Product Overview
The WK73R series are wide terminal type flat chip resistors featuring high reliability and performance. They are suitable for various applications including power supply circuits, ECUs, and automotive-related systems. These resistors offer a resistance tolerance of 0.5% and a temperature coefficient of 10010-6/K, and are compatible with both reflow and flow soldering methods. They meet EU-RoHS requirements, with specific exclusions for lead glass in electrode, resistor element, and glass.
Product Attributes
- Brand: KOA
- Product Type: Flat Chip Resistors (Wide Terminal Type)
- Coating Color: Black
- Certifications: EU-RoHS compliant, AEC-Q200 qualified
- Reference Standards: IEC 60115-8, JIS C 5201-8, EIAJ RC-2134C
Technical Specifications
| Type | Size Code | Dimensions (mm) L x W x t | 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 x 0.35 | 0.33W*1 | - | 125 | 100 | 101M | 75V | 100V | TP: 10,000 |
| WK73R1J | 1J (0306) | 1.6 x 0.8 x 0.45 | 0.5W*1 | - | 125 | 100 | 101M | 150V | 200V | TD: 5,000 |
| WK73R2A | 2A (0508) | 2.0 x 1.25 x 0.55 | 0.75W*1 | - | 125 | 100 | 20.5k1M | 200V | 400V | TD: 5,000 |
| WK73R2A | 2A (0508) | 2.0 x 1.25 x 0.55 | 1W*1 | - | 125 | 100 | 1020k | 200V | 400V | TD: 5,000 |
| WK73R2B | 2B (0612) | 3.2 x 1.6 x 0.6 | 0.75W | 70 | 125 | 100 | 101M | - | - | TP: 5,000 |
| WK73R2B | 2B (0612) | 3.2 x 1.6 x 0.6 | 1W*1 | - | 115 | 100 | 109.76k | - | - | TP: 5,000 |
| WK73R2H | 2H (1020) | 5.0 x 2.5 x 0.75 | 1W | 70 | 125 | 100 | 10430k | - | - | TE: 4,000 |
| WK73R2H | 2H (1020) | 5.0 x 2.5 x 0.75 | 1W | 70 | 125 | 200 | 432k1M | - | - | TE: 4,000 |
| WK73R2J | 2J (1218) | 4.6 x 3.1 x 0.4 | 1W | 70 | 100 | 100 | 10510k | - | - | TE: 4,000 |
| WK73R2J | 2J (1218) | 4.6 x 3.1 x 0.4 | 1W | 70 | 100 | 200 | 511k1M | - | - | TE: 4,000 |
| WK73R3A | 3A (1225) | 6.3 x 3.1 x 0.45 | 1.5W | 70 | 125 | 100 | 10330k | - | - | TE: 4,000 |
| WK73R3A | 3A (1225) | 6.3 x 3.1 x 0.45 | 1.5W | 70 | 125 | 200 | 332k1M | - | - | TE: 4,000 |
| WK73R3A | 3A (1225) | 6.3 x 3.1 x 0.45 | 2W*1 | - | 115 | 100 | 10330k | - | - | TE: 4,000 |
| WK73R3A | 3A (1225) | 6.3 x 3.1 x 0.45 | 2W*1 | - | 115 | 200 | 332k1M | - | - | TE: 4,000 |
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(2% + 0.005 ) | 0.2 | - | Rated voltage2.5 for 5s (WK73R1E, WK73R2A, WK73R2B, WK73R3A) Rated voltage2.0 for 5s (Other types) |
| Resistance to soldering heat | R(1% + 0.005 ) | 0.2 | - | 2605, 10s1s |
| Terminal strength (Bending test) | R(1% + 0.005 ) | 0.1 | - | Holding point 90mm, Bending 1 time. Bending 5mm |
| Rapid change of temperature | R(0.5% + 0.005 ) | 0.3 | - | -55 (30min.) /+125 (30min.) 100 cycles |
| Moisture resistance | R(3% + 0.005 ) (1E) R(2% + 0.005 ) (others) | 1 (1E) 0.2 (others) | - | 402, 90%95%RH, 1000h 1.5h ON/0.5h OFF cycle |
| Endurance at 70 | R(3% + 0.005 ) (1E) R(2% + 0.005 ) (others) | 1 (1E) 0.2 (others) | - | 702, 1000h 1.5h ON/0.5h OFF cycle |
| High temperature exposure | R(1% + 0.005 ) | 0.2 | - | +155, 1000h |
Applications
- Power supply, ECU etc.
- Automotive related applications
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.
2410121658_KOA-WK73R3ATTE680J_C346173.pdf
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