (11)
Lower Threshold Voltage Device set for 5V (11)
60
95
140
75
15
mV
mV
Hysteresis
Device set for 5V (11)
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Micrel, Inc.
MIC29150/29300/29500/29750
Electrical Characteristics(4, 13) (Continued)
VIN = VOUT + 1V; IOUT = 10mA; TJ = 25°C. Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Parameter
Condition
Min.
Typ.
Max.
0.8
Units
ENABLE Input − MIC29xx1/MIC29xx2
Input Logic Voltage
Low (OFF)
High (ON)
V
2.4
600
750
V
EN = 26V
100
10
Enable Pin
µA
µA
2
4
Input Current
VEN = 0.8V
Note 12
0.7
Regulator Output
Current in Shutdown
500
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Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics (MIC2915x)
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10
Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics (MIC2915x) (Continued)
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11
Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics (MIC2930x)
M9999-122012-B
December 2012
12
Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics (MIC2930x) (Continued)
M9999-122012-B
December 2012
13
Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics (MIC2950x)
M9999-122012-B
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14
Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics (MIC2950x) (Continued)
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December 2012
15
Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics − MIC2975x
M9999-122012-B
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16
Micrel, Inc.
MIC29150/29300/29500/29750
Typical Characteristics − MIC2975x (Continued)
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Micrel, Inc.
MIC29150/29300/29500/29750
Functional Diagram
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Micrel, Inc.
MIC29150/29300/29500/29750
Application Information
Thermal Design
The
MIC29150/29300/29500/29750
are
high-
Linear regulators are simple to use. The most
complicated design parameters to consider are thermal
characteristics. Thermal design requires the following
application-specific parameters:
performance low-dropout voltage regulators suitable for
all moderate to high-current voltage regulator
applications. Their 350mV to 425mV typical dropout
voltage at full load make them especially valuable in
battery powered systems and as high efficiency noise
filters in “post-regulator” applications. Unlike older NPN-
pass transistor designs, where the minimum dropout
voltage is limited by the base-emitter voltage drop and
collector-emitter saturation voltage, dropout performance
of the PNP output of these devices is limited merely by
the low VCE saturation voltage.
• Maximum ambient temperature, TA
• Output Current, IOUT
• Output Voltage, VOUT
• Input Voltage, VIN
First, we calculate the power dissipation of the regulator
from these numbers and the device parameters from this
datasheet.
A trade-off for the low-dropout voltage is a varying base
driver requirement. But Micrel’s Super ßeta PNP®
process reduces this drive requirement to merely 1% of
the load current.
PD = IOUT
(
1.01VIN − VOUT
)
Eq. 1
The MIC29150/29300/29500/29750 family of regulators
are fully protected from damage due to fault conditions.
Current limiting is provided. This limiting is linear; output
current under overload conditions is constant. Thermal
shutdown disables the device when the die temperature
exceeds the 125°C maximum safe operating
temperature. Line transient protection allows device (and
load) survival even when the input voltage spikes
between –20V and +60V. When the input voltage
exceeds approximately 32V, the over voltage sensor
disables the regulator. The output structure of these
regulators allows voltages in excess of the desired
output voltage to be applied without reverse current flow.
MIC29xx1 and MIC29xx2 versions offer a logic level
ON/OFF control: when disabled, the devices draw nearly
zero current.
where the ground current is approximated by 1% of IOUT
Then the heat sink thermal resistance is determined with
Equation 2:
.
T
− T
A
JMAX
θ
=
−
(
θ
+ θ
CS
)
Eq. 2
SA
JC
P
D
where TJMAX ≤ 125°C and θCS is between 0 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 and the
regulator. The low-dropout properties of Micrel Super
ßeta PNP® regulators allow very significant reductions in
regulator power dissipation and the associated heat sink
without compromising performance. When this technique
is employed, a capacitor of at least 0.1µF is needed
directly between the input and regulator ground.
An additional feature of this regulator family is a common
pinout: a design’s current requirement may change up or
down yet use the same board layout, as all of these
regulators have identical pinouts.
MIC29XXX
Please refer to Application Note 9 and Application Hint
17 for further details and examples on thermal design
and heat sink specification.
VOUT
VIN
OUT
IN
With no heat sink in the application, calculate the
junction temperature to determine the maximum power
dissipation that will be allowed before exceeding the
maximum junction temperature of the MIC29152. The
maximum power allowed can be calculated using the
thermal resistance (θJA) of the D-Pak adhering to the
following criteria for the PCB design: 2 oz. copper and
100mm2 copper area for the MIC29152.
GND
Figure 3. Linear Regulators Require Only
Two Capacitors for Operation
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Micrel, Inc.
MIC29150/29300/29500/29750
For example, given an expected maximum ambient
temperature (TA) of 75°C with VIN = 3.3V, VOUT = 2.5V,
and IOUT = 1.5A, first calculate the expected PD using
Equation 3:
Where the regulator is powered from a source with high
AC impedance, a 0.1µF capacitor connected between
Input and GND is recommended. This capacitor should
have good characteristics to above 250kHz.
Minimum Load Current
PD=(3.3V–2.5V)1.5A–(3.3V)(0.016A)=1.1472W
Eq. 3
The MIC29150–29750 regulators are specified between
finite loads. If the output current is too small, leakage
currents dominate and the output voltage rises. The
following minimum load current swamps any expected
leakage current across the operating temperature range,
as shown in Table 2:
Next, calcualte the junction temperature for the expected
power dissipation.
TJ=(θJA×PD)+TA=(56°C/W×1.1472W)+75°C
=139.24°C
Device
Minimum Load
5mA
MIC29150
MIC29300
MIC29500
MIC29750
Eq. 4
7mA
10mA
Now determine the maximum power dissipation allowed
that would not exceed the IC’s maximum junction
temperature (125°C) without the useof a heat sink by:
10mA
Table 2. Minimum Load Currents
PD(MAX) = (TJ(MAX)–TA)/θJA
= (125°C–75°C)/(56°C/W) = 0.893W
Eq. 5
Adjustable Regulator Design
The adjustable regulator versions, MIC29xx2 and
MIC29xx3, allow programming the output voltage
anywhere between 1.25V and the 25V. Two resistors are
used. The resistor values are calculated by Equation 6:
Capacitor Requirements
For stability and minimum output noise, a capacitor on
the regulator output is necessary. The value of this
capacitor is dependent upon the output current; lower
V
OUT
− 1
Eq. 6
R1 = R2 ×
1.240
currents
allow
smaller
capacitors.
The
MIC29150/29300/29500/29750 regulators are stable
with the following minimum capacitor values at full load,
as noted in Table 1:
where VOUT is the desired output voltage. Figure 4 shows
component definition. Applications with widely varying
load currents may scale the resistors to draw the
minimum load current required for proper operation (see
“Minimum Load Current” sub-section).
Device
Full Load Capacitor
MIC29150
MIC29300
MIC29500
MIC29750
10µF
10µF
10µF
22µF
Table 1. Minimum Capacitor Values at Full Load
This capacitor need not be an expensive low ESR type:
aluminum electrolytics are adequate. In fact, extremely
low ESR capacitors may contribute to instability.
Tantalum capacitors are recommended for systems
where fast load transient response is important.
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Micrel, Inc.
MIC29150/29300/29500/29750
MIC29152BT
V
IN
V
OUT
R1
R2
10µF
22µF
Figure 4. Adjustable Regulator with Resistors
Error Flag
MIC29xx1 and MIC29xx3 versions feature an Error Flag,
which looks at 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. It may sink 10mA. Low
output voltage signifies a number of possible problems,
including an overcurrent fault (the device is in current
limit) and low input voltage. The flag output is inoperative
during overtemperature shutdown conditions.
Enable Input
MIC29xx1 and MIC29xx2 versions feature an enable
(EN) input that allows ON/OFF control of the device.
Special design allows “zero” current drain when the
device is disabled—only microamperes of leakage
current flows. The EN input has TTL/CMOS compatible
thresholds for simple interfacing with logic, or may be
directly tied to ≤30V. Enabling the regulator requires
approximately 20µA of current.
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Micrel, Inc.
MIC29150/29300/29500/29750
Package Information(1)
3-Pin TO-220 (T)
5-Pin TO-220 (T)
Note:
1. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com.
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Micrel, Inc.
MIC29150/29300/29500/29750
Package Information(1) (Continued)
5-Pin TO-263 (U)
3-Pin TO-263 (U)
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Micrel, Inc.
MIC29150/29300/29500/29750
Package Information(1) (Continued)
5-Pin TO-247 (WT)
3-Pin TO-247 (WT)
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Micrel, Inc.
MIC29150/29300/29500/29750
Package Information(1) (Continued)
5-Pin TO-252 (D)
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
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
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.
© 2012 Micrel, Incorporated.
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相关型号：
MIC29752WWTTR
1.25 V-25V ADJUSTABLE POSITIVE LDO REGULATOR, 0.75V DROPOUT, SFM5, ROHS COMPLIANT, TO-247, 5 PIN
MICREL
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