52 Ohmite Mfg. Co. 1600 Golf Rd., Suite 850, Rolling Meadows, IL 60008 • Tel. 1-866-9-OHMITE • Fax 1-847-574-7522 • www.ohmite.com • info@ohmite.com
TCH35 Series
35 Watt TO220 Style
Thick Film Power Resistors
0.390–0.410"
(9.91–10.41mm)
0.112–0.120"
(2.85–3.05mm)
ø0.139–0.148"
(3.55–3.75mm)
0.046–0.054"
(1.17–1.37mm)
0.027–0.034"
(0.70–0.86mm)
0.500–0.579"
(12.70–14.70mm)
0.190–0.210"
(4.83–5.33mm)
0.047–0.055"
(1.20–1.40mm)
0.230–0.250"
(5.85–6.35mm)
0.571–0.591"
(14.50–15.00mm)
0.157" max.
(5.00mm)
0.022–0.028"
(0.55–0.70mm)
0.159–0.190"
(4.06–4.82mm)
0.080–0.089"
(2.05–2.25mm)
Ohmite’s new TCH35 TO220
package resistor provides 35
watts of steady state power
when properly used in today’s
well defined heat sink applica-
tions.
These very low intuction
resistors are built under pro-
prietary processes that deliver
75% more power handling
capability than other TO-220
package resistors of similar
size.
Standard lead forms are
provided for manual or auto-
matic insertion.
A single screw mounting
tab connects to the heat sink
and should be accompanied
by the use of a thermal com-
pound. The TCH35 Series
offers a low thermal resistance
to the heat sink of <4.28°C/W.
FEATURES
• 35W Power Rating @ 25°C
• Very Low Inductance Design
• Single Screw Mounting
• Low Thermal Resistance to Heat
Sink @ RTH<4.28°C/W
• Resistance Element is
Electrically Insulated from Metal
Heat Sink Mounting Tab
APPLICATIONS
• Switching Power Supplies
• Snubbers
• High Frequency
• Voltage Regulation
• Low Energy Pulse Loading
SPECIFICATIONS
Electrical
Resistance Range: 0.1Ω to 10KΩ
(higher values on request subject
to derating)
Resistance Tolerance:
± 5% standard
± 1% available on request
Temperature Coefficient:
Referenced to 25°C, ∆R taken at
+105°C
10Ω and above ±50 ppm°C
1Ω to 10Ω ±(100ppm + 0.002Ω)/°C
Max. Operating Voltage: 350V
Dielectric Strength: 1800 VAC
Insulation Resistance: 10GΩ min.
Momentary Overload: 2x rated
power for 5 seconds as long as
the applied voltage ≤1.5 times the
continuous operating voltage,
where ∆R ±(0.3% + 0.01Ω) max
Lead Material: Tinned Copper
Maximum Torque: 0.9 Nm
Power Rating: 35 Watts @ 25°C
Case Temperature. See Derating
Curve
Working Temperature Range:
-55°C to +175°C
PERFORMANCE DATA
Load Life MIL-R-39009, 2000 Hours @ Rated Pwr ∆R = ± (1.0% + 0.01) Ω
Thermal Shock MIL-R-STD-202, Method 107, Cond. F ∆R = ± (0.3% + 0.01) Ω max
High Freq Vibration MIL-R-STD-202, Method 204, Cond. D ∆R = ± (0.2% + 0.01) Ω max
Terminal Strength MIL-R-STD-202, Method 211, Cond. A ∆R = ± (0.2% + 0.01) Ω max
(Pull Test) 2.4N
Moisture Resistance MIL-R-STD-202, Method 106 ∆R = ± (0.5% + 0.01) Ω max
TAH20 Series
20 Watt TO220 Style
Thick Film Power Resistors
0.400–0.420"
(10.15–10.67mm)
0.630–0.650"
(16.00–16.52mm)
0.450–0.550"
(11.43–13.97mm)
0.100–0.160"
(2.54–4.06mm)
0.045–0.055"
(1.14–1.40mm)
0.026–0.034"
(0.66–0.86mm)
0.190–0.210"
(4.82–5.34mm)
0.115–0.135"
(2.92–3.44mm)
0.016–0.024"
(0.40–0.60mm)
0.060–0.080"
(1.52–2.04mm)
The TAH20 is a completely
encapsulated thick film resistor
in the TO220 package outline.
Rated for 20 watts @ 25°C
case temperature, these resis-
tors are electrically isolated,
and molded in a high tempera-
ture case.
Designed for heat sink
mounting, the symmetrical
package is ready for use with
snap-on style heat sinks (we
recommend use of thermal
grease). The TAH20 Series is
very low intuction, and avail-
able in a wide range of resist-
ance values in standard 5%
tolerance, and 1% available by
special order.
FEATURES
• 20 Watt Power Rating at 25°C
Case Temperature
• High Pulse Tolerant Design
• Quick-snap Molded Package
• Very Low Inductance Design
• Resistor Package Electrically
Isolated from Heat Sink
• Low Thermal Resistance to Heat
Sink @ RTH<6.25°C/W
• Tube Packaging Available
APPLICATIONS
• Frequency Conversion
• High Frequency Balancing
• Snubbers
SPECIFICATIONS
Electrical
Resistance Range: 0.05Ω to
10KΩ, other values available
upon request
Tolerance: ±5% stock
1% Available on request
Temperature Coefficient:
Referenced to 25°C,
∆R taken at +105°C;
1 to 10Ω: ±(100ppm+0.002Ω)/°C
10Ω & up: ±50ppm/°C
Max Operating Voltage: 350V
Dielectric Strength: 1,800 VAC
Power Rating: 20W @ 25°C
Case Temperature. See derating
curve
Insulation Resistance:
10GΩ min.
Momentary Overload:
2x rated power for 5 seconds
where applied voltage ≤1.5 times
max. operating voltage. ∆R ±
(0.3% + 0.001Ω) max.
Lead Material: Tinned Copper
Mounting: Requires the use of a
snap-on style heat sink. A ther-
mal compound should be proper-
ly applied.
PERFORMANCE DATA
Load Life MIL-R-39009, 2000 Hours @ Rated Pwr ∆R = ±(1.0% + 0.001) Ω
Thermal Shock MIL-R-STD-202, Method 107, Cond. F ∆R = ±(0.3% + 0.001) Ω max
High Freq Vibration MIL-R-STD-202, Method 204, Cond. D ∆R = ±(0.2% + 0.001) Ω max
Terminal Strength MIL-R-STD-202, Method 211, Cond. A ∆R = ±(0.2% + 0.001) Ω max
(Pull Test) 2.4N
Moisture Resistance MIL-R-STD-202, Method 106 ∆R = ±(0.5% + 0.01) Ω max
