DDF3311 Datasheet, PDF (6/6 Pages) API Technologies Corp – PIN Diode Drivers

DD320
DD420
DD620
DD350
DD450
DD650
Three, Four, and Six Channel High Current
Drivers
M ultiple independent medium speed drivers with
separate input logic mode controls. Logic inputs
are true TTL unit loads.
1. Inputs are inverting when M ode control has a logic
high input.
2. Inputs are non-inverting when M ode control has a
logic low input.
3. M ode control and input pins are interchangeable
within any one channel.
4. The negative output current does not vary with \/ee
which should not exceed -5V when driving
grounded anode diodes to avoid high power dissi-
pation in the drivers.
5. The last two digits of the part number signify out-
put current. Other currents are available on
special order.
1
+5V
Output #1
M ode Control #1
Input #1
Output #2
M ode Control #2
Input #2
Output #3
M ode Control #3
Input #3
Ground
11
645
SQ
MAX
DD320/420/620
DD320/420/620
XXXX
TOP VIEW
500 M IN
TYP
22
Vee (-SV to – 15V)
Output #6
M ode Control #6
Input #6
Output #5
M ode Control #5
Input #5
Output #4
M ode Control #4
Input #4
Ground
12
.150
MAX
M ETAL W ELDED PACK AGE
.015
Pkg
Bottom
.067
APPLICATION NOTES
PIN Diode Sw itching Times
PIN diodes are used as RF switches because of their
low off-capacitance/on-resistance product. However,
they store a significant charge during conduction that
must be removed before they will turn off. Typically,
this is specified as storage time (TS), which is made to
look better than it might be by rating it with a high ratio
of reverse (IR) to forward (IF) current. W hen switching
these diodes with a non-spiking driver, the typical TS
will be multiplied by the specified ratio. For example,
the M A 47120 has a TS of 12 ns with IF=20 mA and IR=
200 mA . W ith symmetrical currents as delivered by
high current drivers, the TS becomes 120 ns. High
speed drivers supply a spike of several hundred mA at
turn-on and turn-off to shorten the TS of the PIN diode.
Heat Sinking
The power dissipated in PIN diode switches is conducted
to the bottom of the package. The thin walls leading to
the top of the package represent a high thermal resistance.
The total power in the hybrid is the sum of it own current
drain multiplied by the voltage of each supply plus the output
current of each driver multiplied by the supply voltage less
the VF of the PIN diode.
The total can be substantial especially in the multiple
high current drivers. If your calculations show that the
hybrid should be heat sunk, you may find it convenient
to place it top down on the PC board so that the bottom
of the hybrid may be mounted directly to the metal
case of your package.
Other Diode Drivers
In addition to these standard circuits, Spectrum Microwave produces a wide range of custom-designed drivers. These include a dual
ECL-input driver (DD212) and a 28-channel 50 mA driver (DD2850). Spectrum Microwave is also one of the largest custom hybrid
manufacturers in the United States. Please contact the factory or your local representative for a quote on your driver requirements or
your own custom hybrid circuit.