AD7778
PRODUCTIONLC2MOS, High Speed, 8-Channel 10-Bit ADC
- Part Models
- 1
- 1ku List Price
- Starting From $29.70
Overview
- 8-Channel
- Fast 10-bit ADC
- 5 V supply
- Half-Scale Conversion Option
- Fast Interface Port
- Power-Down Mode
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.
APPLICATIONS
- Instrumentation
Documentation
Data Sheet 1
Technical Articles 2
Obsolete Data Sheet 1
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 Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| AD7778ASZ | 44-Lead MQFP (13.9mm x 10mm) |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Oct 18, 2016 - 16_0034 Assembly Relocation of Select LQFP,LQFP_EP,MQFP,TQFP,TQFP_EP Products to Stats ChipPAC China Jiangyin |
||
| AD7778ASZ | PRODUCTION | |
|
Aug 19, 2009 - 07_0024 Package Material Changes for SOT23, MiniSO, MQFP, PDIP, PLCC, SOIC (narrow and wide body), SSOP, TSSOP and TSSOP exposed pad |
||
| AD7778ASZ | PRODUCTION | |
|
Jan 5, 2009 - 07_0077 Certification of STATSChipPAC Shanghai, China and AMKOR Philippines as additional sources for Assembly & Test of QFP Packages |
||
| AD7778ASZ | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.