Rainbow Electronics MAX19999 - Manual (Page 15)

MAX19999
Dual, SiGe High-Linearity, 3000MHz to
4000MHz Downconversion Mixer with LO Buffer
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Detailed Description
The MAX19999 provides high linearity and low noise fig-
ure for a multitude of 3000MHz to 4000MHz WiMAX and
LTE base-station applications. This device operates over
an LO range of 2650MHz to 3700MHz and an IF range of
50MHz to 500MHz. Integrated baluns and matching cir-
cuitry allow 50
Ω single-ended interfaces to the RF and
LO ports. The integrated LO buffer provides a high drive
level to the mixer core, reducing the LO drive required at
the MAX19999’s input to a range of -3dBm to +3dBm.
The IF port incorporates a differential output, which is
ideal for providing enhanced 2RF-2LO performance.
RF Input and Balun
The MAX19999’s two RF inputs (RFMAIN and RFDIV)
provide a 50
Ω match when combined with a series DC-
blocking capacitor. This DC-blocking capacitor is
required because the input is internally DC shorted to
ground through each channel’s on-chip balun. When
using a 1.5pF DC-blocking capacitor, the RF port input
return loss is typically 15dB over the RF frequency
range of 3200MHz to 3900MHz.
LO Input, Buffer, and Balun
A two-stage internal LO buffer allows a wide input
power range for the LO drive. All guaranteed specifica-
tions are for an LO signal power from -3dBm to +3dBm.
The on-chip low-loss balun, along with an LO buffer,
drives the double-balanced mixer. All interfacing and
matching components from the LO input to the IF out-
puts are integrated on chip.
High-Linearity Mixer
The core of the MAX19999 is a pair of double-bal-
anced, high-performance passive mixers. Exceptional
Pin Description
PIN NAME FUNCTION
1 RFMAIN Main Channel RF Input. Internally matched to 50Ω. Requires an input DC-blocking capacitor.
2, 5, 6, 8, 12, 15,
18, 23, 28, 31, 34
GND Ground. Not internally connected. Ground these pins or leave unconnected.
3, 7, 20, 22, 24,
25, 26, 27
GND
Ground. Internally connected to the exposed pad (EP). Connect all ground pins and the exposed
pad together.
4, 10, 16, 21,
30, 36
V CC
Power Supply. Connect bypass capacitors as close as possible to the pin (see the Typical
Application Circuit).
9 RFDIV
Diversity Channel RF Input. This input is internally matched to 50Ω. Requires a DC-blocking
capacitor.
11 IFD_SET
IF Diversity Amplifier Bias Control. Connect a resistor from this pin to ground to set the bias
current for the diversity IF amplifier.
13, 14 IFD+, IFD-
Diversity Mixer Differential IF Output. Connect pullup inductors from each of these pins to V CC
(see the Typical Application Circuit).
17 LO_ADJ_D
LO Diversity Amplifier Bias Control. Connect a resistor from this pin to ground to set the bias
current for the diversity LO amplifier.
19 LO
Local Oscillator Input. This input is internally matched to 50Ω. Requires an input DC-blocking
capacitor.
29 LO_ADJ_M
LO Main Amplifier Bias Control. Connect a resistor from this pin to ground to set the bias current
for the main LO amplifier.
32, 33 IFM-, IFM+
Main Mixer Differential IF Output. Connect pullup inductors from each of these pins to V CC
(see the Typical Application Circuit).
35 IFM_SET
IF Main Amplifier Bias Control. Connect a resistor from this pin to ground to set the bias current for
the main IF amplifier.
— EP
Exposed Pad. Internally connected to GND. Solder this exposed pad to a PCB pad that uses
multiple ground vias to provide heat transfer out of the device into the PCB ground planes. These
multiple via grounds are also required to achieve the noted RF performance