RF2418TR7 RFMD, RF2418TR7 Datasheet - Page 4

• Manufacturer Part Number: RF2418TR7
• Description: IC LNA MIXER LOW CURRENT 14-SOIC
• Manufacturer: RFMD
• Series: RF2418r

Specifications of RF2418TR7

• Rf Type: ISM, UHF
• Frequency: 400MHz ~ 1.1GHz
• Number Of Mixers: 1
• Gain: 23dB
• Noise Figure: 2.4dB
• Current - Supply: 26mA
• Voltage - Supply: 3 V ~ 6.5 V
• Package / Case: 14-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Other names: 689-1013-2

RF2418
4 of 12
Pin
1
2
3
4
5
6
7
8
9
Function
IF2 OUT
IF1 OUT
RF BYP
LNA IN
IF BYP
VDD1
VDD2
LO IN
GND
Description
A series 10nH matching inductor is necessary to achieve specified gain
and noise figure at 900MHz. 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 DC path to ground (i.e. an inductor or resistor to
ground) is, however, acceptable at this pin. If a blocking capacitor is
required, a value of 22pF is recommended.
Ground connection. Keep traces physically short and connect immediately
to ground plane for best performance.
Supply Voltage for the LNA only. A 22pF external bypass capacitor is
required and an additional 0.01μF is required if no other low frequency
bypass capacitors are near by. 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.
For large input signals, VDD1 may be disconnected, resulting in the LNA’s
gain changing from +11dB to -26dB and current drain decreasing by 4mA.
If the LNA is never required for use, then this pin can be left unconnected
or grounded, and Pin 11 is used as the first input.
Power supply for the IF buffer amplifier. If the high impedance mixer output
is being used, then this pin is not connected.
If this pin is connected to ground, an internal 10pF capacitor is connected
in parallel with the mixer output. This capacitor functions as an LO trap,
which reduces the amount of LO to IF bleed-through and prevents high LO
voltages at the mixer output from degrading the mixer’s dynamic range. At
higher IF frequencies, this capacitance, along with parasitic layout capaci-
tance, should be parallel resonated out by the choice of the bias inductor
value at pin 7. If the internal capacitor is not connected to ground, the
buffer amplifier could become unstable. A ~10pF capacitor should be
added at the output to maintain the buffer’s stability, but the gain will not
be significantly affected.
50Ω buffered (open source) output port, one of two output options. Pin 7
must have a bias resistor to V
ground (see Buffered Output Application Schematic) in order to turn the
buffer amplifier on. Current drain will increase by approximately 8mA at
5V, and by approximately 5mA at 3V. It is recommended that these bias
resistors be less than 1kΩ.
High impedance (open drain) output port, one of two output options. This
pin must be connected to V
bias the mixer, even when using IF2 Output. In addition, a 0.01μF bypass
capacitor is required at the other end of the bias resistor or inductor. The
ground side of the bypass capacitor should connect immediately to ground
plane. This output is intended to drive high impedance IF filters. The rec-
ommended matching network is shunt L, series C (see the application
schematic, high impedance output). This topology will provide matching,
bias, and DC-blocking.
Mixer LO input. A high-pass matching network, such as a single shunt
inductor (as shown in the application schematics), is the recommended
topology because it also rejects IF noise at the mixer input. This filtering is
required to achieve the specified noise figures. 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 DC path to ground (i.e. an induc-
tor or resistor to ground) is, however, acceptable at this pin. If a blocking
capacitor is required, a value of 22pF is recommended.
Connection for the external bypass capacitor for the mixer RF input
preamp. 1000pF is recommended. The trace length between the pin and
the capacitor should be minimized. The ground side of the bypass capaci-
tor should connect immediately to ground plane.
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at ([phone] or [e-mail].
DD
DD
through a resistor or inductor in order to
and pin 6 must have a bias resistor to
Interface Schematic
LO IN
LNA IN
Rev A7 DS060203
IF2 OUT
IF1 OUT