SA9500 datasheet(4/22 Pages) PHILIPS

4 / 22 page

Philips Semiconductors

Product specification

SA9500

Dual-band, CDMA/AMPS downconverter IC

1998 Aug 11

PIN CONFIGURATION

FM IF

FM IFB

GND

PCS RF

PCS RFB

PCS/CEL SEL

PWR ON/OFF

CEL RF

GND

VCC

CDMA IF

CDMA IFB

GND

CDMA/FM SEL

CEL LO IN

GND

LO GAIN

LO OUT

SR01688

Figure 2.

Pin Configuration

PIN DESCRIPTION

SYMBOL

DESCRIPTION

FM IF

Non-inverting FM IF output

FM IFB

Inverting FM IF output

GND

Analog ground

PCS RF

non-inverting PCS RF input

PCS RFB

Inverting PCS RF input

PCS/CEL SEL

PCS and cellular band select

PWR ON/OFF

Power enable

CEL RF

Cellular RF input

GND

Ground

VCC

Power supply

LO OUT

LO output to synthesizer

GND

Ground

LO GAIN

Logic signal which adjusts the gain of

the LO buffer

GND

Ground

GND

Ground

CEL LO

Cellular LO input

CDMA/FM SEL

CDMA and FM mode select in the

cellular band; selects LO buffer output

frequency in PCS mode

GND

Ground

CDMA IFB

Inverting CDMA IF output

CDMA IF

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.

SA9500 Datasheet(PDF) 4 Page - NXP Semiconductors

SA9500 Datasheet(HTML) 4 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Datasheet Download

Link URL