Anonymous Verified Buyer
" Very responsive and helpful, competitive pricing. Good source! "
July 2025
USB-5681
USB-5681, 10 MHz to 18 GHz, 50 kHz Bandwidth, RF Power Sensor Device
Actual item may vary if no part number is provided on quote request.
✔ 2 Year Warranty Included
✔ Free Domestic Ground Shipping
✔ NIST Calibration Available
Andrew Gar**** Verified Buyer
" Amazing to work with and had my order within 1 week after purchasing with all NI certs and data that were needed. "
March 2025
Said Sai**** Verified Buyer
" Competent contact for highly specialized components. The support team is very knowledgeable. Many thanks for the help and the fast shipping! "
January 2025
Bob C**** Verified Buyer
" Jason was able to get our emergency situation taken care of quickly and professionally. "
May 2025
Gregg Flecki**** Verified Buyer
" Great service and great products. This is my 2nd time using Apex Waves, truly impressed. "
January 2025
Carol Zimme**** Verified Buyer
" Very responsive and helpful, competitive pricing. Good source! "
July 2025
Andrew Gar**** Verified Buyer
" Amazing to work with and had my order within 1 week after purchasing with all NI certs and data that were needed. "
March 2025
Said Sai**** Verified Buyer
" Competent contact for highly specialized components. The support team is very knowledgeable. Many thanks for the help and the fast shipping! "
January 2025
Bob C**** Verified Buyer
" Jason was able to get our emergency situation taken care of quickly and professionally. "
May 2025
Gregg Flecki**** Verified Buyer
" Great service and great products. This is my 2nd time using Apex Waves, truly impressed. "
January 2025
National Instruments USB-5681 RF Power Sensor Device
The USB-5681 (part number: 781214-01) from National Instruments is a compact but powerful RF Power Sensor Device. Designed with maximum measurement precision in a conveniently small package, the NI USB-5681 is especially well suited for deployment in mobile applications. The device is capable of operating in two modes: hardware-triggered and software-triggered.
The USB-5681 RF Power Sensor Device is a favorite for wideband applications, as it supports a wide range of frequencies and operates within the frequency ranging of 10 MHz to 18 GHz. The compatible input signal strength for the Power Sensor Device is in the range of – 40 dBm to + 20 dBm. This overall range is categorized in two sub-ranges: +20 dBm to -7 dBm and -7 dBm to -40 dBm for the measurement results. The USB-5681 features a bandwidth support of 50 kHz between signal and channel, and it has a measurement speed of 100 S/s. The typical level of uncertainty in the linearity of the measurements performed by the device is less than 3 %.
The USB-5681 is designed according to the safety standards of IEC 61010-1, EN 61010-1, UL 61010-1, CSA C22.2 No. 61010-1. During operation, the Power Sensor Device requires an input of 5 VDC voltage from the host USB alongside 450 mA of current. The damage protections of the module permit a maximum voltage in the range of ±20 VDC and an absolute power of +30 dBm at the RF port.
Physically, the model weighs in at 0.51 lb (230 g). When the RF connector and silicone cover are removed, the dimensions of USB-5681 measure 25 mm × 45 mm × 110 mm. The environmental specifications are designed to safeguard the device against damage from external factors, and they include an operating temperature range of 0 to 50 °C and a storage temperature range of -40 °C to +71 °C. The relative humidity range suitable for operating conditions depends on the specific temperature. For 50 °C, the noncondensing relative humidity is 45%. It measures at 75% and 95% for 40 °C and 30 °C respectively.
The USB-5681 has been declared Obsolete by National Instruments, but the RF Power Sensor Device will remain available with Apex Waves in perpetuity for both Purchase and Repairs!
| Model | USB-5681 |
|---|---|
| Manufacturer | National Instruments |
| Part Number | 781214-01 |
| Type | RF Power Sensor Device |
| Frequency Range | 10 MHz to 18 GHz |
| Input Range | -40 dBm to +20 dBm |
| Calibration Interval | 1 year |
| Typical Current | 450 mA |
| Dimensions | 0.9 x 1.77 x 4.22 in. |
| Weight | 0.51 lb. |
| USB-5681 Manual | User Manual and Maintenance Manual Available for Download |
| Price | Contact a sales representative for a quote. |
Associated part numbers for USB-5681:
National Instruments USB-5681 Frequently Asked Questions
Question: What trigger sources are there for the device?
Answer: The trigger sources of the USB-5681 are immediate, external, internal, and software.
Question: What is the operating shock of the USB-5681?
Answer: The USB-5681 has an operating shock with a 30 g peak, an 11 ms pulse, and is half-sine.
Question: What is the system measurement resolution for the device?
Answer: The USB-5681 has a resolution of 0.01 dB.
Question: How many slots does the Power Sensor have in Time Slot Mode?
Answer: There are a maximum of 128 slots in Time Slot Mode.
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Eligible returns may be accepted within 30 days at Apex Waves’ discretion. A 25% restocking fee applies; non-refundable and built-to-order products are excluded.
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