MICREL MIC29510

MIC29510/29512
Micrel
MIC29510/29512
5A Fast-Response LDO Regulator
Preliminary Information
General Description
Features
The MIC29510 and MIC29512 are high-current, high-accuracy, low-dropout voltage regulators featuring fast transient
recovery from input voltage surges and output load current
changes. These regulators use a PNP pass element that
features Micrel’s proprietary Super ßeta PNP™ process.
The MIC29510/2 is available in two versions: the three pin
fixed output MIC29510 and the five pin adjustable output
voltage MIC29512. All versions are fully protected against
overcurrent faults, reversed input polarity, reversed lead
insertion, overtemperature operation, and positive and negative transient voltage spikes.
A TTL compatible enable (EN) control pin supports external
on/off control. If on/off control is not required, the device may
be continuously enabled by connecting EN to IN.
The MIC29510/2 is available in the standard three and five
pin TO-220 package with an operating junction temperature
range of 0°C to +125°C.
•
•
•
•
•
•
•
Fast transient response
5A current capability
700mV dropout voltage at full load
Low ground current
Accurate 1% guaranteed tolerance
“Zero” current shutdown mode (MIC29512)
Fixed voltage and adjustable versions
Applications
•
•
•
•
•
Pentium™ and Power PC™ processor supplies
High-efficiency “green” computer systems
High-efficiency linear power supplies
High-efficiency switching supply post regulator
Battery-powered equipment
For applications requiring even lower dropout voltage, input
voltage greater than 16V, or an error flag, see the MIC29500/
29501/29502/29503.
Ordering Information
Part Number
Temp. Range*
Voltage
Current
Package
MIC29510-3.3BT
0°C to +125°C
3.3V
5.0A
TO-220-3
MIC29510-5.0BT
0°C to +125°C
5.0V
5.0A
TO-220-3
MIC29512BT
0°C to +125°C
Adj.
5.0A
TO-220-5
* Junction Temperature
Typical Application
MIC29510
VIN
OUT
IN
MIC29512
On
Off
VOUT
EN
OUT
IN
ADJ
VOUT
R1
VIN
GND
GND
R2
 R1 
+ 1
V OUT = 1. 240 
 R2

Fixed Regulator Configuration
Adjustable Regulator Configuration
3-96
1997
MIC29510/29512
Micrel
Pin Configuration
1 2 3
12345
MIC29510BT
MIC29512BT
On all devices, the Tab is grounded.
Pin Description
3
3-Pin TO-220 (MIC29510)
Pin Number
Pin Name
Pin Function
1
IN
2
GND
Ground: Internally connected to tab (ground).
3
OUT
Regulated Output
Unregulated Input: +16V maximum supply.
5-Pin TO-220 (MIC29512)
Pin Number
Pin Name
Pin Function
1
EN
Enable (Input): Logic-level ON/OFF control.
2
IN
Unregulated Input: +16V maximum supply.
3
GND
Ground: Internally connected to tab (ground).
4
OUT
Regulated Output
5
ADJ
Output Voltage Adjust: 1.240V feedback from external resistive divider.
Absolute Maximum Ratings
Operating Ratings
Input Supply Voltage (Note 1) ....................... –20V to +20V
Power Dissipation .................................... Internally Limited
Storage Temperature Range ................... –65°C to +150°C
Lead Temperature (Soldering, 5 sec.) ...................... 260°C
Operating Junction Temperature ................. 0°C to +125°C
θJC (TO-220) ............................................................. 2°C/W
θJA (TO-220) ........................................................... 55°C/W
1997
3-97
MIC29510/29512
Micrel
Electrical Characteristics
All measurements at TJ = 25°C unless otherwise noted. Bold values are guaranteed across the operating temperature range.
Parameter
Condition
Max
Units
Output Voltage
10mA ≤ IO ≤ IFL, (VOUT + 1V) ≤ VIN ≤ 8V (Note 2)
2
%
Line Regulation
IO = 10mA, (VOUT + 1V) ≤ VIN ≤ 8V
0.06
0.5
%
Load Regulation
VIN = VOUT + 1V, 10mA ≤ IOUT ≤ IFULL LOAD (Notes 2, 6)
0.2
1
%
∆VO / ∆T
Output Voltage Temperature Coefficient (Note 6)
20
100
ppm/°C
Dropout Voltage
∆VOUT = – 1%, (Note 3)
MIC29510/29512 IO = 100mA
IO = 750mA
IO = 1.5A
IO = 3A
IO = 5A
80
200
320
500
700
200
mV
mV
mV
mV
mV
MIC29510/29512 IO = 750mA, VIN = VOUT + 1V
IO = 1.5A
IO = 3A
IO = 5A
3
10
36
100
150
mA
mA
mA
mA
2
3
mA
Ground Current
Min
IGNDDO Ground Pin
Current at Dropout
VIN = 0.5V less than specified VOUT. IOUT = 10mA
Current Limit
MIC29510/29512 VOUT = 0V (Note 4)
en, Output Noise Voltage
(10Hz to 100kHz) IL = 100mA
CL = 47µF
Typ
–2
5.0
1000
20
6.5
A
260
µVRMS
Reference (MIC29512 only)
Reference Voltage
10mA ≤ IO ≤ IFL, VOUT + 1V ≤ VIN ≤ 8V (Note 2)
Adjust Pin Bias Current
Reference Voltage
Temperature Coefficient
1.215
40
(Note 7)
Adjust Pin Bias Current
Temperature Coefficient
3-98
1.265
VMAX
80
120
nA
nA
20
ppm/°C
0.1
nA/°C
1997
MIC29510/29512
Micrel
Parameter
Conditions
Min
Low (Off)
High (On)
2.4
Typical
Max
Units
0.8
V
V
Enable Input (MIC29512 only)
Input Logic Voltage
Enable (EN) Pin Input Current
Regulator Output
Current in Shutdown
VEN = VIN
15
30
75
µA
µA
VEN = 0.8V
–
2
4
µA
µA
(Note 8)
10
20
µA
µA
General Note: Devices are ESD sensitive. Handling precautions recommended.
Note 1:
The maximum continuous supply voltage is 16V.
Note 2:
Full Load current is defined as 5A for the MIC29510/29512. For testing, VOUT is programmed to 5V.
Note 3:
Dropout voltage is defined as the input-to-output differential when the output voltage drops to 99% of its nominal value with VOUT + 1V applied
to VIN.
Note 4:
For this test, VIN is the larger of 8V or VOUT + 3V.
Note 5:
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.
Note 6:
Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 7:
VREF ≤ VOUT ≤ (VIN – 1 V), 2.4V ≤ VIN ≤ 16V, 10mA < IL ≤ IFL, TJ ≤ TJ MAX.
Note 8:
VEN ≤ 0.8V and VIN ≤ 8V, VOUT = 0.
3
Block Diagram
OUT
IN
EN
On/Off
Bias
O.V.
ILIMIT
28V
16V
Reference
Feedback
ADJ
Thermal
Shutdown
GND
1997
3-99
MIC29510/29512
Micrel
Typical Characteristics
VOUT
3.525V nominal
MIC29512
EN
VIN = VOUT + 1V
OUT
IN
OUTPUT VOLTAGE
MIC29512 Load Transient Response
(See Test Circuit Schematic)
0.1µF
93.1k
1%
ADJ
49.9k
1%
GND
4 × 330µF
AVX
TPSE337M006R0100
tantalum
+20mV
3.525V
–20mV
1ms/division
LOAD CURRENT
VOUT load (not shown):
Intel® Power Validator
MIC29512 Load Transient Response Test Circuit
5A
200mA
0mA
INPUT VOLTAGE
4.525V
4.525V
200µs/division
IOUT = 5A
COUT = 10µF
IOUT = 5A
COUT = 100µF
OUTPUT VOLTAGE
+20mV
6.525V
200µs/division
3.525V
–20mV
MIC2951x Dropout Voltage
vs. Output Current
+20mV
3.525V
–20mV
MIC2951x Dropout Voltage
vs. Temperature
MIC29510-3.3
Dropout Characteristics
1.0
0.8
0.6
0.4
0.2
0
0
1
2
3
4
OUTPUT CURRENT (A)
5
5.0
0.8
0.6
ILOAD = 5A
0.4
0.2
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3-100
OUTPUT VOLTAGE (V)
1.0
DROPOUT VOLTAGE (V)
OUTPUT VOLTAGE
MIC29512 Line Transient Response
with 5A Load, 100µF Output Capacitance
6.525V
DROPOUT VOLTAGE (V)
INPUT VOLTAGE
MIC29512 Line Transient Response
with 5A Load, 10µF Output Capacitance
VIN = 4.3V
4.0
ILOAD = 10mA
3.0
ILOAD = 5A
2.0
1.0
0.0
0
2
4
INPUT VOLTAGE (V)
6
1997
MIC29510/29512
Micrel
MIC2951x-3.3 Ground Current
vs. Supply Voltage
100
0
8
8
0.0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
2
50
0
1
2
3
4
OUTPUT CURRENT (A)
5
40
30
VEN = 5V
20
10
VEN = 2V
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3
100
VIN = 4.3V
ILOAD = 5A
50
10
3.34
3.32
3.30
3.28
3.26
3.24
3 DEVICES
3.22
3.20
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
MIC29512 Enable Current
vs. Temperaure
150
9
8
7
VOUT = 0V
6
5
4
3
2
1
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
MIC29512 Adjust Pin Current
vs. Temperature
MIC2951x Output Impedance
vs. Frequency
80
10
60
40
20
ILOAD = 10mA
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
1
0.1
0.01
0.001
10x100
25
0
ENABLE CURRENT (µA)
OUTPUT VOLTAGE (V)
50
200
MIC2951x Short Circuit
Current vs. Temperature
125
75
MIC2951x-3.3 Ground Current
vs. Temperature
MIC29510-3.3 Output Voltage
vs. Temperature
3.38
3.36
VIN = 4.3V
FREQUENCY (Hz)
1997
20
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3.40
100
-10
0
10
INPUT VOLTAGE (V)
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
150
ADJUST PIN CURRENT (nA)
GROUND CURRENT (mA)
MIC2951x-3.3 Ground Current
vs. Output Current
MIC2951x Ground Current
vs. Temperature
IOUT = 500mA
RLOAD = 100Ω
3-101
1x106
IOUT = 10mA
0.2
4
0.0
-0.5
-20
8
6
0.5
100x103
0.4
2
4
6
SUPPLY VOLTAGE (V)
1.0
10x103
0.6
0
1.5
1x103
MIC2951x Ground Current
vs. Temperature
GROUND CURRENT (mA)
GROUND CURRENT (mA)
0.8
2
4
6
SUPPLY VOLTAGE (V)
ILOAD = 5A
50
0
0
GROUND CURRENT (mA)
2
150
VOUT = 3.3V
2.0
CURRENT (A)
4
200
OUTPUT IMPEDANCE (Ω)
6
2.5
GROUND CURRENT (mA)
GROUND CURRENT (mA)
GROUND CURRENT (mA)
RLOAD = 10mA
8
MIC2951x Ground
Current vs. Input Voltage
250
100x100
MIC2951x-3.3 Ground Current
vs. Supply Voltage
10
MIC29510/29512
Micrel
Applications Information
The MIC29510 and MIC29512 are high performance lowdropout voltage regulators suitable for all moderate to highcurrent voltage regulator applications. Their 600mV of 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.
A trade-off for the low dropout voltage is a varying base drive
requirement. But Micrel’s Super ßeta PNP™ process reduces this drive requirement to merely 2 to 5% of the load
current.
MIC29510/512 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 maximum safe operating temperature. Transient protection allows device (and load) survival even when the input voltage spike 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. The MIC29512 version offers a
logic level ON/OFF control: when disabled, the devices draw
nearly zero current.
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 Micrel’s highcurrent Super ßeta PNP™ regulators have identical pinouts.
VIN
VOUT
Figure 3. The MIC29510 LDO regulator requires only
two capacitors for operation.
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
First, we calculate the power dissipation of the regulator from
these numbers and the device parameters from this datasheet.
PD = IOUT × (1.02VIN – VOUT)
Where the ground current is approximated by 2% of IOUT.
Then the heat sink thermal resistance is determined with this
formula:
TJ MAX – TA
θSA = —————— – (θJC + θCS)
PD
Where TJ MAX ≤ 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.
Please refer to Application Note 9 for further details and
examples on thermal design and heat sink specification.
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 currents allow
smaller capacitors. MIC29510/2 regulators are stable with a
minimum capacitor value of 47µF 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.
Where the regulator is powered from a source with a high AC
impedance, a 0.1µF capacitor connected between Input and
GND is recommended. This capacitor should have good
characteristics to above 250kHz.
Transient Response and 5V to 3.3V Conversion
The MIC29510/2 have excellent response to variations in
input voltage and load current. By virtue of their low dropout
voltage, these devices do not saturate into dropout as readily
as similar NPN-based designs. A 3.3V output Micrel LDO will
maintain full speed and performance with an input supply as
low as 4.2V, and will still provide some regulation with
supplies down to 3.8V, unlike NPN devices that require 5.1V
or more for good performance and become nothing more
than a resistor under 4.6V of input. Micrel’s PNP regulators
provide superior performance in “5V to 3.3V” conversion
applications than NPN regulators, especially when all tolerances are considered.
3-102
1997
MIC29510/29512
Micrel
Adjustable Regulator Design
the 16V maximum operating rating of the family. Two resistors are used. Resistors can be quite large, up to 100kΩ,
because of the very high input impedance and low bias
current of the sense comparator. The resistor values are
calculated by:
VOUT
R1 = R2 × ( –—— – 1 )
1.240
MIC29512BT
VIN
4.75 to 5.25
VOUT
R1
100k
10µF
3.45V
47µF
R2
56.2k
VOUT = 1.240V × [1 + (R1 / R2)]
Figure 4. Adjustable Regulator with Resistors
The adjustable regulator version, MIC29512, allows programming the output voltage anywhere between 1.25V and
Where VO is the desired output voltage. Figure 4 shows
component definition.
Enable Input
The MIC29512 versions features 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 VIN. Enabling the regulator
requires approximately 20µA of current into the EN pin.
3
Resistor Value Table for the MIC29512 Adjustable Regulator
Voltage
2.85
2.9
3.0
3.1
3.15
3.3
3.45
3.6
3.8
4.0
4.1
1997
Standard (Ω)
R1
100k
100k
100k
100k
100k
100k
100k
100k
100k
100k
100k
3-103
R2
76.8k
75.0k
69.8k
66.5k
64.9k
60.4k
56.2k
52.3k
48.7k
45.3k
43.2k