MICREL MIC37100_07

MIC37100/37101/37102
1A Low-Voltage µCap LDO
General Description
Features
The MIC37100, MIC37101, and MIC37102 are 1A low• Fixed and adjustable output voltages to 1.24V
dropout, linear voltage regulators that provide low-voltage,
• µCap Regulator, 10µF ceramic output capacitor stable
high-current output from an extremely small package.
• 280mV typical dropout at 1A
Utilizing Micrel’s proprietary Super βeta PNP® pass
– Ideal for 3.0V to 2.5V conversion
element, the MIC37100/01/02 offers extremely low dropout
– Ideal for 2.5V to 1.8V, 1.65V or 1.5V conversion
(typically 280mV at 1A) and low ground current (typically
• 1A minimum guaranteed output current
11mA at 1A).
• 1% initial accuracy
The MIC37100 is a fixed output regulator offered in the
SOT-223 package. The MIC37101 and MIC37102 are
• Low ground current
fixed and adjustable regulators, respectively, in a thermally
• Current limiting and thermal shutdown
enhanced power 8-pin SOIC (small outline package) and
• Reversed-leakage protection
the SOT-223 package. The MIC37102 is also available in
• Fast transient response
the S-PAK power package, for applications that require
• Low-profile SOT-223 package
higher power dissipation or higher operating ambient
• Power SO-8 package
temperatures.
• S-PAK package (MIC37102 only)
The MIC37100/01/02 is ideal for PC add-in cards that
need to convert from standard 5V to 3.3V, 3.3V to 2.5V or
2.5V to 1.8V or lower. A guaranteed maximum dropout
Applications
voltage of 500mV over all operating conditions allows the
• LDO linear regulator for PC add-in cards
MIC37100/01/02 to provide 2.5V from a supply as low as
3V and 1.8V from a supply as low as 2.3V.
• PowerPC® power supplies
The MIC37100/01/02 is fully protected with overcurrent
• High-efficiency linear power supplies
limiting and thermal shutdown. Fixed output voltages of
• SMPS post regulator
1.5V, 1.65V, 1.8V, 2.5V and 3.3V are available on
• Multimedia and PC processor supplies
MIC37100/01 with adjustable output voltages to 1.24V on
• Battery chargers
MIC37102.
• Low-voltage microcontrollers and digital logic
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
___________________________________________________________________________________________________________
Typical Application
350
GND
300
2.5V
10F
ceramic
DROPOUT (mV)
VIN
3.3V
MIC37100
OUT
IN
Dropout
vs. Output Current
2.5VOUT
250
200
150
3.3VOUT
100
50
2.5V/1A Regulator
0
0
0.25
0.5
0.75
OUTPUT CURRENT (A)
1
Super βeta PNP is a registered trademark of Micrel, Inc.
PowerPC is a registered trademark of IBM Corporation
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
September 2007
M9999-090607
Micrel, Inc.
MIC37100/37101/37102
Ordering Information
Part Number
Voltage
Temperature Range
Package
Pb-Free /
RoHS Compliant
Standard
MIC37100-1.5BS
MIC37100-1.5WS*
1.5V
–40° to +125°C
SOT-223
MIC37100-1.65BS
MIC37100-1.65WS*
1.65V
–40° to +125°C
SOT-223
MIC37100-1.8BS
MIC37100-1.8WS*
1.8V
–40° to +125°C
SOT-223
MIC37100-2.5BS
MIC37100-2.5WS*
2.5V
–40° to +125°C
SOT-223
MIC37100-3.3BS
MIC37100-3.3WS*
3.3V
–40° to +125°C
SOT-223
MIC37101-1.5BM
MIC37101-1.5YM
1.5V
–40° to +125°C
8-Pin SOIC
MIC37101-1.65BM
MIC37101-1.65YM
1.65V
–40° to +125°C
8-Pin SOIC
MIC37101-1.8BM
MIC37101-1.8YM
1.8V
–40° to +125°C
8-Pin SOIC
Contact Factory
MIC37101-2.1YM
2.1V
–40° to +125°C
8-Pin SOIC
MIC37101-2.5BM
MIC37101-2.5YM
2.5V
–40° to +125°C
8-Pin SOIC
MIC37101-3.3BM
MIC37101-3.3YM
3.3V
–40° to +125°C
8-Pin SOIC
MIC37102BM
MIC37102YM
Adj.
–40° to +125°C
8-Pin SOIC
MIC37102BR
MIC37102WR*
Adj.
–40° to +125°C
5-Pin S-PAK
* RoHS compliant with ‘high-melting solder’ exemption.
Pin Configuration
GND
5
4
3
2
1
TAB
TAB
1
IN
2
ADJ
OUT
GND
IN
EN
3
GND OUT
SOT-223 (S)
MIC37100-x.x (Fixed)
5-Pin S-PAK (R)
MIC37102 (Adjustable)
EN 1
8
GND
EN 1
8
GND
IN 2
7
GND
IN 2
7
GND
OUT 3
6
GND
OUT 3
6
GND
FLG 4
5
GND
ADJ 4
5
GND
8-Pin SOIC
MIC37101-x.x (Fixed)
September 2007
8-Pin SOIC
MIC37102 (Adjustable)
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MIC37100/37101/37102
Pin Description
Pin Number
MIC37100
SOT-223
Pin Number
MIC37101
SOIC-8
Pin Number
MIC37102
SOIC-8
Pin Number
MIC37102
S-PAK
Pin Name
—
1
1
1
EN
Enable (Input): CMOS-compatible control input. Logic
high = enable, logic low or open = shutdown.
Supply (Input).
Pin Description
1
2
2
2
IN
3
3
3
4
OUT
Regulator Output.
—
4
—
—
FLG
Flag (Output): Open-collector error flag output. Active
low = output under voltage.
—
—
4
5
ADJ
Adjustment Input: Feedback input. Connect to resistive
voltage-divider network.
2, TAB
5–8
5–8
3, TAB
GND
Ground.
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MIC37100/37101/37102
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) .......................................... 0V to +6.5V
Enable Voltage (VEN)...................................................+6.5V
Lead Temperature (soldering, 5 sec.)........................ 260°C
Storage Temperature (Ts) .........................–65°C to +150°C
ESD Rating(3)
Supply Voltage (VIN)...................................... +2.25V to +6V
Enable Voltage (VEN)............................................ 0V to +6V
Maximum Power Dissipation (PD(max))(4)
Junction Temperature (TJ) ........................ –40°C to +125°C
Package Thermal Resistance
SOT-223 (θJC) ....................................................15°C/W
SOIC-8 (θJC).......................................................20°C/W
S-PAK-5 (θJC).......................................................2°C/W
Electrical Characteristics
VIN = VOUT + 1V; VEN = 2.25V; TJ = 25°C, bold values indicate –40°C< TJ < +125°C, unless noted.
Symbol
Parameter
Condition
VOUT
Output Voltage
10mA
10mA ≤ IOUT ≤ 1A, VOUT + 1V ≤ VIN ≤ 6V
Line Regulation
IOUT = 10mA, VOUT + 1V ≤ VIN ≤ 6V
VIN = VOUT + 1V, 10mA ≤ IOUT ≤ 1A
Load Regulation
∆VOUT/∆T
Output Voltage Temp. Coefficient
VDO
Dropout Voltage
IGND
IOUT(lim)
Ground Current
(6)
(7)
Current Limit
Min
Typ
Max
Units
1
2
%
%
0.06
0.5
%
0.2
1
–1
–2
(6)
40
%
pm/°C
IOUT = 100mA, ∆VOUT = –1%
125
200
mV
IOUT = 500mA, ∆VOUT = –1%
210
350
mV
IOUT = 750mA, ∆VOUT = –1%
250
400
mV
IOUT = 1A, ∆VOUT = –1%
280
500
mV
IOUT = 100mA, VIN = VOUT + 1V
650
µA
IOUT = 500mA, VIN = VOUT + 1V
3.5
mA
IOUT = 750mA, VIN = VOUT + 1V
6.7
mA
IOUT = 1A, VIN = VOUT + 1V
11
25
mA
VOUT = 0V, VIN = VOUT + 1V
1.6
2.5
A
0.8
V
Enable Input
VEN
Enable Input Voltage
logic low (off)
logic high (on)
IEN
Enable Input Current
V
2.25
VEN = 2.25V
1
10
30
µA
2
4
µA
µA
0.01
1
2
µA
µA
210
500
mV
VEN = 0.8V
Flag Output
IFLG(leak)
Output Leakage Current
VOH = 6V
VFLG(do)
Output Low Voltage
VIN = 2.250V, IOL, = 250µA
VFLG
Low Threshold
% of VOUT
High Threshold
% of VOUT
93
%
99.2
Hysteresis
1
%
%
MIC37102 Only
1.228
1.215
Reference Voltage
Adjust Pin Bias Current
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1.240
1.252
1.265
V
V
40
80
120
nA
nA
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Micrel, Inc.
MIC37100/37101/37102
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. PD(max) = (TJ(max) – TA) ÷ θJA, where θJA depends upon the printed circuit layout. See “Applications Information” section.
5. Output voltage temperature coefficient is ∆VOUT(worst case) ÷ (TJ(max) – TJ(min)) where TJ(max) is +125°C and TJ(min) is –40°C.
6. VDO = VIN – VOUT when VOUT decreases to 98% of its nominal output voltage with VIN = VOUT + 1V. For output voltages below 2.25V, dropout voltage is
the input-to-output voltage differential with the minimum input voltage being 2.25V. Minimum input operating voltage is 2.25V.
7. IGND is the quiescent current. IIN = IGND + IOUT.
8. VEN ≤ 0.8V, VIN ≤ 6V, and VOUT = 0V.
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Micrel, Inc.
MIC37100/37101/37102
Typical Characteristics
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Micrel, Inc.
MIC37100/37101/37102
Typical Characteristics (continued)
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MIC37100/37101/37102
Typical Characteristics (continued)
September 2007
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MIC37100/37101/37102
Functional Characteristics
September 2007
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MIC37100/37101/37102
Functional Diagrams
OUT
IN
Ref.
1.240V
Thermal
Shutdown
MIC37100
MIC37100 Fixed Regulator Block Diagram
OUT
IN
1.180V
FLAG
Ref.
1.240V
EN
Thermal
Shutdown
GND
MIC37101
MIC37101 Fixed Regulator with Flag and Enable Block Diagram
OUT
IN
Ref.
1.240V
ADJ
EN
Thermal
Shutdown
GND
MIC37102
MIC37102 Adjustable Regulator Block Diagram
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MIC37100/37101/37102
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.
Application Information
The MIC37100/01/02 is a high-performance low-dropout
voltage regulator suitable for moderate to high-current
voltage regulator applications. Its 500mV dropout voltage
at full load and overtemperature makes it especially
valuable in battery-powered systems and as highefficiency noise filters in post-regulator applications.
Unlike older NPN-pass transistor designs, where the
minimum dropout voltage is limited by the base-to-emitter
voltage drop and collector-to-emitter saturation voltage,
dropout performance of the PNP output of these devices
is limited only by the low VCE saturation voltage.
A trade-off for the low dropout voltage is a varying base
drive requirement. Micrel’s Super βeta PNP® process
reduces this drive requirement to only 2% of the load
current.
The MIC37100/01/02 regulator is fully protected from
damage due to fault conditions. Linear current limiting is
provided. Output current during overload conditions is
constant. Thermal shutdown disables the device when the
die temperature exceeds the maximum safe operating
temperature. The output structure of these regulators
allows voltages in excess of the desired output voltage to
be applied without reverse current flow.
VIN
CIN
MIC37100-x.x
IN
OUT
GND
Input Capacitor
An input capacitor of 1µF or greater is recommended
when the device is more than 4 inches away from the bulk
ac supply capacitance or when the supply is a battery.
Small, surface mount, ceramic chip capacitors can be
used for bypassing. Larger values will help to improve
ripple rejection by bypassing the input to the regulator,
further improving the integrity of the output voltage.
Error Flag
The MIC37101 features an error flag (FLG), which
monitors the output voltage and signals an error condition
when this voltage drops 5% below its expected value. The
error flag is an open-collector output that pulls low under
fault conditions and may sink up to 10mA. Low output
voltage signifies a number of possible problems, including
an overcurrent fault (the device is in current limit) or low
input voltage. The flag output is inoperative during
overtemperature conditions. A pull-up resistor from FLG
to either VIN or VOUT is required for proper operation. For
information regarding the minimum and maximum values
of pull-up resistance, refer to the graph in the “Typical
Characteristics” section of the data sheet.
VOUT
COUT
Enable Input
The MIC37101 and MIC37102 versions feature an
active-high enable input (EN) that allows on-off control of
the regulator. Current drain reduces to “zero” when the
device is 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
Figure 1. Capacitor Requirements
Output Capacitor
The MIC37100/01/02 requires an output capacitor to
maintain stability and improve transient response. As a
µCap LDO, the MIC37100/01/02 can operate with
ceramic output capacitors as long as the amount of
capacitance is 10µF or greater. For values of output
capacitance lower than 10µF, the recommended ESR
range is 200mΩ to 2Ω. The minimum value of output
capacitance recommended for the MIC37100/01/02 is
4.7µF.
For 10µF or greater the ESR range recommended is less
than 1Ω. Ultra-low ESR ceramic capacitors are
recommended for output capacitance of 10µF or greater
to help improve transient response and noise reduction at
high frequency. 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
September 2007
Transient Response and 3.3V to 2.5V or 2.5V to 1.8V,
1.65V or 1.5V Conversion
The MIC37100/01/02 has excellent transient response to
variations in input voltage and load current. The device
has been designed to respond quickly to load current
variations and input voltage variations. Large output
capacitors are not required to obtain this performance. A
standard 10µF output capacitor, is all that is required.
Larger values help to improve performance even further.
By virtue of its low-dropout voltage, this device does not
saturate into dropout as readily as similar NPN-based
designs. When converting from 3.3V to 2.5V or 2.5V to
1.8V, or lower, the NPN based regulators are already
operating in dropout, with typical dropout requirements
of 1.2V or greater. To convert down to 2.5V or 1.8V
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Micrel, Inc.
MIC37100/37101/37102
without operating in dropout, NPN-based regulators
require an input voltage of 3.7V at the very least. The
MIC37100 regulator will provide excellent performance
with an input as low as 3.0V or 2.5V respectively. This
gives the PNP based regulators a distinct advantage
over older, NPN based linear regulators.
Thermal resistance consists of two main elements, θJC
(junction-to-case thermal resistance) and θCA (case-toambient thermal resistance). See Figure 3. θJC is the
resistance from the die to the leads of the package. θCA
is the resistance from the leads to the ambient air and it
includes θCS (case-to-sink thermal resistance) and θSA
(sink-to-ambient thermal resistance).
Minimum Load Current
The MIC37100/01/02 regulator is specified between
finite loads. If the output current is too small, leakage
currents dominate and the output voltage rises. A 10mA
minimum load current is necessary for proper regulation.
SOIC-8
Adjustable Regulator Design
MIC37102
VIN
IN
VOUT
OUT
JA
R1
EN
ENABLE
SHUTDOWN
ADJ
GND
R2
JC
ground plane
heat sink area
CA
COUT
AMBIENT
printed circuit board
R1 ⎞
⎛
VOUT = 1.240V ⎜1 +
⎟
R2 ⎠
⎝
Figure 3. Thermal Resistance
Figure 2. Adjustable Regulator with Resistors
The MIC37102 allows programming the output voltage
anywhere between 1.24V and the 6V maximum
operating rating of the family. Two resistors are used.
Resistors can be quite large, up to 1MΩ, because of the
very high input impedance and low bias current of the
sense comparator. The resistor values are calculated by:
⎞
⎛V
R1 = R2⎜⎜ OUT − 1⎟⎟
1.240
⎠
⎝
Where VO is the desired output voltage. Figure 2 shows
component definition. Applications with widely varying
load currents may scale the resistors to draw the
minimum load current required for proper operation (see
above).
September 2007
COPPER AREA (mm 2)
Power SOIC-8 Thermal Characteristics
One of the secrets of the MIC37101/02’s performance is
its power SO-8 package featuring half the thermal
resistance of a standard SO-8 package. Lower thermal
resistance means more output current or higher input
voltage for a given package size.
Lower thermal resistance is achieved by joining the four
ground leads with the die attach paddle to create a
single-piece electrical and thermal conductor. This
concept has been used by MOSFET manufacturers for
years, proving very reliable and cost effective for the
user.
700
TJA =
50°C
55°C
65°C
75°C
85°C
Using the power SOIC-8 reduces the θJC dramatically
and allows the user to reduce θCA. The total thermal
resistance, θJA (junction-to-ambient thermal resistance)
is the limiting factor in calculating the maximum power
dissipation capability of the device. Typically, the power
SOIC-8 has a θJC of 20°C/W, this is significantly lower
than the standard SOIC-8 which is typically 75°C/W. θCA
is reduced because pins 5 through 8 can now be
soldered directly to a ground plane which significantly
reduces the case-to-sink thermal resistance and sink to
ambient thermal resistance.
Low-dropout linear regulators from Micrel are rated to a
maximum junction temperature of 125°C. It is important
not to exceed this maximum junction temperature during
operation of the device. To prevent this maximum
junction temperature from being exceeded, the
appropriate ground plane heat sink must be used.
600
500
400
300
200
100
0
0
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Figure 4. Copper Area vs. Power SO-8
Power Dissipation
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Micrel, Inc.
MIC37100/37101/37102
Figure 4 shows copper area versus power dissipation
with each trace corresponding to a different temperature
rise above ambient.
From these curves, the minimum area of copper
necessary for the part to operate safely can be
determined. The maximum allowable temperature rise
must be calculated to determine operation along which
curve.
∆T = TJ(max) – TA(max)
TJ(max) = 125°C
TA(max) = maximum ambient operating temperature.
For example, the maximum ambient temperature is
50°C, the ∆T is determined as follows:
∆T = 125°C – 50°C
∆T = 75°C
Using Figure 4, the minimum amount of required copper
can be determined based on the required power
dissipation. Power dissipation in a linear regulator is
calculated as follows:
PD = (VIN – VOUT) IOUT + VIN × IGND
If we use a 2.5V output device and a 3.3V input at an
output current of 1A, then our power dissipation is as
follows:
PD = (3.3V – 2.5V) × 1A + 3.3V × 11mA
PD = 800mW + 36mW
PD = 836mW
From Figure 4, the minimum amount of copper required
to operate this application at a ∆T of 75°C is 160mm2.
September 2007
Quick Method
Determine the power dissipation requirements for the
design along with the maximum ambient temperature at
which the device will be operated. Refer to Figure 5,
which shows safe operating curves for three different
ambient temperatures: 25°C, 50°C and 85°C. From
these curves, the minimum amount of copper can be
determined by knowing the maximum power dissipation
required. If the maximum ambient temperature is 50°C
and the power dissipation is as above, 836mW, the
curve in Figure 5 shows that the required area of copper
is 160mm2.
The θJA of this package is ideally 63°C/W, but it will vary
depending upon the availability of copper ground plane
to which it is attached.
COPPER AREA (mm 2)
900
800
T = 125°C
J
700
TA = 85°C
50°C 25°C
600
500
400
300
200
100
0
0
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
Figure 5. Copper Area vs. Power-SOIC
Power Dissipation
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Micrel, Inc.
MIC37100/37101/37102
Package Information
SOT-223 (S)
5-Pin S-PAK (R)
September 2007
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Micrel, Inc.
MIC37100/37101/37102
8-Pin SOIC (M)
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, Incorporated.
September 2007
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