Motorola Commercial Series Service Information page 24

3-8
IC Designator
U201
Freq Synthesizer
U251
VCO / Buffer
Pin Pin Function
24 Ref osc XTAL2
25 Ref osc warp output
26 Superfilter cap
27 Superfilter base (NU)
28 Superfilter output
29 NC2
30 Superfilter input
31 NC3
32 Prescaler input
33 Prescaler ground
34 Prescaler Vdd
35 Prescaler Vref (NU)
36 Digital Vdd
37 TEST1 (NU)
38 TEST2 (NU)
39 Bias 2
40 Bias 1
41 Modulation output
42 CCOMP (NU)
43 Steering line IOUT
44 PD ground
45 Steering line IADAPT
46 Adapt switch (NU)
47 Voltage from charge pump
48 AUX1 output (NU)
1 TX VCO current adjust
2 RX VCO current adjust
3 Superfiltered input
4 Collector RF in amp
5 RX VCO base
6 RX VCO emitter
7 RX switch output (NU)
8 RX buffered VCO output
9 GND_FLAG
10 TX buffered VCO output
11 GND_BUFFERS
TROUBLESHOOTING TABLES
DC Voltage Comments (Condition)
0
3.00
4.48
3.76
4.52
0
4.96
0
1.97
GND
2.99
1.97
2.99
0.01
0
3.38 (typ) (1.34V in TX mode)
1.50 (typ) (3.20V in TX mode)
3.42 (typ) (1.62V typ in TX mode)
0.05
9.62 (typ) Depends on frequency
GND
9.62 (typ) Depends on frequency
0
12.8
2.98
4.50
4.35
4.51
4.35
1.27
0.48
0
3.36
GND
3.36
GND