MICRF002 / 022
QwikRadio
tm
Low Power UHF Receiver
Preliminary Information
General Description
The MICRF002, an enhanced version of the MICRF001 and MICRF011,
is a single chip OOK (ON-OFF Keyed) Receiver IC for remote wireless
applications, employing Micrel’s latest QwikRadio
tm
technology. This
device is a true “antenna-in, data-out” monolithic device. All RF and IF
tuning is accomplished automatically within the IC, which eliminates
manual tuning and reduces production costs. Receiver functions are
completely integrated. The result is a highly reliable yet extremely low
cost solution for high volume wireless applications. Because the
MICRF002 is a true single-chip radio receiver, it is extremely easy to
apply, minimizing design and production costs, and improving time to
market.
The MICRF002 provides two fundamental modes of operation, FIXED
and SWP. In FIXED mode, the device functions like a conventional
superheterodyne receiver, with an (internal) local oscillator fixed at a
single frequency based on an external reference crystal or clock. As with
any conventional superheterodyne receiver, the
transmit
frequency must
be accurately controlled, generally with a crystal or SAW (Surface
Acoustic Wave) resonator.
In SWP mode, the MICRF002 sweeps the (internal) local oscillator at
rates greater than the baseband data rate. This effectively “broadens”
the RF bandwidth of the receiver to a value equivalent to conventional
super-regenerative receivers. Thus the MICRF002 can operate with less
expensive LC transmitters without additional components or tuning, even
though the receiver topology is still superheterodyne. In this mode the
reference crystal can be replaced with a less expensive
±
0.5% ceramic
resonator.
The MICRF002 provides two feature enhancements over the
MICRF001/011, (1) a Shutdown Mode, which may be used for duty-
cycle operation, and (2) a “Wakeup” function, which provides a logical
indication of an incoming RF signal. These features make the
MICRF002 ideal for low and ultra-low power applications, such as RKE
and RFID.
All post-detection (demodulator) data filtering is provided on the
MICRF002, so no external filters need to be designed. Any one of four
filter bandwidths may be selected externally by the user. Bandwidths
range in binary steps, from 0.625kHz to 5kHz (SWP mode) or 1.25kHz to
10kHz (FIXED mode). The user only needs to program the appropriate
filter selection based on data rate and code modulation format.
Features
•
•
•
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•
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•
Complete UHF receiver on a monolithic chip
Frequency range 300 to 440 MHz
Typical range over
200
meters with monopole
antenna
Data rates to 2.5kbps (SWP), 10kbps (FIXED)
Automatic tuning, no manual adjustment
No Filters or Inductors required
Low Operating Supply Current—240
µ
A at 315MHz
(10:1 Duty Cycle)
Shutdown
Mode for Duty-Cycle Operation in excess
of 100:1
Wakeup
Function to Enable External Decoders and
Microprocessors
Very low RF re-radiation at the antenna
CMOS logic interface to standard decoder and
microprocessor ICs
Extremely low external part count
•
•
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Applications
Automotive Remote Keyless Entry
Long Range RFID
Remote Fan/Light Control
Garage Door/Gate Openers
Typical Operating Circuit
385.5 MHz, 1200 bps OOK RECEIVER
Micrel Inc.
•
1849 Fortune Drive San Jose, Ca 95131
•
USA
•
tel + 1 (408) 944-0800
•
fax + 1 (408) 944-0970
•
http://www.micrel.com
MICRF002
QwikRadio
tm
Micrel
Ordering Information
Part Number
MICRF002BN
MICRF002BM
MICRF022BN
MICRF022BM
Temperature Range
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
Package
16-Pin DIP
16-Pin SOIC
8-Pin DIP
8-Pin SOIC
The standard 16-pin package provides the user with complete control of MICRF002 mode and filter selection. An 8-pin
standard part is also available for very low cost applications. The 8-pin version comes pre-programmed in SWP mode, with
Demodulator Filter bandwidth set to 5000Hz, and SHUT pin externally available. Other 8-pin configurations are available.
Contact the factory for details.
Pin Configuration (DIP and SOIC)
July 1999
2
MICRF002
MICRF002
QwikRadio
tm
Micrel
Pin Description
(Pin numbers for the 8-pin version are identified in parentheses)
Pin Number
1
2/3
Pin Name
SEL0
VSSRF
Pin Function
This pin, in conjunction with SEL1, programs the desired Demodulator Filter Bandwidth. This pin is
internally pulled-up to VDD. See Table 1.
This pin is the ground return for the RF section of the IC. The bypass capacitor connected from VDDRF to
VSSRF should have the shortest possible lead length. For best performance, connect VSSRF to VSSBB
at the power supply only (i.e., keep VSSBB currents from flowing through VSSRF return path).
This pin is the ground return for the IC. The bypass capacitor connected from VDD to VSS should have
the shortest possible lead length.
This is the receive RF input, internally ac-coupled. Connect this pin to the receive antenna. Input
impedance is high (FET gate) with approximately 2pF of shunt (parasitic) capacitance. For applications
located in high ambient noise environments, a fixed value band-pass network may be connected between
the ANT pin and VSSRF to provide additional receive selectivity and input overload protection. (See
“Application Note TBD”.)
This pin is the positive supply input for the RF section of the IC. VDDBB and VDDRF should be connected
directly at the IC pins. Connect a low ESL, low ESR decoupling capacitor from this pin to VSSRF, as short
as possible.
This pin is the positive supply input for the baseband section of the IC. VDDBB and VDDRF should be
connected directly at the IC pins.
This pin is the positive supply input for the IC. Connect a low ESL, low ESR decoupling capacitor from this
pin to VSSRF, as short as possible.
This capacitor extracts the (DC) average value from the demodulated waveform, which becomes the
reference for the internal data slicing comparator. Treat this as a low-pass RC filter with source impedance
of 118kΩ (for REFOSC frequency ft = 4.90MHz, see Note 5). A standard
±
20% X7R ceramic capacitor is
generally sufficient.
Unused Pin
This is the ground return for the baseband section of the IC. The bypass and output capacitors connected
to VSSBB should have the shortest possible lead lengths. For best performance, connect VSSRF to
VSSBB at the power supply only (i.e., keep VSSBB currents from flowing through VSSRF return path).
The output data signal. CMOS level compatible.
A logic input for Shutdown Mode control. Pull this pin low to place the IC into operation. This pin in
internally pulled-up to VDD.
An output signal, active low when the IC detects an incoming RF signal, determined by monitoring for data
preamble. CMOS level compatible.
Integrating capacitor for on-chip AGC (Automatic Gain Control). The Decay/Attack time-constant (TC) ratio
is nominally set as 10:1. Use of 0.47uF or greater is strongly recommended for best range performance.
Use low-leakage type capacitors for duty-cycle operation (Dip Tantalum, Ceramic, Polyester). (See
“Application Note
TBD.)
This pin, in conjunction with SEL0, programs the desired Demodulator Filter Bandwidth. This pin in
internally pulled-up to VDD. See Table 1.
This is the timing reference for on-chip tuning and alignment. Connect either a ceramic resonator or crystal
(mode dependent) between this pin and VSSBB, or drive the input with an AC coupled 0.5Vpp input clock.
Use ceramic resonators without integral capacitors. Note that if operating in FIXED mode, a crystal must
be used; however in SWP mode, one may use either a crystal or ceramic resonator. See
“Application Note
TBD”
for details on frequency selection and accuracy.
This logic pin controls the operating mode of the MICRF002. When SWEN = HIGH, the MICRF002 is in
SWP mode. When SWEN = LOW, the device operates as a conventional single-conversion
superheterodyne receiver. (See
“Application Note TBD”
for details.) This pin is internally pulled-up to VDD.
Demodulator Bandwidth (Hz)
SWP Mode
5000
2500
1250
625
FIXED Mode
10000
5000
2500
1250
(1)
4
(2)
VSS
ANT
5
VDDRF
6
(3)
7
(4)
VDDBB
VDD
CTH
8
9
N/C
VSSBB
10
(5)
11
(6)
12
13
(7)
DO
SHUT
WAKEB
CAGC
14
15
(8)
SEL1
REFOSC
16
SWEN
SEL0
1
0
1
0
SEL1
1
1
0
0
Table 1
Nominal Demodulator (Baseband) Filter Bandwidth
vs. SEL0, SEL1 and Mode
July 1999
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MICRF002
MICRF002
QwikRadio
tm
Micrel
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VDDRF, VDDBB)..................................+7V
Voltage on any I/O Pin........................VSS-0.3 to VDD+0.3
Junction Temperature..............................................+150°C
Storage Temperature Range....................-65°C to + 150°C
Lead Temperature (soldering, 10 seconds)..............+ 260°C
Operating Ratings
Supply Voltage (VDDRF, VDDBB)..................4.75V to 5.5V
Ambient Operating Temperature (T
A
)............-40°C to +85°C
Package Thermal Resistance
θ
JA
(16 Pin DIP).........90°C/W
Package Thermal Resistance
θ
JA
(16 Pin SOIC)....120°C/W
This device is ESD sensitive: Meets Class 1ESD
test requirements (Human body Model, HBM), in
accordance with MIL-STD-883C, Method 3015. Do
not operate or store near strong electrostatic
fields.
Use appropriate ESD precautions.
Electrical Characteristics
Unless otherwise stated, these specifications apply for Ta = -40°C to 85°C, 4.75<VDD<5.5V. All voltages are with respect to
Ground; Positive currents flow into device pins. CAGC = 4.7µF, CTH = .047µF, VDDRF= VDDBB = VDD. REFOSC
frequency = 4.90MHz.
Parameter
Power Supply
Operating Current
Operating Current
Standby Current
RF/IF Section
Receiver Sensitivity
IF Center Frequency
IF 3dB Bandwidth
RF Input Range
Receive Modulation Duty-Cycle
Maximum Receiver Input
Spurious Reverse Isolation
AGC Attack / Decay ratio
AGC Leakage Current
Local Oscillator Stabilization Time
Demod Section
CTH Source Impedance
CTH Source Impedance Variation
CTH Leakage Current
Demod Filter Bandwidth
Demod Filter Bandwidth
Digital/Control Section
REFOSC Input Impedance
Input Pull up Current
Input High Voltage
Input Low Voltage
Output Current
Output High Voltage
Output Low Voltage
Output Tr, Tf
Test Conditions
Continuous Operation
10:1 Duty Cycle
SHUT = VDD
Note 1, 3
Note 4
Note 3, 4
MIN
TYP
2.4
240
0.5
-103
0.86
0.43
MAX
UNITS
mA
µA
µA
dBm
MHz
MHz
300
20
Rsc = 50Ω
ANT pin, Rsc = 50Ω Note 2
T(Attack) / T(Decay)
Ta = 85°C
To 1% of Final Value
Note 5
-15
Ta = 85°C
SEL0 = SEL1 = SWEN = VDD, Note 4, 6
SEL0 = SEL1 = VDD, SWEN = VSS
Note 4, 6
±100
4160
8320
-20
30
0.1
±100
2.5
118k
440
80
MHz
%
dBm
µVrms
nA
msec
Ω
+15
%
nA
Hz
Hz
200k
SEL0, SEL1, SWEN, SHUT=VSS
SEL0, SEL1, SWEN
SEL0, SEL1, SWEN
DO, WAKEUP pins, Push-Pull
DO, WAKEUP pins, Iout = -1µA
DO. WAKEUP pins, Iout = +1µA
DO, WAKEUP pins, Cload=15pF
0.9VDD
0.1VDD
10
0.2VDD
10
8
0.8VDD
Ω
µA
V
V
µA
V
V
µsec
July 1999
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MICRF002
MICRF002
Note 1:
QwikRadio
tm
Micrel
Note 2:
Note 3:
Sensitivity is defined as the average signal level measured at the input necessary to achieve 10e-2 Bit Error Rate (BER). The
input signal is defined as a return-to-zero (RZ) waveform with 50% average duty cycle (e.g., Manchester Encoded Data) at a
data rate of 300bps. The RF input is assumed to be matched into 50Ω.
Spurious reverse isolation represents the spurious components which appear on the RF input (ANT) pin measured into 50Ω
with an input RF matching network.
Sensitivity, a commonly specified Receiver parameter, provides an indication of the Receiver’s input referred noise, generally
input thermal noise. However, it is possible for a more sensitive receiver to exhibit range performance no better than that of a
less sensitive receiver, if the “ether” noise is appreciably higher than the thermal noise. “Ether” noise refers to other interfering
“noise” sources, such as FM radio stations, pagers, etc.
A better indicator of achievable receiver range performance is usually given by its Selectivity, often stated as Intermediate
Frequency (IF) or Radio Frequency (RF) bandwidth, depending on receiver topology. Selectivity is a measure of the rejection
by the receiver of “ether” noise. More selective receivers will almost invariably provide better range. Only when the receiver
selectivity is so high that most of the noise on the receiver input is actually thermal will the receiver demonstrate sensitivity-
limited performance.
Parameter scales linearly with REFOSC frequency ft. For any REFOSC frequency other than 4.90MHz, compute new
parameter value as the ratio [(REFOSC FREQ (in MHz) / 4.90] * [Parameter Value @ 4.90MHz]. Example: For REFOSC
Freq. ft = 6.00MHz, [Parameter Value @ 6.00MHz] = (6.00 / 4.90) * [Parameter Value @ 4.90MHz].
Parameter scales inversely with REFOSC frequency ft. For any REFOSC frequency other than 4.90MHz, compute new
parameter value as the ratio [4.90 / (REFOSC FREQ (in MHz)] * [Parameter Value @ 4.90MHz]. Example: For REFOSC
Freq. ft = 6.00MHz, [Parameter Value @ 6.00MHz] = (4.90 / 6.00) * [Parameter Value @ 4.90MHz].
Demod filter bandwidths are related in a binary manner, so any of the (lower) nominal filter values may be derived simply by
dividing this parameter value by 2, 4, or 8 as desired.
Note 4:
Note 5:
Note 6:
July 1999
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MICRF002
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