MD59-0022 M/A-COM, Inc., MD59-0022 Datasheet - Page 3

• Manufacturer Part Number: MD59-0022
• Manufacturer: M/A-COM, Inc.

Specifications subject to change without notice.
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External Circuitry Parts List
C10, C11, C12, C13
Operating Instructions
The MD59-0022 is a highly integrated MMIC upconverter/driver
for the 1710-1910 MHz PCS band. The upconverter/driver provides
exceptional RF performance while consuming low DC current and
is packaged in a low cost plastic package. It is ideal for light weight
battery operated portable radio systems.
The transmit chain consists of a balanced IF amplifier, balanced
mixer with single-ended RF output and a two stage RF driver
amplifier as shown in the block diagram on the previous page.
Surface mount resistors, inductors and capacitors are used in
conjunction with the IC for an optimum performance, tunability
and ease of use. A schematic, showing the IC and required external
components, is shown on page 2.
An external self-bias resistor R1, which is RF bypassed, allows the
current in the driver amplifier to be varied to obtain the required
linear output power. By placing a bipolar transistor in series with
the self-bias resistor, as shown in the schematic, the current
consumption in the driver can be dynamically switched to provide a
high and low power mode of operation. In high power mode, the
bipolar transistor is on and the driver output stage is self-biased
through R1 to provide +9 dBm of linear output power. By switching
off the transistor, the output stage is biased through the higher
resistance R2 thus reducing the current by ~25 mA to give 2 dBm
of linear output power. The dual bipolar (U4) shown in the
assembly drawing may be replaced by a smaller single transistor
package with similar performance.
An external filter is required between the mixer output and driver
amplifier input to reduce the amplitude of the image and local
oscillator signals coming out of the mixer. This filter should have a
50
FET mixer which provides exceptional linearity and isolation with
low loss and no DC current.
PCS CDMA Upconverter / Driver 1710—1910 GHz
Ref. Designation
C2, C4, C5, C9,
North America: Tel. [phone], Fax [phone]
Europe: Tel. [phone], Fax[phone]
Asia/Pacific: Tel.[phone], Fax [phone]
C1, C3 C8
input and output impedance. The mixer is a balanced resistive
C6, C7
L2, L3
R1
R2
U1
U2
U3
U4
L1
J1
DCT114Y
E Series
1000 pF
Connect
270 nH
XFMR
Value
82 nH
33 pF
10 pF
18
68
ETL
DC
RF Bypass
RF / IF Bypass
IF Matching
IF Matching
RF Choke
Source Bias Resistor
Source Bias Resistor for low
current mode
MD59-0022 Upconverter / Driver
Filter LO and Image signals
5:1 Transformer for IF matching
Bipolar transistor for current
switching (ROHM)
10 PIN DC Connector
Purpose
Cross Section View
The IFA input ports are externally matched to 265
impedance using two off chip capacitors and an off chip inductor.
This allows maximum flexibility of intermediate frequency and IF
filter. The IFA output ports are matched to the mixer using off chip
inductors, which are also used for DC bias injection. A matching
network such as that shown below can be used to match both the
input and output of the IFA at the required frequency. The inductor
also acts as a choke for the DC supply line.
The LO input port is internally matched to 50
amplifier amplifies the -10 dBm input signal to the level required to
drive the mixer. Performance can be enhanced slightly with a drive
level of -5 dBm.
All DC supply lines must be properly bypassed at RF frequencies to
obtain optimum performance and at lower frequency to maintain
unconditional stability. Capacitors C1, C3 and C8 are RF bypass
capacitors for the LO amplifier and the driver amplifier. The value
and placement of these capacitors are critical in determining the
frequency response of these amplifiers. Capacitor C11 is a source
bypass capacitor for the second stage of the driver amplifier. The
placement of this capacitor will affect the gain of the amplifier. For
best performance, all the RF bypass capacitors should be placed as
shown in the recommended PCB diagram shown above. Capacitors
C2, C4, C5 and C9 are 1000 pF low frequency DC supply bypass
capacitors. Their value and placement are less critical than the
other capacitors. However, for best results, these capacitors should
be located as close to the package leads as possible.
Recommended PCB Configuration
Ground
Routing
Customer
RF
DC
Components
RF Traces +
MD59-0022
. A LO buffer
differential
V 2.0