Preliminary
8-126
RF2461
Rev A13 010607
8
Pin
Function
Description
Interface Schematic
1
LNA GAIN
Controls the bypass feature of the LNA. A logic low (< 1.0V) selects the
bypass mode. A logic high (>2.0V) turns on the LNA.
2MIX GAIN
Controls the bypass feature of the mixer pre-amp. A logic low (< 1.0V)
selects the bypass mode. A logic high (>2.0V) turns on the pre-amp.
3LNA IN
LNA input pin.
4
VCC1
VCC pin for all circuits except the LO. Buffer/bias circuitry.
5
GND1B
LNA emitter. This pin provides the DC path to ground for the LNA. A
lumped element or a transmission line inductor can be placed between
this pin and ground to degenerate the LNA. This will decrease the gain,
increase the IP3, and increase the NF of the LNA. As the value of
inductance is increased, these effects will become more pronounced.
6LNA OUT
LNA output pin.
See pin 3.
7
ISET2
An external resistor R2 connected to this pin sets the current of the pre-
amp and the mixer.
8
ISET1
An external resistor R3 connected to this pin sets the current of the
LNA when IP SET is high (see pin 19).
9
GND3B
Ground pin for pre-amp circuit. A 3.3nH inductor is used between pin 9
and ground to degenerate the mixer pre-amp. Degenerating the pre-
amp will reduce the gain, increase the IP3 and affect the pre-amp input
impedance.
10
MIX IN
Mixer pre-amp input pin.
See pin 9.
11
IF1-
Second differential output pin for the first mixer.
See pin 12.
12
IF1+
First differential output pin for the first mixer. Open collector. A current
combiner external network performs a differential to single-ended con-
version and sets the output impedance. A DC blocking cap must be
present if the IF filter input has a DC path to ground. Mixer (IF2+ and
IF-) needs to “see” a differential impedance between 2k
Ω to 4kΩ.
13
BYPASS
Bypass pin for the LO bias reference.
14
IF2-
Second differential output pin for the second mixer.
See pin 15.
LNA GAIN
MIX GAIN
LNA IN
LNA OUT
GND1B
MIX IN
GND3B
VCC2
IF1-
IF1+
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
