August
2005 1 M9999-082605-B
MIC49300
3.0A Low Voltage LDO Regulator w/Dual Input Volt
ages
General Description
The MIC49300 is a high-bandwidth, low-dropout, 3.0A volt-
age regulator ideal for powering core voltages of low-power
confi guration allowing for very low output impedance and
very fast transient response.
The MIC49300 requires a bias input supply and a main input
supply, allowing for ultra-low input voltages on the main supply
rail. The input supply operates from 1.4V to 6.5V and the bias
supply requires between 3V and 6.5V for proper operation.
The MIC49300 offers fi xed output voltages from 0.9V to 1.8V
and adjustable output voltages down to 0.9V.
The MIC49300 requires a minimum of output capacitance for
stability, working optimally with small ceramic capacitors.
The MIC49300 is available in a 5-pin S-Pak. It operates over
a junction temperature range of –40°C to +125°C.
Typical Application
MIC49300BR
GND
C
OU
T
=
10µF
Ceramic
BIAS
BIAS
IN
IN
OUT
OUT
C
BIAS
= 1µ
F
Ceramic
V
OU
T
= 1.0V
V
IN
= 1.5V
V
BIAS
= 3.3V
ADJ
ADJ
C
IN
= 1µ
F
Ceramic
R1
R2
Low Voltage,
Fast Transient Response Regulator
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
Load Transient Response
TIME (20µs/div.)
VOUT
20mV/div
IOUT
2A/div
VBIAS = 5V
VIN = 2.5V
VOUT = 1.8V
COUT = 10µF Ceramic
Features
• Input Voltage Range:
V
IN
: 1.4V to 6.5V
V
BIAS
: 3.0V to 6.5V
•
Stable with 1µF ceramic capacitor
• ±1% initial tolerance
• Maximum dropout voltage (V
IN
-V
OUT
) of 500mV over
temperature
•
Adjustable output voltage down to 0.9V
• Ultra fast transient response (Up to 10MHz bandwidth)
• Excellent line and load regulation specifi cations
• Logic controlled shutdown option
• Thermal shutdown and current limit protection
• Power S-Pak package
• Junction temperature range: –40°C to 125°C
Applications
• Graphics processors
• PC Add-In Cards
• Microprocessor core voltage supply
• Low voltage digital ICs
• High Effi ciency Linear power supplies
• SMPS post regulators
MIC49300 Micrel, Inc.
M9999-082605-B
2 August 2005
Pin Confi guration
5
VOUT
4
VBIAS
3
2
VIN
1
EN/ADJ.
GND
5-Lead S-Pak (R)
Pin Description
Pin Number Pin Name Pin Function
1 Enable Enable (Input): CMOS compatible input. Logic high = enable, logic low =
shutdown.
ADJ. Adjustable regulator feedback input. Connect to resistor voltage divider.
4 VIN Input voltage which supplies current to the output power device.
5 VOUT Regulator Output.
2 VBIAS Input Bias Voltage for powering all circuitry on the regulator with the excep-
tion of the output power device.
3 GND Ground (TAB is connected to ground on S-Pak).
Ordering Information
Part Number RoHS Compliant* Output Current Voltage Temperature Range Package
MIC49300-0.9BR MIC49300-0.9WR* 3A 0.9V –40°C to +125°C S-Pak-5
MIC49300-1.2BR MIC49300-1.2WR* 3A 1.2V –40°C to +125°C S-Pak-5
MIC49300-1.5BR MIC49300-1.5WR* 3A 1.5V –40°C to +125°C S-Pak-5
MIC49300-1.8BR MIC49300-1.8WR* 3A 1.8V –40°C to +125°C S-Pak-5
MIC49300BR MIC49300WR* 3A ADJ. –40°C to +125°C S-Pak-5
Other voltages available. Contact Micrel for details.
*RoHS compliant with 'high-melting solder' exemption.
1 Enable Enable (Input): CMOS compatible input. Logic high = enable, logic low =
ADJ. Adjustable regulator feedback input. Connect to resistor voltage divider.
4 VIN Input voltage which supplies current to the output power device.
5 VOUT Regulator Output.
2 VBIAS Input Bias Voltage for powering all circuitry on the regulator with the excep-
3 GND Ground (TAB is connected to ground on S-Pak).
Pin Number Pin Name Pin Function
1 Enable Enable (Input): CMOS compatible input. Logic high = enable, logic low =
ADJ. Adjustable regulator feedback input. Connect to resistor voltage divider.
4 VIN Input voltage which supplies current to the output power device.
5 VOUT Regulator Output.
2 VBIAS Input Bias Voltage for powering all circuitry on the regulator with the excep-
3 GND Ground (TAB is connected to ground on S-Pak).
Pin Number Pin Name Pin Function
1 Enable Enable (Input): CMOS compatible input. Logic high = enable, logic low =
ADJ. Adjustable regulator feedback input. Connect to resistor voltage divider.
4 VIN Input voltage which supplies current to the output power device.
5 VOUT Regulator Output.
2 VBIAS Input Bias Voltage for powering all circuitry on the regulator with the excep-
3 GND Ground (TAB is connected to ground on S-Pak).
Part Number RoHS Compliant* Output Current Voltage Temperature Range Package
MIC49300-0.9BR MIC49300-0.9WR* 3A 0.9V –40°C to +125°C S-Pak-5
MIC49300-1.2BR MIC49300-1.2WR* 3A 1.2V –40°C to +125°C S-Pak-5
MIC49300-1.5BR MIC49300-1.5WR* 3A 1.5V –40°C to +125°C S-Pak-5
MIC49300-1.8BR MIC49300-1.8WR* 3A 1.8V –40°C to +125°C S-Pak-5
MIC49300BR MIC49300WR* 3A ADJ. –40°C to +125°C S-Pak-5
Part Number RoHS Compliant* Output Current Voltage Temperature Range Package
MIC49300-0.9BR MIC49300-0.9WR* 3A 0.9V –40°C to +125°C S-Pak-5
MIC49300-1.2BR MIC49300-1.2WR* 3A 1.2V –40°C to +125°C S-Pak-5
MIC49300-1.5BR MIC49300-1.5WR* 3A 1.5V –40°C to +125°C S-Pak-5
MIC49300-1.8BR MIC49300-1.8WR* 3A 1.8V –40°C to +125°C S-Pak-5
MIC49300BR MIC49300WR* 3A ADJ. –40°C to +125°C S-Pak-5
Part Number RoHS Compliant* Output Current Voltage Temperature Range Package
MIC49300-0.9BR MIC49300-0.9WR* 3A 0.9V –40°C to +125°C S-Pak-5
MIC49300-1.2BR MIC49300-1.2WR* 3A 1.2V –40°C to +125°C S-Pak-5
MIC49300-1.5BR MIC49300-1.5WR* 3A 1.5V –40°C to +125°C S-Pak-5
MIC49300-1.8BR MIC49300-1.8WR* 3A 1.8V –40°C to +125°C S-Pak-5
MIC49300BR MIC49300WR* 3A ADJ. –40°C to +125°C S-Pak-5
Part Number RoHS Compliant* Output Current Voltage Temperature Range Package
MIC49300-0.9BR MIC49300-0.9WR* 3A 0.9V –40°C to +125°C S-Pak-5
MIC49300-1.2BR MIC49300-1.2WR* 3A 1.2V –40°C to +125°C S-Pak-5
MIC49300-1.5BR MIC49300-1.5WR* 3A 1.5V –40°C to +125°C S-Pak-5
MIC49300-1.8BR MIC49300-1.8WR* 3A 1.8V –40°C to +125°C S-Pak-5
MIC49300BR MIC49300WR* 3A ADJ. –40°C to +125°C S-Pak-5
Part Number RoHS Compliant* Output Current Voltage Temperature Range Package
MIC49300-0.9BR MIC49300-0.9WR* 3A 0.9V –40°C to +125°C S-Pak-5
MIC49300-1.2BR MIC49300-1.2WR* 3A 1.2V –40°C to +125°C S-Pak-5
MIC49300-1.5BR MIC49300-1.5WR* 3A 1.5V –40°C to +125°C S-Pak-5
MIC49300-1.8BR MIC49300-1.8WR* 3A 1.8V –40°C to +125°C S-Pak-5
MIC49300BR MIC49300WR* 3A ADJ. –40°C to +125°C S-Pak-5
August
2005 3 M9999-082605-B
MIC49300 Micrel, Inc.
Electrical Characteristics
T
A
TA
T
= 25°C with V
A = 25°C with V
A
BIAS
= V
OUT
+2.1V; V
IN
= V
OUT
+ 1V;
bold
values indicate –40°C < T
J
< +125°C,
Note 4
; unless otherwise specifi ed.
Parameter Conditions Min Typ Max Units
Output Voltage Accuracy At 25°C, fi xed voltage options –1 +1 %
Over temperature range
–2
+2
%
Line Regulation V
IN
= 2.0V to 6.5V
–0.1
0.01
+0.1
%/V
Load Regulation I
L
= 0mA to 3A 0.2
L = 0mA to 3A 0.2
L
0.5
%
Dropout Voltage (V
IN
– V
OUT
) I
L
= 1.5A 125
L = 1.5A 125
L
200
mV
I
L
= 3A 280
L = 3A 280
L
400
mV
Dropout Voltage (V
BIAS
– V
OUT
) I
L
= 3A 1.5
L = 3A 1.5
L
2.1
V
Note 4
Ground Pin Current,
Note 5
I
L
= 0mA 2
L = 0mA 2
L
5
mA
I
L
= 3A 25
L = 3A 25
L
50
mA
Ground Pin Current in Shutdown V
EN
≤ 0.6V, (I
BIAS
+ I
CC
),
Note 6
0.07
5
µA
Current thru V
BIAS
I
L
= 0mA 20
L = 0mA 20
L
35
mA
I
L
= 3A 50
L = 3A 50
L
150
mA
Current Limit V
OUT
= 0V 6.5
9
A
Enable Input, Note 6
Enable Input Threshold Regulator enable
1.6
V
(Fixed Voltage only) Regulator shutdown
0.6
V
Enable Pin Input Current 0.1 1.0 µA
Reference
Reference Voltage Adjustable option only 0.891 0.9 0.909 V
0.882
0.918
V
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Note 4.
For V
OUT
≤1V, V
BIAS
dropout specifi cation does not apply due to a minimum 3V V
BIAS
input.
Note 5.
I
GND
= I
BIAS
+ (I
IN
– I
OUT
). At high loads, input current on V
IN
will be less than the output current, due to drive current being supplied by V
BIAS
.
Note 6.
Fixed output voltage versions only.
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
IN
)
........................................................
8V
Bias Supply Voltage (V
BIAS
)
............................................
8V
Enable Input Voltage (V
EN
)
.............................................
8V
Power Dissipation
.....................................
Internally Limited
ESD Rating,
Note 3
......................................................
2kV
Operating Ratings
(Note 2)
Supply Voltage (V
IN
)
.........................................
1.4V to 6.5V
Bias Supply Voltage (V
BIAS
)
................................
3V to 6.5V
Enable Input Voltage (V
EN
)
...............................
0V to
V
BIAS
Junction Temperature Range
..............
–40°C ≤T
J
≤ +125°C
Package Thermal Resistance
S-PAK
(θ
JC
)
...........................................................
2°C/W
Parameter Conditions Min Typ Max Units
Output Voltage Accuracy At 25°C, fi xed voltage options –1 +1 %
Over temperature range
Line Regulation V
Load Regulation I
) I
I
) I
I
I
Ground Pin Current in Shutdown V
I
I
Current Limit V
Parameter Conditions Min Typ Max Units
Output Voltage Accuracy At 25°C, fi xed voltage options –1 +1 %
= 0mA to 3A 0.2
= 1.5A 125
= 3A 280
= 3A 1.5
= 0mA 2
= 3A 25
0.07
= 0mA 20
= 3A 50
= 0V 6.5
Parameter Conditions Min Typ Max Units
Output Voltage Accuracy At 25°C, fi xed voltage options –1 +1 %
0.01
= 0mA to 3A 0.2
= 1.5A 125
= 3A 280
= 3A 1.5
= 0mA 2
= 3A 25
0.07
= 0mA 20
= 3A 50
= 0V 6.5
Parameter Conditions Min Typ Max Units
Output Voltage Accuracy At 25°C, fi xed voltage options –1 +1 %
mA
Parameter Conditions Min Typ Max Units
Output Voltage Accuracy At 25°C, fi xed voltage options –1 +1 %
%
%/V
%
mV
mV
V
mA
mA
µA
mA
mA
A
Enable Input Threshold Regulator enable
(Fixed Voltage only) Regulator shutdown
Enable Pin Input Current 0.1 1.0 µA
(Fixed Voltage only) Regulator shutdown
Enable Pin Input Current 0.1 1.0 µA
V
(Fixed Voltage only) Regulator shutdown
Enable Pin Input Current 0.1 1.0 µA
V
Enable Pin Input Current 0.1 1.0 µA
V
V
Enable Pin Input Current 0.1 1.0 µA
Reference Voltage Adjustable option only 0.891 0.9 0.909 V
Reference Voltage Adjustable option only 0.891 0.9 0.909 V
Reference Voltage Adjustable option only 0.891 0.9 0.909 V
Reference Voltage Adjustable option only 0.891 0.9 0.909 V
Reference Voltage Adjustable option only 0.891 0.9 0.909 V
V
MIC49300 Micrel, Inc.
M9999-082605-B
4 August 2005
Functional Diagram
V
OUT
Enable
Enable
Bandgap
Bandgap
Bandgap
Bandgap
V
BIAS
V
IN
Ilimit
Ilimit
Ilimit
Ilimit
V
IN
Open
Open
Circuit
Circuit
R1
R2
Fixed
Adj.
Fixed
V
EN
/
ADJ
August
2005 5 M9999-082605-B
MIC49300 Micrel, Inc.
0
50
100
150
200
250
300
0 0.5 1 1.5 2 2.5 3
VIN DROPOUT (mV)
OUTPUT CURRENT (A)
VIN Dropout
vs. Output Current
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
0 0.5 1.0 1.5 2.0 2.5 3.0
VBIAS DROPOUT (V)
OUTPUT CURRENT (A)
VBIAS Dropout
vs. Output Current
0
50
100
150
200
250
300
350
400
-40 -20 0 20 40 60 80 100 120
VIN DROPOUT (mV)
TEMPERATURE (°C)
Dropout vs.
Temperature (Input Supply)
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
OUTPUT VOLTAGE (V)
SUPPLY VOLTAGE (V)
Dropout Characteristics
VBIAS = 5V
100mA
3A
0
5
10
15
20
25
0 0.5 1 1.5 2 2.5 3 3.5 4
B
IAS CURRENT (mA)
INPUT SUPPLY (V)
Bias Current
vs. Input Supply
VOUT = 1.8V
VBIAS = 5V
IOUT = 0mA
IOUT = 100mA
0
100
200
300
400
500
600
700
800
900
1000
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
BIAS CURRENT (mA)
SUPPLY VOLTAGE (V)
Bias Current
vs. Supply Voltage
IOUT = 1A
IOUT = 3A
IOUT = 2A
0
5
10
15
20
25
30
35
0 0.5 1.0 1.5 2.0 2.5 3.0
BIAS CURRENT (mA)
OUTPUT CURRENT (A)
Bias Current
vs. Output Current
VBIAS = 5V
VIN = 2.5V
0
5
10
15
20
25
30
35
-40 -20 0 20 40 60 80 100 120
BIAS CURRENT (mA)
TEMPERATURE (°C)
Bias Current
vs. Temperature
IOUT = 100mA
IOUT = 100µA
IOUT = 500mA
0
10
20
30
40
50
60
-40 -20 0 20 40 60 80 100 120
BIAS CURRENT (mA)
TEMPERATURE (°C)
Bias Current
vs. Temperature
IOUT = 1A
IOUT = 3A
IOUT = 2A
1.764
1.774
1.784
1.794
1.804
1.814
1.824
1.834
-40 -20 0 20 40 60 80 100 120
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
Output Voltage
vs. Temperature
0
1
2
3
4
5
6
7
8
9
-40 -20 0 20 40 60 80 100 120
SHORT CIRCUIT CURRENT (A)
TEMPERATURE (°C)
Short Circuit
vs. Temperature
Typical Characteristics
MIC49300 Micrel, Inc.
M9999-082605-B
6 August 2005
Applications Information
The MIC49300 is an ultra-high performance, low dropout linear
regulator designed for high current applications requiring fast
transient response. The MIC49300 utilizes two input supplies,
signifi cantly reducing dr
opout voltage, perfect for low-voltage,
DC-to-DC conversion. The MIC49300 requires a minimum
of external components and obtains a bandwidth of up to
10MHz. As a µCap regulator, the output is tolerant of virtually
any type of capacitor including ceramic and tantalum.
The MIC49300 regulator is fully protected from damage due
to fault conditions, offering linear current limiting and thermal
shutdown.
Bias Supply Voltage
V
BIAS
, requiring relatively light current, provides power to the
control portion of the MIC49300. V
BIAS
requires approximately
33mA for a 1.5A load current. Dropout conditions require
the base current to the pass transistor. This allows the pass
element to be driven into saturation, reducing the dropout to
300mV at a 1.5A load current. Bypassing on the bias pin is
recommended to improve performance of the regulator dur-
V
BIAS
to ground help reduce high frequency noise from being
good design practice. Good bypass techniques typically in-
clude one larger capacitor such as a 1µF ceramic and smaller
valued capacitors such as 0.01µF or 0.001µF in parallel with
that larger capacitor to decouple the bias supply. The V
BIAS
minimum V
BIAS
input voltage of 3V.
Input Supply Voltage
V
IN
provides the high current to the collector of the pass
transistor. The minimum input voltage is 1.4V, allowing con-
version from low voltage supplies.
Output Capacitor
The MIC49300 requires a minimum of output capacitance
to maintain stability. However, proper capacitor selection
MIC49300 is specifi cally designed to be stable with virtually
any capacitance value and ESR. A 1µF ceramic chip capaci-
tor should satisfy most applications. Output capacitance can
be increased without bound. See typical characteristics for
examples of load transient response.
X7R dielectric ceramic capacitors are recommended because
of their temperature performance. X7R-type 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 or a
tantalum capacitor to ensure the same capacitance value over
the operating temperature range. Tantalum capacitors have a
very stable dielectric (10% over their operating temperature
range) and can also be used with this device.
Input Capacitor
An input capacitor of 1µF 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, surfac-
emount, ceramic chip capacitors can be used for the bypass-
ing. 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.
Thermal Design
Linear regulators are simple to use. The most complicated
design parameters to consider are thermal characteristics.
Thermal design requires the following application-specifi c
parameters:
• Maximum ambient temperature (T
A
• Maximum ambient temperature (TA
• Maximum ambient temperature (T
)
• Output Current (I
OUT
)
• Output Voltage (V
OUT
)
• Input Voltage (V
IN
)
• Ground Current (I
GND
)
First, calculate the power dissipation of the regulator from these
numbers and the device parameters from this datasheet.
P
D
= V
IN
×
I
IN
+ V
BIAS
×
I
BIAS
– V
OUT
×
I
OUT
The input current will be less than the output current at high
output currents as the load increases. The bias current is
a sum of base drive and ground current. Ground current
is constant over load current. Then the heat sink thermal
resistance is determined with this formula:
θ
SA
J(MAX)
A
D
T T
J(MAX)
T T
J(MAX)
A
T T
A
P
D
P
D
=
( )
θ θ
( )
θ θ
JC
( )
JC
θ θ
JC
θ θ
( )
θ θ
JC
θ θ
CS
( )
CS
θ θ+θ θ
( )
θ θ+θ θ
T T±T T
–
The heat sink may be signifi cantly reduced in applications
where the maximum input voltage is known and large com-
pared 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 the
MIC49300 allow signifi cant reductions in regulator power dis-
sipation and the associated heat sink without compromising
performance. When this technique is employed, a capacitor of
at least 1µF is needed directly between the input and regula-
tor ground. Refer to Application Note 9 for further details and
examples on thermal design and heat sink specifi cation.
Minimum Load Current
The MIC49300, unlike most other high current regulators,
does not require a minimum load to maintain output voltage
regulation.
Power Sequencing
There is no power sequencing requirement for V
IN
and V
BIAS
,
giving more fl exibility to the user.
August
2005 7 M9999-082605-B
MIC49300 Micrel, Inc.
Adjustable Regulator Design
The MIC49300 adjustable version allows programming the
output voltage anywhere between 0.9Vand 5V. Two resistors
are used. The resistor value between V
OUT
and the adjust pin
should not exceed 1k
Ω
. Larger values can cause instability.
The resistor values are calculated by:
R1
R2
V
OUT
VOUT
V
= ×
R2
= ×
R2
0 9
−1
0 9.0 9
Where V
OUT
is the desired output voltage.
Enable
The fi xed output voltage versions of the MIC49300 feature an
active high enable input (EN) that allows on-off control of the
regulator. Current drain reduces to “zero” when the device is
sn}tñ◊wn, with only microamperes of leakage current. The
EN input has TTL/CMOS compatible thresholds for simple
logic interfacing. EN may be directly tied to V
IN
and pulled
up to the maximum supply voltage
MIC49300 Micrel, Inc.
M9999-082605-B
8 August 2005
Package Information
5-Pin S-Pak (R)
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 datasheet 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 specifi cations at any time without notifi cation to the customer.
Micrel Products are not
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 signifi cant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Incorporated.