as shown in Figure 1(c). Adjust-
able limiting is achieved by set-
ting the A pin to a DC voltage
~0.7 volts higher than the de-
sired minimum voltage, and the
C pin to a DC voltage ~0.7 volt
lower than the desired maxi-
mum voltage.
mesh bonds (500–line/inch or
equivalent) should be used at
the RF input and output ports.
These bonds must be kept as
short as possible to minimize
parasitic inductance. DC bias
may be supplied through con-
ventional 0.7–mil gold wire
bonds. In both cases, ther-
mosonic wedge bonding is rec-
ommended.
Applications
The TC231 can be used as a pro-
tection circuit for ESD and DC
transients, as a Reverse Power
Protection (RPP) device, or as
an RF limiter with optional pow-
er detection.
The different modes of use re-
quire different attachments.
These are described under Op-
eration.
If the voltage is not forced, the
capacitor will function as a peak
detector.
As an ESD protection device,
the TC231 can protect ESD sen-
sitive components. The degree
of protection depends on the
protected components charac-
teristics. ESD damage level for
the TC231 by itself is around
2400V using the human body
model.
Biasing
Diodes are ESD sensitive. ESD
preventive measures must be
employed in all aspects of stor-
age, handling and assembly.
ESD precautions, handling con-
siderations, and die attach and
bonding methods are critical
factors in successful diode per-
formance and reliability. Please
refer to Agilent Application
Note #54, "GaAs MMIC ESD, Die
Attach and Bonding Guidelines"
for additional information on
these subjects.
None required for traditional
operation. For adjustable limit-
ing, the bias voltage will set the
limiting value as described un-
der Operation.
Operation
The TC231 has three primary
modes of operation. 10 dBm and
18 dBm limiting can be done
with no active bias required. See
Figures 1(a) & 1(b). Both of
these uses will provide ESD pro-
tection at the limiting value. For
adjustable limiting and detec-
tion, the bias should be applied
Assembly Techniques
See Figure 11 for bond pad loca-
tions.
Epoxy die–attach using a con-
ductive epoxy and solder die–
attach using a fluxless gold–tin
solder preform are both suitable
assembly methods. Gold wire
Not Biased
Not Biased
Biased
DGND1
A1
2
C1
2
DGND2
DGND1 A1
2
C1 DGND2
2
DGND1
A1
2
C1
2
DGND2
IN1
IN2
OUT1
OUT1
IN1
IN1
OUT1
OUT2
OUT2
IN2
OUT2
IN2
2
2
2
2
DGND3
DGND4
A2
C2
2
2
DGND3
DGND4
A2
C2
DGND3
DGND4
A2
C2
10 dBm Limiting
(a)
18 dBm Limiting
(b)
Adjustable Limiting & Detection
(c)
Figure 1.
TC231 Functional Topologies
TC231/rev.3.0
3
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
