MIC39100/1/2
1A, Low-Voltage, Low-Dropout Regulator
General Descr i ption
The MIC39100, MIC39101, and MIC39102 are 1A low-
dropout linear voltage regulators that provide low-voltage,
high-current output from an extremely small package.
Utilizing Micrel’s proprietary Super βeta PNP® pass
element, the MIC39100/1/2 offers extremely low dropout
(typically 410mV at 1A) and low ground current (typically
11mA at 1A).
The MIC39100 is a fixed output regulator offered in the
SOT-223 package. The MIC39101 and MIC39102 are
fixed and adjustable regulators, respectively, in a thermally
enhanced power 8-lead SOIC package.
The MIC39100/1/2 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. A guaranteed maximum dropout voltage of 630mV
over all operating conditions allows the MIC39100/1/2 to
provide 2.5V from a supply as low as 3.13V and 1.8V from
a supply as low as 2.43V.
The MIC39100/1/2 is fully protected with overcurrent
limiting, thermal-shutdown, and reverse-battery protection.
Fixed voltages of 5.0V, 3.3V, 2.5V, and 1.8V are available
on MIC39100/1 with adjustable output voltages to 1.24V
on MIC39102.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• Fixed and adjustable output voltages to 1.24V
• 410mV typical dropo ut at 1A
− Ideal for 3.0V to 2.5V conversion
− Ideal for 2.5V to 1.8V conversion
• 1A minimum guaranteed output current
• 1% initial accuracy
• Low ground current
• Current-limiting and thermal-shutdown protection
• Reversed-battery and reversed-leakage protection
• Fast transient response
• Low-profile SOT-223 package
• Power SO-8 package
Applications
• LDO linear regulat or f or PC add-in cards
• High-efficiency linear power supplies
• SMPS post regulator
• Multimedia and PC pr ocessor supplies
• Battery chargers
• Low-voltage micr ocontrollers and digital l ogi c
Typical Applicatio ns
2.5V/1A Regulato r
2.5V/1A Regulator with Error Flag
1.5V/1A Adjustable Regu lator
Super βeta PNP is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
June 3, 2015 Revision 3.0
Micrel, Inc.
MIC39100/1/2
Ordering I nfor m ati on
Part Number
Voltage
EN
Flag
Adjustable
Junction Tem perature Range
Package
MIC39100-1.8WS(1) 1.8V –40°C to +125° C SOT-223
MIC39100-2.5WS
(1)
2.5V –40°C to +125°C SOT-223
MIC39100-3.3WS
(1)
3.3V –40°C to +125°C SOT-223
MIC39100-5.0WS(1) 5.0V –40°C to +125° C SOT-223
MIC39101-1.8YM 1.8V √ √ –40°C to +125°C SOIC-8
MIC39101-2.5YM 2.5V √ √ –40°C to +125°C SOIC-8
MIC39101-3.3YM 3.3V √ √ –40°C to +125°C SOIC-8
MIC39101-5.0YM 5.0V √ √ –40°C to +125°C SOIC-8
MIC39102YM Adjustable √ √ –40°C to +125°C SOIC-8
Note:
1. RoHS-compliant with “high-melting solder” exemption.
Pin Configuration
MIC39100-xx
Fixed
SOT-223 (S)
(Top View)
MIC39101-xx
Fixed
SOIC-8 (M)
(Top View)
MIC39102
Adjustable
SOIC-8 (M)
(Top View)
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Micrel, Inc.
MIC39100/1/2
Pin Description
Part Number
MIC39100 Part Number
MIC39101 Part Number
MIC39102 Pi n Name Pin Function
1 1 EN Enable (Input): CMOS-compatible control input. Logic HIGH =
enable; logic LOW or OPEN = shutdown.
1 2 2 IN Supply (Input)
3 3 3 OUT Regulator Output.
4 FLG Flag (Output ): Open-collector error f l ag output. A ctive LOW =
output undervoltage.
4 ADJ Adjustable I nput: Feedback input. Connect to resisti v e voltage-
divider network.
2, TAB 5 − 8 5 − 8 GND Ground.
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MIC39100/1/2
Absolute Ma xi mu m Ratings(2)
Supply Voltage (VIN) ....................................... −20V to +20V
Enable Voltage (VEN) .................................................... +20V
Lead Temperature (soldering, 5s) .............................. 260°C
Storage Temperature (TS) ......................... −65°C to +150°C
ESD Rating ................................................................. Note 5
Operating Ratings(3)
Supply Voltage (VIN) .................................... +2.25V to +16V
Enable Voltage (VEN) .................................................... +16V
Maximum Power Dissipation (PD(MAX)) ....................... Note 4
Junction Temperature (TJ) ........................ −40°C to +125°C
Package Thermal Resistance
SOT-223 (θJC) .................................................. +15°C/W
SOIC-8 (θJC) ..................................................... +20°C/W
Electrical Characteristics(6)
VIN = VOUT + 1V; VEN = 2.25V; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Symbol
Parameter
Condition
Min.
Typ.
Max.
Units
VOUT Output Voltage 10mA −1 +1 %
10mA ≤ IOUT ≤ 1A, VOUT +1V ≤ VIN ≤ 8V
−2
+2
Line Regulat ion IOUT = 10mA, VOUT + 1V ≤ VIN ≤ 16V 0.06 0.5 %
Load Regulati on VIN = VOUT + 1V, 10mA ≤ IOUT ≤ 1A 0.2 1 %
∆VOUT/∆T Output Voltage Temperature
Coefficient(7) 40 100 ppm/°C
VDO Dropout Voltage(8)
IOUT = 100mA, ∆VOUT = −1% 140 200
mV
250
IOUT = 500mA, ∆VOUT = −1% 275
IOUT = 750mA, ∆VOUT = −1% 300 500
IOUT = 1A, ∆VOUT = −1% 410 550
630
IGND Ground Current(9)
IOUT = 100mA, VIN = VOUT + 1V 400 µA
IOUT = 500mA, VIN = VOUT + 1V 4
mA IOUT = 750mA, VIN = VOUT + 1V 6.5
IOUT = 1A, VIN = VOUT + 1V 11
20
IOUT(LIM) Current Limit VOUT = 0V , VIN = VOUT + 1V 1.8 2.5 A
Notes:
2. Exceeding the absolute maximum ratings may damage the device.
3. The device is not guaranteed to function outside its operating ratings.
4. PD(MAX) = (TJ(MAX) − TA) ÷ θJA, where θJA depends upon the printed circuit layout (see Applications Information).
5. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.
6. Specification for packaged product only.
7. Output voltage temperature coefficient is ∆VOUT(WORST CASE) ÷ (TJ(MAX) − TJ(MIN)), where TJ(MAX) = +125°C and TJ(MIN) = −40°C.
8. VDO = VIN – VOUT when VOUT decreases to 99% 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.
9. IGND is the quiescent current (IIN = IGND + IOUT).
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Micrel, Inc.
MIC39100/1/2
Electrical Characteristics(6)
VIN = VOUT + 1V; VEN = 2.25V; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Symbol Parameter Condition Min. Typ. Max. Units
Enable Input
VEN Enable Input Voltage Log ic LOW (Off)
0.8
V
Logic HIGH (On)
2.25
IEN Enable Input Cur rent
VEN = 2.25V 1 15 30
µA
75
VEN = 0.8V 2
4
Flag Output
IFLG(LEAK) Output Leakage Voltage VOH = 16V 0.01 1 µA
2
VFLG(DO) Output Low Voltage VIN = 2.250V, IOL = 250µA(10) 210 300 mV
400
VFLG
Low Threshold % of VOUT 93
% High Threshol d % of VOUT 99.2
Hysteresis 1
MIC39102 Only
Reference Voltage IOUT = 10m A 1.228 1.240 1.252
V
1.215 1.265
Note 11 1.203 1.277
Adjust Pin Bias Current 40 80 nA
120
Reference Voltage
Temperature Coefficie nt 20 ppm/°C
Adjust Pin Bias Current
Temperature Coefficie nt 0.1 nA/°C
Notes:
10. For a 2.5V device, VIN = 2.250V (device is in dropout).
11. VREF ≤ VOUT ≤ (VIN – 1V), 2.25V ≤ VIN ≤ 16V, 10mA ≤ IL ≤ 1A, TJ = TMAX.
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MIC39100/1/2
Typical Characteristics
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MIC39100/1/2
Typical Characteristics (Continued)
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MIC39100/1/2
Typical Characteristics (Continued)
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MIC39100/1/2
Functional Characteristics
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MIC39100/1/2
Functional Diagrams
MIC39100 Fixed Regulato r Block Diagram
MIC39101 Fixed Regulato r with Flag and Enable Block Diagram
MIC39102 Adjustable Regu lator Block Dia gram
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MIC39100/1/2
Applications Information
The MIC39100/1/2 is a high-performance low-dropout
voltage regulator suitable for moderate to high-current
voltage regulator applications. Its 630mV dropout voltage
at full load and overtemperature makes it especially
valuable in battery-powered systems and as high-
efficiency 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 MIC39100/1/2 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. Transient protection allows device (and load)
survival even when the input voltage spikes above and
below nominal. The output structure of these regulators
allows voltages in excess of the desired output voltage to
be applied without reverse current flow.
Figure 1. Capacitor Require ments
Output Capacitor
The MIC39100/1/2 requires an output capacitor to
maintain stability and improve transient response. Proper
capacitor selection is important to ensure proper operation.
The MIC39100/1/2 output capacitor selection is dependent
upon the equivalent series resistance (ESR) of the output
capacitor to maintain stability. When the output capacitor is
10µF or greater, the output capacitor should have an ESR
less than 2Ω. This will improve transient response as well
as promote stability. Ultra-low ESR capacitors (<100mΩ),
such as ceramic-chip capacitors, may promote instability.
These very low ESR levels may cause an oscillation
and/or underdamped transient response. A low-ESR solid
tantalum capacitor works extremely well and provides
good transient response and stability over temperature.
Aluminum electrolytics can also be used, as long as the
ESR of the capacitor is <2Ω.
The value of the output capacitor can be increased without
limit. Higher capacitance values help to improve transient
response and ripple rejection and reduce output noise.
Input Capacitor
An input capacitor of 1µF or greater is recommended when
the device is more than four 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 i ntegrity of the output volt age.
Error Flag
The MIC39101 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 related graph in the
Typical Characteristics section of t he datasheet.
Enable Input
The MIC39101 and MIC39102 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 (µA) of leakage current .
The EN input has TTL/CMOS-comparable thresholds for
simple logic interfacing. EN can be directly tied to VIN and
pulled-up to the maxim um supply voltage.
Transient Response and 3.3V to 2.5 V or 2.5V to 1.8V
Conversion
The MIC39100/1/2 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, preferably tantalum, 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, 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 without operating
in dropout, NPN-based regulators require an input voltage
of 3.7V at the very least .
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MIC39100/1/2
The MIC39100 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.
Minimum Load Current
The MIC39100/1/2 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 ne cessary for proper regulation.
Adjustable Regulator Design
The MIC39102 allows programming the output voltage
anywhere between 1.24V and the 16V 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 Equation 1:
−= 1
V
240.1V
2R1
ROUT
Eq. 1
Where VOUT 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 operatio n ( Fi gure 2).
+= 2
R1R
1V240
.1V
OUT
Figure 2. Adjustable Regulator with Resistors
Power SOIC-8 Thermal Characteristics
One of the secrets of the MIC39101/2’s performance is its
power 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.
Thermal resistance consists of two main elements, θJC
(junction-to-case thermal resistance) and θCA (case-to-
ambient 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).
Figure 3. Thermal Resistance
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, which is significantly lower than the
standard SOIC-8 (typically 75°C/W). θCA is reduced due to
the capability of soldering Pins 5 − 8 directly to a ground
plane. This significantly reduces the case-to-sink thermal
resistance as well as the 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.
Figure 4 shows copper area versus power dissipation with
each trace corresponding to a different temperature rise
above ambient.
June 3, 2015 12 Revision 3.0
Micrel, Inc.
MIC39100/1/2
Figure 4. Copper Area vs. Power SOIC
Power Dissipation (∆TJA)
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.
For example, the maximum ambient temperature is 50°C,
the ∆T is determine d as i n Equat ion 2:
∆T = 125°C – 50°C
∆T = 75°C Eq. 2
Where:
∆T = TJ(MAX) − TA(MAX)
TJ(MAX) = 125°C
TA(MAX) = Maximum ambient operating temperature
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 in E quation 3:
PD = (VIN – VOUT) IOUT + VIN × IGND Eq. 3
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 in
Equation 4:
PD = (3.3V – 2.5V) × 1A + 3.3V × 11mA
PD = 800mW + 36mW Eq. 4
PD = 836mW
From Figure 4, the minimum amount of copper required to
operate this applic at i on at a ∆T of 75°C is 160mm2.
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 Figur e 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.
Figure 5. Copper Area vs. Pow er SOIC
Power Dissipation (TA)
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Micrel, Inc.
MIC39100/1/2
Revision Hi stor y
Date
Change Description/Edits by:
Rev.
07/25/05 Initial release of datasheet. No editable fil e available on M arcom server. 1.0
08/25/05 “B” rev created; no listing of s ignificant c hanges/edits made present. No edit able file available on Marcom
server. 2.0
06/03/15 Complete overhaul of DS, including changes to Applications, Electrical Characteristics(6) table and Notes,
Applications Information, and Package Information and Re c ommended Landing Pattern (12). 3.0
June 3, 2015 17 Revision 3.0
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Micrel:
MIC39101-2.5YM MIC39101-3.3YM MIC39101-1.8YM MIC39101-5.0YM MIC39102YM MIC39100-1.8WS
MIC39100-3.3WS TR MIC39100-5.0WS MIC39100-5.0WS TR MIC39100-2.5WS MIC39100-3.3WS MIC39102YM
TR MIC39100-1.8WS TR MIC39101-1.8YM TR MIC39101-2.5YM TR MIC39101-5.0YM TR MIC39100-2.5WS TR
MIC39101-3.3YM TR MIC39100-1.8WS-TR MIC39100-5.0WS-TR MIC39101-1.8YM-TR MIC39100-3.3WS-TR
MIC39101-2.5YM-TR MIC39102YM-TR MIC39101-3.3YM-TR MIC39100-2.5WS-TR MIC39101-5.0YM-TR
