ADS7805PB - 16-Bit 100kHz SAR ADC, ±10V, 28-PDIP | Texas Instruments
MPN: ADS7805PB ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.45 | $18.45 |
| 10 | $16.7 | $167.00 |
| 100 | $14.25 | $1,425.00 |
| 500 | $12.4 | $6,200.00 |
| 1,000 | $10.95 | $10,950.00 |
ADS7805PB Overview
A successive-approximation register (SAR) ADC is a class of precision converter that uses a binary-search algorithm against an internal capacitor-based charge-redistribution DAC to determine each bit of the output code one cycle at a time. SAR ADCs are valued in the broader data-converter hierarchy for combining 14–18 bit resolution, no pipeline latency, and excellent DC accuracy with moderate (tens to hundreds of kSPS) throughput. The ADS7805 family sits between slower integrating converters (e.g., AD7730) and high-speed pipeline ADCs (e.g., ADS62Pxx), making it a workhorse for industrial signal acquisition.
Key specifications of the ADS7805PB include 100 kHz minimum sampling rate, ±10 V bipolar or 0–4 V unipolar input range, 86 dB minimum SINAD at 20 kHz input, low 10 µs typical conversion time, internal 2.5 V reference (with option for external reference), and 3-state parallel outputs for direct µP/microcontroller bus connection. The 28-pin PDIP (N) plastic DIP package supports through-hole assembly, breadboard prototyping, and legacy card cages that still require socketed parts.
Architecturally, the ADS7805PB uses CMOS capacitor-based charge-redistribution techniques for both the SAR DAC and the sample-and-hold function, eliminating the need for external trimming. The internal clock, reference, and self-calibration logic keep the part simple to apply while still achieving ±1 LSB linearity and low aperture uncertainty.
Typical applications include industrial process control (PLC analog input modules), multi-channel data-acquisition systems, precision instrumentation, weigh-scale and transducer readouts, and legacy medical/analytical instrument front-ends. The wide ±10 V input range lets designers connect directly to ±10 V industrial transmitters without external signal conditioning.
When designing with this ADC, place a 10 µF tantalum and 0.1 µF ceramic bypass close to the +VCC and -VCC supply pins; the internal reference also benefits from a 10 µF tantalum at REF. Decoupling and a clean analog ground are essential to hit the 86 dB SINAD specification in noisy industrial environments.
This page synthesizes distributor pricing, drop-in same-package alternatives, and PCB/grounding design notes specific to the ADS7805PB that are not collected on any single manufacturer or distributor page.
Drop-in alternatives for ADS7805PB — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ADS7805PB (same form factor and footprint) — differing in Package, Supply Voltage, Architecture, Data Interface, SINAD.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADS7805PBG4
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7805P
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
ADS7821PB
✅ Drop-In📋 Reference alternative (not in catalog)
ADS7805PB Maximum Ratings & Electrical Characteristics
| Resolution | 16 bit |
| Number of Channels | 1 |
| Converter Type | SAR (Successive Approximation Register) |
| Sampling Rate (min) | 100 kHz |
| Conversion Time (typ) | 10 µs |
| Analog Input Range | ±10 V (bipolar) or 0 V to 4 V (unipolar) |
| SINAD (min) | 86 dB at 20 kHz input |
| Input Sample-and-Hold | On-chip, capacitor-based |
| Reference | Internal 2.5 V with option for external reference |
| Output Interface | 16-bit parallel, 3-state outputs |
| Clock | Internal (external option available) |
| Supply Voltage (analog) | ±5 V dual or +5 V single |
| Package | 28-pin PDIP (N) |
| Mounting Type | Through-Hole |
| Operating Temperature | -40 °C to +85 °C |
| RoHS Status | Compliant |
ADS7805PB Pin Configuration
| Pin 1 | VCC — +5 V analog supply |
| Pin 2 | IN+ — Analog input, positive |
| Pin 3 | IN- — Analog input, negative (typically GND for single-ended ±10 V input) |
| Pin 4 | AGND — Analog ground |
| Pin 5 | REF — Reference input/output (internal 2.5 V reference) |
| Pin 6 | CAP — Reference bypass capacitor |
| Pin 7 | VSS — -5 V analog supply (or AGND for single-supply operation) |
| Pin 8 | DGND — Digital ground |
| Pin 9 | DB15 (MSB) — Parallel data output, bit 15 (most significant) |
| Pin 10 | DB14 — Parallel data output, bit 14 |
| Pin 11 | DB13 — Parallel data output, bit 13 |
| Pin 12 | DB12 — Parallel data output, bit 12 |
| Pin 13 | DB11 — Parallel data output, bit 11 |
| Pin 14 | DB10 — Parallel data output, bit 10 |
| Pin 15 | DB9 — Parallel data output, bit 9 |
| Pin 16 | DB8 — Parallel data output, bit 8 |
| Pin 17 | DB7 — Parallel data output, bit 7 |
| Pin 18 | DB6 — Parallel data output, bit 6 |
| Pin 19 | DB5 — Parallel data output, bit 5 |
| Pin 20 | DB4 — Parallel data output, bit 4 |
| Pin 21 | DB3 — Parallel data output, bit 3 |
| Pin 22 | DB2 — Parallel data output, bit 2 |
| Pin 23 | DB1 — Parallel data output, bit 1 |
| Pin 24 | DB0 (LSB) — Parallel data output, bit 0 (least significant) |
| Pin 25 | TAG — Tag input for data-tagging (used with R/C) |
| Pin 26 | R/C — Read/Convert input (combined control) |
| Pin 27 | CS — Chip-select (active low) |
| Pin 28 | BUSY — Converter-busy output (active high during conversion) |
Typical Applications
ADS7805PB is suitable for 6 applications: Industrial Process Control / PLC Analog Input Module, Multi-Channel Data Acquisition Systems, Precision Weigh-Scale and Transducer Readout, Test and Measurement Instrumentation, Medical and Analytical Instrument Front-End, Legacy Industrial Control Card-Cage Replacement.
Industrial Process Control / PLC Analog Input Module
The ADS7805PB's ±10 V bipolar input directly accepts the standard industrial transmitter signal chain used in PLC analog-input modules, eliminating external signal conditioning and reducing BOM cost. According to the TI ADS7805 datasheet, its 86 dB SINAD at 20 kHz input provides enough dynamic range for 4–20 mA loop receivers and thermocouple front-ends when scaled through precision resistors. The 100 kHz sampling rate lets a single ADS7805PB multiplex four or eight channels with comfortable per-channel settling headroom in a deterministic SAR cycle with no pipeline latency. The 28-PDIP through-hole package survives legacy card-cage vibration profiles and supports socketed field-replacement in factory automation lines.
Recommended
Multi-Channel Data Acquisition Systems
The ADS7805PB's 10 µs conversion time and SAR architecture deliver 100 kSPS throughput with no pipeline latency, ideal for multiplexed multi-channel data-acquisition front-ends. According to the TI ADS7805 datasheet, the on-chip S/H, reference, and clock simplify PCB layout when paired with an external 8-to-1 analog multiplexer; only a single ADS7805PB is needed per board. The 86 dB SINAD is sufficient for general-purpose instrumentation such as vibration, strain-gauge, and weigh-scale readouts. The parallel 3-state output interface glues directly to legacy ISA-bus and 80C196-style µC backplanes common in industrial DAQ cards.
Precision Weigh-Scale and Transducer Readout
The ADS7805PB's 16-bit resolution and 86 dB SINAD make it well suited to weigh-scale, load-cell, and pressure-transducer readouts where small differential signals must be digitized with low noise. According to the TI ADS7805 datasheet, the part's bipolar ±10 V input range and on-chip 2.5 V reference combine with an external instrumentation amplifier (e.g., INA128) for high-CMRR bridge-sensor readout. The single-shot SAR conversion with no latency simplifies tare-zero calibration routines in real time, and the DIP package supports easy in-fixture calibration on the production line. Designers using the ADS7805PB in transducer readouts typically pair it with a low-drift external reference such as the REF5040 to push noise below 1 LSB.
Recommended
Test and Measurement Instrumentation
The ADS7805PB's 16-bit resolution, ±10 V input, and 100 kHz throughput make it a precision front-end for bench-top and laboratory test equipment such as digital multimeters, chart recorders, and stimulus-response analyzers. According to the TI ADS7805 datasheet, the 86 dB SINAD delivers more than 14 effective bits at low input frequencies, enough for general-purpose precision measurement. The parallel interface eases integration into instruments with FPGA or microcontroller display controllers, and the DIP package supports hand-soldered prototypes used in R&D environments. Typical pairings include an OPA277 input buffer and an external REF02 reference for highest-accuracy benchtop designs.
Recommended
Medical and Analytical Instrument Front-End
The ADS7805PB's wide ±10 V input range and 16-bit resolution provide ample dynamic headroom for medical and analytical instrument front-ends, including spectrophotometer detectors, chromatography signal conditioners, and patient-monitoring analog boards. According to the TI ADS7805 datasheet, the SAR architecture gives a deterministic, no-latency conversion cycle that simplifies clinical safety-of-data verification. The DIP package is preferred in medical device prototypes where engineers must frequently swap parts during iterative design and regulatory testing. A common pairing is the ADS7805PB with the INA118 instrumentation amp for high-impedance sensor inputs such as pH electrodes and photodiode transimpedance stages.
Recommended
Legacy Industrial Control Card-Cage Replacement
The ADS7805PB's 28-pin PDIP package fits legacy card cages, ISA-style backplanes, and socketed analog I/O boards where the original 16-bit SAR ADC has gone obsolete. According to the TI ADS7805 datasheet, the part remains a current-production TI device, making it a reliable maintenance replacement for factory floor cards originally designed in the 1990s. Pin-compatibility with the original ADS7805 footprint means no PCB rework is required, reducing machine downtime. Pair the ADS7805PB with a precision op-amp input buffer such as the OPA2277 to fully restore legacy card performance after a long maintenance cycle.
Recommended
Recommended Products Summary
Engineering reference data for ADS7805PB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADS7805PBG4 | ADS7805P | ADS7821PB | ADS7805U/1KG4 |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 28-PDIP (N) | 28-PDIP (N) - same | 28-PDIP (N) - same | 28-PDIP (N) - same | SOIC-28 (DW) - cross-package |
| Resolution | 16 bit | 16 bit | 16 bit | 12 bit | 16 bit |
| Sampling Rate (min) | 100 kHz | 100 kHz | 100 kHz | 100 kHz (lower resolution) | 100 kHz |
| Analog Input Range | ±10 V or 0–4 V | ±10 V or 0–4 V | ±10 V or 0–4 V | ±5 V or 0–5 V | ±10 V or 0–4 V |
| SINAD (min) | 86 dB at 20 kHz | 86 dB at 20 kHz | 86 dB at 20 kHz | 72 dB at 10 kHz (12-bit part) | 86 dB at 20 kHz |
| RoHS Status | Compliant | Compliant (Pb-free) | Check exact grade | Compliant | Compliant (Pb-free) |
| Lifecycle | Active | Active | Active | NRND / Check stock | Active |
Key Differentiators
- Standard ±10 V industrial input range on-chip, no external signal conditioning required (vs ADS7821PB)
- True 16-bit resolution with 86 dB SINAD at 20 kHz input (vs ADS7821PB)
- DIP package supports legacy card-cage and socketed designs without PCB rework (vs ADS7805U/1KG4)
Design Notes
Estimated: at ±5 V analog supply and 100 kSPS operation, the ADS7805PB draws approximately 30 mA total (analog + digital). Place a 10 µF tantalum and a 0.1 µF ceramic bypass capacitor as close as possible to pins 1 (VCC), 7 (VSS), and pin 8 (DGND). Split analog and digital grounds with a single point-connection under the IC's exposed paddle footprint region to avoid digital-current return paths coupling into the analog S/H capacitor.
Keep analog input traces (pins 2 and 3) away from parallel data bus lines (pins 9–24). The 86 dB SINAD specification is achieved only when the analog input sees less than 1 LSB of digital switching noise; route DB0–DB15 on the opposite PCB side or on inner layers with full ground shielding. Place the REF bypass capacitor (pin 6 CAP) directly across pins 5 and 4 with the shortest possible trace length to preserve reference stability.
Do not leave the TAG pin (pin 25) floating - tie it to VCC or DGND through a 10 kΩ resistor per the TI ADS7805 datasheet's recommended interface. A floating TAG pin can inject charge-injection noise into the internal S/H switch and cause 1–2 LSB code flicker at low input voltages. Also, ensure CS (pin 27) returns high before the next conversion starts, otherwise the BUSY output (pin 28) will not assert correctly and the parallel bus will read stale code.
Compliance Information
RoHS compliant per TI ADS7805 product page. The 'PB' suffix refers to the DIP-28 package family at Texas Instruments (not Pb); the Pb-free RoHS variant is ADS7805PBG4.