MICRF500
Micrel
MICRF500
700MHz to 1.1GHz RadioWire™ RF Transceiver
Final
General Description
The MICRF500 is a single chip UHF transceiver designed for
spread spectrum communication (FHSS) intended for ISM
(Industrial, Scientific and Medical) and SRD (Short Range
Device) frequency bands from 700MHz to 1100MHz with
FSK data rates up to 128k baud.
The transmitter consists of a PLL frequency synthesizer and
a power amplifier. The frequency synthesizer consists of a
voltage-controlled oscillator (VCO), a crystal oscillator, dual-
modulus prescaler, programmable frequency dividers and a
phase-detector. The loop filter is external for flexibility and
can be a simple passive circuit. The VCO is a Colpitts
oscillator which requires an external resonator and varactor.
FSK modulation can be applied externally to the VCO. The
synthesizer has two different N, M and A frequency dividers.
FSK modulation can also be implemented by switching
between these dividers (max. 2400bps). The lengths of the N
and M and A registers are 12, 10 and 6 bits respectively. For
all types of FSK modulation, data is entered at the DATAIXO
pin (see application circuit). The output power of the power
amplifier can be programmed to eight levels. A lock detect
circuit detects when the PLL is in lock.
In receive mode the PLL synthesizer generates the local
oscillator (LO) signal. The N, M and A values that give the LO
frequency are stored in the N0, M0 and A0 registers. The
receiver is a zero intermediate frequency (IF) type in order to
make channel filtering possible with low-power integrated
low-pass filters. The receiver consists of a low-noise amplifier
(LNA) that drives a quadrature mixer pair. The mixer outputs
feed two identical signal channels in phase quadrature. Each
channel includes a preamplifier, a third order Sallen-Key RC
low pass filter that protects the following gyrator filter from
strong adjacent channel signals and finally, a limiter. The
main channel filter is a gyrator capacitor implementation of a
seven-pole elliptic low pass filter. The elliptic filter minimizes
the total capacitance required for a given selectivity and
dynamic range. The cut-off frequency of the Sallen-Key RC
filter can be programmed to four different frequencies: 10kHz,
30kHz, 60kHz and 200kHz. An external resistor adjusts the
cut-off frequency of the gyrator filter. The demodulator de-
modulates the I and Q channel outputs and produces a digital
data output. It detects the relative phase of the I and the Q
channel signal. If the I channel signal lags the Q channel, the
FSK tone frequency lies above the LO frequency (data ‘1’). If
the I channel leads the Q channel, the FSK tone lies below the
LO frequency (data ‘0’). The output of the receiver is available
on the DATAIXO pin. A RSSI (Receive Signal Strength
Indicator) circuit indicates the received signal level.
RadioWire™
A two pin serial interface is used to program the circuit.
External components are necessary for RF input and output
impedance matching and decoupling of power. Other exter-
nal components are the VCO resonator circuit with varactor,
crystal, feedback capacitors and components for FSK modu-
lation with the VCO, loop filter, bias resistors for the power
amplifier and gyrator filters. A T/R switch can be implemented
with 2-pin diodes. This gives maximum input sensitivity and
transmit output power.
Features
•
•
•
•
•
Frequency range: 700MHz to 1100MHz
Modulation: FSK
RF output power: 10dBm
Sensitivity (19.2k bauds, BER=10
-3
): –104dBm
Maximum data rate: 128k bauds
Applications
•
•
•
•
•
•
•
Telemetry
Remote metering
Wireless controller
Wireless data repeaters
Remote control systems
Wireless modem
Wireless security system
Ordering Information
Part Number
MICRF500BLQ
Ambient Temp. Range
–40°C to +85°C
Package
44-Lead LQFP
RadioWire is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
March 2003
1
MICRF500
MICRF500
Micrel
Pin Description, cont’t
Pin Number
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Pin Name
PA_C
PABIAS
RFOUT
RFGND
RFVDD
RFIN
RFGND2
LNA_C
MIXERGND
MIXERVDD
MIXIOUTP
MIXIOUTN
IFIINP
IFIINN
MIXQOUTP
MIXQOUTN
IFQINP
IFQINN
ICHC
QCHC
VB_IP
Pin Function
Capacitor for Slow Ramp Up/Down of PA
External Bias Resistor for Power Amplifier
Power Amplifier Output
LNA, PA and Substrate Ground
LNA and PA Power
Low Noise RF Amplifier (LNA) Input
LNA First Stage Ground
External LNA Stabilizing Capacitor
Mixer Ground
Mixer Power
I-Channel Mixer Positive Output
I-Channel Mixer Negative Output
I-Channel IF Amplifier Positive Input
I-Channel IF Amplifier Negative Input
Q-Channel Mixer Positive Output
Q-Channel Mixer Negative Output
Q-Channel IF Amplifier Positive Input
Q-Channel IF Amplifier Negative Input
I-Channel Amplifier Capacitor
Q-Channel Amplifier Capacitor
Gyrator Filter Resistor
March 2003
3
MICRF500
MICRF500
Micrel
Absolute Maximum Ratings
(Note 1)
Maximum Supply Voltage (V
DD
) ................................... +7V
Maximum NPN Reverse Base-Emitter Voltage .......... +2.5V
Storage Temperature Range (T
S
) ............ –55°C to +150°C
ESD Rating,
Note 3 ....................................................
500V
Operating Ratings
(Note 2)
Supply Voltage (V
IN
) ................................... +2.5V to +3.4V
Ambient Temperature (T
A
) ......................... –40°C to +85°C
Package Thermal Resistance
TQFP(θ
JA
)-Multilayer board ............................. 46.3°C/W
Electrical Characteristics
F
REF
= 850MHz, V
DD
= 2.5 to 3.4V, T
A
= 25°C, unless otherwise specified.
Parameter
Overall
Operating Frequency
Power Down Current
Logic High Input, V
IH
Logic Low Input, V
IL
DATAIXO, Logic High Output (V
OH
)
DATAIXO, Logic Low Output (V
OL
)
LockDet, Logic High Output (V
OH
)
LockDet, Logic Low Output (V
OL
)
Clock/Data Frequency
Clock/Data Duty-Cycle
Data Setup to Clock (rising edge)
VCO and PLL Section
Prescaler Divide Ratio
Reference Frequency
PLL Lock Time (int. modulation)
PLL Lock Time (ext. modulation)
Rx – (Tx with PA on) Switch Time
Charge Pump Current
Transmit Section
Output Power
Transmit Data Rate (ext. modulation)
Note 4
Transmit Data Rate (int. modulation)
Note 5
Frequency Deviation to
Modulation Rate Ratio
Current Consumption
Transmit Mode
unfiltered FSK
10 dBm, R
LOAD
= 50Ω
1.0
1.5
50
mA
f
OUT
= 850MHz
R
LOAD
= 50Ω, V
DD
= 3.0V
10
19.2
128
2.4
dBm
kbauds
kbauds
4kHz loop filter bandwidth
1kHz loop filter bandwidth
1kHz loop filter bandwidth
1
4
2.5
±95/±380 ±125/±500 ±155/±620
64/65
40
MHz
ms
ms
ms
µA
25
25
I
OH
= –500µA
I
OL
= 500µA
I
OH
= –100µA
I
OL
= 100µA
V
DD
-0.25
0.25
10
75
70%
30%
V
DD
-0.3
0.3
700
850
<1
1100
2
MHz
µA
V
DD
V
DD
V
V
V
V
MHz
%
ns
Condition
Min
Typ
Max
Units
MICRF500
4
March 2003
MICRF500
Parameter
Receive Section
Receiver Sensitivity
(Note 6)
Input 1dB Compression Level
Input IP3
Input Impedance
RSSI Dynamic Range
RSSI Output Voltage
Adjacent Channel Rejection:
f
C
= 10kHz
f
C
= 30kHz
f
C
= 60kHz
f
C
= 200kHz
Blocking Immunity (1MHz)
P
IN
= –100dBm
P
IN
= –30dBm
25kHz channel spacing
100kHz channel spacing
200kHz channel spacing
700kHz channel spacing
RC filter:
RC filter:
RC filter:
RC filter:
f
C
= 10kHz
f
C
= 30kHz
f
C
= 60kHz
f
C
= 200kHz
Condition
f
IN
= 850MHz
BER=10
-3
–104
6
–34
–24
22.5-j28.5
60
0.7
2.1
26
37
45
48
66
61
59
53
175
1
gyrator filter f
C
= 60kHz
12
300
Min
Typ
Max
Micrel
Units
dBm
dBm
dBm
W
dB
V
V
dB
dB
dB
dB
dB
dB
dB
kHz
ms
mA
µA
Maximum Receiver Bandwidth
Receiver Settling Time
Current Consumption
Receive Mode
Current Consumption XCO
Note 1.
Note 2.
Note 3.
Note 4.
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Modulation is applied to the VCO and therefore the modulation cannot have any DC component. Some kind of coding is needed to ensure that
the modulation is DC free, e.g., Manchester code or block code. With Manchester code the bitrate is half the baudrate, but with 3B4B block
code the bitrate is
3
/
4
of the baudrate.
Bitrate is the same as the baudrate.
Measured at 19.2k bauds and frequency deviation
±25kHz
(external modulation), jitter of received data: < 45%.
Note 5:
Note 6:
Output Power
vs. Current @ 25°C
15
10
P
OUT
(dBm)
5
0
-5
-10
10 15 20 25 30 35 40 45 50
I
TOT
(mA)
March 2003
5
MICRF500
嵌入式系统
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