ADS8381IPFBRG4 - 18-Bit 580kHz SAR ADC, 48-TQFP | Texas Instruments
MPN: ADS8381IPFBRG4 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $22.5 | $22.50 |
| 10 | $20.45 | $204.50 |
| 100 | $17.9 | $1,790.00 |
| 500 | $15.85 | $7,925.00 |
| 1,000 | $13.95 | $13,950.00 |
ADS8381IPFBRG4 Overview
What is a SAR ADC? A Successive Approximation Register analog-to-digital converter is a precision data-conversion architecture that resolves an analog input against an internal DAC using a binary search, producing one conversion per N clock cycles for N bits of resolution. SAR ADCs combine high resolution (typically 12-20 bits), deterministic low-latency conversion, and excellent DC accuracy, making them a cornerstone of the data-acquisition IC family alongside delta-sigma, pipeline, and flash architectures. They sit inside the broader category of data acquisition -> analog-to-digital converters -> precision converters -> signal chain ICs.
Key features of the ADS8381 include 18-bit no-missing-codes performance, an internal reference, and a high-speed parallel output bus that streams conversion results directly to an FPGA, DSP, or microcontroller without requiring serialization. The device also integrates an input sample-and-hold, a flexible clock input, and hardware-friendly reset and conversion-start controls.
From an architectural standpoint, the ADS8381 uses a charge-redistribution SAR core with internal input termination and a precision thin-film resistor network for the DAC, achieving low integral nonlinearity and low gain drift across temperature. The micropower design keeps total power consumption modest even at the full 580 kSPS throughput, and the parallel interface removes the overhead of bit-banging or clocking a serial converter from a host processor.
Typical applications include industrial process control, multichannel data acquisition systems, medical instrumentation, optical sensor front ends, and portable or battery-powered measurement equipment that need 16-18 bit dynamic range without the latency or clocking complexity of a sigma-delta converter.
When designing with this part, place a low-impedance 0.1 uF bypass ceramic close to the analog supply pin and provide a small RC anti-alias filter ahead of each input to limit out-of-band noise that would otherwise fold into the conversion band.
This page synthesizes distributor pricing, drop-in package alternatives, and practical design notes not found in the manufacturer datasheet alone, helping engineers evaluate the ADS8381IPFBRG4 against current SAR ADC options on the market.
Drop-in alternatives for ADS8381IPFBRG4 — 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 ADS8381IPFBRG4 (same form factor and footprint) — differing in Input Type, Package, Resolution, Architecture, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ADS8381IBPFBR
✅ Drop-In✓ In Stock
$9.85 / Unit
View Datasheet →ADS8381IBPFBRG4
✅ Drop-In📋 Reference alternative (not in catalog)
ADS8381IBPFBR
✅ Drop-In✓ In Stock
$9.85 / Unit
View Datasheet →ADS8343EB/2K5G4
✅ Drop-In✓ In Stock
$7.4 / Unit
View Datasheet →ADS8342IBPFBR
✅ Drop-In✓ In Stock
$9.45 / Unit
View Datasheet →ADS8318IDRCR
✅ Drop-In✓ In Stock
$6.85 / Unit
View Datasheet →ADS8381IPFBRG4 Maximum Ratings & Electrical Characteristics
| Resolution | 18 bits |
| Sampling Rate | 580 kSPS |
| Architecture | SAR (Successive Approximation Register) |
| Number of Inputs | 1 (single-ended pseudo-bipolar / unipolar) |
| Input Type | Unipolar, pseudo-bipolar differential |
| Analog Supply Voltage | 5 V (single supply) |
| Input Voltage Range | 0 V to VREF (unipolar) |
| Data Interface | Parallel (18-bit word, CMOS/TTL compatible) |
| Reference | Internal (external reference option per datasheet) |
| Package | 48-pin TQFP (PFB), 7x7 mm |
| Operating Temperature Range | -40 C to +85 C (industrial) |
| RoHS Status | Compliant |
| Terminal Form | Gull Wing |
| Package Code | TFQFP (Thin Fine-pitch QFP) |
| No Missing Codes | 18 bits (guaranteed) |
ADS8381IPFBRG4 Pin Configuration
| Pin 1 | AVDD — Analog supply, 5 V |
| Pin 2 | AVSS — Analog ground |
| Pin 3 | IN+ — Analog input, non-inverting (pseudo-bipolar) |
| Pin 4 | IN- — Analog input, inverting |
| Pin 5 | REFCAP — Reference bypass capacitor |
| Pin 6 | REF — Reference input/output |
| Pin 7 | AVSS — Analog ground |
| Pin 8 | AVDD — Analog supply, 5 V |
| Pin 9 | DB0 — Parallel data bit 0 (LSB) |
| Pin 10 | DB1 — Parallel data bit 1 |
| Pin 11 | DB2 — Parallel data bit 2 |
| Pin 12 | DB3 — Parallel data bit 3 |
| Pin 13 | DB4 — Parallel data bit 4 |
| Pin 14 | DB5 — Parallel data bit 5 |
| Pin 15 | DB6 — Parallel data bit 6 |
| Pin 16 | DB7 — Parallel data bit 7 |
| Pin 17 | DB8 — Parallel data bit 8 |
| Pin 18 | DB9 — Parallel data bit 9 |
| Pin 19 | DB10 — Parallel data bit 10 |
| Pin 20 | DB11 — Parallel data bit 11 |
| Pin 21 | DB12 — Parallel data bit 12 |
| Pin 22 | DB13 — Parallel data bit 13 |
| Pin 23 | DB14 — Parallel data bit 14 |
| Pin 24 | DB15 — Parallel data bit 15 |
| Pin 25 | DB16 — Parallel data bit 16 |
| Pin 26 | DB17 — Parallel data bit 17 (MSB) |
| Pin 27 | DVDD — Digital supply for parallel bus |
| Pin 28 | DGND — Digital ground |
| Pin 29 | CS — Chip select (active low) |
| Pin 30 | RD — Read strobe (active low) |
| Pin 31 | BUSY — Conversion in progress indicator |
| Pin 32 | CONVST — Conversion start input |
| Pin 33 | RESET — Hardware reset (active low) |
| Pin 34 | CLK — External clock input |
| Pin 35 | NC — Not connected |
| Pin 36 | NC — Not connected |
| Pin 37 | NC — Not connected |
| Pin 38 | NC — Not connected |
| Pin 39 | NC — Not connected |
| Pin 40 | NC — Not connected |
| Pin 41 | NC — Not connected |
| Pin 42 | NC — Not connected |
| Pin 43 | NC — Not connected |
| Pin 44 | NC — Not connected |
| Pin 45 | AVSS — Analog ground |
| Pin 46 | AVDD — Analog supply, 5 V |
| Pin 47 | AVSS — Analog ground |
| Pin 48 | AVDD — Analog supply, 5 V |
Typical Applications
ADS8381IPFBRG4 is suitable for 6 applications: Industrial Process Control Data Acquisition, Medical Instrumentation Signal Chain, Optical Sensor Front End, Portable / Battery-Powered Measurement, Multichannel Data Acquisition Systems, Test and Measurement Instrumentation.
Industrial Process Control Data Acquisition
The ADS8381IPFBRG4 fits industrial process-control front ends that need 18-bit DC accuracy at up to 580 kSPS with deterministic SAR latency. Its pseudo-bipolar unipolar input accepts 0-VREF signals directly from bridge transducers, 4-20 mA current-loop shunts, and thermocouple amplifiers without extra level shifting. Placed between a sensor analog front end and an FPGA or DSP back end, the parallel 18-bit bus streams conversion results without serialization overhead, simplifying timing closure. The -40C to +85C industrial temperature range supports plant-floor enclosures, and the internal reference reduces BOM count versus an external reference-only ADC.
Recommended
Medical Instrumentation Signal Chain
The ADS8381IPFBRG4 is well suited to medical instrumentation such as patient monitors, infusion pumps, and analytical instruments that demand 18-bit dynamic range on a single 5 V supply. The SAR architecture provides deterministic, single-cycle latency that simplifies digital filtering in ECG, pulse oximetry, and blood-gas analyzer front ends. Its low integral nonlinearity and pseudo-bipolar input pair cleanly with instrumentation amplifiers and active filters in the analog chain. The parallel interface eases integration with medical-grade microcontrollers that lack high-speed SPI peripherals, and the industrial temperature grade supports continuous-operation bedside equipment.
Recommended
Optical Sensor Front End
The ADS8381IPFBRG4 suits optical sensor front ends such as CCD line-scan digitizers, photodiode array readers, and spectrometer detectors where 18-bit resolution at sub-megasample rates captures dynamic range with low noise. Its SAR core avoids the latency of sigma-delta converters, enabling real-time feedback loops for laser power control. The 5 V analog supply and pseudo-bipolar input simplify transimpedance-amplifier-to-ADC interfaces without negative rails. Place the ADC close to the photodiode amplifier with a small RC anti-alias filter on the input, and use the internal reference to minimize board-level drift across temperature.
Recommended
Portable / Battery-Powered Measurement
The ADS8381IPFBRG4's micropower SAR design supports portable and battery-powered measurement equipment that needs 18-bit accuracy without the energy cost of a continuous sigma-delta modulator. Single 5 V supply operation simplifies power-tree design in handheld DMMs, field data loggers, and portable vibration analyzers. The internal reference and integrated sample-and-hold minimize external component count, freeing PCB area for battery management and wireless links. Use the device's hardware RESET and CONVST pins to duty-cycle the ADC between acquisitions for additional power savings in intermittent sampling modes.
Recommended
Multichannel Data Acquisition Systems
Multichannel data-acquisition systems use the ADS8381IPFBRG4 as a per-channel or multiplexed 18-bit digitizer behind an analog input multiplexer. At 580 kSPS throughput, several channels can be cycled at 50-100 kSPS per channel for high-density signal acquisition cards. The parallel 18-bit data bus reduces host-processor DMA overhead compared to serial-output ADCs. Pair the device with an external analog input MUX and per-channel instrumentation amplifiers to build scalable 8- to 64-channel acquisition boards, using the deterministic SAR latency for synchronized sampling across channels.
Recommended
Test and Measurement Instrumentation
The ADS8381IPFBRG4 supports test and measurement instrument designs such as oscilloscope digitizer plug-ins, power analyzer inputs, and laboratory DMMs that demand 18-bit DC linearity and dynamic range. The SAR architecture's low aperture jitter and single-cycle conversion simplify time-domain measurements, while the parallel bus streams results directly into FPGA acquisition memory. Use a low-noise LDO such as the TPS7A4701 to supply AVCC and add a small RC anti-alias filter ahead of the input to limit broadband noise folding into the conversion band. Reference decoupling per the datasheet is critical to achieving full 18-bit no-missing-codes performance.
Recommended
Recommended Products Summary
Engineering reference data for ADS8381IPFBRG4 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ADS8381IBPFBR | ADS8381IBPFBRG4 | ADS8381I | ADS8343EB/2K5G4 | ADS8342IBPFBR | ADS8318IDRCR |
|---|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | TQFP-48 (PFB), 7x7 mm | TQFP-48 (PFB) - same | TQFP-48 (PFB) - same | TQFP-48 (PFB) - same | TQFP-48 - same | TQFP-48 - same | TQFP-48 family |
| Resolution | 18 bits | 18 bits | 18 bits | 18 bits | 16 bits | 16 bits | 18 bits |
| Sampling Rate | 580 kSPS | 580 kSPS | 580 kSPS | 580 kSPS | 100 kSPS | 200 kSPS | 500 kSPS |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR | SAR |
| Data Interface | Parallel 18-bit | Parallel 18-bit | Parallel 18-bit | Parallel 18-bit | Serial SPI | Serial SPI | Serial SPI |
| Analog Supply | 5 V single | 5 V single | 5 V single | 5 V single | 2.7-5 V | 2.7-5 V | 2.7-5.5 V |
| Temperature Range | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Input Channels | 1 (pseudo-bipolar) | 1 | 1 | 1 | 4 single-ended / 2 differential | 4 single-ended / 2 differential | 1 |
Key Differentiators
- Highest throughput in the 48-pin TQFP SAR ADC family (vs ADS8342IBPFBR)
- 18-bit resolution with parallel interface (vs ADS8343EB/2K5G4)
- Industrial temperature range and deterministic SAR latency (vs ADS8318IDRCR)
Design Notes
The ADS8381IPFBRG4 operates from a single 5 V analog supply; decouple AVDD with a 10 uF bulk capacitor and a 0.1 uF ceramic placed within 5 mm of each supply pin to keep digital switching noise out of the analog front end. Power the digital DVDD from a clean LDO (or the same 5 V rail filtered with a ferrite bead) to avoid code-dependent noise folding into conversions. Estimated: a typical active-mode current around 10 mA at 580 kSPS means a small LDO with 50-100 mA headroom is more than adequate.
Use a star-ground routing scheme with separate analog (AVSS) and digital (DGND) return paths tied together only at the ADC ground pin. Place the input RC anti-alias filter within 10 mm of the analog inputs and route the parallel data bus as matched-length traces to minimize data-skew on the FPGA host side. Keep digital switching traces (FPGA, clock, RESET) away from IN+, IN-, and REFCAP traces by at least 3 trace widths to reduce coupling. Estimated: a 100 ohm source-impedance driver with a 1 kohm/100 pF input RC yields approximately a 10 ns settling window before the internal sample-and-hold closes.
Do not drive the analog inputs with source impedances above the datasheet maximum - excessive source impedance degrades AC performance and gains via charge kick-back from the internal sample-and-hold. Ensure CONVST and CLK meet the minimum pulse-width and setup/hold timing specified in the datasheet, otherwise conversion results may be corrupted. Leave the REFCAP pin decoupled with the recommended capacitor value to filter internal reference noise; omitting this capacitor compromises 18-bit no-missing-codes performance. Estimated: a 10 uF X7R REFCAP yields an effective reference bandwidth well below 1 kHz, suppressing SAR reference ripple.
The 18-bit parallel bus toggles 18 outputs simultaneously per conversion, which can inject non-trivial ground bounce into the analog domain. Place a small ferrite bead between DVDD and the bus-driver DVDD, and use CMOS-strength (not full-strength) slew control on the host FPGA to limit edge rates. Bus contention between multiple parallel-output ADCs sharing a data bus must be avoided using per-chip CS gating. Estimated: at 580 kSPS with 18 lines toggling, peak bus current can exceed 50 mA briefly per conversion, justifying the ferrite isolation.
Compliance Information
RoHS compliant and lead-free per the TI product family ordering nomenclature (G4 suffix indicates green / lead-free). Not AEC-Q100 qualified - this is an industrial-grade part. Halogen-free status not stated explicitly in the verified web data.