Product Overview
The WK73R series are wide terminal type flat chip resistors featuring high reliability and performance. They offer a resistance tolerance of 0.5% and a temperature coefficient of 10010-6/K. These resistors are suitable for both reflow and flow solderings and comply with EU-RoHS requirements. They are qualified for AEC-Q200, making them ideal for automotive applications.
Product Attributes
- Brand: KOA
- Product Type: Flat Chip Resistors (Wide Terminal Type)
- Coating Color: Black
- Certifications: EU-RoHS compliant, AEC-Q200 qualified
- Material: Thick Film
Technical Specifications
| Type | Size Code | Dimensions (mm) L x W | Power Rating | Rated Ambient Temp. | Rated Terminal Part Temp. | T.C.R. (10-6/K) | Resistance Range () | Max. Working Voltage | Max. Overload Voltage | Taping & Q'ty/Reel (pcs) |
| WK73R1E | 1E (0204) | 1.0 x 0.5 | 0.33W*1 | - | 125 | 100 | 101M | 75V | 100V | 10,000 (TP) |
| WK73R1J | 1J (0306) | 1.6 x 0.8 | 0.5W*1 | - | 125 | 100 | 101M | 150V | 200V | 5,000 (TD) |
| WK73R2A | 2A (0508) | 2.0 x 1.25 | 0.75W*1 | - | 125 | 100 | 20.5k1M | 200V | 400V | 5,000 (TD) |
| WK73R2A | 2A (0508) | 2.0 x 1.25 | 1W*1 | - | 125 | 100 | 1020k | 200V | 400V | 5,000 (TD) |
| WK73R2B | 2B (0612) | 3.2 x 1.6 | 0.75W | 70 | 125 | 100 | 101M | - | - | 5,000 (TE) |
| WK73R2B | 2B (0612) | 3.2 x 1.6 | 1W*1 | - | 115 | 100 | 109.76k | - | - | 5,000 (TE) |
| WK73R2H | 2H (1020) | 5.0 x 2.5 | 1W | 70 | 125 | 100 | 10430k | - | - | 4,000 (TE) |
| WK73R2H | 2H (1020) | 5.0 x 2.5 | 1W | - | 115 | 200 | 432k1M | - | - | 4,000 (TE) |
| WK73R2J | 2J (1218) | 4.6 x 3.1 | 1W | 70 | 100 | 100 | 10510k | - | - | 4,000 (TE) |
| WK73R2J | 2J (1218) | 4.6 x 3.1 | 1W | - | 115 | 200 | 511k1M | - | - | 4,000 (TE) |
| WK73R3A | 3A (1225) | 6.3 x 3.1 | 1.5W | 70 | 125 | 100 | 10330k | - | - | 4,000 (TE) |
| WK73R3A | 3A (1225) | 6.3 x 3.1 | 2W*1 | - | 115 | 100 | 10330k | - | - | 4,000 (TE) |
| WK73R3A | 3A (1225) | 6.3 x 3.1 | 2W*1 | - | 115 | 200 | 332k1M | - | - | 4,000 (TE) |
Applications
- Power supply circuits
- ECU (Electronic Control Unit)
- Automotive related applications
Performance
| Test Items | Performance Requirements | Limit | Typical | Test Methods |
| Resistance | Within specified tolerance | - | - | At 25 |
| T.C.R. | Within specified T.C.R. | - | - | +25/55 and +25/125 |
| Overload (Short time) | R(0.005 ) | 2 | 0.2 | WK73R1E, WK73R2A, WK73R2B, WK73R3A: Rated voltage2.5 for 5s WK73R2B, WK73R2H, WK73R2J, WK73R3A: Rated voltage2.0 for 5s |
| Resistance to soldering heat | R(0.005 ) | 1 | 0.2 | 2605, 10s1s |
| Terminal strength (Bending test) | R(0.005 ) | 1 | 0.1 | Holding point 90mm, Bending 1 time. Bending 5mm |
| Rapid change of temperature | R(0.005 ) | 0.5 | 0.3 | -55 (30min.) /+125 (30min.) 100 cycles |
| Moisture resistance | R(0.005 ) | 3:1E 2:another | 1:1E 0.2:another | 402, 90%95%RH, 1000h (1.5h ON/0.5h OFF cycle) |
| Endurance at 70 | R(0.005 ) | 3:1E 2:another | 1:1E 0.2:another | 702, 1000h (1.5h ON/0.5h OFF cycle) |
| High temperature exposure | R(0.005 ) | 1 | 0.2 | +155, 1000h |
Precautions for Use
The substrate of chip resistors is alumina. Cracks may occur at the connection of solder (solder fillet portion) due to the difference of the coefficient of thermal expansion from a mounting board when heat stress like heat cycle, etc. are repeatedly given to them. Care should be taken to the occurrence of the cracks when the change in ambient temperature or ON/OFF of load is repeated, especially when WK73 series which have self-heating. The occurrence of the crack by heat stress may be influenced by the size of a pad, solder volume, heat radiation of mounting board etc., so please pay careful attention to designing when a big change in ambient temperature and conditions for use like ON/OFF of load can be assumed.
2409300002_KOA-WK73R3ATTE820J_C340338.pdf
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