Preliminary
RF2494
Pin
1
Function Description
Interface Schematic
The power enable pin. When PD is >V - 300mV, the part is biased
PD
CC
on. When PD is <300mV, then the part is turned off and typically draws
less than 1µA.
Supply voltage for bias circuits and logic control. A 10pF external
bypass capacitor is required and an additional 0.01µF is required if no
other low frequency bypass capacitors are nearby. The trace length
between the pin and the bypass capacitors should be minimized. The
ground side of the bypass capacitors should connect immediately to
ground plane.
2
VCC1
Supply voltage for LO_Buffer. A 10pF bypass capacitor is required and See pin 6.
an additional 0.01µF is required if there is no other low frequency
bypass capacitor in the area. The trace length between the pin and the
bypass capacitors should be minimized. The ground side of the bypass
capacitors should connect immediately to ground plane.
3
4
VCC2
The inverting open collector output of the mixer. This pin needs to be
MIXOUT-
MIX OUT+
MIX OUT-
externally biased and DC isolated from other parts of the circuit. This
output can drive a Balun, with MIXOUT+, to convert to unbalanced to
drive a SAW filter. The Balun can be either broadband (transformer) or
narrowband (discrete LC matching). Alternatively, MIXOUT+ may be
used alone to drive a SAW single-ended, with an RF choke (high Z at
IF) from VCC to MIXOUT-.
The non-inverting open collector output of the mixer. This pin needs to See pin 4.
be externally biased and DC isolated from other parts of the circuit.
This output can drive a Balun, with MIXOUT+, to convert to unbalanced
to drive a SAW filter. The Balun can be either broadband (transformer)
or narrowband (discrete LC matching). Alternatively, MIXOUT+ may be
used alone to drive a SAW single-ended, with an RF choke (high Z at
IF) from VCC to MIXOUT+.
5
6
MIXOUT+
LO IN
8
LO input pin. This input needs a DC-blocking cap. External matching is
recommended to 50Ω.
VCC2
LO IN
This control pin allows the mixer output pins to be put into a high
impedance state. This allows the transmit signal path to share the
same IF filter as the receiver.
7
RX EN
Supply voltage for mixer preamp.
See pin 10.
See pin 10.
8
9
VCC3
GND3
Ground pin for mixer preamp. This lead inductance is intended to be
similar to VCC3 lead inductance.
Mixer RF Input port. This pin is NOT internally DC-blocked. An external
blocking capacitor must be provided if the pin is connected to a device
with DC present. A value of >22pF is recommended. To minimize the
noise figure it is recommended to have a bandpass filter before this
input. This will prevent the noise at the image frequency from being
converted to the IF.
VCC3
10
MIX IN
MIX IN
GND3
Not connected.
Not connected.
11
12
NC
NC
Rev A0 010730
8-55
RFMD [ RF MICRO DEVICES ]
