Micrel MIC49300BR 3.0a low voltage ldo regulator w/dual input voltage Datasheet

MIC49300
3.0A Low Voltage LDO Regulator w/Dual Input Voltages
General Description
Features
The MIC49300 is a high-bandwidth, low-dropout, 3.0A voltage regulator ideal for powering core voltages of low-power
microprocessors. The MIC49300 implements a dual supply
configuration 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 fixed 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.
• Input Voltage Range:
VIN: 1.4V to 6.5V
VBIAS: 3.0V to 6.5V
• Stable with 1µF ceramic capacitor
• ±1% initial tolerance
• Maximum dropout voltage (VIN-VOUT) of 500mV over
temperature
• Adjustable output voltage down to 0.9V
• Ultra fast transient response (Up to 10MHz bandwidth)
• Excellent line and load regulation specifications
• 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 Efficiency Linear power supplies
SMPS post regulators
Typical Application
MIC49300BR
IN
OUT
VOUT = 1.0V
VOUT
20mV/div
VIN = 1.5V
Load Transient Response
R1
VBIAS = 3.3V
CBIAS = 1µF
Ceramic
BIAS
ADJ
GND
R2 COUT = 10µF
Ceramic
IOUT
2A/div
CIN = 1µF
Ceramic
VBIAS = 5V
VIN = 2.5V
VOUT = 1.8V
COUT = 10µF Ceramic
Low Voltage,
Fast Transient Response Regulator
TIME (20µs/div.)
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
August 2005
1
M9999-082605-B
MIC49300
Micrel, Inc.
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
MIC49300WR*
3A
ADJ.
–40°C to +125°C
S-Pak-5
MIC49300BR
Other voltages available. Contact Micrel for details.
*RoHS compliant with 'high-melting solder' exemption.
Pin Configuration
5
4
3
2
1
VOUT
VIN
GND
VBIAS
EN/ADJ.
5-Lead S-Pak (R)
Pin Description
Pin Number
Pin Name
1
Enable
4
Pin Function
Enable (Input): CMOS compatible input. Logic high = enable, logic low =
shutdown.
ADJ.
Adjustable regulator feedback input. Connect to resistor voltage divider.
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 exception of the output power device.
3
GND
M9999-082605-B
Ground (TAB is connected to ground on S-Pak).
2
August 2005
MIC49300
Micrel, Inc.
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 2)
Supply Voltage (VIN) ........................................................ 8V
Bias Supply Voltage (VBIAS) ............................................ 8V
Enable Input Voltage (VEN) ............................................. 8V
Power Dissipation ..................................... Internally Limited
ESD Rating, Note 3 ...................................................... 2kV
Supply Voltage (VIN) .........................................1.4V to 6.5V
Bias Supply Voltage (VBIAS) ................................3V to 6.5V
Enable Input Voltage (VEN) ............................... 0V to VBIAS
Junction Temperature Range ..............–40°C ≤TJ ≤ +125°C
Package Thermal Resistance
S-PAK(θJC) ........................................................... 2°C/W
Electrical Characteristics
TA = 25°C with VBIAS = VOUT +2.1V; VIN = VOUT + 1V; bold values indicate –40°C < TJ < +125°C, Note 4; unless otherwise specified.
Parameter
Conditions
Min
Typ
Output Voltage Accuracy
At 25°C, fixed voltage options
Over temperature range
Line Regulation
VIN = 2.0V to 6.5V
Load Regulation
IL = 0mA to 3A
0.2
0.5
%
Dropout Voltage (VIN – VOUT)
IL = 1.5A
125
200
mV
–1
–2
–0.1
0.01
Max
Units
+1
+2
%
%
+0.1
%/V
IL = 3A
280
400
mV
Dropout Voltage (VBIAS – VOUT)
Note 4
IL = 3A
1.5
2.1
V
Ground Pin Current, Note 5
IL = 0mA
25
Ground Pin Current in Shutdown
VEN ≤ 0.6V, (IBIAS + ICC), Note 6
Current thru VBIAS
IL = 0mA
IL = 3A
VOUT = 0V
IL = 3A
Current Limit
mA
25
50
mA
0.07
5
µA
20
35
mA
50
150
mA
6.5
9
A
0.6
V
V
0.1
1.0
µA
0.9
0.909
0.918
V
V
Enable Input, Note 6
Enable Input Threshold
(Fixed Voltage only)
1.6
Regulator enable
Regulator shutdown
Enable Pin Input Current
Reference
Reference Voltage
Adjustable option only
0.891
0.882
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 VOUT ≤1V, VBIAS dropout specification does not apply due to a minimum 3V VBIAS input.
Note 5.
IGND = IBIAS + (IIN – IOUT). At high loads, input current on VIN will be less than the output current, due to drive current being supplied by VBIAS.
Note 6.
Fixed output voltage versions only.
August 2005
3
M9999-082605-B
MIC49300
Micrel, Inc.
Functional Diagram
VBIAS
VIN
Ilimit
VEN / ADJ
Fixed
Enable
Bandgap
Adj.
VIN Open
Circuit
Fixed
M9999-082605-B
4
R1
VOUT
R2
August 2005
MIC49300
Micrel, Inc.
Typical Characteristics
VIN Dropout
vs. Output Current
1.7
350
100
50
VIN DROPOUT (mV)
150
1.5
1.4
1.3
1.2
1.1
0.5
1
1.5
2
2.5
OUTPUT CURRENT (A)
1
3
0.5 1.0 1.5 2.0 2.5
OUTPUT CURRENT (A)
20
15
10
1.834
VBIAS = 5V
VIN = 2.5V
0.5 1.0 1.5 2.0 2.5
OUTPUT CURRENT (A)
VOUT = 1.8V
VBIAS = 5V
1000
900
1.804
1.794
1.784
1.774
1.764
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
I
OUT
= 100mA
20
15
I
OUT
= 100µA
10
5
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
9
Bias Current
vs. Supply Voltage
IOUT = 2A
700
600
500
IOUT = 3A
400
300
IOUT = 1A
200
100
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
SUPPLY VOLTAGE (V)
60
IOUT = 500mA
25
Output Voltage
vs. Temperature
1.814
800
Bias Current
vs. Temperature
30
3.0
1.824
August 2005
5
35
25
0
0
B
Bias Current
vs. Output Current
30
100
0
0 0.5 1 1.5 2 2.5 3 3.5 4
INPUT SUPPLY (V)
BIAS CURRENT (mA)
BIAS CURRENT (mA)
10
0.4
0.2
VBIAS = 5V
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
SUPPLY VOLTAGE (V)
5
IOUT = 0mA
15
1.0
0.8
0.6
35
OUTPUT VOLTAGE (V)
20
3A
150
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
IOUT = 100mA
SHORT CIRCUIT CURRENT (A)
OUTPUT VOLTAGE (V)
1.4
1.2
25
100mA
200
3.0
Bias Current
vs. Input Supply
Dropout Characteristics
2.0
1.8
1.6
250
50
0
BIAS CURRENT (mA)
0
300
BIAS CURRENT (mA)
200
0
400
1.6
250
VBIAS DROPOUT (V)
VIN DROPOUT (mV)
300
Dropout vs.
Temperature (Input Supply)
VBIAS Dropout
vs. Output Current
50
40
Bias Current
vs. Temperature
IOUT = 3A
IOUT = 2A
30
20
10
IOUT = 1A
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Short Circuit
vs. Temperature
8
7
6
5
4
3
2
1
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
5
M9999-082605-B
MIC49300
Micrel, Inc.
Applications Information
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, surfacemount, ceramic chip capacitors can be used for the bypassing. 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-specific
parameters:
• Maximum ambient temperature (TA)
• Output Current (IOUT)
• Output Voltage (VOUT)
• Input Voltage (VIN)
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,
significantly reducing dropout 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
VBIAS, requiring relatively light current, provides power to the
control portion of the MIC49300. VBIAS requires approximately
33mA for a 1.5A load current. Dropout conditions require
higher currents. Most of the biasing current is used to supply
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 during line and load transients. Small ceramic capacitors from
VBIAS to ground help reduce high frequency noise from being
injected into the control circuitry from the bias rail and are
good design practice. Good bypass techniques typically include 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 VBIAS
input voltage must be 1.6V above the output voltage with a
minimum VBIAS input voltage of 3V.
Input Supply Voltage
VIN provides the high current to the collector of the pass
transistor. The minimum input voltage is 1.4V, allowing conversion from low voltage supplies.
Output Capacitor
The MIC49300 requires a minimum of output capacitance
to maintain stability. However, proper capacitor selection
is important to ensure desired transient response. The
MIC49300 is specifically designed to be stable with virtually
any capacitance value and ESR. A 1µF ceramic chip capacitor 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.
M9999-082605-B
• Ground Current (IGND)
First, calculate the power dissipation of the regulator from these
numbers and the device parameters from this datasheet.
PD = VIN × IIN + VBIAS × IBIAS – VOUT × IOUT
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:
 TJ(MAX) ± TA 
θSA = 

 PD – θ JC + θCS 
(
)
The heat sink may be significantly reduced in applications
where the maximum input voltage is known and 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 the
MIC49300 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 1µF 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 specification.
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 VIN and VBIAS,
giving more flexibility to the user.
6
August 2005
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 VOUT and the adjust pin
should not exceed 1kΩ. Larger values can cause instability.
The resistor values are calculated by:
V

R1 = R2 ×  OUT −1
 0. 9

Where VOUT is the desired output voltage.
Enable
The fixed 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 VIN and pulled
up to the maximum supply voltage
August 2005
7
M9999-082605-B
MIC49300
Micrel, Inc.
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 specifications at any time without notification 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 significant 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.
M9999-082605-B
8
August 2005
Similar pages