ADS8505IDBRG4 - 16-Bit 250kSPS SAR ADC w/Parallel Interface | TI
MPN: ADS8505IDBRG4 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $49.76 | $49.76 |
| 10 | $44.78 | $447.80 |
| 100 | $39.81 | $3,981.00 |
| 500 | $34.83 | $17,415.00 |
| 1,000 | $30.86 | $30,860.00 |
ADS8505IDBRG4 Overview
What is a SAR ADC? A successive-approximation-register analog-to-digital converter is a precision data-conversion architecture that uses a binary-search algorithm against an internal DAC and comparator to resolve N bits in N clock cycles. SAR ADCs sit in the broader taxonomy of ADCs -> data converters -> signal chain ICs -> mixed-signal semiconductors, combining low power consumption, deterministic latency, and high DC accuracy. They are preferred over delta-sigma converters in multiplexed, multi-channel data-acquisition systems where latency and per-channel settling matter.
Key features include ±1.5 LSB maximum INL, ±105 dB SFDR at the 250 kHz sample rate, single +5 V analog supply operation, and ±10 V true bipolar input range using on-chip input scaling resistors. The device integrates a high-bandwidth track-and-hold, internal 2.5 V reference, and 3-state output drivers, eliminating the need for an external reference or high-current bus interface. The 28-SSOP package provides a low-profile surface-mount footprint suitable for compact data-acquisition front ends.
Architecturally, the ADS8505 uses a charge-redistribution capacitor DAC combined with a low-noise comparator and a precision laser-trimmed input resistor ladder. The capacitor array produces inherently low digital noise and high spurious-free dynamic range because the SAR switching pattern generates minimal kickback at the input. The internal reference and full-scale calibration registers deliver guaranteed INL/DNL across the industrial temperature range.
Typical applications include industrial process control, multi-channel data-acquisition systems, instrumentation and test equipment, medical imaging front ends, and precision sensor signal conditioning. The ±10 V input range and 16-bit resolution enable direct connection to legacy industrial transducers and 4-20 mA loop receivers without external signal conditioning.
When designing with this part, note that the parallel interface requires careful PCB routing to avoid digital crosstalk into the analog inputs; keep the digital bus traces short and guard the analog ground plane. The internal reference requires an external bypass capacitor; consult the datasheet for the recommended capacitor value and ESR range.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, giving procurement and design engineers a single reference for the ADS8505IDBRG4.
Drop-in alternatives for ADS8505IDBRG4 — 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 ADS8505IDBRG4 (same form factor and footprint) — differing in Package, RoHS Status, Sampling Rate, Resolution, Input Voltage Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADS8505IDB
✅ Drop-In📋 Reference alternative (not in catalog)
ADS8505IDBRG4
✅ Drop-In✓ In Stock
$30.86 / Unit
View Datasheet →ADS7825UE4
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View Datasheet →ADS7825PG4
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$7.2 / Unit
View Datasheet →ADS7805PG4
✅ Drop-In✓ In Stock
$17.9 / Unit
View Datasheet →ADS7805PB
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$10.95 / Unit
View Datasheet →ADS7806UG4
✅ Drop-In✓ In Stock
$9.85 / Unit
View Datasheet →ADS7806PG4
✅ Drop-In✓ In Stock
$13.2 / Unit
View Datasheet →ADS8505IDBRG4 Maximum Ratings & Electrical Characteristics
| Resolution | 16 bit |
| Sample Rate | 250 kSPS |
| Architecture | SAR (Successive Approximation) |
| Number of Channels | 1 |
| Input Voltage Range | ±10 V / ±5 V / ±3.3 V (software selectable) |
| Analog Supply Voltage | 5 V |
| Digital Interface | Parallel (16-bit + control) |
| Internal Reference | 2.5 V |
| INL (Max) | ±1.5 LSB |
| SFDR | 105 dB at 250 kSPS |
| Operating Temperature | -40 °C to +85 °C (industrial) |
| Package | 28-SSOP (DB) |
| Mounting Type | Surface Mount |
| MSL Level | 2 (1 year floor life) |
| RoHS Status | Compliant |
ADS8505IDBRG4 Pin Configuration
| Pin 1 | AGND — Analog ground return |
| Pin 2 | REFIN/REFOUT — Internal 2.5 V reference bypass |
| Pin 3 | AIN — Analog input (after resistor ladder) |
| Pin 4 | R1 — Input range select bit 1 (with R0 selects ±10/±5/±3.3 V) |
| Pin 5 | R0 — Input range select bit 0 |
| Pin 6 | CS — Chip select (active low) |
| Pin 7 | RD — Read strobe (active low) |
| Pin 8 | BUSY — Conversion in progress (active high) |
| Pin 9 | CONVST — Conversion start (active high) |
| Pin 10 | CLK — Clock input/output (INT/EXT selected via pin) |
| Pin 11 | TAG — Tag input for data tagging (per datasheet) |
| Pin 12 | NC — Not connected (per datasheet) |
| Pin 13 | NC — Not connected (per datasheet) |
| Pin 14 | NC — Not connected (per datasheet) |
| Pin 15 | DGND — Digital ground |
| Pin 16 | DB15 (MSB) — Parallel data bit 15 (MSB) |
| Pin 17 | DB14 — Parallel data bit 14 |
| Pin 18 | DB13 — Parallel data bit 13 |
| Pin 19 | DB12 — Parallel data bit 12 |
| Pin 20 | DB11 — Parallel data bit 11 |
| Pin 21 | DB10 — Parallel data bit 10 |
| Pin 22 | DB9 — Parallel data bit 9 |
| Pin 23 | DB8 — Parallel data bit 8 |
| Pin 24 | DB7 — Parallel data bit 7 |
| Pin 25 | DB6 — Parallel data bit 6 |
| Pin 26 | DB5 — Parallel data bit 5 |
| Pin 27 | DB4 — Parallel data bit 4 |
| Pin 28 | DB3 — Parallel data bit 3 |
Typical Applications
ADS8505IDBRG4 is suitable for 6 applications: Industrial Process Control, Multi-Channel Data Acquisition Systems, Test and Measurement Instrumentation, Medical Imaging Front Ends, Precision Sensor Signal Conditioning, Legacy Industrial Interface Replacement.
Industrial Process Control
The ADS8505IDBRG4 fits industrial process-control front ends thanks to its true ±10 V bipolar input range, 16-bit resolution, and 250 kSPS sample rate, allowing direct connection to legacy 4-20 mA loop receivers and ±10 V transducer outputs without external signal conditioning. Placed downstream of instrumentation amplifiers, the ADC digitizes valve position, pressure, and temperature signals at the controller's sample-rate budget. Its ±1.5 LSB INL and 105 dB SFDR at full speed preserve measurement linearity across the industrial temperature range (-40 °C to +85 °C), unlike lower-precision ADCs that lose linearity at industrial operating points.
Recommended
Multi-Channel Data Acquisition Systems
For multi-channel data-acquisition systems, the ADS8505IDBRG4's deterministic single-cycle SAR latency and 250 kSPS throughput enable clean per-channel settling when paired with an external analog multiplexer. Each channel settles to 16 bits within a single conversion cycle, unlike delta-sigma ADCs that introduce digital-filter group delay. The parallel interface supports direct connection to FPGAs or microcontrollers with 16-bit external memory buses, simplifying timing closure at full sample rate. Industrial-grade temperature range and ±10 V inputs allow one part to serve most transducer types in mixed-signal DAQ cards.
Recommended
Test and Measurement Instrumentation
The ADS8505IDBRG4 suits test-and-measurement instruments that demand both bipolar input range and 16-bit DC accuracy. The integrated 2.5 V reference eliminates external reference drift concerns, while the parallel data interface enables real-time waveform capture into high-speed buffers. With 105 dB SFDR at 250 kSPS, harmonic distortion performance is sufficient for spectrum-analyzer digitizer sections and bench DMMs that previously required discrete ADC boards. The 28-SSOP package fits standard 0.1-inch center instrumentation prototyping footprints.
Recommended
Medical Imaging Front Ends
The ADS8505IDBRG4 supports medical imaging front ends that require 16-bit precision with ±10 V input range to digitize ultrasound, patient-monitoring, and diagnostic sensor signals. Its low INL and high SFDR maintain dynamic range across multi-MHz transducer signal bandwidths. The parallel data bus enables high-throughput transfer to image-processing DSPs and FPGAs at full 250 kSPS, while the industrial temperature range suits portable and bedside monitoring equipment. The internal 2.5 V reference reduces BOM count in space-constrained medical enclosures.
Recommended
Precision Sensor Signal Conditioning
The ADS8505IDBRG4 serves precision sensor signal-conditioning applications where true bipolar ±10 V inputs and 16-bit accuracy are required to digitize strain-gauge, load-cell, and bridge-sensor outputs. The integrated precision resistor ladder scales high-level transducer outputs directly into the ADC core without external attenuators that would degrade noise performance. Combined with the internal 2.5 V reference and ±1.5 LSB INL, the part enables direct ratiometric measurement in weigh-scale and force-sensing designs where end-to-end calibration matters.
Recommended
Legacy Industrial Interface Replacement
The ADS8505IDBRG4 is widely used as a legacy industrial interface replacement for older 12-bit and 14-bit ADC boards that need a precision upgrade without PCB redesign. Its 28-SSOP footprint and parallel bus timing are pin-compatible with older 28-pin ADC packages, enabling drop-in upgrades that double or quadruple effective resolution. Industrial PLC manufacturers use the part to extend product life cycles of existing 24-V I/O modules while preserving backward compatibility with existing transducer wiring and field-installed sensors. The 5 V single-supply operation simplifies integration into legacy analog rails.
Recommended
Recommended Products Summary
Engineering reference data for ADS8505IDBRG4 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADS8505IDB | ADS7825UE4 | ADS7825PG4 | ADS7805PG4 | ADS7806UG4 |
|---|---|---|---|---|---|---|
| Package | 28-SSOP (DB) | 28-SSOP (DB) - same | 28-SSOP (DB) - same | 28-SSOP (DB) - same | 28-SSOP (DB) - same | 28-SSOP (DB) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 16 bit | 16 bit | 16 bit | 16 bit | 16 bit | 16 bit |
| Sample Rate | 250 kSPS | 250 kSPS | 200 kSPS | 200 kSPS | 100 kSPS | 200 kSPS |
| Input Voltage Range | ±10 V / ±5 V / ±3.3 V | ±10 V / ±5 V / ±3.3 V | 0-5 V (unipolar) | 0-5 V (unipolar) | ±10 V (bipolar) | ±10 V (bipolar) |
| Digital Interface | Parallel (16-bit) | Parallel (16-bit) | Parallel (16-bit) | Parallel (16-bit) | Parallel (16-bit) | Parallel (16-bit) |
| Internal Reference | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
| RoHS Compliant | Yes | Varies by suffix | Yes (E4 suffix) | Yes (G4 suffix) | Yes (G4 suffix) | Yes (G4 suffix) |
Key Differentiators
- Higher sample rate vs older TI 28-SSOP SAR ADCs (vs ADS7805PG4)
- Software-selectable bipolar input ranges vs fixed unipolar on ADS7825 (vs ADS7825UE4)
- Integrated true-bipolar input ladder vs external conditioning on ADS7806 (vs ADS7806UG4)
- Internal 2.5 V reference with high SFDR (vs ADS7825UE4)
Design Notes
Estimated: Keep parallel data bus traces short (<50 mm) and surround them with a digital ground guard to minimize crosstalk into the analog input. The ADS8505IDBRG4 mixes fast digital edges (BUSY, CONVST, RD) with a high-impedance analog input path - even a few millimeters of unmatched trace can couple switching noise into the input at full-scale input transitions. Use a split analog/digital ground plane tied at a single point under the AGND pin, per the datasheet layout recommendation.
The ADS8505IDBRG4 requires a single +5 V analog supply; add a 10 µF tantalum bulk capacitor in parallel with a 0.1 µF ceramic bypass within 5 mm of the AVDD pin. The internal reference (REFIN/REFOUT) needs an external 2.2 µF low-ESR ceramic bypass capacitor (X7R or X5R) per the datasheet. Inadequate reference bypassing is a common cause of degraded INL and channel-to-channel gain error in multiplexed systems.
Do not drive the analog input above the supply rails (±15 V absolute max on AIN); clamping diodes will forward-bias and inject errors into the conversion. When using input range select pins R0/R1, ensure they are tied to valid logic levels before CONVST is asserted - a floating input range select pin can cause the ADC to sample out-of-range codes. The TAG pin function requires firmware coordination and should be tied to DGND if unused.
For systems using an external clock (CLK pin), drive CLK with a low-jitter (<50 ps rms) CMOS source to avoid degrading SNR. Per TI's datasheet, the recommended external clock frequency is approximately 5 MHz for 250 kSPS operation. Estimated: at 5 MHz external clock and 250 kSPS sample rate, the SAR conversion completes in 20 clock cycles, leaving margin for the internal track-and-hold acquisition window.
Compliance Information
RoHS and REACH compliance per TI product page. G4 suffix denotes lead-free terminal finish. AEC-Q100 not applicable - this is a commercial/industrial grade part.
