ADS7800AH Equivalent & Substitute Parts

Part Overview

The ADS7800AH is a 12-bit Analog to Digital Converter manufactured by Texas Instruments, designed for single-ended input data acquisition applications. This device features a Successive Approximation Register (SAR) architecture with an internal reference and operates at a sampling rate of 333 kSPS. The ADS7800AH is currently in Last Time Buy status, indicating end-of-life production. Finding equivalent substitute parts is necessary to ensure design continuity and maintain supply chain reliability for new production runs and long-term system support.

Substiute Parts

ADS7800AH

Texas InstrumentsIn Stock: 2423ADS7800AH Datasheet

Current PartRFQ

ADS8661IPWR

Texas InstrumentsIn Stock: 1866ADS8661IPWR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The ADS8661IPWR is identified as a manufacturer-recommended substitute for the ADS7800AH. Substitution eligibility is determined by the following core parameters:

Matching Parameters:

• Resolution: Both devices are 12-bit ADCs
• Number of Inputs: Both support single input configuration
• Architecture: Both utilize SAR (Successive Approximation Register) topology
• Reference Type: Both feature internal voltage references
• Manufacturer: Both are Texas Instruments products
• Compliance: Both are ROHS3 Compliant and REACH Unaffected

Differing Parameters:

• Sampling Rate: ADS8661IPWR operates at 1.25 MSPS (higher than ADS7800AH at 333 kSPS)
• Input Type: ADS8661IPWR supports Differential, Pseudo-Differential, and Single Ended inputs (expanded capability)
• Data Interface: ADS8661IPWR uses SPI (vs. Parallel in ADS7800AH)
• Package: ADS8661IPWR uses 16-TSSOP Surface Mount (vs. 24-CDIP Through Hole)
• Mounting Type: ADS8661IPWR is Surface Mount (vs. Through Hole)
• Supply Voltage - Digital: ADS8661IPWR operates at 1.65V ~ 3.3V (vs. 5V fixed)
• Operating Temperature Range: ADS8661IPWR extends to -40°C ~ 125°C (vs. -40°C ~ 85°C)
• Product Status: ADS8661IPWR is Active (vs. Last Time Buy)

Parameter Comparison

Engineering Selection Recommendations

The ADS8661IPWR is the manufacturer-recommended substitute for the ADS7800AH. Both devices maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment.

The ADS8661IPWR offers several advantages for new designs: Active product status ensures long-term availability and support, an extended operating temperature range (-40°C ~ 125°C) provides broader environmental compatibility, and higher sampling rate capability (1.25 MSPS) enables faster data acquisition when required.

Design migration requires consideration of interface changes. The shift from parallel to SPI data interface necessitates firmware or microcontroller interface modifications. The transition from through-hole to surface-mount packaging requires PCB layout redesign. The reduced pin count (16-TSSOP vs. 24-CDIP) simplifies board routing. Digital supply voltage flexibility (1.65V ~ 3.3V) allows integration with modern low-power digital systems.

Frequently Asked Questions (FAQ)

Q: Can the ADS8661IPWR directly replace the ADS7800AH without design changes?

A: No. While both are 12-bit SAR ADCs with internal references from Texas Instruments, the ADS8661IPWR requires design modifications. The data interface changes from parallel to SPI, the package changes from 24-CDIP through-hole to 16-TSSOP surface-mount, and digital supply voltage requirements differ. PCB layout and firmware interface code must be updated.

Q: What are the key compatibility criteria between these devices?

A: Compatibility is established through matching resolution (12-bit), single input configuration, SAR architecture, internal reference type, and manufacturer source. Both devices support single-ended input operation and maintain identical regulatory compliance status (ROHS3, REACH unaffected).

Q: Does the higher sampling rate of the ADS8661IPWR affect compatibility?

A: The 1.25 MSPS sampling rate of the ADS8661IPWR exceeds the 333 kSPS rate of the ADS7800AH. This represents enhanced capability rather than a compatibility issue. Designs requiring the original 333 kSPS rate can operate the ADS8661IPWR at lower effective sampling rates through firmware control.

Q: What are the package and mounting implications?

A: The ADS7800AH uses a 24-pin through-hole DIP package suitable for breadboarding and legacy PCB designs. The ADS8661IPWR uses a 16-pin surface-mount TSSOP package, reducing board footprint and pin count but requiring SMT assembly capabilities and PCB redesign.

Q: Are there supply voltage compatibility concerns?

A: The ADS7800AH requires fixed 5V analog and digital supplies. The ADS8661IPWR operates with 4.75V ~ 5.25V analog supply and 1.65V ~ 3.3V digital supply. This flexibility allows the substitute to integrate with modern 3.3V digital systems while maintaining 5V analog signal compatibility.

Q: What is the significance of the Last Time Buy status for the ADS7800AH?

A: Last Time Buy status indicates Texas Instruments has discontinued production of the ADS7800AH. Existing inventory is available for final orders, but long-term supply is not guaranteed. Migration to the active ADS8661IPWR is recommended for designs requiring extended product lifecycle support.