Micrel MIC49200 2a low voltage ldo with dual input voltage Datasheet

MIC49200
2A Low Voltage LDO
with Dual Input Voltages
General Description
The MIC49200 is a high-bandwidth, low-dropout, 2A
voltage regulator ideal for powering core voltages of lowpower microprocessors. The MIC49200 implements a
dual supply configuration allowing for very low output
impedance and very fast transient response.
The MIC49200 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 MIC49200 offers fixed output
voltages from 0.9V to 1.8V and adjustable output voltages
down to 0.9V.
The MIC49200 requires a minimum of output capacitance
for stability, working optimally with small ceramic
capacitors.
The MIC49200 is available in a 5-pin S-Pak. Its operating
temperature range is –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
• Input Voltage Range:
VIN: 1.4V to 6.5V
VBIAS: 3.0V to 6.5V
• Stable with 1µF ceramic output capacitors
• ±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
• Junction temperature range: –40°C to 125°C
Applications
•
•
•
•
•
•
•
Set-top box
Graphics processors
PC add-in cards
Microprocessor core voltage supply
Low voltage digital ICs
High efficiency linear power supplies
SMPS post regulators
Typical Application
Output Voltage
(50mV/div)
Load Transient
VIN = 2.8V
VOUT = 1.8V
Output Current
(1A/div)
VBIAS = 4V
Low Voltage, Fast Transient Response Regulator
COUT = 1µF
Time (40µs/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
January 2006
M9999-011306
(408) 955-1690
Micrel, Inc.
MIC49200
Ordering Information
Part Number
RoHS Compliant
Output
Current
Voltage
Junction
Temperature Range
Package
MIC49200-1.0WR*
2A
1.0V
–40°C to +125°C
S-Pak-5
MIC49200-1.8WR*
2A
1.8V
–40°C to +125°C
S-Pak-5
MIC49200WR*
2A
Adj
–40°C to +125°C
S-Pak-5
* RoHS compliant with ‘high-melting solder’ exemption.
Pin Configuration
5-Pin S-Pak (R)
Pin Description
Pin Number
S-Pak-5
Pin Name
1
EN
Enable (Input): CMOS compatible input. Logic High = enable; Logic Low =
shutdown.
ADJ
Adjustable regulator feedback input. Connect to resistor voltage divider.
2
VBIAS
3
GND
Ground (TAB is connected to ground on S-Pak).
4
VIN
Input voltage which supplies current to the output power device.
5
VOUT
January 2006
Pin Function
Input Bias voltage for powering all circuitry on the regulator with the exception of the
output power device.
Regulator Output.
2
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MIC49200
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) ................................................ 8V
Bias Supply Voltage (VBIAS) ..................................... 8V
Enable Input Voltage (VEN)...................................... 8V
Power Dissipation............................. Internally Limited
ESD Rating(3) .........................................................3kV
Supply voltage (VIN)....................................1.4V to 6.5V
Bias Supply Voltage (VBIAS)...........................3V to 6.5V
Enable Input Voltage (VEN)............................0V to 6.5V
Junction Temperature ...................-40°C ≤ TJ ≤ +125°C
Package Thermal Resistance
S-Pak (θJA) ................................................. 2°C/W
Electrical Characteristics(4)
TA = 25°C with VBIAS = VOUT + 2.2V; VIN = VOUT + 1V; bold values indicate –40°C ≤ TJ ≤ +125°C(5), unless noted.
Parameter
Conditions
Min
Output Voltage Accuracy
At 25°C
Over temperature range (IOUT = 10mA)
Typ
Max
Units
-1
+1
%
-2
+2
%
Line Regulation
VIN = VOUT + 1V to 6.5V
0.01
+0.1
%/V
Load Regulation
IL = 10mA to 2A
0.2
1
1.5
%
%
Dropout Voltage (VIN – VOUT)
IL = 750mA
130
200
mV
300
mV
400
mV
500
mV
530
mV
625
mV
-0.1
(Note 5)
IL = 1.5A
280
400
IL = 2A
Dropout Voltage (VBIAS – VOUT)
(Note 5)
IL = 750mA
1.3
IL = 1.5A
1.65
1.75
IL = 2A
V
1.9
V
2.1
V
2.0
V
2.2
Ground Current (Note 6)
IL = 0mA
15
IL = 2A
15
Ground Pin Current in Shutdown
VEN ≤ 0.6V, (VBIAS + IINPUT) (Note 7)
Current thru VBIAS
IL = 0mA
IL = 2A
Current Limit
Enable Input Threshold
VOUT = 0V
2.5
Regulator enable
25
mA
30
mA
0.5
1
µA
2
µA
9
15
mA
25
mA
40
120
mA
3.5
5.3
A
6
A
V
1.6
0.6
V
0.1
1
µA
0.9
0.909
V
0.918
V
Regulator shutdown
Enable Pin Input Current
Independent of state
V
mA
Reference
Reference Voltage
Adjustable version
0.891
0.882
January 2006
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MIC49200
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating range.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Specification for packaged product only.
5. For VOUT ≤ 1.1V, VBIAS dropout specification does not apply due to a minimum 3V VBIAS input. Dropout voltage is defined as the input-to-output
differential at which the output voltage drops 2% below its nominal value measured at 1V differential for VIN and 2.2V differential for VBIAS.
For outputs below 1.4V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 1.4V.
6. IGND = IBIAS + (IIN – IOUT). At high loads, input current on VIN will be less then the output current, due to drive current being supplied by VBIAS.
7. Fixed output voltage versions only.
January 2006
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MIC49200
Functional Diagram
VBIAS
VIN
Ilimit
VEN/ADJ
Fixed
Enable
Bandgap
Adj.
R1
Fixed
January 2006
5
VOUT
R2
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MIC49200
Typical Characteristics
Power Supply Rejection Ratio
(Input Supply)
120
Power Supply Rejection Ratio
(Bias Supply)
80
350
60
2A
80
100mA
60
300
250
40
200
VIN = VOUT + 1V
= 1.5V
V
20 VOUT = 4V
BIAS
COUT = 1µF
0
0.01 0.1
1
10
100 1,000
FREQUENCY (kHz)
VIN = VOUT + 1V
20 VOUT = 1.5V
VBIAS = 4V
COUT = 1µF
IOUT = 2A
0
0.01 0.1
1
10
100 1,000
FREQUENCY (kHz)
Dropout Voltage
(Bias Supply)
Dropout Voltage
vs. Temperature
(Input Supply)
40
1.8
1.6
1.4
1.2
1
0.8
0.6
VIN = VOUT + 1V
VOUT = 1.5V
VBIAS = 5V
COUT = 1µF
0.4
0.2
0
1.6
1.4
1200 1600 2000
OUTPUT CURRENT (mA)
Dropout Characteristics
(Input Supply)
10mA
550
500
IOUT = 2A
450
VIN = VOUT +1V
400
VOUT = 1.5V
350
VBIAS = 5V
300
COUT = 1µF
250
I
= 1A
200 OUT
150
IOUT = 100mA
100
50
0
1.6
1.2
2A
1.0
1.0
0.8
0.8
0.6
0.6
0.4
0.4
VBIAS = 5V
VOUT = 1.5V
COUT = 1µF
0.2
0
0
1.80
1.75
1.70
1.65
1.60
1.55
1.50
1.45
1.40
1.35
1.30
1.25
1.20
1
2
3
4
5
INPUT VOLTAGE (V)
6
Output Voltage
vs. Temperature
TEMPERATURE (°C)
January 2006
10mA
0
0
300
50
0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
IOUT = 2A
IOUT = 1A
IOUT = 100mA
VIN = VOUT +1V
VOUT = 1.5V
0.2 VBIAS = 5V
COUT = 1µF
0
Load Regulation
1.52
1.51
2A
1.50
1.49
1.48
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
1
2
3
4
5
BIAS VOLTAGE (V)
6
Maximum Bias Current
vs. Bias Voltage
1.47
1.46
300
200
200
150
150
VIN = VOUT + 1V
VOUT = 1.5V
IOUT = 2A
COUT = 1µF
VADJ = 0V
3.5 4.0 4.5 5.0 5.5 6.0 6.5
BIAS VOLTAGE (V)
6
VIN = VOUT + 1V
VOUT = 1.5V
VBIAS = 5V
COUT = 1µF
OUTPUT CURRENT (A)
250
0
3
1200 1600 2000
OUTPUT CURRENT (mA)
Dropout Voltage
vs. Temperature
(Bias Supply)
250
50
VIN = VOUT + 1V
VOUT = 1.5V
VBIAS = 5V
COUT = 1µF
100
TEMPERATURE (°C)
Dropout Characteristics
(Bias Supply)
0.2
100
VIN = VOUT + 1V
VOUT = 1.5V
VBIAS = 5V
150
TEMPERATURE (°C)
1.4
1.2
Dropout Voltage
(Input Supply)
400
2A
100
450
100
50
0
Maximum Bias Current
vs. Temperature
IBIAS
VIN = VOUT +1V
VOUT = 1.5V
VBIAS = 5V
COUT = 1µF
VADJ = 0V
TEMPERATURE (°C)
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Micrel, Inc.
50
45
MIC49200
Bias Current
vs. Temperature
IOUT = 2A
40
35
30
V =V
+ 1V
25 VIN =OUT
OUT 1.5V
20 VBIAS = 5V
= 1µF
C
15 OUT
10
5
0
50
IOUT = 1.5A
10
IOUT = 100mA
14
VIN = VOUT + 1V
VOUT = 1.5V
VBIAS = 5V
COUT = 1µF
1200 1600 2000
OUTPUT CURRENT (A)
Bias Current
vs. Bias Voltage
12
2
VBIAS = VOUT + 2.1V
1 V
OUT = 1.5V
COUT = 1µF
0
1.5
2.5
3.5
4.5
5.5
INPUT VOLTAGE (V)
14
12
IOUT=0A
10
10
8
8
8
6
6
6
4
4
4
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
BIAS VOLTAGE (V)
30
Bias Current
vs. Bias Voltage
VIN = VOUT + 1V
2 VOUT = 1.5V
COUT = 1µF
0
3 3.5 4 4.5 5 5.5 6
BIAS VOLTAGE (V)
50
2
6.5
Bias Current
vs. Bias Voltage
6.5
Bias Current
vs. Bias Voltage
IOUT = 100mA
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
BIAS VOLTAGE (V)
50
40
IOUT = 750mA
20
IOUT=0A
3
IOUT = 0A
2
Ground Current
vs. Input Voltage
4
20
Ground Current
vs. Bias Voltage
10
5
30
0
12
6
40
TEMPERATURE (°C)
14
Bias Current
vs. Output Current
40
Bias Current
vs. Bias Voltage
IOUT = 2A
IOUT = 1.5A
10
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
30
30
20
20
10
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
10
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
BIAS VOLTAGE (V)
0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
BIAS VOLTAGE (V)
0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
BIAS VOLTAGE (V)
Bias Current
vs. Input Voltage
Bias Current
vs. Input Voltage
Reference Voltage
vs. Input Voltage
20
18
0.901
250
16
14
12
10
200
100mA
750mA
150
0mA
8
6
4
2
0
0
300
0.900
100
VOUT = 1.5V
VBIAS = 5V
COUT = 1µF
0.5
1.0
1.5
2.0
INPUT VOLTAGE (V)
January 2006
2.5
VOUT = 1.5V
= 5V
V
50 CBIAS = 1µF
OUT
0
0
2A
0.5
1.0
1.5
2.0
INPUT VOLTAGE (V)
7
2.5
0.899
1.5
VOUT = 1.5V
VBIAS = 5V
COUT = 1µF
2.5
3.5
4.5
5.5
INPUT VOLTAGE (V)
6.5
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0.901
MIC49200
Reference Voltage
vs. Bias Voltage
4.0
0.900
Short Circuit Current
vs. Temperature
1.6
3.5
1.4
3.0
1.2
2.5
1.0
2.0
0.8
1.5
0.899
3
1.6
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
3.5
4 4.5 5 5.5 6
BIAS VOLTAGE (V)
6.5
Enble Threshold
vs. Temperature
1.4
ON
1.2
1.0
OFF
0.8
0.6
0.4
0.2
0
VIN = VOUT + 1V
VOUT = 1V
VBIAS = 5V
COUT = 1µF
TEMPERATURE (°C)
January 2006
1.0
0.5
0
4.0
ON
OFF
0.6
VIN = VOUT + 1V
VOUT = 1V
VBIAS = 5V
COUT = 1µF
0.4
0.2
VIN = VOUT + 1V
VOUT = 1V
COUT = 1µF
TEMPERATURE (°C)
0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
BIAS VOLTAGE (V)
Current Limit
vs. Input Voltage
Current Limit
vs. Bias Voltage
4.0
3.5
3.5
3.0
3.0
2.5
2.5
2.0
2.0
1.5
1.5
1.0
1.0
VOUT = 1.5V
VBIAS = 3.3V
COUT = 1µF
0.5
0
1.5
Enable Threshold
vs. Bias Voltage
2.5
3.5
4.5
5.5
INPUT VOLTAGE (V)
8
6.5
0.5
0
2
VIN = VOUT + 1V
VOUT = 1.5V
COUT = 1µF
3
4
5
BIAS VOLTAGE (V)
6
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Micrel, Inc.
MIC49200
Functional Characteristics
Output Voltage
(20mV/div)
Line Transient (VBIAS)
Output Voltage
(20mV/div)
Line Transient (VIN)
VBIAS = 6V
Bias Voltage
(2V/div)
VOUT = 1.5V
VBIAS = 3.3V
VBIAS = 4V
VIN = 2.8V
VOUT = 1.8V
COUT = 1µF
COUT = 1µF
IOUT = 2A
IOUT = 2A
Time (100µs/div)
Time (20µs/div)
Enable Turn-On
Load Transient
Output Voltage
(50mV/div)
VIN = 3.3V
Enable
(2V/div)
Input Voltage
(2V/div)
VIN = 5V
VIN = 2.8V
VBIAS = 4V
Output Current
(1A/div)
Output Voltage
(1V/div)
VOUT = 1.8V
VIN = VOUT + 1V
VOUT = 1.8V
VBIAS = 4V
COUT = 1µF
COUT = 1µF
Time (40µs/div)
Time (4µs/div)
January 2006
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Applications Information
The MIC49200 is an ultra-high performance, lowdropout linear regulator designed for high current
applications requiring fast transient response. The
MIC49200 utilizes two input supplies, significantly
reducing dropout voltage, perfect for low-voltage, DCto-DC conversion. The MIC49200 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
type and tantalum type capacitors.
The MIC49200 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 MIC49200. VBIAS requires
approximately 40mA 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 thereby reducing the dropout to 400mV
at a 2A 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 represent good
design practice. Good bypass techniques typically
include one larger capacitor such as 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 2.1V
above the output voltage with a minimum VBIAS input
voltage of 3 volts.
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 MIC49200 requires a minimum of output
capacitance to maintain stability. However, proper
capacitor selection is important to ensure desired
transient response. The MIC49200 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 Characteristic”
subsection for examples of load transient response.
January 2006
MIC49200
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" away from the bulk
supply capacitance, or when the supply is a battery.
Small, surface-mount, 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)
• 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
As the load increases, the input current will be less
than the output current at high output currents. The
bias current is a sum of base drive and ground
current. Ground current is constant over load current.
The heat sink thermal resistance is determined with
this formula:
θ SA =
10
TJ(MAX) − TA
PD
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Micrel, Inc.
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
MIC49200 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 MIC49200, unlike most other high current
regulators, does not require a minimum load to
maintain output voltage regulation.
January 2006
MIC49200
Adjustable Regulator Design
The
MIC49200
adjustable
version
allows
programming the output voltage anywhere between
0.9V and 5V. Two resistors are used. The resistor
value between VOUT and the adjust pin should not
exceed 10kΩ. Larger values can cause instability. The
resistor values are calculated by:
⎛R
⎞
VOUT = 0.9⎜⎜ 1 + 1⎟⎟
⎝ R2
⎠
Where VOUT is the desired output voltage.
Enable
The fixed output voltage versions of the MIC49200
feature an active high enable input (EN) that allows
on-off control of the regulator. Supply currents reduce
to “zero” when the device is in shutdown, 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.
11
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Micrel, Inc.
MIC49200
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 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.
© 2005 Micrel, Inc.
January 2006
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