Product Overview
The WK73R series are wide terminal type flat chip resistors featuring high reliability and performance. They are suitable for both reflow and flow solderings and meet EU-RoHS requirements. These resistors are ideal for applications in power supply circuits, ECUs, and automotive-related systems, offering precise resistance values and excellent temperature coefficient.
Product Attributes
- Brand: KOA
- Product Type: Flat Chip Resistors (Wide Terminal Type)
- Coating Color: Black
- Certifications: EU-RoHS compliant (excluding Pb-glass in electrode, resistor element, and glass), AEC-Q200 qualified
- Reference Standards: IEC 60115-8, JIS C 5201-8, EIAJ RC-2134C
- Material: Alumina substrate
Technical Specifications
| Type | Nominal Resistance | Resistance Tolerance | Power Rating | T.C.R. (10-6/K) | Resistance Range () | Max. Working Voltage | Max. Overload Voltage | Taping & Q'ty/Reel (pcs) | Rated Ambient Temp. | Rated Terminal Part Temp. |
| WK73R1E | D:0.5% F:1% | D:0.5% F:1% | 0.33W1 | 100 | 101M | 75V | 100V | TP: 10,000 | - | 125 |
| WK73R1J | D:0.5% F:1% | D:0.5% F:1% | 0.5W1 | 100 | 101M | 150V | 200V | TD: 5,000 | - | 125 |
| WK73R2A | D:0.5% F:1% | D:0.5% F:1% | 0.75W1 | 100 | 20.5k1M | 200V | 400V | TD: 5,000 | - | 125 |
| WK73R2A | D:0.5% F:1% | D:0.5% F:1% | 1W1 | 100 | 1020k | 200V | 400V | TD: 5,000 | - | 125 |
| WK73R2B | D:0.5% F:1% | D:0.5% F:1% | 0.75W | 100 | 101M | - | - | TP: 5,000 | 70 | 125 |
| WK73R2B | D:0.5% F:1% | D:0.5% F:1% | 1W1 | 100 | 109.76k | - | - | TP: 5,000 | 115 | 125 |
| WK73R2H | D:0.5% F:1% | D:0.5% F:1% | 1W | 100 | 10430k | - | - | TE: 4,000 | 70 | 125 |
| WK73R2H | D:0.5% F:1% | D:0.5% F:1% | 1W | 200 | 432k1M | - | - | TE: 4,000 | 70 | 125 |
| WK73R2J | D:0.5% F:1% | D:0.5% F:1% | 1W | 100 | 10510k | - | - | TE: 4,000 | 70 | 100 |
| WK73R2J | D:0.5% F:1% | D:0.5% F:1% | 1W | 200 | 511k1M | - | - | TE: 4,000 | 70 | 100 |
| WK73R3A | D:0.5% F:1% | D:0.5% F:1% | 1.5W | 100 | 10330k | - | - | TE: 4,000 | 70 | 125 |
| WK73R3A | D:0.5% F:1% | D:0.5% F:1% | 1.5W | 200 | 332k1M | - | - | TE: 4,000 | 70 | 125 |
| WK73R3A | D:0.5% F:1% | D:0.5% F:1% | 2W1 | 100 | 10330k | - | - | TE: 4,000 | 115 | 125 |
| WK73R3A | D:0.5% F:1% | D:0.5% F:1% | 2W1 | 200 | 332k1M | - | - | TE: 4,000 | 115 | 125 |
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 | ||
| OverloadShort time | R(0.005 ) | 2 | 0.2 | Rated voltage2.5 for 5s (WK73R1E, WK73R2A, WK73R2B, WK73R3A) Rated voltage2.0 for 5s |
| Resistance to soldering heat | R(0.005 ) | 1 | 0.2 | 2605, 10s1s |
| Terminal strength | R(0.005 ) | 1 | 0.1 | Bending test: 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 |
Dimensions
| Type (Inch Size Code) | Dimensions (mm) | Weight (1000pcs) (g) | ||||
| L | W | c | d | t | ||
| 1E0204 | 0.50.05 | 1.00.05 | 0.10.05 | 0.150.05 | 0.350.05 | 0.65 |
| 1J0306 | 0.80.1 | 1.60.1 | 0.150.1 | 0.20.1 | 0.450.1 | 2.13 |
| 2A0508 | 1.250.15 | 2.00.15 | 0.30.2 | 0.350.2 | 0.550.1 | 4.93 |
| 2B0612 | 1.60.15 | 3.20.2 | 0.30.2 | 0.450.15 | 0.60.1 | 12.0 |
| 2H1020 | 2.50.15 | 5.00.15 | 0.40.2 | 0.750.15 | 30.2 | |
| 2J1218 | 3.10.15 | 4.60.15 | 0.40.2 | 33.3 | ||
| 3A1225 | 6.30.15 | 0.450.2 | 45.6 | |||
Type Designation
| Instance | Example |
| Product Code | WK73R |
| Nominal Resistance | D,F: 4 digits J : 3 digits |
| Resistance Tolerance | D:0.5% F :1% J :5% |
| Power Rating | 1E:0.33W 1J:0.5W 2A:0.75W 1W 2B:0.75W 1W 2H:1W 2J:1W 3A:1.5W 2W |
| Terminal Surface Material | T : Sn |
| Taping | WK73R TP:2mm pitch punch paper TD:4mm pitch punch paper TE:4mm pitch plastic embossed BK:Bulk |
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-WK73R2HTTE36R0F_C340326.pdf
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