Products > Power Supplies > AD637SQ

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RMS-to-DC Converter

  • Package/Case :
  • DIP-14
  • Product Categories :
  • Analog Functions ; RMS to DC Converters
  • RoHs Status:
  • Lead free / RoHS Compliant
  • In-stock:
  • 110


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AD637SQ Product Details

The AD637SQ is a complete, high accuracy, rms-to-dc converter that computes the true rms value of any complex waveform. It offers performance that is unprecedented in integrated circuit rms-to-dc converters and comparable to discrete and modular techniques in accuracy, bandwidth, and dynamic range. The AD637SQ computes the true root mean square, mean square, or absolute value of any complex ac (or ac plus dc) input waveform and gives an equivalent dc output voltage. The true rms value of a waveform is more useful than an average rectified signal because it relates directly to the power of the signal. The rms value of a statistical signal relates to the standard deviation of the signal.

Superior crest factor compensation permits measurements of signals with crest factors of up to 10 with less than 1% additional error. The wide bandwidth of the AD637SQ permits the measurement of signals up to 600 kHz with inputs of 200 mV rms and up to 8 MHz when the input levels are above 1 V rms.

Direct dB value of the rms output with a range of 60 dB is available on a separate pin. An externally programmed reference current allows the user to select the 0 dB reference voltage to correspond to any level between 0.1 V and 2.0 V rms.

A chip select connection on the AD637SQ permits the user to decrease the supply current from 2.2 mA to 350 µA during periods when the rms function is not in use. This feature facilitates the addition of precision rms measurement to remote or handheld applications where minimum power consumption is critical. In addition, when the AD637SQ is powered down, the output goes to a high impedance state. This allows several AD637s to be tied together to form a wideband true rms multiplexer.

The input circuitry of the AD637SQ is protected from overload voltages in excess of the supply levels. The inputs are not damaged by input signals if the supply voltages are lost.

The AD637SQ is laser wafer trimmed to achieve rated performance without external trimming. The only external component required is a capacitor that sets the averaging period. The value of this capacitor also determines low frequency accuracy, ripple level, and settling time.

The on-chip buffer amplifier is used either as an input buffer or in an active filter configuration. The filter can be used to reduce the amount of ac ripple, thereby increasing accuracy.

The AD637SQ is available in accuracy Grade J and Grade K for commercial temperature range (0°C to 70°C) applications, accuracy Grade A and Grade B for industrial range (−40°C to +85°C) applications, and accuracy Grade S rated over the −55°C to +125°C temperature range. All versions are available in hermetically sealed, 14-lead SBDIP, 14-lead CERDIP, and 16-lead SOIC_W packages.



  • High accuracy 0.02% maximum nonlinearity, 0 V to 2 V rms input 0.10% additional error to crest factor of 3
  • Computes True rms Square Mean square Absolute value
  • dB output (60 dB range)
  • Wide bandwidth 8 MHz at 2 V rms input 600 kHz at 100 mV rms
  • Chip select/power-down feature allows Analog three-state operation Quiescent current reduction from 2.2 mA to 350 μA
  • 14-lead SBDIP, 14-lead low cost CERDIP, and 16-lead SOIC_W

AD637SQ Pinout
(Picture: Pinout)

AD637SQ Block Diagram
(Picture: Diagram)

Technical Parameters

  • BW 3 dBtyp | Hz
  • 8M
  • Vin rmsmax | V rms
  • 7
  • Crest Factor Error @ CF=3
  • 0.1
  • Total Error
  • ±0.5 ±0.2 (mV±% of rdg)
  • Voutmax | V
  • 13.5
  • dB Output
  • Yes
  • Istyp | A
  • 2.2m
  • Vs spanmin | V
  • 6
  • Vs spanmax | V
  • 36

AD637SQ Documents

  • AD637 Technical Documentation/Data sheet

AD637SQ Related Products

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Estimated Delivery Time: Sep 22 - Sep 27 days (choose Expedited at checkout).

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  • Lead Time
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  • $2.00-$3.00 (0.10 KG)
  • 7-30 days

Processing Time:Shipping fee depend on different zone and country.


  • Terms of payment
  • Hand Fee
  • Payment Site
  • charge US$30.00 banking fee.
  • charge 4.0% service fee.
  • charge 3.5% service fee.
  • charge US$0.00 banking fee.
  • charge US$0.00 banking fee.

We provide high quality products, thoughtful service and after sale guarantee

  • We have rich products, can meet your various needs.

    We have rich products, can meet your various needs.

  • Minimum order quantity starts from 1pcs.

    Minimum order quantity starts from 1pcs.

  • Lowest international shipping fee starts from US$2.00.

    Lowest international shipping fee starts from US$2.00.

  • 90 days quality guarantee for all products.

    90 days quality guarantee for all products.


  • Step1:Product

    Step1: Products

  • Step2:Vacuum packaging

    Step2: Vacuum Packaging

  • Step3:Anti-static bag

    Step3: Anti-Static Bag

  • Step4:Individual packaging

    Step4: Individual Packaging

  • Step5:Packaging boxes

    Step5: Packaging Boxes

  • Step6:bar-code shipping tag

    Step6: Bar-Code Shipping Tag

All the products will packing in anti-staticbag. Ship with ESD antistatic protection.

Outside ESD packing’s lable will use ourcompany’s information: Part Mumber, Brand and Quantity.

We will inspect all the goods before shipment,ensure all the products at good condition and ensure the parts are new originalmatch datasheet.

After all the goods are ensure no problems afterpacking, we will packing safely and send by global express. It exhibitsexcellent puncture and tear resistance along with good seal integrity.

Jotrin ESD packing


1.We provide 90 days warranty.

2.If some of the items you received aren't of perfect quality, we would resiponsibly arrange your refund or replacement. But the items must remain their orginal condition.


Q: How does Jotrin guarantee that AD637SQ is the original manufacturer or agent of AD?
We have a professional business development department to strictly test and verify the qualifications of AD original manufacturers and agents. All AD suppliers must pass the qualification review before they can publish their AD637SQ devices; we pay more attention to the channels and quality of AD637SQ products than any other customer. We strictly implement supplier audits, so you can purchase with confidence.
Q: How to find the detailed information of AD637SQ chips? Including AD original factory information, Analog Functions ; RMS to DC Converters application, AD637SQ pictures?
You can use Jotrin's intelligent search engine, or filter by Analog Functions ; RMS to DC Converters category, or find it through Analog Devices, Inc Information page.
Q: Are the AD's AD637SQ price and stock displayed on the platform accurate?
The AD's inventory fluctuates greatly and cannot be updated in time, it will be updated periodically within 24 hours. After submitting an order for AD637SQ, it is recommended to confirm the order with Jotrin salesperson or online customer service before payment.
Q: Can I place an order offline?
Yes. We accept offline orders.
We can provide order placement service. You only need to log in, click "My Orders" to enter the transaction management, and you will see the "Order Details" interface. After checking it, select all and click "Place Order". In addition, you can enjoy coupons or other selected gifts when placing orders online.
Q: What forms of payment can I use in Jotrin?
TT Bank, Paypal, Credit Card, Western Union, and Escrow is all acceptable.
Q: How is the shipping arranged and track my package?
Customers can choose industry-leading freight companies, including DHL, FedEx, UPS, TNT, and Registered Mail.
Once your order has been processed for shipment, our sales will send you an e-mail advising you of the shipping status and tracking number.
Note: It may take up to 24 hours before carriers will display tracking information. In normal conditions, Express delivery needs 3-5 days, Registered Mail needs 25-60 days.
Q: What is the process for returns or replacement of AD637SQ?
All goods will implement Pre-Shipment Inspection (PSI), selected at random from all batches of your order to do a systematic inspection before arranging the shipment. If there is something wrong with the AD637SQ we delivered, we will accept the replacement or return of the AD637SQ only when all of the below conditions are fulfilled:
(1)Such as a deficiency in quantity, delivery of wrong items, and apparent external defects (breakage and rust, etc.), and we acknowledge such problems.
(2)We are informed of the defect described above within 90 days after the delivery of AD637SQ.
(3)The AD637SQ is unused and only in the original unpacked packaging.
Two processes to return the products:
(1)Inform us within 90 days
(2)Obtain Requesting Return Authorizations
More details about return electronic components please see our Return & Change Policy.
Q: How to contact us and get support, such as AD637SQ datasheet pdf, AD637 pin diagram?
Need any After-Sales service, please feel free contact us:

Analog Devices, Inc

Analog Devices, Inc. was founded by two MIT graduates, Ray Stata and Matthew Lorber in 1965. The same year, the company released its first product, the model 101 op amp, which was a hockey-puck sized module used in test and measurement equipment. In 1967, the company published the first issue of its...
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