SA9500 Просмотр технического описания (PDF) - Philips Electronics
Номер в каталоге
Компоненты Описание
производитель
SA9500 Datasheet PDF : 22 Pages
| |||
Philips Semiconductors
Dual-band, CDMA/AMPS downconverter IC
Product specification
SA9500
PIN CONFIGURATION
FM IF 1
FM IFB 2
GND 3
PCS RF 4
PCS RFB 5
PCS/CEL SEL 6
PWR ON/OFF 7
CEL RF 8
GND 9
VCC 10
20 CDMA IF
19 CDMA IFB
18 GND
17 CDMA/FM SEL
16 CEL LO IN
15 GND
14 GND
13 LO GAIN
12 GND
11 LO OUT
SR01688
Figure 2. Pin Configuration
PIN DESCRIPTION
PIN SYMBOL
1 FM IF
2 FM IFB
3 GND
4 PCS RF
5 PCS RFB
6 PCS/CEL SEL
7 PWR ON/OFF
8 CEL RF
9 GND
10 VCC
11 LO OUT
12 GND
13 LO GAIN
14 GND
15 GND
16 CEL LO
17 CDMA/FM SEL
18 GND
19 CDMA IFB
20 CDMA IF
DESCRIPTION
Non-inverting FM IF output
Inverting FM IF output
Analog ground
non-inverting PCS RF input
Inverting PCS RF input
PCS and cellular band select
Power enable
Cellular RF input
Ground
Power supply
LO output to synthesizer
Ground
Logic signal which adjusts the gain of
the LO buffer
Ground
Ground
Cellular LO input
CDMA and FM mode select in the
cellular band; selects LO buffer output
frequency in PCS mode
Ground
Inverting CDMA IF output
Non-inverting CDMA IF output
FUNCTIONAL DESCRIPTION
Mode Selection Logic
The SA9500 downconverter IC has several modes of operation for
which the selection logic is summarized in Table 1 and defined in
detail in Table 2. Different mode selections require different portions
of the circuit to be active. It should be noted that only the states
specified in Table 2 are valid selections for operation.
Local Oscillator Section
Drive for the local oscillator is provided through a single ended input
via pin16. The LO signal has to be AC-coupled into the circuit and
needs to be externally matched. Inside the circuit, the LO signal is
amplified and buffered to drive: Either the cellular CDMA mixer or
FM mixer or the frequency doubler for the PCS mixer LO and
additionally one of the LO output buffers. The mode selection
summary in Table 1 shows the logic to apply to pins 6 and 17 to
choose one of four possible modes. The LO output buffer can supply
either the same frequency as that input on pin 16 or doubled
frequency LO in CDMA PCS modes. The LO output power range
can be programmed between high gain and low gain (idle mode)
settings with LO gain on pin 13.
Cellular and PCS Mixers
The SA9500 has one single ended cellular band RF input which
feeds either the cellular CDMA mixer or the cellular FM mixer
circuits. Each mixer is optimized to meet cellular band CDMA or
analog FM requirements. The cellular FM mixer has its own
dedicated differential output on pins 1 and 2 which should be
externally matched to the FM IF SAW filter. The cellular CDMA
mixer shares the same output pins with the CDMA PCS mixer.
Selection between these two mixers is via pin 6 (PCS/CEL) and as
the two mixers are never on at the same time, it allows a common
CDMA SAW filter to be used for both bands. The CDMA PCS mixer
has a differential RF input which should be used with an external
balun matching circuit. To avoid upsetting the internal biasing, the
RF inputs at both cellular and PCS band mixers should be
AC-coupled. The CDMA and FM IF mixer outputs are of the open
collector type. So, they should be biased to the supply voltage VCC
with external tuning inductors which can also serve in the matching
of the IF SAW filter.
1998 Aug 11
4
Share Link: 