Conexant RF137 Datasheet
Data Sheet
Conexant - Proprietary
Doc. No. 100777C
Data Subject to Change October 11, 2000
RF137
Transceiver For GSM Applications
The RF137 Transceiver is a highly integrated device optimized for use in singleband or multi-band Global System for Mobile Communications (GSM) applications.
In the receive path, the device consists of selectable gain Intermediate Frequency
(IF) amplifiers and an image reject downconverter with differential IF outputs.
In the transmit path, the device consists of an In-Phase and Quadrature (I/Q)
modulator and a frequency translational loop designed to perform frequency upconversion with high output spectral purity. This loop has a phase/frequency
detector, a charge-pump, a mixer, and buffers for the required isolation between
RF output, Local Oscillator (LO), and IF inputs.
In addition, the RF137 features an on-chip, dual-loop UHF/VHF frequency
synthesizer circuit. It includes two sets of reference dividers, phase/frequency
detectors, charge pumps, prescalers, main dividers, and control circuits.
The device package and pinout of the RF137 are shown in Figure 1. A block
diagram is shown in Figure 2.
The signal pin assignments and functional pin descriptions are found in Table 1.
The absolute maximum ratings of the device are provided in Table 2, and the
operating conditions and electrical specifications are provided in Table 3.
Features
• Image-reject mixer for downconversion to 2nd IF
• 24 dB selectable attenuation on 1st IF amplifier
• 12 dB selectable attenuation on 2nd IF amplifier
• Integrated transmit path with high phase accuracy
• Reduced filtering requirements for the transmit path
• Wide RF and IF range for multi-band operation
• Integrated, fully programmable dual loop
synthesizer
• Integrated local oscillator phase shifters
• On-chip second local oscillator
• Low supply voltage down to 2.7 V
• Separate enable lines for transmit, receive, and
synthesizer modes for power management
• 48-pin Thin Quad Flat Pack (TQFP) (7mm x 7mm)
package
Applications
• GSM900/DCS1800/PCS1900 digital cellular
telephony
100777C-1_100500
GND
VCC
TLCPO
VCCB
GND
GND
TXIFIN+
TXIFIN-
TXI+
TXQ-
TXI-
TXQ+
1
2
3
4
5
6
7
8
9
10
11
12
TXMO+
CLK
TXMO-
LE
DATA
GND
VCCB
UCPO
FREF
VCCB
GND
VCPO
141516171819202122
231324
TXENA
VCC
TXRFIN+
TXRFIN-
GND
IF1IN +
LOIN+
LOIN-
IF1IN -
SXENA
RXENA
RXMXO
474645444342414039
384837
RES1
VCC
RES2
IF2IN+
IF2INIF2O+
BPC
GND
VCC
GND
LD
IF2O-
36
35
34
33
32
31
30
29
28
27
26
25
Figure 1. RF137 Pinout – 48-Pin TQFP
RF137 Transceiver
2
Conexant - Proprietary
100777C
October 11, 2000 Data Subject to Change
C018
Bias
Rx
Sx
Rx
Sx
BPC
TLCPO
GSEL1
PFD
90˚
VHF
Synthesizer
UHF
Synthesizer
3-Wire
Control
Tx
Tx
TX LO2
90˚
Ceramic
Filter
TXQ+
TXQ-
TXI+
TXI-
TXMO+
TXMO-
CHP
IF1IN+
IF1IN-
RES1
RES2
LO1IN+
LO1IN-
TXRFIN+
TXRFIN-
TXIFIN+
TXIFIN-
RXMXO
GSEL2
RX LO2
SX LO2
÷2
÷4
RXENA
TXENA
SXENA
VCPO
FREF
UCPO
CLK
DATA
LE
LD
IF2O+
IF2O-
IF2IN+
IF2IN-
÷2
÷4
÷2
÷4
÷1
÷2
÷1
÷2
+
Figure 2. RF137 Block Diagram
Technical Description
The RF137 Transceiver consists of three main sections:
•
Receive (Rx) section
•
Transmit (Tx) section
•
Synthesizer (Sx) section
The Rx, Tx, and Sx sections can be powered up or down
independently by setting RXENA, TXENA, and SXENA high or
low.
The signal pin assignments and functional pin descriptions are
found in Table 1. Table 2 provides the absolute maximum
ratings of the RF137. The general electrical characteristics are
provided in Table 3.
Receive Section
. The receive section consists of the following
functional blocks:
•
A first IF amplifier (selectable gain step of 24 dB).
•
An image reject mixer that downconverts from a first IF to a
second IF.
•
A buffer amplifier that precedes a second IF ceramic filter.
•
A second IF amplifier (selectable gain step of 12 dB) with
differential outputs.
The first IF amplifier is a Programmable Gain Amplifier (PGA)
with selectable gains of +18 or –6 dB. The amplifier gain is
controlled by a three-wire bus. The first IF amplifier is at a high
gain state when bit S7 = 1 (Rx Gain Sel1) and CO = 1 or at a
low gain state when bit S7 = 0 (Rx Gain Sel1) and CO = 1.
The image reject mixer relaxes the first IF filtering requirements
at the image frequency of the second mixer. Image rejection is
achieved for a high side/low side injection when bit S9 is set to
the appropriate logic level and CO = 1. Table 4 defines the
three-wire bus control and output states.
Transceiver RF137
100777C
Conexant - Proprietary
3
Data Subject to Change October 11, 2000
Table 1. RF137 Signal Description
Pin # Name Description Pin # Name Description
1 GND Ground 25 LD Lock detect output
2 TLCPO Translational loop c harge pump output 26 IF2O– 2nd IF output
3 VCCB Supply for synthesizers 27 IF2O+ 2nd IF output
4 VCC Supply for transceiver 28 IF2IN– 2nd IF input reference
5 GND Ground 29 IF2IN+ 2nd IF input
6 TXIFIN+ TxIF translati on loop input 30 GND Ground
7 TXIFIN– TxIF translation loop input 31 VCC Supply for transceiver
8 GND Ground 32 RES2 Resonator pin for VHF oscillator
9 TXI+ Tx modulator input 33 RES1 Resonator pin for VHF oscillat or
10 TXI– Tx modulator input 34 VCC Supply for transceiver
11 TXQ+ Tx modulator input 35 GND Ground
12 TXQ– Tx modulator input 36 BPC Bypass capacitor
13 TXMO+ Positive polari ty TX modulator output 37 SXENA Synthesizer enable
14 TXMO– Negative polarity TX modulator output 38 RXMXO Rx mixer output
15 LE Latch enable input 39 RXENA Receiver enable
16 CLK Clock input 40 IF1IN– 1st IF input
17 DATA Data input 41 IF1IN+ 1st IF input
18 VCCB Supply for synthesizers 42 LOIN– UHF local oscillator input reference
19 UCPO UHF loop charge pump output 43 LOIN+ UHF local oscillator input
20 GND Ground 44 GND Ground
21 FREF Reference input 45 VCC Supply for transceiver
22 GND Ground 46 TXRFIN– Transmit input reference
23 VCPO VHF loop charge pump output 47 TXRFIN+ Transmit input
24 VCCB Supply for synthesizers 48 TXENA Transmit enable
Table 2. Absolute Maximum Ratings
Parameter Minimum Maximum Units
Ambient Operating Temperature –30 +85 °C
Storage Temperature –40 +125 °C
Power Dissipation +600 mW
Supply Voltage (VCC)+4.0V
Input Voltage Range GND Vcc V
Supply Voltage (V
CCB
)4.0V
RF137 Transceiver
4
Conexant - Proprietary
100777C
October 11, 2000 Data Subject to Change
Table 3. RF137 Electrical Specifications (1 of 4)
(TA = 25
°°°°
C, Vcc = 3.0 V, except where specified)
Parameter Symbol Test Condition Min Typical Max Units
IF Amplifier/Mixer
Input impedance ZIN differential 1000//
0.5
Ω
//pF
Input operating frequenc y FN 70 450 MHz
Voltage gain:
High gain mode
Low gain mode
AV
S7 = 1, CO = 1
S7 = 0, CO = 1
+16.5
–7
+18
–6
+19
–5
dB
dB
Gain step variation dAV 0.5 dB
Single-sideband noise f igure NF High gain mode 7 8 dB
Input 1 dB compression point
High gain mode
Low gain mode
P1dB
–35
–9
–32
–7
dBV
dBV
Mixer spurious l evel Pin = –51 dBV –50 dBc
Image rejection 35 45 dB
Output impedance ZOUT 330// 2.2
Ω
//pF
Output operating frequency FOUT 14.6 MHz
2nd IF Amplifier
Input impedance ZIN 330// 2.2
Ω
//pF
Operating frequency FIF 14.6 MHz
Voltage gain:
High gain mode
Low gain mode
AV
S8 = 1, CO = 1
S8 = 0, CO = 1
17
5
18
6
19
7
dB
dB
Gain step variati on versus frequency dAV 0.5 dB
Noise figure NF 7 dB
Input P1dB P1dB low gain mode –25 –22 dBV
Output impedance ZOUT differential 1000//
1.2
Ω
//pF
Receiver
Gain temperature coefficient without ceramic f ilter 0.03 0.04
dB/°C
Power supply rejection ratio 0.5 dB/V
Input common mode rejection ratio FIN = 400 MHz 65 dB
I/Q Modulator
Input impedance ZIN differential @ 100 kHz 750// 3.3
kΩ//pF
Input common mode voltage range VCM 0.85 1.35 VCC–
1.35
V
Input offset vol tage VOS 1 5 mV
Input common mode rejecti on ratio FIN = 100 kHz
FIN = 1 MHz
75
55
dB
Output operating frequency FOUT 70 425 MHz
Output impedance ZOUT differential @400MHz 600// 3.1
Ω
//pF
Transceiver RF137
100777C
Conexant - Proprietary
5
Data Subject to Change October 11, 2000
Table 3. RF137 Electrical Specifications (2 of 4)
(TA = 25
°°°°
C, Vcc = 3.0 V, except where specified)
Parameter Symbol Test Condition Min Typical Max Units
I/Q Modulator (conti nued)
Differential output voltage –20 –15 dBV
Output noise power NO 10 MHz offset –130 –126 dBc/Hz
LO feedthrough –43 –40 dBc
Sideband suppression 45 dB
Spurious (Note 1)
@200 kHz offset
@300 kHz offset
–60
–60
–40
–45
dBc
dBc
Translational Loop
Transmit frequency (input from VCO) fTX 800 2000 MHz
LO input frequency fLO 800 2000 MHz
IF frequency:
with divide-by- 2
with divide-by- 1
fIF
S4 = 1, CO = 1
S4 = 0, CO = 1
70
70
425
300
MHz
Transmit input power PIN
with external 50
Ω
termination
–13 –10 –7 dBm
Transmit input impedance ZIN differential 300// 0.3
Ω
pF
LO input power PIN
With external 50
Ω
termination
–13 –10 –7 dBm
LO input impedance ZIN differential 300// 0.3
Ω
pF
Tx output noise NO @ 20 MHz off set
(Note 2)
–165 –162 dBc/Hz
Charge pump output current
source/sink
source/sink
high impedance output
IOUT
S10 = 0, CO = 1
S10 = 1, CO = 1
±
1.0
±
0.5
0.02
mA
mA
mA
Tx output spurs (N ote 3):
2X spurs
3X spurs
4X spurs
5X spurs
–65
–70
–70
<–70
dBc
dBc
dBc
dBc
Device turn-on and lock time (with respect to enable input) 1 MHz loop bandwidth 30 100
µ
s
VHF VCO
Operating frequency (depends on external resonator) FVCO 300 850 MHz
Tuning voltage range:
varactor ground referenced
varactor supply referenced
0.5
VCC–
0.5
V
V
Phase noise (Note 4) 10 MHz offset, FVCO =
800 MHz, resonator Q =
20
–145 dBc/Hz
Loading...