Philips Semiconductors

Product specification

SA612A

Double-balanced mixer and oscillator

1997 Nov 07

3

ABSOLUTE MAXIMUM RATINGS

SYMBOL

PARAMETER

RATING

UNIT

Maximum operating voltage

9

V

Storage temperature

-65 to +150

°C

Operating ambient temperature range SA612A

-40 to +85

°C

AC/DC ELECTRICAL CHARACTERISTICS

SYMBOL

PARAMETER

TEST CONDITION

LIMITS

UNIT

SYMBOL

PARAMETER

TEST CONDITION

Min

Typ

Max

UNIT

Power supply voltage range

4.5

8.0

V

DC current drain

2.4

3.0

mA

Input signal frequency

500

MHz

Oscillator frequency

200

MHz

Noise figured at 45MHz

5.0

dB

Third-order intercept point at 45MHz

-13

dBm

Conversion gain at 45MHz

14

17

dB

RF input resistance

1.5

k

Ω

RF input capacitance

3

pF

Mixer output resistance

(Pin 4 or 5)

1.5

k

Ω

DESCRIPTION OF OPERATION

The SA612A is a Gilbert cell, an oscillator/buffer, and a temperature

compensated bias network as shown in the equivalent circuit. The

Gilbert cell is a differential amplifier (Pins 1 and 2) which drives a

balanced switching cell. The differential input stage provides gain

and determines the noise figure and signal handling performance of

the system.

The SA612A is designed for optimum low power performance.

When used with the SA614A as a 45MHz cordless phone/cellular

radio 2nd IF and demodulator, the SA612A is capable of receiving

-119dBm signals with a 12dB S/N ratio. Third-order intercept is

typically -15dBm (that’s approximately +5dBm output intercept

because of the RF gain). The system designer must be cognizant of

this large signal limitation. When designing LANs or other closed

systems where transmission levels are high, and small-signal or

signal-to-noise issues not critical, the input to the SA612A should be

appropriately scaled.