Philips Semiconductors

Objective data

SA58641

High performance mixer FM IF system

with high-speed RSSI

2004 Dec 16

13

Table 1.

DECT Application Circuit Electrical Characteristics

RF frequency = 110.592 MHz; IF frequency = 9.8 MHz; RF level = –45 dBm; FM modulation = 100 kHz with

±288 kHz peak deviation.

SYMBOL

PARAMETER

TEST CONDITIONS

TYPICAL

UNITS

PG

Conversion power gain

13

dB

NF

Noise Figure at 110 MHz

12

dB

IIP3

Third order input intercept

Matched f1 = 110.592 MHz; f2 = 110.892 MHz

–15

dBm

RF input resistance

690

Ω

RF input capacitance

3.6

pF

IF section

IF amp gain

330

Ω load

38

dB

Limiter amp gain

330

Ω load

54

dB

Data level

130

3 dB data bandwidth

700

kHz

RF/IF section (internal LO)

System RSSI output

RF level = –10 dBm

1.4

V

RF level = –83 dBm

10

dB

NOTE:

RF GENERATOR

SPECTRUM

ANALYZER

SCOPE

DC VOLTMETER

110.592 MHz

RSSI

DATA

SA58641 DEMO BOARD

LO / GENERATOR

120.392 MHz

SR02527

Figure 11.

SA58641 Application Circuit Test Set Up

NOTES:

1. RF generator: Set your RF generator at 110.592 MHz, use a 100 kHz modulation frequency and a

±288 kHz deviation.

2. Layout: The layout is very critical in the performance of the receiver. We highly recommend our demo board layout.

3. RSSI: The smallest RSSI voltage (i.e., when no RF input is present and the input is terminated) is a measure of the quality of the layout and

design. If the lowest RSSI voltage is 500 mV or higher, it means the receiver is in regenerative mode. In that case, the receiver sensitivity

will be worse than expected.

4. Supply bypass and shielding: All of the inductors, the quad tank, and their shield must be grounded. A 0.1

µF bypass capacitor on the supply

pin improves sensitivity.