SA602A Datasheet, PDF (3/11 Pages) NXP Semiconductors – Double-balanced mixer and oscillator

Philips Semiconductors
Double-balanced mixer and oscillator
BLOCK DIAGRAM
8
7
6
5
VCC
VOLTAGE
REGULATOR
OSCILLATOR
Product specification
SA602A
GROUND
1
2
3
4
Figure 2. Block Diagram
SR00069
AC/DC ELECTRICAL CHARACTERISTICS
V_CC = +6V, T_A = 25°C; unless otherwise stated.
SYMBOL
PARAMETER
V_CC
f_IN
f_OSC
R_IN
C_IN
Power supply voltage range
DC current drain
Input signal frequency
Oscillator frequency
Noise figure at 45MHz
Third-order intercept point
Conversion gain at 45MHz
RF input resistance
RF input capacitance
Mixer output resistance
TEST CONDITIONS
RF_IN = -45dBm: f₁ = 45.0MHz
f₂ = 45.06MHz
(Pin 4 or 5)
LIMITS
SA602A
UNITS
MIN
TYP MAX
4.5
8.0
V
2.4
2.8
mA
500
MHz
200
MHz
5.0
5.5
dB
-13
-15 dBm
14
17
dB
1.5
kΩ
3
3.5
pF
1.5
kΩ
DESCRIPTION OF OPERATION
The SA602A 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 SA602A is designed for optimum low power performance.
When used with the SA604 as a 45MHz cellular radio second IF and
demodulator, the SA602A is capable of receiving -119dBm signals
with a 12dB S/N ratio. Third-order intercept is typically -13dBm (that
is 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 are not critical, the input to the SA602A should be
appropriately scaled.
Besides excellent low power performance well into VHF, the
SA602A is designed to be flexible. The input, RF mixer output and
oscillator ports can support a variety of configurations provided the
designer understands certain constraints, which will be explained
here.
The RF inputs (Pins 1 and 2) are biased internally. They are
symmetrical. The equivalent AC input impedance is approximately
1.5k || 3pF through 50MHz. Pins 1 and 2 can be used
interchangeably, but they should not be DC biased externally.
Figure 5 shows three typical input configurations.
The mixer outputs (Pins 4 and 5) are also internally biased. Each
output is connected to the internal positive supply by a 1.5kΩ
resistor. This permits direct output termination yet allows for
balanced output as well. Figure 6 shows three single ended output
configurations and a balanced output.
1997 Nov 07
3