MIC2039
High-Accuracy, High-Side, Adjustable
Current Limit Power Switch
General Descr i ption
The MIC2039 is a high-side MOSFET power distribution
switch providing increased system reliability by using 5%
current-limit accuracy.
The MIC2039 has an operating input voltage range from
2.5V to 5.5V, is internally current limited, and has thermal
shutdown to protect the device and system. The MIC2039
is offered with either active-high or active-low logic level
enable input controls. It has an open drain fault status
output flag with a built-in 32ms delay that asserts low
during overcurrent or thermal-shutdo wn condit ion s.
The MIC2039 switches feature an adjustable output
current limit that is resistor programmable from 0.2A to
2.5A. The MIC2039 switch also offers a unique, Kickstart
feature that allows momentary high-current surges up to
the secondary current limit (ILIMIT_2nd) during startup or
while operating in steady state. This is useful for charging
loads with high inrush currents, such as capacitors. After
an overcurrent condition is established, these switches
enter into a constant current-limit mode unless the die
temperature excee ds t he thermal-shutdown specif ica t ion.
The MIC2039 is available in 6-pin SOT-23 and 6-pin
2mm × 2mm thin DFN packages. The MIC2039 has an
operating junction tem perature range of −40°C to +125°C.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• ±5% current limit acc uracy
• Input supply range fro m 2.5V to 5.5V
• Low quiescent curr ent: 100µA typical (swit ch ON)
• 75mΩ typical RDS(ON) at 5.0V
• 0.2A to 2.5A adjustable output current
• Kickstart − momentary secondary current-limit threshold
(120ms period)
• Soft-start functionality
• Undervoltage lock out (UVLO)
• Fast 10µs short-circuit response time (non-Kickstart
options)
• Fault status output flag
• Logic-controll ed enable (active-high, active-low)
• Thermal shutdown
• Pin compatible with the MIC2009/MIC2019
• 6-pin 2mm × 2mm thin DFN and 6-pi n SOT-23
packages
• Junction temperature range from −40°C to +125°C
Applications
• USB peripherals and USB 2.0/3.0 compatible
• DTV/STB
• Notebooks and cons um er electronics
• General-purpose power distribution
Typical Applicatio n
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
December 8, 2014 Revision 1.3
Micrel, Inc.
MIC2039
Ordering I nfor m ati on
Part Number Top
Mark(1) Current
Limit Enable Kickstart Package
MIC2039AYM6 39AA Adjustable Active High No SOT-23-6L
MIC2039BYM6 39BB Adjustable Active Low No SOT-23-6L
MIC2039AYMT 3A9 Adjustable Active Hig h No 6-pin 2mm x 2mm Thin D FN(2)
MIC2039BYMT B39 Adjustable Active Low No 6-pin 2mm x 2mm Thin DFN
(2)
MIC2039EYM6 39AE Adjustable Active High Yes SOT-23-6L
MIC2039FYM6 39AF Adjustable Active Low Yes SOT-23-6L
MIC2039EYMT D39 Adjustable Active High Yes 6-pin 2mm x 2mm Thin DFN(2)
MIC2039FYMT F39 Adjustable Active Low Yes 6-pin 2mm x 2mm Thin D FN(2)
Note:
1. Under-bar symbol ( _ ) may not be to scale.
2. Thin DFN is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
SOT-23 6-pin (M6)
Top View
2mm x 2mm 6-pin Thin DFN (MT)(3)
(Top View)
Notes:
3. Thin DFN ▲ = Pin 1 identifier.
December 8, 2014 2 Revision 1.3
Micrel, Inc.
MIC2039
Pin Description
Pin Number
Pin Name Pin Function
SOT-23-6L 6-Pin
2mm x 2mm
Thin DFN
1 6 VIN Input: Power switch and logic supply inp ut.
2 5 GND Ground: Inp ut and output return pin.
3 4 EN Enable (Input): Logic compatible, enabl e c ontrol input that allows s witc h turn-
on/off. Do not leave the EN pi n floating.
4 3 FAULT/
Fault Status Flag (Output): Active-low, open-dr ain output. A logic low state
indicates an overcurrent or thermal shutdown condition. An overcurrent
condition must last longer than tFAULT/ to assert FA ULT/. A pull-up resistor
(10kΩ recommended) to an external supply is required.
5 2 ILIMIT Current Limit Set: Curr ent limit adjust setting. Connect a resist or from this pin
to GND to set the current limit, but do not leave the ILIMIT pin floating.
6 1 VOUT Switch Output: P ower switch o utput.
— EP ePad Exposed P ad: Exposed pad on bottom of package. Connect to electr ical
ground for optimum thermal di s sipation.
December 8, 2014 3 Revision 1.3
Micrel, Inc.
MIC2039
Absolute Ma xi mu m Ratings(4)
VIN to GND ....................................................... −0.3V to +6V
VOUT to GND .................................................... −0.3V to +6V
VILIMIT to GND .................................................. −0. 3V t o +6V
VEN to GND ...................................................... −0.3V to +6V
VFAULT/ to GND ................................................. −0.3V to +6V
FAULT/ Current (IFAULT/) .............................................. 25mA
Maximum Power Dissipation (PD) ............. Internally Limited
Lead Temperature (soldering, 10s) ............................ 260°C
Storage Temperature (TS) ......................... −65°C to +150°C
ESD Rating(6)
HBM ......................................................................... 3kV
MM ......................................................................... 300V
Operating Ratings(5)
Supply Voltage (VIN) ..................................... +2.5V to +5.5V
VEN, VFAULT/ ................................................... −0.3V to +5.5V
VILIMIT, VOUT ........................................................ −0.3V to VIN
Junction Temperat ure (TJ) ........................ –40°C to +125°C
Package Thermal R esistance
SOT-23-6 (θJA) .............................................. 177.2°C/W
6-pin 2mm × 2mm Thin DFN (θJA) ..................... 90°C/W
Electric al Characteristics(7)
VIN = VEN = 5V; CIN = 1µF; TJ = 25°C. Bold values indicate –40°C≤ TA ≤ +85°C, unless noted.
Symbol Parameter Condition Min. Typ. Max. Units
Power Supply Input
VIN Input Voltage R ange
2.5
5.5
V
VUVLO Input Supply Undervoltag e
Lockout Threshold VIN rising 2.0 2.25 2.5 V
VIN falling 1.9 2.15 2.4 V
VUVLOHYS Input Sup ply Undervoltage
Lockout Threshold Hysteresis VIN rising or VIN falling 100 mV
IDD Supply Current
Switch OFF
(IOUT = 0A)
Active-high Enable (A ) : VEN = 0V,
VIN = 5V 0.75 5
µA
Active-low Enable (B): VEN = VIN = 5V
Switch ON
(IOUT = 0A)
Active-high Enable (A ) : VEN = 1.5V,
VIN = 5V 100 300
Active-low Enable (B): VEN = 0V,
VIN = 5V
Power MOSFET
RDS(ON) Switch On Resist anc e
VIN = 2.5V, IOUT = 350mA 100
177
mΩ VIN = 3.3V, IOUT = 350mA 85
145
VIN = 5V, IOUT = 350mA 75 125
ILKG Output Leakage Cur rent Switch Off, VOUT = 0V 0.22 15 µA
Notes:
4. Exceeding the absolute maximum ratings may damage the device.
5. The device is not guaranteed to function outside its operating ratings.
6. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.
7. Specification for packaged product only
December 8, 2014 4 Revision 1.3
Micrel, Inc.
MIC2039
Electric al Characteristics(7) (Continued)
VIN = VEN = 5V; CIN = 1µF; COUT = 1µF TJ = 25°C. Bold v alues indicate –40°C ≤ TJ ≤ +125°C, unless noted otherwise.
Symbol Parameter Condition Min. Typ. Max. Units
Current Limit
ILIMIT Current Limit
(Resistor values are standard
0.1% values)
RLIMIT = 115Ω, VIN = 5V, VOUT = 0.8V × VIN 2.35 2.5 2.65
A
RLIMIT = 115Ω, VIN = 2.5V, VOUT = 0V 2.6 2.85 3.1
RLIMIT = 145Ω, VIN = 5V, VOUT = 0.8V × VIN 1.90 2.0 2.10
RLIMIT = 287Ω, VIN = 5V, VOUT = 0.8V × VIN 0.95 1.0 1.05
RLIMIT = 576Ω, VIN = 5V, VOUT = 0.8V × VIN 0.475 0.50 0.525
RLIMIT = 1.45kΩ, VIN = 5V, VOUT = 0.8V × VIN 0.19 0.20 0.21
ILIMIT_2nd Secondary Current Limit
(Kickstart parts only) VOUT = 0V 2.2 3.2 6 A
I/O
VEN Enable Voltage Logic Low 0.5 V
Logic High
1.5
IEN Enable Input Cur rent 0V ≤ VEN ≤ 5V 1 µA
RFAULT/ FAULT/ Output Resistance IOUT = 10mA 25 Ω
IFAULT/_OFF FAULT/ Off Current VFAULT/ = VIN 10 µA
Thermal Protection
TSD Thermal-Shutdown Threshol d TJ rising 157 °C
TSDHYS Thermal-Shutdown
Hysteresis 15 °C
Timing Sp ecifications (AC Parameters)
tRISE Output T urn-on Rise Time(8) RLOAD = 10Ω; COUT = 1µF 700 µs
tFALL Output T urn-off Fall Time(8) VEN = OFF; RLOAD = 10Ω; COUT = 1µF 32 µs
tON_DLY Output Turn-on Delay(8) RLOAD = 10Ω; COUT = 1µF 700 µs
tOFF_DLY Output Turn-off Delay
(8)
RLOAD = 10Ω; COUT = 1µF 5 µs
tSC_RESP Short Circuit Response
Time(8) VOUT = 0V (short circuit) 10 µs
tFAULT/ Overcurrent Fault R es ponse
Delay Time(8) Non-Kickstart parts 16 32 49 ms
tKICKSTART Overcurrent Fault Res ponse
Delay During Kickstart(8) Kickstart parts only 64 120 200 ms
Note:
8. See “Timing Diagrams” (Figures 1 through 4).
December 8, 2014 5 Revision 1.3
Micrel, Inc.
MIC2039
Timing Diagrams
Figure 1. Output Ris e /Fa ll Time
Figure 2. Turn -On/Off Delay
December 8, 2014 6 Revision 1.3
Micrel, Inc.
MIC2039
Timing Diagrams (Continued)
Figure 3. Short Circuit Response Time and Overcurrent Fault Flag Delay (Non-Kickstart)
Figure 4. Overcurrent Fault Flag Delay (Kickstart)
December 8, 2014 7 Revision 1.3
Micrel, Inc.
MIC2039
Typical Characteristics
I nput Supply Current
vs. Temperature
0
25
50
75
100
125
150
175
200
-50 -25 025 50 75 100 125
TEM PERATURE ( °C)
SUPPL Y CURRENT ( µA)
V
IN
= 5V
I
OUT
= 0m A
VI N OFF Current
vs. Temperature
0.00
0.25
0.50
0.75
1.00
1.25
1.50
-50 -25 025 50 75 100 125
TEM PERATURE ( °C)
SUPPL Y OF F CURRENT (µ A)
VIN = 5V
VEN = OF F
IOUT = 0m A
Undervol tage Lockout
vs. Temperature
1.50
1.75
2.00
2.25
2.50
-50 -25 025 50 75 100 125
TEM PERATURE ( °C)
UVLO THRESHO L D ( V )
VIN Falling
VIN Rising
R
DS(ON)
vs. Temperature
0
25
50
75
100
125
-50 -25 025 50 75 100 125
TEM PERATURE ( °C)
R
DS(ON)
(mΩ)
V
IN =
5V
I
OUT
= 350m A
R
DS(ON)
vs. Output Current
0
25
50
75
100
125
0.0 0.5 1.0 1.5 2.0 2.5
O UT PUT CURRENT (A)
R
DS(ON)
(mΩ)
V
IN
= 5V
T
A
= 25°C
R
DS(ON)
vs. Output Current
0
25
50
75
100
125
0.0 0.5 1.0 1.5 2.0 2.5
O UT PUT CURRENT (A)
R
DS(ON)
(mΩ)
V
IN
= 3.3V
T
A
= 25°C
0
10
20
30
40
50
-50 -25 025 50 75 100 125
F AULT/ RESPONSE TIME (ms)
T EMPERAT URE (°C)
FAULT/ Resp onse Time
vs. Temperatu re
V
IN
= 5V
I
LIMIT
= 1A
NON-KICKSTART
0
50
100
150
200
250
-50 -25 025 50 75 100 125
F AULT/ RESPONSE TIME (ms)
T EMPERAT URE (°C)
FAULT/ Response Time
vs. Temperatu re
VIN = 5V
ILIMIT = 1A
KICKSTART
0
50
100
150
200
250
0.0 0.5 1.0 1.5 2.0 2.5
F AULT/ RESPONSE TIME (ms)
OUTPUT CURRENT (A)
FAULT/ Response Time
v s. O utp ut C urr ent
V
IN
= 5V
T
A
= 25°C
KICKSTART
December 8, 2014 8 Revision 1.3
Micrel, Inc.
MIC2039
Typical Characteristics (Continued)
Output Leakage Current
vs. Temperature
0
1
2
3
4
5
-50 -25 025 50 75 100 125
TEM PERATURE ( °C)
O UT PUT LEAKAGE (µA)
VIN = 5V
VEN = OF F
IOUT = 0m A
VIN - VOUT
vs. Output Current
0
50
100
150
200
250
0.0 0.5 1.0 1.5 2.0 2.5
O UT PUT CURRENT (A)
VI N - VOUT ( m V)
V
IN
= 5V
T
A
= 25°C
Current Lim it Set Resistor
vs. Output Current
0
250
500
750
1000
1250
1500
0.0 0.5 1.0 1.5 2.0 2.5
O UT PUT CURRENT (A)
R
SET
(Ω)
V
IN
= 5V
T
A
= 25°C
December 8, 2014 9 Revision 1.3
Micrel, Inc.
MIC2039
Functional Characteristics
December 8, 2014 10 Revision 1.3
Micrel, Inc.
MIC2039
Functional Characteristics (Continued)
December 8, 2014 11 Revision 1.3
Micrel, Inc.
MIC2039
Functional Characteristics ( C ontinued)
December 8, 2014 12 Revision 1.3
Micrel, Inc.
MIC2039
Functional Diagram
Figure 5. MIC2039 Block Diagram
December 8, 2014 13 Revision 1.3
Micrel, Inc.
MIC2039
Functional Descript ion
The MIC2039 is a high-side MOSFET power-distribution
switch that provides increased system reliability by using
5% current limit accuracy. The MIC2039 is internally
current limited and has thermal shutdown, which
protects the device and system.
The MIC2039 has a soft-start circuit that minimizes in-
rush current by slowing the turn-on time. Additionally, the
MIC2039 has an optional Kickstart feature, which
momentarily overrides the normal current-limiting
function to allow hig her i nrush and/or transient currents.
Soft-Start
Soft-start reduces the power-supply input surge current
at startup by controlling the output voltage rise time. The
input surge appears while the output capacitor is
charged up. A slower output rise time draws a lower
input surge current.
KICKSTART Inrush Overcurrent Filter
The MIC2039EYxx and MIC2039FYxx are equipped with
a secondary current limit that allows high inrush current
transients to pass for a set period before the primary
current-limit circuitry becomes active. The FAULT/ status
flag does not assert during the Kickstart period (typically
120ms), which eliminates any false (FAULT/) assertions.
The Kickstart function is active during initial startup or
while operating in steady state.
Input Capacitor
Micrel recommends a 1µF to 10µF ceramic input
capacitor for most applications.
Place the input capacitor on the same side of the board
and next to the MIC2039 to minimize the voltage ringing
during transient and short-circuit conditions. Using two
vias for each end of the capacitor to connect to the
power and ground plane is also recommended.
Micrel recommends X7R or X5R dielectric ceramic
capacitors 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 tem perat ure range.
Output Capacitor
The output capacitor type and placement criteria are the
same as for the input capacitor. See the “Input
Capacitor” section f or a detailed description.
Enable
The MIC2039 offers either an active-high or active-low
enable input (EN) that allows ON/OFF control of the
switch output. The current through the device reduces to
near “zero” when the device is shut down, with only
microamperes of leakage current. The EN input can be
directly tied to VIN or driven by a voltage that is equal to
or less than VIN; do not leave this pin floating.
Adjustable Current Limit
The MIC2039 current limit is adjustable from 0.2A to
2.5A by connecting a resistor from the ILIMIT pin to
GND. The following equation determines t he resistor:
LIMIT
I
LIMIT
R/289≅
Eq. 1
where ILIMIT is the typical current limit from the electrical
table. If the output current exceeds the set current limit,
the MIC2039 switch enters constant current limit mode.
The maximum allowable current limit can be less than
the full specified and/or expected current if the MIC2039
is not mounted on a circuit board with sufficiently low
thermal resistance. Table 1 shows resistor values (1%)
for select current limit settings.
Table 1. Resist or Selection fo r Adjustable Current Limit
ILIMIT 0.2A 0.5A 1.0A 2A 2.5A
RLIMIT 1.45kΩ 576Ω 287Ω 145Ω 115Ω
December 8, 2014 14 Revision 1.3
Micrel, Inc.
MIC2039
High Current Limit Application Consi derations
For higher current applications, a robust circuit design is
necessary to avoid part failure due to large voltage
and/or current swings. When dealing with fast AC
transients at higher current limits, the use of a local
bypass capacitor is critical in order to maintain a stable
input supply. For proper operation, minimizing stray
and/or parasitic inductance from the supply to VIN (of IC)
and VOUT (of IC) to the actual load can be achieved
through a compact circuit design. Table 2 below lists the
recommended input/output capacitors for the higher DC
current limit settings:
Table 2. Recommended CIN/COUT vs ILIMIT
*These recommended values are for wire/traces less than 3 inches
from the supply to the input and from the output to the load. For
lengthy connections (>6 inches), use a 4.7μF (ILIMIT = 1A) and 22μF
(ILIMIT > 2A) input capacitor.
Thermal Design
To help reduce the thermal resistance, the ePad
(underneath the IC) should be soldered to the PCB
ground. The placement of thermal vias either underneath
or near the ePad is highly recommended. Thermal
design requires the following application-specific
parameters:
• Maximum ambient temperature (TA)
• Output current (I OUT)
• Input voltage (VIN)
• Current limit (ILIMIT)
When the MIC2039 is in constant current limit mode, it
may exceed the overtemperature threshold. If this
occurs, the overtemperature condition will shut down the
MIC2039 switch and the fault status flag will go active
(assert low). After the switch cools down, it automatically
turns on again. The user can maximize the MIC2039
power dissipation by either lowering the thermal
resistance on the exposed pad (only the DFN package
has an exposed pad) on the printed circuit board, or by
limiting the maximum al l owable ambient temper ature.
Thermal Measurements
It is always wise to measure the IC’s case temperature
to make sure that it is within its operating limits. Although
this might seem like an elementary task, it is very easy
to get false results. The most common mistake is to use
the standard thermal couple that comes with the thermal
voltage meter. This thermal couple wire gauge is large,
typically 22 gauge, and behaves like a heatsink,
resulting in a lower case measurement.
There are two suggested methods for measuring the IC
case temperature: a thermal couple or an infrared
thermometer. If a thermal couple is used, it must be
constructed of 36 gauge wire or higher to minimize the
wire heatsinking effect. In addition, the thermal couple tip
must be covered in either thermal grease or thermal glue
to make sure that the thermal couple junction is making
good contact to the case of the IC. Thermal couple
5SC-TT-K-36-36 from Omega is adequate for most
applications.
To avoid using messy thermal couple grease or glue, an
infrared thermometer is recommended. Most infrared
thermometers’ spot size is too large for an accurate
reading on small form factor ICs. However, an IR
thermometer from Optris has a 1mm spot size, which
makes it ideal for the 2mm × 2mm thin DFN package.
Also, get the optional stand. The stand makes it easy to
hold the beam on the I C for long periods of time.
ILIMIT
*CIN
COUT
1A 1µF 10µF
2A 10µF 47µF
2.5A 10µF 47µF
December 8, 2014 15 Revision 1.3
Micrel, Inc.
MIC2039
Evaluation Board S chematic
Bill of Materials
Item Part Number Manufacturer Description Qty.
C1, C2 C1608X5R0J105K TDK(9) 1µF/6.3V cera m i c capacitor, X5R, 0603 2
06036D105KAT2A AVX(10)
R1, R2 CRCW060310K0FKEA Vishay/Dale(11) 10kΩ, film resistor, 0603, 1% 2
R3 CRCW06032870FKEA Vishay/Dale 287Ω film resistor, 0603, 1% 1
U1 MIC2039xYMT
Micrel
(12)
High-accuracy, high-side, adjustable current-limit power s witch 1
Notes:
9. TDK: www.tdk.com.
10. AVX.: www.avx.com.
11. Vishay: www.vishay.com.
12. Micrel, Inc.: www.micrel.com.
December 8, 2014 16 Revision 1.3
Micrel, Inc.
MIC2039
PCB Layout (MIC2039xYMT Evaluat ion Boar d)
MIC2039xYMT Evaluation B oard – Top Layer
MIC2039xYMT Evaluation B oard – Bottom Layer
December 8, 2014 17 Revision 1.3
Micrel, Inc.
MIC2039
PCB Layout (MIC2039xYM6 Evaluat ion Board)
MIC2039xYM6 Evaluation Bo ard – Top Layer
MIC2039xYM6 Evaluation Bo ard – Bottom L ayer
December 8, 2014 18 Revision 1.3
Micrel, Inc.
MIC2039
Package I nformation and Recommen d ed La ndi n g Patt er n(13) (Continued)
SOT23-6L (M6)
December 8, 2014 20 Revision 1.3
Micrel, Inc.
MIC2039
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
Micrel, Inc. is a leading global manufacturer of IC solutions for the worldwide high performance linear and power, LAN, and timing & communications
markets. The Company’s products include advanced mixed
-signal, analog & power semiconductors; high-
performance communication, clock
management,
MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs.
Company
customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products.
Corporation headquarters and state
-of-the-
art wafer fabrication facilities are located in San Jose, CA, with regional sales and support offices and
advanced technology design centers situated t
hroughout the Americas, Europe, and Asia.
Additionally, the Company maintains an extensive network
of distributors and reps worldwide.
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished
in this datasheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use.
Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice.
No license, whether expre
ss, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectua
l property right.
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 sus tain li fe, and whose failure to perform can b e reasonably expected to result i n a significant i njury to the user. A
Purchaser’s use or sale of Micrel Products for use in l ife s upport applianc es, dev ices or systems is a Purchaser’s own ri sk a nd Purc haser agrees to fully
indemnify Micrel for any damages resulting from such
use or sale.
© 2014 Micrel, Incorporated.
December 8, 2014 21 Revision 1.3
