MIC29510/29512
5A Fast-Response LDO Regulator
Super ßeta PNP is a trademarks 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
May 2006
M9999-051706
(408) 955-1690
General Description
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.
For applications requiring even lower dropout voltage,
input voltage greater than 16V, or an error flag, see the
MIC29500/29501/29502/29503.
Features
• 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™, Pentium Plus™ and Power PC™
processor supplies
• High-efficiency “green” computer systems
• High-efficiency linear power supplies
• High-efficiency switching supply post regulator
• Battery-powered equipment
Typical Application
Fixed Regulator Configuration
Adjustable Regulator Configuration
Micrel, Inc. MIC29510/29512
May 2006
2 M9999-051706
(408) 955-1690
Ordering Information
Part Number
Standard RoHS Compliant*
Junction Temp. Range Voltage Current Package
MIC29510-3.3BT MIC29510-3.3WT 0ºC to +125ºC 3.3V 5A TO-220-3
MIC29510-5.0BT MIC29510-5.0WT 0ºC to +125ºC 5.0V 5A TO-220-3
MIC29512BT MIC29512WT 0ºC to +125ºC Adj. 5A TO-220-5
* RoHS compliant with ‘high-melting solder’ exemption.
Pin Configur ation
1 2 3 12345
MIC29510BT/WT
MIC29512BT/WT
On all devices, the Tab is grounded
Pin Description
3-Pin TO-220 (MIC29510)
Pin
Number Pin
Name Pin Function
1 IN Unregulated Input: +16V maximum supply.
2 GND Ground: Internally connected to tab (ground).
3 OUT Regulated Output.
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.
Micrel, Inc. MIC29510/29512
May 2006
3 M9999-051706
(408) 955-1690
Absolute Maximum Ratings
Input Supply Voltage
(1)
................................... –20V to +20V
Power Dissipation .....................................Internally Limited
Storage Temperature Range ....................–65°C to +150°C
Ambient Temperature Range (soldering, 5 sec.)....... 260°C
Operating Ratings
Operating Junction Temperature ...................0ºC to +125ºC
(θ
JC
) (TO-220) ............................................................2°C/W
(θ
JA
) (TO-220)...........................................................55°C/W
Electrical Characteristics
All measurements at T
J
= 25°C unless otherwise noted. Bold values are guaranteed across the operating temperature range.
Parameter Conditions Min Typ Max Units
Output Voltage 10mA ≤ I
O
≤ I
FL
, (V
OUT
+ 1V) ≤ V
IN
≤ 8V (Note 2) –2 2 %
Line Regulation I
O
= 10mA, (V
OUT
+ 1V) ≤ V
IN
≤ 8V 0.06 0.5 %
Load Regulation V
IN
= V
OUT
+ 1V, 10mA ≤ I
OUT
≤ I
FULL LOAD
(Notes 2, 6))
0.2 1 %
∆V
O
/∆T Output Voltage Temperature Coefficient (Note 6) 20 100 ppm/ºC
Dropout Voltage ∆V
OUT
= – 1% (Note 3)
MIC29510/29512 I
O
= 100mA
I
O
= 750mA
I
O
= 1.5A
I
O
= 3A
I
O
= 5A
80
200
320
500
700
200
1000
mV
mV
mV
mV
mV
Ground Current MIC29510/29512 I
O
= 750mA, V
IN
= V
OUT
+ 1V
I
O
= 1.5A
I
O
= 3A
I
O
= 5A
3
10
36
100
20
150
mA
mA
mA
mA
I
GNDDO
Ground Pin Current at Dropout V
IN
= 0.5V less than specified V
OUT
. I
OUT
= 10mA 2 3 mA
Current Limit MIC29510/29512 V
OUT
= 0V (Note 4) 5.0 6.5 A
e
n
, Output Noise Voltage
(10Hz to 100kHz) I
L
= 100mA
C
L
= 47µF 260 µV
RMS
Reference (MIC29512 onl y)
Parameter Conditions Min Typ Max Units
Reference Voltage 10mA ≤ I
O
≤ I
FL
, V
OUT
+ 1V ≤ V
IN
≤ 8V (Note 2) 1.215 1.265 V
MAX
Adjust Pin Bias Current 40 80
120 nA
nA
Reference Voltage Temperature
Coefficient
(Note 7)
20
ppm/ºC
Adjust Pin Bias Current Temperature
Coefficient
0.1
nA/ºC
Micrel, Inc. MIC29510/29512
May 2006
4 M9999-051706
(408) 955-1690
Enable Input (MIC29512 only)
Parameter Conditions Min Typ Max Units
Input Logic Voltage Low (Off)
High (On)
2.4 0.8 V
V
V
EN
= V
IN
15
30
75 µA
µA
Enable (EN) Pin Input Current
V
EN
= 0.8V – 2
4 µA
µA
Regulator Output Current in Shutdown (Note 8)
10
20 µA
µA
Notes:
General Note: Devices are ESD sensitive. Handling precautions are recommended.
1. The maximum continuous supply voltage is 16V.
2. Full Load current is defined as 5A for the MIC29510/29512. For testing, V
OUT
is programmed to 5V.
3. Dropout voltage defined as the input-to-output differential when the output voltage drops to 99% of its nominal value with V
OUT
+ 1V applied to
V
IN
.
4. For this test, V
IN
is the larger of 8V or V
OUT
+ 3V.
5. Ground pin current is regulator quiescent current. Total current drawn from the source is the sum of the load current plus the ground pin current.
6. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
7. V
REF
≤ V
OUT
≤ (V
IN
– 1V), 2.4V ≤ V
IN
≤ 16V, 10mA < I
L
≤ I
FL
, T
J
≤ T
J MAX
.
8. V
EN
≤ 0.8V and V
IN
≤ 8V, V
OUT
= 0.
Block Diagram
16V
Micrel, Inc. MIC29510/29512
May 2006
5 M9999-051706
(408) 955-1690
Typical Characteristics
MIC29512 Load Transient Response Test Circuit
Micrel, Inc. MIC29510/29512
May 2006
6 M9999-051706
(408) 955-1690
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
-20 -10 0 10 20
)Am(TNERRUCDNUORG
INPUT VOLTAGE (V)
MIC2951x Ground
Current vs. Input Voltage
R
LOAD
= 100
V
OUT
= 3.3V
3.20
3.22
3.24
3.26
3.28
3.30
3.32
3.34
3.36
3.38
3.40
-60 -30 0 30 60 90 120 150
)V(EGATLOVTUPTUO
TEMPERATURE (°C)
MIC29510-3.3 Output Voltage
vs. Temperature
3 DEVICES
0
20
40
60
80
-60 -30 0 30 60 90 120 150
)An(TNERRUCNIPTSUJDA
TEMPERATURE (°C)
MIC295 12 Adjust Pin Current
vs. Temperature
I
LOAD
= 10mA
0
10
20
30
40
50
-60 -30 0 30 60 90 120 150
(TNERRUCELBANE µ)A
TEMPERATURE (°C)
MIC2951 2 Ena ble Current
vs. Temperaure
V
EN
= 5V
V
EN
= 2V
Micrel, Inc. MIC29510/29512
May 2006
7 M9999-051706
(408) 955-1690
Applications Information
The MIC29510 and MIC29512 are high performance
low-dropout voltage regulators suitable for all moderate
to high-current 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
high-current Super ßeta PNP™ regulators have identical
pinouts.
Figure 3. The MIC29510 requires only
two capacitors for o peration
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, T
A
• Output Current, I
OUT
• Output Voltage, V
OUT
• Input Voltage, V
IN
First, we calculate the power dissipation of the regulator
from these numbers and the device parameters from this
datasheet.
P
D
= I
OUT
× (1.02V
IN
– V
OUT
)
Where the ground current is approximated by 3% of I
OUT
,
then the heat sink thermal resistance is determined with
this formula:
)θ(θ
P
TT
θCSJC
D
AJ(MAX)
SA +−
−
=
Where T
J MAX
≤ 125°C and θ
CS
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.
Micrel, Inc.
MIC29510/29512
May 2006
8 M9999-051706
(408) 955-1690
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.
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, especially when all tolerances are
considered.
Adjustable Regulator Design
The adjustable regulator version, MIC29512, allows
programming the output voltage anywhere between
1.25V and 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:
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−×= 1
1.240
V
R2R1
OUT
Where V
O
is the desired output voltage. Figure 4 shows
component definition.
Adjustable Regulator Design
Figure 4. Adjustable Regulator with Resistors
Enable Input
The MIC29512 version 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 V
IN
.
Enabling the regulator requires approximately 20µA of
current into the EN pin.
Standard (Ω)
Voltage R1 R2
2.85 100k 76.8k
2.9 100k 75.0k
3.0 100k 69.8k
3.1 100k 66.5k
3.15 100k 64.9k
3.3 100k 60.4k
3.45 100k 56.2k
3.525 93.1k 51.1k
3.6 100k 52.3k
3.8 100k 48.7k
4.0 100k 45.3k
4.1 100k 43.2k
Resistor Value Table for the MIC29512 Adjustable Regulator
Micrel, Inc. MIC29510/29512
May 2006
9 M9999-051706
(408) 955-1690
Package Information
3-Pin TO-220 (T)
5-Pin TO-220 (T)
Micrel, Inc. MIC29510/29512
May 2006
10 M9999-051706
(408) 955-1690
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.
© 1997 Micrel, Incorporated.
