MADRCC0002_15 Datasheet, PDF (1/8 Pages) M/A-COM Technology Solutions, Inc. – Dual Linear Driver for Vector Modulators

MADRCC0002
Dual Linear Driver for Vector Modulators
Rev. V7
Features
 Linearizes M/A-COM’s PIN Diode Vector
Modulators Over a 360 Phase Range
 Dual Channels Allow One Driver per Vector
Modulator
 Guaranteed Minimum Output Currents of 20 mA
 Operates with a Single Supply Voltage of +5V
 Low Quiescent Currents
 Single Control Voltage for Each Channel
 6 x 4 mm Chip Scale Package
 Test Boards with Vector Modulators are Available
 Tape and Reel Packaging Available
 PQFN Package
Description
M/A-COM's MADRCC0002 is a dual, break point
free driver that produces a logarithmic output current
suitable for linearizing PIN diode based vector
modulators. This driver, in conjunction with the
external components, as defined in Figure 1,
produces a linearized transfer function between the
input control voltage of the driver and the
attenuation / phase output of the vector modulator.
The MADRCC0002 has been optimized for
linearizing M/A-COM’s Vector Modulators (see Table
1), but will function well with most types of cathode
grounded vector modulators. The driver is packaged
in a 6 x 4 mm Chip Scale Package for commercial
SMT applications. A typical schematic for a dual
linearizer driving a vector modulator is shown in
Figure 1.
Circuit Description:
(Reference Figures 1, 2 and 3)
Note that this is a dual driver. Only the top circuit
will be described, because the bottom circuit is
identical. The input divider, R1 and the sum of R2
and R3, sets the overall transfer function of the cir-
cuit. To increase the transfer function, decrease the
Control Voltage and the value of R1. Temperature
compensation is a function of the temperature
coefficient of the thermistor, R3, and the ratio of R2
to R3, and can only be optimized once the transfer
function and linearity component values have been
established. Varying the value of R4 will optimize
the linearity of the VVA. One can achieve a more
linear transfer function by driving the attenuator
over a smaller portion of its dynamic range. Note
that when the vector modulators called out in Table
1 are driven with the dual linearizer, both amplitude
and phase are affected, which makes it hard to de-
fine linearity. The individual transfer function of
each voltage variable attenuator in the vector
modulator (See Figure 2 for the block diagram) is
linearized as a function of voltage. The two VVAs in
the block diagram are the quad hybrids that are
terminated by two PIN diodes. See Figure 3 for
the transfer function of the SA90-0001 vector
modulator (phase and attenuation vs. control volt-
ages).
Ordering Information
Part Number
Package
MADRCC0002
Bulk Packaging
MADRCC0002TR
Tape & Reel (1K Reel)
MAMDCC0005-DC000
Test Board with Circuit per
Figure 1
(MAMDCC0005,
GSM Vector Modulator)
MAMDCC0002-DC000
Test Board with Circuit per
Figure 1
(MAMDCC0002,
PCS Vector Modulator)
SA90-0001-DC000
Test Board with Circuit per
Figure 1
(SA90-0001,
UMTS Vector Modulator
Note: Reference Application Note M513 for reel size
information.
1
M/A-COM Technology Solutions Inc. (MACOM) and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.
Visit www.macom.com for additional data sheets and product information.
For further information and support please visit:
https://www.macom.com/support