Micrel MICRF112YMM 300mhz to 450mhz, 10dbm, 1.8v to 3.6v, ask/fsk transmitter with shutdown Datasheet

MICRF112
300MHz to 450MHz, +10dBm, 1.8V to 3.6V,
ASK/FSK Transmitter with Shutdown
General Description
Features
The MICRF112 is a high-performance, easy to use, true
“Data-In, RF-Out,” ASK/FSK, phase-locked loop (PLL)
based, transmitter IC for applications in the 300MHz to
450MHz frequency range. These applications include
remote keyless entry (RKE) and tire pressure monitoring
(TPMS). The device needs only a low-cost crystal to
precisely set the desired RF frequency, and a few external
components for matching the power amplifier output to the
antenna.
The MICRF112 operates over the 1.8V to 3.6V operating
range and delivers +10dBm (CW) output power into a 50Ω
load, while consuming 11.5mA of supply current from a
3.0V power supply. In ASK mode, the device consumes
6.9mA of supply current at a data rate of 1kbps
(Manchester 50%). It features a low-power shutdown
mode in which the device typically consumes 50nA of
supply current. This makes it an ideal solution for battery
powered applications.
•
•
•
•
•
•
•
•
•
•
The MICRF112 is rated for the −40°C to +125°C
temperature range, and is available in 10-pin MSOP and
10-pin Ultra-Thin DFN packages. For automotive
applications, where AEC-Q100 qualification is required,
consider the MAQRF112. For ASK-only applications that
do not require shutdown, consider the MICRF113 in
SOT23-6.
Datasheets and support documentation can be found on
Micrel’s website at: www.micrel.com.
1.8V to 3.6V supply voltage range
Up to +10dBm output power (CW)
6.9mA supply current at 1kbps ASK (50% Manchester)
11.5mA supply current at +10dBm (FSK/CW)
1µA shutdown supply current
Data rates up to 50kbps ASK, 10kbps FSK
Crystal or ceramic resonators sets RF frequency
−40°C to +125°C temperature range
10-pin MSOP (3.0mm x 4.9mm)
10-pin Ultra-Thin DFN (2mm x 2mm x 0.4mm)
Applications
•
•
•
•
•
•
•
•
•
Remote keyless entry systems (RKE)
Remote control (STB, HVAC, and appliances)
Garage door openers (GDO)
Tire pressure monitor systems (TPMS)
Outdoor weather stations
Security/Alarm systems
Lighting and fan remote controls
Doorbells
Irrigation control
Typical Application
QwikRadio 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
February 2013
M9999-020713
Micrel, Inc.
MICRF112
Ordering Information
Part Number
Top Mark
Temp. Range
Package
MICRF112YMM
RF112YMM
–40°C to +125°C
10-Pin MSOP
MICRF112YMU
12B
–40°C to +125°C
10-Pin UTDFN
Pin Configuration
10-Pin Ultra-Thin DFN (MU)
(2mm x 2mm x 0.4mm)
Top View
10-Pin MSOP (MM)
Top View
Note: The Pin1 marking symbol could be a circle, triangle, or other symbol.
Pin Description
Pin Number
Pin Name
1
ASK
2
XTLIN
3
XTLOUT
4
VSS
5
XTAL_MOD
6
FSK
FSK Data input
7
EN
Chip enable, active high
8
VSSPA
PA ground
9
PAOUT
PA output
10
VDD
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Pin Function
ASK Data input
Reference oscillator input connection
Reference oscillator output connection
Ground
Reference oscillation modulation port for FSK operation
Positive power supply
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MICRF112
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VDD) ................................................. +4.3V
Voltage on PAOUT ...................................................... +7.2V
Voltage on I/O Pins ........................ VSS – 0.3 to VDD + 0.3
Lead Temperature (soldering, 10s) .......................... +300°C
Storage Temperature (TS) ......................... −65°C to +150°C
ESD Rating.................................................................Note 3
Supply Voltage (VDD) ...................................... 1.8V to 3.6V
Ambient Operating Temperature (TA) ........ -40°C to +125°C
Transmitter Frequency Range ............. 300MHz to 450MHz
Electrical Characteristics(4)
Specifications apply for VDD = 3.0V, TA = 25°C, FreqREFOSC = 13.560MHz, EN = VDD. 1Kbps data rate, 50% duty cycle. RL 50Ω load
(matched)
Parameter
Condition
Min.
Typ.
Max.
Units
1
µA
Power Supply
Standby Supply Current, Iq
EN = VSS
0.05
Mark Supply Current ION
@ 315MHz, POUT = +10dBm
11.5
@ 433.92MHz, POUT = +10dBm
11.6
mA
@ 315MHz
2.4
mA
@ 433.92MHz
2.7
mA
10
dBm
10
dBm
SPACE Supply Current, IOFF
mA
RF Output Section and Modulation Limits:
Output Power Level, POUT
FSK or ASK "Mark"
(4)
@ 315MHz
(4)
@ 433.92MHz
(4)
2nd harm.
−53
dBc
(4)
3rd harm.
−53
dBc
−51
dBc
−65
dBc
80
dBc
22
kHz
@ 630MHz
Harmonics output for
315MHz
@ 945MHz
(4)
@ 867.84MHz
Harmonics Output for
433.92MHz
2nd harm.
(4)
@ 1301.76MHz
3rd harm.
Extinction Ratio for ASK
FSK Modulation
Frequency Deviation
Load capacitor = 10pF, crystal type = HC49/U
Data Rate
10
Kbps
50
Kbps
ASK Modulation
Data Rate
(5)
@ 315MHz
Occupied Bandwidth
<700
kHz
<1000
kHz
@ 100kHz from Carrier
−76
dBc/Hz
@ 1000kHz from Carrier
−79
dBc/Hz
@ 100kHz from Carrier
−72
dBc/Hz
@ 1000kHz from Carrier
−81
dBc/Hz
(5)
@ 433.92MHz
VCO Section
315MHz Single Side Band
Phase Noise
433.92MHz Single Side Band
Phase Noise
Reference Oscillator Section
XTLIN, XTLOUT, XTLMOD
Pin capacitance
2
pF
External Capacitance
See Schematic C17 & C18
18
pF
Crystal: HC49S
400
µs
Oscillator Start-Up Time
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Parameter
MICRF112
Condition
Min.
Typ.
Max.
Units
Digital/Control Section
Output Blanking
STDBY transition from low to high
Digital Input (EN, ASK, and
FSK)
High (VIH)
Digital Input Leakage Current
(EN, ASK, and FSK Pins)
500
µs
0.8 × VDD
V
Low (VIL)
0.2 × VDD
V
High (VIH)
0.05
µA
Low (VIL)
0.05
µA
1.6
V
Undervoltage Lock Out
(UVLO)
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating ratings.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Measured using the circuit shown in the “Test Circuit” section.
5. RBW = 100kHz, OBW measured at −20dBc.
6. Dependent on crystal.
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MICRF112
Test Circuit
MICRF112 Test Circuit with 50Ω Output (MSOP)
Notes:
1. Values without parenthesis are for 433.92MHz and values in parenthesis are for 315MHz.
2. C9 = 100pF for external REF-OSC.
3. For FSK R1 = 0Ω, R2 = NP, R6 = 100k, and R5 = NP.
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MICRF112
50Ω Evaluation Board PCB Layout
Assembly Drawing
MICRF112 50Ω Evaluation Board (MSOP)
Top Layer
MICRF112 50Ω Evaluation Board (MSOP)
Bottom Layer
MICRF112 50Ω Evaluation Board (MSOP)
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MICRF112
Typical Characteristics Using MICRF112, 50Ω Evaluation Board (MSOP)
315MHz OBW, ASK = 1kHz
315MHz OBW, ASK = 50kHz
CW Max Power @ 3V, 315MHz,
(1)
ASK = 1kHz
RF Spectrum 2 Harmonic;
Fundamental at 315MHz
nd
rd
RF Spectrum 3 Harmonic;
Fundamental at 315MHz
315MHz, Power Level at Space,
VDD = 3.0V, ASK = 1kHz
Note:
1. 1.2dB cable loss.
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MICRF112
Typical Characteristics Using MICRF112, 50Ω Evaluation Board (MSOP) (Continued)
315MHz, Zero Span, ASK = 1kHz
315MHz, Zero Span, ASK = 50kHz
315MHz, Phase Noise, ASK = 1kHz,
100kHz Offset, –75.59dBc/Hz
315MHz, Phase Noise, ASK = 1kHz,
1MHz Offset, –78.99dBc/Hz
315MHz, Phase Noise, ASK = CW,
100kHz Offset, –74.39dBc/Hz
315MHz, Phase Noise, ASK = CW,
1MHz Offset, –77.28dBc/Hz
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MICRF112
Typical Characteristics Using MICRF112, 50Ω Evaluation Board (MSOP) (Continued)
433.92MHz OBW, ASK = 1kHz
433.92MHz OBW, ASK = 50kHz
433.92MHz, CW Max Power @ 3V,
(1)
ASK = 1kHz
RF Spectrum 2 Harmonic;
Fundamental at 433.92MHz
nd
rd
RF Spectrum 3 Harmonic;
Fundamental at 433.92MHz
433.92MHz, Power Level at Space,
VDD = 3.0V, ASK = 1kHz
Note:
1. 1.3dB cable loss.
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MICRF112
Typical Characteristics Using MICRF112, 50Ω Evaluation Board (MSOP) (Continued)
433.92MHz Zero Span, 1kHz
433.92ASK Zero Span at 50kHz
433.92MHz Phase Noise, ASK = CW,
100kHz Offset, –81.04dBc/Hz
433.92MHz Phase Noise, ASK = CW,
1MHz Offset, –78.76dBc/Hz
433.92MHz Phase Noise, ASK = 1kHz,
100kHz Offset, –71.73dBc/Hz
433.92MHz Phase Noise, ASK = 1kHz,
1MHz Offset, –81.04dBc/H
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MICRF112
Functional Diagram
Figure 1. Functional Block Diagram MICRF112 10 Pin ASK/FSK Version
Functional Description
Figure 1 shows a functional block diagram of the
MICRF112 transmitter. The MICRF112 can be best
described as a phase-locked transmitter. The system
can be partitioned into six functional blocks: crystal
oscillator, PLL×32, power amplifier, enable control,
undervoltage detect, and open-drain switch for FSK
operation.
Crystal Oscillator
The reference oscillator is a crystal-based Pierce
configuration. It is designed to accept crystals with
frequencies from 9.375MHz to 14.0625MHz.
Figure 2. Reference Oscillator ASK Operation
Crystal Oscillator Parameters for ASK Operation
Figure 2 shows a reference oscillator circuit
configuration for ASK operation. The reference oscillator
can drive crystals with an ESR range from 20Ω to 300Ω.
When the ESR of the crystal is at 20Ω, the crystal
parameter limits are:
ESR
20Ω
2 to 10pF
CPAR
10 to 40fF
CMO
February 2013
When the ESR of the crystal is at 300Ω, the crystal
parameter limits are:
ESR
300Ω
2 to 5pF
CPAR
10 to 40fF
CMO
10 to 30pF
CLOAD
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MICRF112
Crystal Oscillator for FSK Operation
Figure 3 shows the reference oscillator circuit
configuration for FSK operation. To operate the
MICRF112 in FSK mode, one additional capacitor is
needed between XTLOUT pin and the XTAL_MOD pin.
Crystal parameters for FSK operation are the same as
for ASK operation except:
•
When the ESR of crystal is at 20Ω,
CFSK + CLOAD must not exceed 70pF.
•
When the ESR of crystal is at 300Ω,
CFSK + CLOAD must not exceed 30pF.
Power Amplifier
The power amplifier serves two purposes: to buffer the
VCO from external elements and to amplify the phaselocked signal. The power amplifier can produce +10dBm
at 3V (typical).
Enable Control
The enable control gates the ASK data. It only allows
transmission when Lock, Amplitude, and Undervoltage
Detect conditions are valid.
Undervoltage Detect
The undervoltage detect block senses operating voltage.
If the operating voltage falls below 1.6V, the
undervoltage detect block sends a signal to the enable
control block to disable the PA.
Open-Drain Switch
The open-drain switch is used for FSK operation. FSK
data is fed into the FSK pin. The FSK pin is connected to
the gate of the open-drain switch. The open collector is
connected to the XTAL_MOD pin. In Figure 3, a
capacitor is shown connected from the XTAL_MOD pin
to XTLOUT. When the FSK pin goes high, the capacitor
between XTAL_MOD and XTLOUT pulls the frequency
of REFOSC low.
Figure 3. Reference Oscillator FSK Operation
PLL×32
The function of PLL×32 is to provide a stable carrier
frequency for transmission. It is a “divided by 32” phaselocked oscillator.
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MICRF112
Application Information
Figure 4. ASK 433.92MHz and 315MHz (MSOP)
Note: Values in parenthesis are for 315MHz.
Power Control Using an External Resistor
R7 is used to adjust the RF output levels that may be
needed to meet compliance. As an example, Tables 2
and 3 list typical values of conducted RF output levels
and corresponding R7 resistor values for the 50Ω test
board shown in the Test Circuit.
The MICRF112 is ideal for driving a 50Ω source
monopole or a loop antenna. Figure 4 is an example of a
loop antenna configuration. Figure 4 also shows both
315MHz and 433.92MHz ASK configurations for a loop
antenna. In addition to using a different crystal, modified
values are needed for certain frequencies. These are
listed in Table 1.
R7, Ω
Output Power, dBm
IDD, mA
0
10
6.7
9.84375
75
8.5
6.3
13.5600
100
8.0
6.2
500
1.6
4.13
1000
−3.8
4.87
Frequency
(MHz)
L1
(nH)
C5
(pF)
L4
(nH)
C7
(pF)
Y1
(MHz)
315.0
470
10
150
6.8
433.92
680
10
82
4.7
Table 1. Modified Frequency Values
The reference design shown in Figure 4 has an antenna
optimized for using the matching network, as described
in Table 1.
Table 2. ASK Output Power at 1Kbps (Manchester) vs.
External Resistor at 315MHz
R7, Ω
Output Power, dBm
IDD, mA
0
8.68
7.5
75
8.34
7.33
100
8.02
7.3
500
4.34
6.3
1000
0.42
5.5
Table 3. ASK Output Power at 1Kbps (Manchester) vs.
External Resistor at 433.92MHz
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MICRF112
inductance by as much as 10%. To reduce parasitic
inductance, the use of wide traces and a ground plane
under signal traces is recommended. Use vias with low
value inductance for components requiring a connection
to ground.
Output Matching Network
Part of the function of the output network is to attenuate
the second and third harmonics. When matching to a
transmit frequency, be sure not only to optimize for
maximum output power but to attenuate unwanted
harmonics.
Antenna Layout
The antenna trace layout affects directivity. No ground
plane should be under the antenna trace. For consistent
performance, do not place components inside the loop of
the antenna. Gerbers for the Evaluation Board PCB, with
a suggested layout are available on the Micrel web site
at: www.micrel.com.
Layout Issues
PCB layout is extremely important to achieve optimum
performance and consistent manufacturing results. Be
careful with the orientation of the components to ensure
that they do not couple or decouple the RF signal. PCB
trace length should be short, to minimize parasitic
inductance (1in ~ 20nH). For example, depending on
inductance values, a 0.5in trace can change the
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MICRF112
Demo Board PCB Layout
Assembly Drawing
MICRF112 Evaluation Board (MSOP)
Top Layer
MICRF112 Evaluation Board (MSOP)
Bottom Layer
MICRF112 Evaluation Board (MSOP)
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MICRF112
Evaluation Board Schematic
Figure 5. TX112-1 Evaluation Board Schematic (MSOP)
Note: Configuration is for ASK operation. Values in parenthesis are for 315MHz.
Functional Description of the TX112-1
Evaluation Board
Pin
Function Name
Functional Description
J1-1
VDD
1.8V to 3.6V
The layout of the TX112-1 Evaluation Board PCB is
shown on page 15. Figure 5 is a detailed schematic of
the TX112-1. Components labeled “NP” use different
configurations for FSK operation. Table 2 describes
each header pin connector used in the evaluation board.
J1-2
Ground
VSS
J1-3
ASK INPUT
Modulating Data Input, ASK or FSK
J2-1
REF-OSC
External Reference Input
J2-2
GROUND
VSS
J2-3
ENABLE
Enable Input, Active High
Table 4. Header Pin Connectors
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MICRF112
TX112-1-433.92 ASK Bill of Materials
Item
Part Number
C1
GRM21BR60J106KE01L
C2
GRM1885C1H101JA01D
C5
GRM1885C1H100JA01D
Manufacturer
Murata
(1)
Description
Qty.
10µF Capacitor, 0805
1
Murata
100pF Capacitor, 0603
1
Murata
10pF Capacitor, 0603
1
R1,R4,R6
3
C6,C8,C11,C12,C15
5
C7
GRM1885C1H4R7JA01D
Murata
4.7pF Capacitor, 0603
1
C10
GRM188F51H104ZA01D
Murata
0.1µF Capacitor, 0603
1
C13,C14
GRM1885C1H180JA01D
Murata
18pF Capacitor, 0603
2
J1,J2
TSHR-114-S-02-A-GT
L1
0805CS-680XJB
L4
0603CS-082NXJB
L5
ANTENNA LOOP, Part of PCB
R2
CRCW0603100KFKEA
R3,R5,R7
R8,JPR1,JPR2
CRC06030000Z0EA
U1
MICRF112YMM
Y1
SA-13.5600-F-10-C-3-3
Coilcraft
(2)
Coilcraft
(3)
Vishay
Vishay
(4)
Micrel
(5)
HIB
CON3
2
470nH Inductor, 0805
1
150nH Inductor, 0603
1
Antenna
1
100kΩ Resistor, 0603
1
0Ω Resistor, 0603
6
300MHz to 450MHz, +10dBm
ASK/FSK Transmitter with
Shutdown
1
13.560MHz XTAL
1
Notes:
1. Murata Tel: www.murata.com.
2. Coilcraft: www.coilcraft.com.
3. Vishay Tel: www.vishay.com
4. Micrel, Inc.: www.micrel.com.
5. HIB: www.hib.com.br.
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MICRF112
Tx112-1-315MHz ASK Bill of Materials
Item
Part Number
C1
GRM21BR60J106KE01L
C2
GRM1885C1H101JA01D
C5
GRM1885C1H1000JA01D
Manufacturer
Murata
(1)
Description
Qty.
10µF Capacitor, 0805
1
Murata
100pF Capacitor, 0603
1
Murata
10pF Capacitor, 0603
1
R1,R4,R6
3
C6,C8,C11,C12,C15
5
C7
GRM1885C1H6R8JA01D
Murata
4.7pF Capacitor, 0603
1
C10
GRM188F51H104ZA01D
Murata
0.1µF Capacitor, 0603
1
C13,C14
GRM1885C1H180JA01D
Murata
18pF Capacitor, 0603
2
J1,J2
TSHR-114-S-02-A-GT
L1
0805CS-470XJB
L4
0603CS-R15XJB
L5
ANTENNA LOOP, Part of PCB
R2
CRCW0603100KFKEA
R3,R5,R7
R8,JPR1,JPR2
CRC06030000Z0EA
U1
MICRF112YMM
Y1
SA-9.84375-F-10-C-3-3
Coilcraft
(2)
Coilcraft
(3)
Vishay
Vishay
(4)
Micrel
(5)
HIB
CON3
2
470nH Inductor, 0805
1
150nH Inductor, 0603
1
Antenna
1
100kΩ Resistor, 0603
1
0Ω Resistor, 0603
6
300MHz to 450MHz, +10dBm
ASK/FSK Transmitter with
Shutdown
1
9.84375MHz XTAL
1
Notes:
1. Murata Tel: www.murata.com.
2. Coilcraft: www.coilcraft.com.
3. Vishay Tel: www.vishay.com.
4. Micrel, Inc.: www.micrel.com.
5. HIB: www.hib.com.br.
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MICRF112
FSK Operation
The Bill of Materials tables describe the components needed for ASK operation for 433.92MHz and 315MHz.
Table 5 lists the component values that change between ASK and FSK operation. Note that use of a high FSK data rate
may excite parasitic resonant modes with some crystal types. Recommended crystals from the Bill of Materials tables are
good for both ASK and FSK.
Mode
R1
R2
R5
R6
JPR1
JPR2
C8
ASK
NP
100kΩ
0Ω
NP
0Ω
NP
NP
FSK
0Ω
NP
NP
100kΩ
NP
0Ω
3.3pF
(2)
10pF
(1)
Notes:
1. C8 = 3.3pF for 1kHz using HC49/U or HC49US type crystals.
2. C8= 10pF for 10kHz using HC49/U, (high profile) only.
Table 5. ASK and FSK Settings
R3
R4
Constant ON
0Ω
NP
External Standby Control
NP
100kΩ
Table 6. Enable Control (Shutdown)
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MICRF112
Package Information(1)
10-Pin MSOP Package Type (YMM)
Note: The Pin1 marking symbol could be a circle, triangle, or other symbol. Package information is correct as of the publication date. For updates and
most current information, go to www.micrel.com.
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MICRF112
Package Information(1) (Continued)
10-Pin Ultra-Thin DFN 2mm x 2mm x 0.4mm (MU)
Note: The Pin1 marking symbol could be a circle, triangle, or other symbol. Package information is correct as of the publication date. For updates and
most current information, go to www.micrel.com.
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 makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. 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 express, 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 intellectual 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 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.
© 2013 Micrel, Incorporated.
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