1. Products
  2. A/D Converters (ADC)
  3. Precision A/D Converters
  4. Multiplexed A/D Converters
  5. AD7778


Features and Benefits

  • 8-Channel
  • Fast 10-bit ADC
  • 5 V supply
  • Half-Scale Conversion Option
  • Fast Interface Port
  • Power-Down Mode

Product Details

The AD7777 and AD7778 are high speed, multichannel, 10-bit analog-to-digital converters (ADCs) primarily intended for use in R/W head positioning servos found in high density hard disk drives. They have unique input signal conditioning features that make them ideal for use in such single-supply applications.

By setting a bit in a control register within both the 4-channel AD7777 and the 8-channel AD7778, the input channels can be independently sampled or any two channels can be simultaneously sampled. For both the AD7777 and AD7778, the specified input signal range is VBIAS ± VSWING. However, if the RTN pin is biased at, for example, 2 V, the analog input signal range becomes 0 V to 2 V for all input channels (see the Changing the Analog Input Voltage Range section). The bias voltage, VBIAS, is the offset of the midpoint code of the ADC from ground and is supplied either by an onboard reference available to the user (REFOUT) or by an external voltage reference applied to REFIN. The full-scale range (FSR) of the ADC is equal to 2 × VSWING where VSWING is nominally equal to REFIN/2. Additionally, when placed in the half scale conversion mode, the value of REFIN is converted, which allows the channel offsets to be measured.

Control register loading, ADC register reading, channel selection, and the conversion start are under the control of the microprocessor. The twos complement coded ADCs are easily interfaced to a standard 16-bit microprocessor unit bus via their 10-bit data port and standard microprocessor control lines.

The AD7777 / AD7778 are fabricated in linear compatible CMOS (LC2MOS), an advanced, mixed technology process that combines precision bipolar circuits with low power CMOS logic.

The AD7777 is available in a 28-lead, wide-body SOIC package. The AD7778 is available in a 44-lead MQFP.


  • Instrumentation

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
AD7778ASZ Material Declaration Reliability Data 44-Lead MQFP (13.9mm x 10mm)
Wafer Fabrication Data

PCN-PDN Information

Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.

Sample & Buy

Ordering FAQs

See our Ordering FAQs for answers to questions about online orders, payment options and more.


Buy Now Pricing

(**) Displayed Buy Now Price and Price Range is based on small quantity orders.


List Pricing

(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

Please see the latest communication from our CCO regarding lead times.



A Sample link will be shown above, next to the part, only for parts that are included in our sample program. Selecting the Sample button will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Price Table Help