ADS7809U Equivalent & Substitute Parts

Part Overview

The ADS7809U is a 16-bit Analog-to-Digital Converter (ADC) manufactured by Texas Instruments, configured as a single-input SAR (Successive Approximation Register) architecture device in a 20-SOIC surface mount package. This part operates with 5V analog and digital supply voltages, supports external and internal reference configurations, and interfaces via SPI/DSP protocols with a 100 kSPS sampling rate.

The ADS7809U is classified as Last Time Buy, indicating end-of-life status. Equivalent and substitute parts are necessary to maintain design continuity and ensure long-term component availability for new production runs and legacy system support.

Substiute Parts

ADS7809U

Texas InstrumentsIn Stock: 9819ADS7809U Datasheet

Current PartRFQ

ADS8509IDW

Texas InstrumentsIn Stock: 2429ADS8509IDW Datasheet

DirectRFQ

ADS8685IPWR

Texas InstrumentsIn Stock: 17932ADS8685IPWR Datasheet

MFR RecommendedRFQ

AD977ARZ

Analog Devices Inc.In Stock: 1571AD977ARZ Datasheet

DirectRFQ

AD977ARZ-REEL

Analog Devices Inc.In Stock: 1482AD977ARZ-REEL Datasheet

DirectRFQ

AD977ACRZ

Analog Devices Inc.In Stock: 808AD977ACRZ Datasheet

MFR RecommendedRFQ

AD977CRZ

Analog Devices Inc.In Stock: 1332AD977CRZ Datasheet

MFR RecommendedRFQ

AD977CRZRL

Analog Devices Inc.In Stock: 743AD977CRZRL Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the ADS7809U is determined by the following critical parameters:

• Resolution: 16-bit ADC architecture
• Sampling Rate: Minimum 100 kSPS (higher rates acceptable for backward compatibility)
• Number of Inputs: Single input configuration
• Data Interface: SPI protocol support (DSP optional)
• Package: 20-SOIC form factor (mechanical and thermal compatibility)
• Supply Voltages: 5V analog and digital supplies
• Reference Configuration: External and/or internal reference support
• Compliance: ROHS3 compliant, EAR99 classification

Substitute parts are grouped into two categories:

Category 1 - Direct Package Equivalents (20-SOIC): Parts maintaining identical package form factor with matching or superior electrical specifications.

Category 2 - Enhanced Performance Alternatives (Different Package): Parts offering improved specifications (higher sampling rate, extended temperature range, integrated PGA) in alternative packages, requiring PCB layout modification.

Parameter Comparison

Engineering Selection Recommendations

Direct Package Replacement (No PCB Modification Required)

For applications requiring identical 20-SOIC package compatibility with minimal design changes, the following parts are suitable:

• ADS8509IDW (Texas Instruments): Maintains 20-SOIC package and 5V supply specifications. Offers 2.5x higher sampling rate (250 kSPS) while preserving single-ended input configuration. Active product status with ROHS3 compliance. Moisture sensitivity improved to MSL 2.

• AD977ARZ / AD977ARZ-REEL (Analog Devices Inc.): Identical electrical specifications to ADS7809U (16-bit, 100 kSPS, single-ended input, 20-SOIC package). Active product status with full ROHS3 compliance. AD977ARZ-REEL variant provides tape & reel packaging for high-volume production.

• AD977CRZ / AD977CRZRL (Analog Devices Inc.): Matching 16-bit resolution and 100 kSPS sampling rate in 20-SOIC package. AD977CRZRL offers tape & reel format. Active status with ROHS3 compliance.

• AD977ACRZ (Analog Devices Inc.): Enhanced sampling rate of 200 kSPS while maintaining 20-SOIC package footprint and 5V supply requirements. Active product with ROHS3 compliance.

Enhanced Performance Alternative (PCB Layout Modification Required)

• ADS8685IPWR (Texas Instruments): Offers superior specifications including 500 kSPS sampling rate, extended operating temperature range (-40 to 125°C), and integrated programmable gain amplifier (PGA). Requires PCB redesign due to 16-TSSOP package (smaller footprint). Digital supply voltage range expanded to 1.65-5.25V. Recommended for new designs prioritizing performance and thermal margin.

All substitute parts maintain ROHS3 compliance, EAR99 export classification, and are manufactured by established semiconductor suppliers with active product status.

Frequently Asked Questions (FAQ)

Q: Can ADS8509IDW directly replace ADS7809U without PCB changes?

A: Yes. Both parts use the 20-SOIC package with identical pinout compatibility. ADS8509IDW provides higher sampling rate (250 kSPS vs. 100 kSPS) while maintaining 5V supply voltages and single-ended input configuration. No circuit modifications are required.

Q: What is the difference between AD977ARZ and AD977ARZ-REEL?

A: Both parts are electrically identical 16-bit, 100 kSPS ADCs in 20-SOIC packages. AD977ARZ is supplied in tube packaging, while AD977ARZ-REEL uses tape & reel format. Selection depends on production volume and assembly equipment compatibility.

Q: Why does ADS8685IPWR require PCB modification?

A: ADS8685IPWR uses a 16-TSSOP package instead of the 20-SOIC package. This smaller form factor has different pin spacing and layout requirements, necessitating PCB redesign. However, it offers superior performance with 500 kSPS sampling rate and extended temperature range.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance and are classified as REACH Unaffected with EAR99 export status, matching the compliance profile of the ADS7809U.

Q: Which substitute offers the best performance upgrade?

A: ADS8685IPWR provides the highest sampling rate (500 kSPS), extended operating temperature range (-40 to 125°C), and integrated PGA functionality. It is suitable for applications requiring enhanced analog signal conditioning and higher conversion speeds, provided PCB layout can accommodate the 16-TSSOP package.

Q: Can I use AD977ACRZ as a direct replacement?

A: Yes. AD977ACRZ maintains the 20-SOIC package and 5V supply specifications. It offers doubled sampling rate (200 kSPS vs. 100 kSPS) compared to ADS7809U, providing performance headroom while preserving mechanical and electrical compatibility.