MAX19994AETX+T Maxim Integrated Products, MAX19994AETX+T Datasheet - Page 25

• Manufacturer Part Number: MAX19994AETX+T
• Description: RF Mixer Dual SiGe High-Linea rity 1200-2000MHz Do
• Manufacturer: Maxim Integrated Products

Specifications of MAX19994AETX+T

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Each channel of the device has two pins (LO_ADJ__,
IF__SET) that allow external resistors to set the internal
bias currents. Nominal values for these resistors are
given in Table 1. Larger value resistors can be used to
reduce power dissipation at the expense of some per-
formance loss. If ±1% resistors are not readily available,
substitute with ±5% resistors.
Significant reductions in power consumption can also
be realized by operating the mixer with an optional 3.3V
supply voltage. Doing so reduces the overall power con-
sumption by approximately 47%. See the 3.3V Supply
AC Electrical Characteristics table and the relevant 3.3V
curves in the Typical Operating Characteristics section.
For applications requiring optimum RF-to-IF and LO-to-
IF isolation, connect low-ESR inductors from IND_EXT_
(pins 15 and 31) to ground. When improved isolation
is not required, connect IND_EXT_ to ground using 0I
resistance.
A properly designed PCB is an essential part of any
RF/microwave circuit. Keep RF signal lines as short as
possible to reduce losses, radiation, and inductance.
The load impedance presented to the mixer must be
such that any capacitance from both IF_- and IF_+ to
Table 1. Component Values
Dual, SiGe, High-Linearity, 1200MHz to 2000MHz
C2, C7, C14, C16
C10, C11, C12,
DESIGNATION
C19, C20, C21
C9, C13, C15,
L1, L2, L4, L5
C17, C18
C1, C8
C3, C6
C4, C5
L3, L6
L7, L8
Downconversion Mixer with LO Buffer/Switch
QTY
2
4
2
2
5
6
4
2
2
Layout Considerations
Reduced-Power Mode
39pF microwave capacitors (0402)
1.8pF for Extended RF Band applications
(f
39pF microwave capacitors (0402)
0.033FF microwave capacitors (0603)
Not used
0.01FF microwave capacitors (0402)
150pF microwave capacitors (0603)
120nH wire-wound, high-Q inductors (0805)
10nH wire-wound, high-Q inductors (0603). Smaller
values or a 0I resistor can be used at the expense of
some LO leakage at the IF port and RF-to-IF isolation
performance loss.
4.7nH inductor (0603). Installed for Extended RF Band
applications only (1.7GHz to 2GHz).
RF
IND_EXT_ Inductors
= 1.7GHz to 2GHz)
DESCRIPTION
ground does not exceed several picofarads. For the
best performance, route the ground pin traces directly
to the exposed pad under the package. The PCB
exposed pad MUST be connected to the ground plane
of the PCB. Use multiple vias to connect this pad to the
lower-level ground planes. This method provides a good
RF/thermal-conduction path for the device. Solder the
exposed pad on the bottom of the device package to
the PCB. The MAX19994A evaluation kit can be used as
a reference for board layout. Gerber files are available
upon request at www.maxim-ic.com.
Proper voltage-supply bypassing is essential for high-
frequency circuit stability. Bypass each V
TAPMAIN/TAPDIV with the capacitors shown in the
Typical Application Circuit (see Table 1 for component
values). Place the TAPMAIN/TAPDIV bypass capacitors
to ground within 100 mils of the pin.
The exposed pad (EP) of the MAX19994A’s 36-pin thin
QFN-EP package provides a low thermal-resistance
path to the die. It is important that the PCB on which the
device is mounted be designed to conduct heat from
the EP. In addition, provide the EP with a low-inductance
path to electrical ground. The EP MUST be soldered to
a ground plane on the PCB, either directly or through an
array of plated via holes.
Exposed Pad RF/Thermal Considerations
Murata Electronics North America, Inc.
Murata Electronics North America, Inc.
Murata Electronics North America, Inc.
—
Murata Electronics North America, Inc.
Murata Electronics North America, Inc.
Coilcraft, Inc.
Coilcraft, Inc.
TOKO America, Inc.
Power-Supply Bypassing
COMPONENT SUPPLIER
CC
pin and
25