MIC47100
1A High Speed Low VIN LDO
MicroLead Frame and MLF are registered trademark of Amkor Technology
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2008
M9999-022108-A
(408) 944-0800
General Description
The MIC47100 is a high speed, Low V
IN
LDO capable of
delivering up to 1A and designed to take advantage of
point of load applications that use multiple supply rails to
generate a low voltage, high current power supply. The
MIC47100 is stable with only a 1µF ceramic output
capacitor and is available in a thermally enhanced
2mm × 2mm MLF
®
package thus making it an optimal
solution for board-constrained applications.
The MIC47100 has an NMOS output stage offering very
low output impedance. The NMOS output stage offers a
unique ability to respond very quickly to sudden load
changes such as that required by a microprocessor, DSP
or FPGA. The MIC47100 consumes little quiescent
current and therefore can be used for driving the core
voltages of mobile processors, post regulating a core
DC/DC converter in any portable device.
The MIC47100 is available in fixed and adjustable output
voltages in the exposed pad MSOP-8 package and the tiny
2mm × 2mm MLF
®
package with an operating junction
temperature range of -40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
• Operating voltage range:
- Input Supply: 1.0V to 3.6V
- Bias Supply: 2.3V to 5.5V
• 0.8V to 2.0V output voltage range
• High bandwidth – very fast transient response
• PSRR >50dB at 100kHz
• Stable with a 1µF ceramic output capacitor
• Low dropout voltage of 80mV at 1A
• High output voltage accuracy:
- +/- 1.5% initial accuracy
- +/- 2% over temperature
• Logic level enable input
• UVLO on both supply voltages for easy turn-on
• ePad MSOP-8 – small form factor power package
• Thermally enhanced 2mm × 2mm MLF
®
– smallest
solution
Applications:
• Point of Load
• PDAs
• DSP, PLD and FPGA Power Supply
• Low Voltage Post Regulation
___________________________________________________________________________________________________________
Typical Application
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Ordering Information
Part Number Nominal Output
Voltage
(1)
Marking Code Lead Finish Package
MIC47100YML ADJ EAA Pb free 2x2 MLF8
MIC47100-0.8YML 0.8V E08 Pb free 2x2 MLF8
MIC47100-1.0YML 1.0V+ E10 Pb free 2x2 MLF8
MIC47100-1.2YML 1.2V+ E12 Pb free 2x2 MLF8
MIC47100YMME ADJ ZEAAY Pb free MSOP-8 w/ ePad
MIC47100-0.8YMME 0.8V ZE08Y Pb free MSOP-8 w/ ePad
MIC47100-1.0YMME 1.0V+ ZE10Y Pb free MSOP-8 w/ ePad
MIC47100-1.2YMME 1.2V+ ZE12Y Pb free MSOP-8 w/ ePad
Note:
1. Other Voltage available. Co ntact Micrel for details.
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Pin Configur ation
8-pin 2mm x 2mm MLF
®
Fixed and Adjustable (ML) 8-pin Exposed Pad MSOP
Fixed and Adjustable (MME)
Pin Description
Pin Number
MLF Pin Number
MSOP
Pin Name Pin Name
1,2 1,2 IN
Input Supply. Drain of NMOS pass transistor which is the
power input voltage for regulator. The NMOS pass transistor
steps down this input voltage to create the output voltage.
3 3 GND
Ground. Ground pins and exposed pad must be connected
externally.
4 4 BIAS
Bias Supply. The bias supply is the power supply for the
internal circuitry of the regulator.
5 5 EN
Enable: TTL/CMOS compatible input. Logic high = enable,
logic low or open = shutdown
6 (Fixed) 6 (Fixed) FB Feedback Input. Connect to OUT. Optimum load regulation is
obtained when feedback is taken from the actual load point.
6 (Adj) 6 (Adj) ADJ Adjust Input. Connect external resistor divider to program
output voltage.
7,8 7,8 OUT Output. Output Voltage of Regulator
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Absolute Maximum Ratings
(1)
Input Supply Voltage (V
IN
).................................... 0V to +4V
Bias Supply Voltage (V
BIAS
).................................. 0V to +6V
Enable Voltage (V
EN
)............................................ 0V to +6V
Power Dissipation, Internally Limited
(3)
Lead Temperature (soldering, #sec.)......................... 260°C
Storage Temperature (T
s
) ..........................-65°C to +150°C
ESD Rating
(4)
................................................................. 2kV
Operating Ratings
(2)
Input Supply Voltage (V
IN
).............................. 1.0V to +3.6V
Bias Supply Voltage (V
BIAS
)............................ 2.3V to +5.5V
Enable Input Voltage (V
EN
).................................. 0V to V
BIAS
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
ePad MSOP-8 (θ
JA
) ...........................................64°C/W
2mm x 2mm MLF
®
(θ
JA
).....................................90°C/W
Electrical Characteristics
(5)
V
IN
= V
OUT
+0.5V; V
BIAS
= V
OUT
+ 2.1V, I
OUT
= 100µA; T
A
= 25°C, bold values indicate –40°C< T
A
< +125°C, unless noted.
Parameter Condition Min Typ Max Units
UVLO Thresholds
(6)
Bias Supply
Input Supply
1.9
0.7 2.1
0.85
2.3
1.0 V
UVLO Hysteresis V
BIAS
V
IN
70
25
mV
Variation from nominal V
OUT
-1.5 +1.5 % Output Voltage
Accuracy Variation from nominal V
OUT
; -40°C to +125°C -2.0 +2.0 %
Output Voltage Line
Regulation (Bias
Supply)
V
BIAS
= V
OUT
+ 2.1V to 5.5V
-0.1 0.015 0.1 %/V
Output Voltage Line
Regulation
(Input Supply)
V
IN
= V
OUT
+ 0.5V to 3.6V
-0.05 0.005 0.05 %/V
Load Regulation I
OUT
= 10mA to 1A 0.2 0.5 %
Input Supply Dropout
Voltage
I
OUT
= 100mA;
I
OUT
= 500mA;
I
OUT
= 1A;
8.5
37
80
50
250
mV
mV
mV
Bias Supply Dropout
Voltage
I
OUT
= 100mA;
I
OUT
= 500mA;
I
OUT
= 1A
1.15
1.25
1.35
2.1
V
V
V
Ground current from
V
BIAS
I
OUT
= 1mA
I
OUT
= 1A
350
350
500
500 µA
µA
Shutdown current
from V
BIAS
EN < 0.2V 0.1 1.0 µA
Ground current from
V
IN
I
OUT
= 1A 6 µA
Shutdown current
from V
IN
EN < 0.2V 0.1 1.0 µA
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Ripple Rejection f = 1kHz; C
OUT
= 1.0µF; I
OUT
= 100mA
f = 100kHz; C
OUT
= 1.0µF; I
OUT
= 100mA
f = 500kHz; C
OUT
= 1.0µF; I
OUT
= 100mA
80
55
45
dB
dB
dB
Current Limit V
IN
= 2.7V; V
OUT
= 0V 1.1 1.6 2.5 A
Output Voltage Noise C
OUT
=1µF; 10Hz to 100kHz; I
OUT
= 100mA 63 µV
RMS
Over-temperature
Shutdown
160
°C
Over-temperature
Shutdown Hysteresis
20
°C
Enable Inputs
Logic Low 0.2 V Enable Voltage
Logic High 1.0 V
VIL < 0.2V 1 µA Enable Input Current
VIH = 1.2V 6 µA
Turn-on Time C
OUT
= 1µF; 90% of typical V
OUT
35 500 µs
Reference Voltage (Adjustable Option Only)
Reference Voltage 0.69
0.686
0.7 0.71
0.714
V
V
ADJ pin Input current 20 nA
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation of any T
A
(ambient temperature) is P
D(max)
= T
J(max)
– T
A
) / θ
JA
. Exceeding the maximum allowable power
dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
5. Specification for packaged product only.
6. Both UVLO thresholds must be met for the output voltage to be allowed to turn-on. If either of the two input voltages are below the UVLO thresholds,
the output is kept off.
Micrel, Inc. MIC47100
February 2008 6
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Typical Characteristics
Micrel, Inc. MIC47100
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Micrel, Inc. MIC47100
February 2008 8
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Functional Characteristics
Micrel, Inc. MIC47100
February 2008 9
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Functional Diagram
MIC47100 Block Diagram
Micrel, Inc. MIC47100
February 2008 10
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Applications Information
The MIC47100 is a high speed, dual supply NMOS LDO
designed to take advantage of point-of-load applications that
use multiple supply rails to generate a low voltage, high
current power supply. The MIC47100 can source 1A of
output current while only requiring a 1µF ceramic output
capacitor for stability.
The MIC47100 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 MIC47100. Bypassing on
the bias pin is recommended to improve performance
of the regulator during line and load transients. Small
ceramic capacitors from V
BIAS
-to-ground help reduce
high frequency noise from being injected into the
control circuitry from the bias rail and are good design
practice.
Input Supply Voltage
V
IN
provides the supply to power the LDO. The
minimum input voltage is 1V, allowing conversion from
low voltage supplies.
Output Capacitor
The MIC47100 requires an output capacitor of 1µF or
greater to maintain stability. The design is optimized
for use with low-ESR ceramic chip capacitors. High
ESR capacitors may cause high frequency oscillation.
The output capacitor can be increased, but
performance has been optimized for a 1µF ceramic
output capacitor and does not improve significantly
with larger capacitance.
X7R/X5R dielectric-type 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 capacitor to ensure
the same minimum capacitance over the equivalent
operating temperature range.
Input Capacitor
The MIC47100 is a high-performance, high bandwidth
device. Therefore, it requires a well-bypassed input
supply for optimal performance. A 1µF capacitor is
required from the input to ground to provide stability.
Low-ESR ceramic capacitors provide optimal
performance at a minimum of space. Additional high-
frequency capacitors, such as small-valued NPO
dielectric-type capacitors, help filter out high-
frequency noise and are good practice in any RF-
based circuit.
Minimum Load Current
The MIC47100, unlike most other regulators, does not
require a minimum load to maintain output voltage
regulation.
Adjustable Regulator Design
The MIC47100 adjustable version allows
programming the output voltage anywhere between
0.8V and 2.0V. Two resistors are used. The R1
resistor value between V
OUT
and the adjust pin should
not exceed 10kΩ. Larger values can cause instability.
R2 connects between the adjust pin and ground. The
resistor values are calculated by:
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−×= 1
0.7
V
R2R1
OUT
Where V
OUT
is the desired output voltage.
Enable/Shutdown
The MIC47100 comes with a single active-high enable
pin that allows the regulator to be disabled. Forcing
the enable pin low disables the regulator and sends it
into a “zero” off-mode-current state. In this state,
current consumed by the regulator goes nearly to
zero. Forcing the enable pin high enables the output
voltage. The active-high enable pin uses CMOS
technology and the enable pin cannot be left floating;
a floating enable pin may cause an indeterminate
state on the output.
Thermal Considerations
The MIC47100 is designed to provide 1A of
continuous current in a very small package. Maximum
ambient operating temperature can be calculated
based on the output current and the voltage drop
across the part. Given that the input voltage is 1.8V,
the output voltage is 1.2V and the output current is
1A. The actual power dissipation of the regulator
circuit can be determined using the equation:
P
D
= (V
IN
– V
OUT1
) I
OUT
+ V
BIAS
I
GND
Because this device is CMOS, the ground current is
insignificant for power dissipation and can be ignored
for this calculation.
P
D
= (1.8V – 1.2V) × 1A
P
D
= 0.6W
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To determine the maximum ambient operating
temperature of the package, use the junction-to-
ambient thermal resistance of the device and the
following basic equation:
P
D(MAX)
=
T
J(MAX)
- T
A
JA
⎝
⎛
T
J(max)
= 125°C, the maximum junction temperature of
the die θ
JA
thermal resistance = 90°C/W.
The table below shows junction-to-ambient thermal
resistance for the MIC47100 in the MLF
®
package.
Package
θ
JA
Recommended
Minimum
Footprint
θ
JC
8-pin 2mm x 2mm
MLF
®
90°C/W 2°C/W
Thermal Resistance
Substituting P
D
for P
D(max)
and solving for the ambient
operating temperature will give the maximum
operating conditions for the regulator circuit. The
junction-to-ambient thermal resistance for the
minimum footprint is 90°C/W.
The maximum power dissipation must not be
exceeded for proper operation.
For example, when operating the MIC47100-1.2YML
at an input voltage of 1.8V and a 1A load with a
minimum footprint layout, the maximum ambient
operating temperature T
A
can be determined as
follows:
CT WC TC
W
A
A
°=
°
−°
=
71
)/90(
)125(
6.0
Therefore, a 1.2V application with 1A of output current
can accept an ambient operating temperature of 71°C
in a 2mm x 2mm MLF
®
package. For a full discussion
of heat sinking and thermal effects on voltage
regulators, refer to the “Regulator Thermals” section
of
Micrel’s Designing with Low-Dropout Voltage
Regulators
handbook. This information can be found
on Micrel's website at:
http://www.micrel.com/_PDF/other/LDOBk_ds.pdf
Micrel, Inc.
MIC47100
February 2008 12
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Package Information
8-Pin 2mm×2mm MLF (ML)
Micrel, Inc.
MIC47100
February 2008 13
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8-Pin e-Pad MSOP (MME)
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
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical impla
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.
can nt
© 2008 Micrel, Incorporated.
