2004 Littelfuse, Inc. E8 - 1 http://www.littelfuse.com
Thyristor Product Catalog +1 972-580-7777
Diac
HT and ST Series
E8
General Description
Teccor’s HT and ST Series of bilateral trigger diacs offer a range
of voltage characteristics from 27 V to 70 V.
A diac semiconductor is a full-wave or bidirectional thyristor. It is
triggered from a blocking state to a conduction state for either
polarity of applied voltage whenever the amplitude of applied
voltage exceeds the breakover voltage rating of the diac.
The Teccor line of diacs features glass-passivated junctions to
ensure long-term reliability and parameter stability. Teccor’s
glass offers a rugged, reliable barrier against junction
contamination.
The diac specifications listed in this data sheet are for standard
products. Special parameter selections such as close tolerance
voltage symmetry are available. Consult the factory for more
information about custom design applications.
R
o
H
S
Features
•RoHS Compliant
• Bilateral triggering device
• Glass-passivated junctions
• Wide voltage range selections
ST Series
• Epoxy SMT package
• High-temperature, solder-bonded die attachment
HT Series
• DO-35 trigger package
• Pre-tinned leads
E8
DO-214
DO-35
Diac Data Sheets
http://www.littelfuse.com E8 - 2 2004 Littelfuse, Inc.
+1 972-580-7777 Thyristor Product Catalog
General Notes
• Lead solder temperature is +230 °C for 10-second maximum;
≥1/16" (1.59 mm) from case.
• See “Package Dimensions” section of this catalog.
Electrical Specification Notes
(1) Breakover voltage symmetry as close as 1 V is available from the
factory on these products.
(2) See Figure E8.4 and Figure E8.5 for test circuit and waveforms.
(3) Typical switching time is 900 nano-seconds measured at IPK
(Figure E8.4) across a 20 Ω resistor (Figure E8.5). Switching time
is defined as rise time of IPK between the 10% to 90% points.
(4) See V-I Characteristics.
Bilateral Trigger DIAC Specifications
• Maximum Ratings, Absolute-Maximum Values
– Maximum Trigger Firing Capacitance: 0.1 µF
– Device dissipation (at TA = -40 °C to +40 °C):
250 mW for DO-35 and 300 mW for DO-214
– Derate above +40 °C:
3.6 mW/°C for DO-35 and 3 mW/°C for DO-214
• Temperature Ranges
Storage: -40 °C to +125 °C
Operating (Junction): -40 °C to +125 °C
V-I Characteristics
* Mounted on 1 cm2 copper foil surface; two-ounce copper foil
Electrical Characteristics TC = 25°C
Part No. VBO ∆VBO VBB IBO ITRM
DO-35 DO-214
Breakover Voltage
(Forward and
Reverse)
Volts
Breakover Voltage
Symmetry
∆VBO =
[ | +VBO | - | - VBO | ]
Volts
Dynamic
Breakback
Voltage
(3)
| ∆V± |
Volts
Peak Breakover
Current
at
Breakover
Voltage
µAmps
Peak Pulse
Current
for 10 µs
120 PPS
TA ≤40 °C
Amps
MIN MAX MAX MIN MAX MAX
HT-32 ST-32 27 37 3 (1) 10 (2) 25 2
HT-32A / HT-5761 28 36 2 (1) 7 at 10 mA (4) 25 2
HT-32B / HT-5761A ST-32B 30 34 2 (1) 7 at 10 mA (4) 25 2
HT-34B ST-34B 32 36 2 (1) 10 (2) 25 2
HT-35 ST-35 30 40 3 (1) 10 (2) 25 2
HT-36A / HT-5762 ST-36A 32 40 2 (1) 7 at 10 mA (4) 25 2
HT-36B ST-36B 34 38 2 (1) 10 (2) 25 2
HT-40 ST-40 35 45 3 (1) 10 (2) 25 2
HT-60 56 70 4 20 (2) 25 1.5
HT and ST Series Thermal Resistance
Junction to Lead - RθJL: °C/W
Junction to Ambient [RθJA]: °C/W
(based on maximum lead temperature of
90 °C for DO-214 and 85 °C for DO-35 devices)
Y Package
DO-35
S Package
DO-214
100 [278] °C/W 65 °C/W *
10 mA
Breakover
Current
I
BO
-V
BO
Voltage
Current
Breakover
Voltage
V
BO
+V
BO
V
Data Sheets Diac
2004 Littelfuse, Inc. E8 - 3 http://www.littelfuse.com
Thyristor Product Catalog +1 972-580-7777
Figure E8.1 Typical Diac/Triac Full-wave Phase Control Circuit Using
Lower Voltage Diacs.
Figure E8.2 Repetitive Peak On-state Current versus Pulse Duration
120 V ac
60 Hz
LOAD — Up to 1500 W
3.3 k
200 k
0.1 µF
100 V
HT-35
Bilateral
Trigger
Diac
Triac
Q2015L5 MT2
MT1
G
12
46 200 4006001000 2000 4000 10000
.001
.002
.003
.005
0.1
0.2
0.3
3.0
0.5
5.0
.01
0.02
0.03
0.05
1.0
10
2.0
Repetitive Peak On-state Current (ITRM) – Amps
Base Pulse Duration – µs
Safe Operating
Area
10 20 40 60 100
PULSE REPETITION RATE = 120 pps
TA = 40 ˚C
HT-60
HT-32x, -34x, -35, -36x, -40
HT-5761, -5761A, -5762
ST-32x, -34x, -35, -36x, -40
Diac Data Sheets
http://www.littelfuse.com E8 - 4 2004 Littelfuse, Inc.
+1 972-580-7777 Thyristor Product Catalog
Figure E8.3 Normalized VBO Change versus Junction Temperature
Figure E8.4 Test Circuit Waveforms (Refer to Figure E8.5.)
Figure E8.5 Circuit Used to Measure Diac Characteristics
(Refer to Figure E8.4.)
Figure E8.6 Peak Output Current versus Triggering Capacitance
(Per Figure E8.5 with RL of 20 Ω)
-8
-6
-4
-2
0
+2
+4
+6
+8
-40 -20 0 +20 +40 +60 +80 +100 +120 +140
Junction Temperature (TJ) – ˚C
Percentage of VBO Change – %
ST Series
HT Series
∆V+
∆V-
VC
0
-VBO
IL
+IPK
0t
-IPK
t
+VBO
Typical pulse base width is 10 µs
120 V rms
60 Hz
47 k
D.U.T.
RL
20 Ω
1%
VC
100 k
*
CTIL
0.1 µF
* Adjust for one firing in each half cycle. D.U.T. = Diac
Triggering Capacitance (C
T
) – µF
Peak Output Current (I
PK
) – mA
.01 .02 .03 .04 .05 .06 .07 .08 .09
0
50
100
150
200
250
300
Typical (35 V Device)
.10
