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RF137 Datasheet PDF : 15 Pages
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RF137
Transceiver
Block
LO
TX
Receive
TRX
SX
Table 4. RF137 Control Bits and Output States
C0 Bit
Function
Description
1
S1 RX LO ÷2/÷4
S2 SX LO2 ÷2/÷4
S3 TX LO ÷2/÷4
1
S4 TX IF ÷1/÷2
S5 TX MIX OUT ÷1/÷2
S6 TX LO Injection
Selects the division ratio for RX LO2 (0 = division ratio is 2; 1 = division ratio is 4)
Selects the division ratio for SX LO2 (0 = division ratio is 2; 1 = division ratio is 4)
Selects the division ratio for TX LO2 (0 = division ratio is 2; 1 = division ratio is 4)
Selects the division ratio for TX IF (0 = division ratio is 1; 1 = division ratio is 2)
Selects the division ratio for TX MIX output signal (0 = division ratio is 1; 1 = division ratio is 2)
Selects between high-side and low-side injection of first LO input with respect to transmit RF (0 =
low side; 1 = high side)
1
S7 RX Gain Select 1
Selects RX 1st IF amplifier gain (0 = low gain; 1 = high gain)
S8 RX Gain Select 2
Selects RX 2nd IF amplifier gain (0 = low gain; 1 = high gain)
S9 RX LO Injection
Selects LO injection (0 = low side injection; 1 = high side injection)
1
S10 TX TL CP Current
Charge pump current in translation loop circuit (0 = low current, 1 = high current)
S11 Reserved
S11 bit may be programmed as “don’t care.”
S12 VHF LO BUF
Selects the state of LO buffer. Needs to be “1” for correct operation (0 = LO buffer off; 1 = LO
buffer on)
0
S1 IF/RF
Selects one of the synthesizers, either the VHF or UHF (0 = VHF is selected; 1 = UHF is selected
S2 R/N
Selects the R count or N count register within the synthesizer. The N count register also controls
the phase detector current and inversion (or phase comparison reference signal) (0 = N counter
register selected; 1 = R counter register selected)
S3 S2=0: Prescaler
frequency response
Determines the maximum input frequency at which the prescaler will operate. S1=1 (UHF): 0 = 1.2
GHz, 1 = 2.0 GHz; S1=0 (VHF): 0 = 260 MHz, 1 = 450 MHz
S2=1: Output invert
Controls polarity of charge pump output (0 = normal operation; 1 = inverted)
S4 S2=0: Synthesizer power Powers down the synthesizers. Only the synthesizer indicated by S1 is affected (0 = Normal
down
operation; 1 = Power down)
S2=1: Lock detect/Test
mode select
Used to select the test mode or lock detect output on pin 25 (0 = selects the test mode output,
where S8 and S9 select the signal multiplexed to pin 25; 1 = selects the translational loop lock
detect signal for output to pin 25).
S5- S2=0: N counter
S22
This 18-bit value is loaded into the N counter latch. This value sets the cascaded division ratio of
the prescaler and N counter (S22=MSB, S5=LSB). For the VHF N divider (16-bit), bits S21 and
S22 are “don’t care”.
The least significant bits (S5-S9 for UHF N divider; S5-S7 for VHF N divider) set the prescaler
counter.
S5- S2=1: Output current
S6
These bits set the charge pump output current.
S1=1
UHF:
00=0.8, 01=1.2, 10=1.8, 11=2.7 [mA]
S1=0
VHF:
00=0.5, 01=0.8, 10=1.2, 11=1.8 [mA]
S7 S2=1: CP output
impedance
The charge pump output is changed to a high impedance output. Only the charge pump output
selected by S1 bit is affected (0 = Normal operation; 1 = output impedance)
S8- S2=1, S4 = 0: Test mode These bits select which signal is output at pin 25 (LD) when the test mode output is selected (S2 =
S9
1, S4 = 0).
00 = (Lock detect of VHF) AND (lock detect of UHF)
01 = Output of R divider
10 = Output of N divider
11 = Output of lock detect VHF (S1=0) or UHF (S1=1)
S10- S2=1: R counter
S22
These 13 bits set the reference divider value (S22=MSB, S10=LSB).
8
October 11, 2000
Conexant - Proprietary
Data Subject to Change
100777C
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