ADS8481IRGZR - 18-Bit 1MSPS SAR ADC w/Ref | Texas Instruments
MPN: ADS8481IRGZR ✓ Hoạt độngADS8481IRGZR Tóm tắt
An SAR ADC is a sampling converter that uses a charge-redistribution capacitor array and a comparator to digitize an input voltage in N successive approximation steps - one per bit of resolution. SAR ADCs occupy the broad product hierarchy: ADC (analog-to-digital converter) -> data converter -> signal chain IC -> semiconductor. The ADS8481 sits in the precision, medium-speed, single-channel SAR niche favored where high resolution and deterministic latency are required - in contrast to delta-sigma ADCs that offer higher dynamic range at lower bandwidth. The ADS8481 family is also categorized as a micropower sampling data acquisition ADC, emphasizing its low power consumption relative to its 1 MSPS throughput.
Key features include 1 MSPS sampling rate, 18-bit NMC over temperature, internal 4.096-V low-drift reference, hardware-configurable output bus width, and an inherent sample-and-hold front end that accepts pseudo-differential unipolar input signals. The internal reference and reference buffer eliminate the need for an external reference IC, simplifying BOM and reducing board area in multichannel designs.
The architecture combines a precision input sample-and-hold, a charge-redistribution CDAC, an internal 4.096-V bandgap reference, and a digital interface engine that packs results into 18-bit, 16-bit, or 8-bit words to fit the host's bus width. Because SAR conversion is performed in a single conversion cycle of fixed duration, throughput latency is deterministic and well-suited to multiplexed or closed-loop control applications where timing predictability is critical.
Typical applications include industrial process control and data acquisition, multi-axis motor control with position feedback, test and measurement instrumentation, weigh scales and strain-gauge digitizers, and medical instrumentation signal chains. Choose this ADC when a 18-bit, 1 MSPS, single-channel SAR with an internal reference is required in a compact VQFN-48 footprint.
When designing with this device, ensure the input common-mode voltage is within the pseudo-differential input range and provide adequate decoupling on REFIN/REF and AVDD pins. The exposed thermal pad (EP) must be soldered to a continuous ground copper pour to keep junction temperature within safe limits.
This page synthesizes distributor stock, drop-in pin-compatible alternatives, and practical layout guidance for the 48-pin VQFN exposed-pad variant (RGZ suffix) of the ADS8481 family - complementary to the bare-die or QFP variants discussed in the broader product family datasheet.
Bộ thay thế dễ dàng lắp đặt cho ADS8481IRGZR — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với ADS8481IRGZR (cùng hình factor và footprint) — khác nhau ở Package, Input Type, Data Interface, Operating Temperature, Analog Supply Voltage.
ADS8481IBRGZR
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADS8481IRGZT
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADS8481IBRGZT
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADS8472IRGZR
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADS8472IBRGZR
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADS8481IRGZR Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 18 bits |
| Tỷ lệ lấy mẫu | 1 MSPS (max) |
| Architecture | SAR (Successive Approximation Register) |
| Number of Channels | 1 |
| Input Type | Pseudo-differential, unipolar, single-ended |
| Phạm vi điện áp đầu vào | 0 V to +4.096 V (with internal reference) |
| Internal Reference Voltage | 4.096 V |
| Data Interface | Parallel (18-bit / 16-bit / 8-bit bus modes) |
| No Missing Codes | 18-bit NMC over temperature |
| Offset Error | ±0.1 mV |
| Power Consumption | Micropower |
| Nhiệt độ hoạt động | -40 C to +85 C |
| Hộp | 48-pin VQFN Exposed Pad (RGZ), Tape & Reel |
| Package Outline | VQFN EP 48-pin |
| Kiểu lắp đặt | Surface Mount |
Cấu hình chân ADS8481IRGZR
| Chân 1 | AVDD — Analog supply voltage |
| Chân 2 | REFIO — Reference input/output |
| Chân 3 | REFM — Reference ground (negative) |
| Chân 4 | REFP — Reference positive bypass |
| Chân 5 | AINM — Analog negative input (pseudo-differential) |
| Chân 6 | AINP — Analog positive input (pseudo-differential) |
| Chân 7 | AGND — Analog ground |
| Chân 8 | REFCAP — Reference bypass capacitor |
| Chân 9 | RESET — Hardware reset input |
| Chân 10 | CONVST — Conversion start input |
| Chân 11 | RD — Read strobe / parallel output enable |
| Chân 12 | BYTE — Bus width select (18/16/8-bit) |
| Chân 13 | DC — Duty cycle / acquisition control |
| Chân 14 | CS — Chip select input |
| Chân 15 | BUSY — Conversion busy output |
| Chân 16 | NC — Not connected (per datasheet) |
| Chân 17 | EOC — End-of-conversion output |
| Chân 18 | DVDD — Digital supply voltage |
| Chân 19 | DGND — Digital ground |
| Chân 20 | DB0 — Parallel data bit 0 (LSB) |
| Chân 21 | DB1 — Parallel data bit 1 |
| Chân 22 | DB2 — Parallel data bit 2 |
| Chân 23 | DB3 — Parallel data bit 3 |
| Chân 24 | DB4 — Parallel data bit 4 |
| Chân 25 | DB5 — Parallel data bit 5 |
| Chân 26 | DB6 — Parallel data bit 6 |
| Chân 27 | DB7 — Parallel data bit 7 |
| Chân 28 | DB8 — Parallel data bit 8 |
| Chân 29 | DB9 — Parallel data bit 9 |
| Chân 30 | DB10 — Parallel data bit 10 |
| Chân 31 | DB11 — Parallel data bit 11 |
| Chân 32 | DB12 — Parallel data bit 12 |
| Chân 33 | DB13 — Parallel data bit 13 |
| Chân 34 | DB14 — Parallel data bit 14 |
| Chân 35 | DB15 — Parallel data bit 15 |
| Chân 36 | DB16 — Parallel data bit 16 |
| Chân 37 | DB17 — Parallel data bit 17 (MSB) |
| Chân 38 | TAG — Tag input for synchronization |
| Chân 39 | NC — Not connected (per datasheet) |
| Chân 40 | NC — Not connected (per datasheet) |
| Chân 41 | NC — Not connected (per datasheet) |
| Chân 42 | NC — Not connected (per datasheet) |
| Chân 43 | NC — Not connected (per datasheet) |
| Chân 44 | NC — Not connected (per datasheet) |
| Chân 45 | NC — Not connected (per datasheet) |
| Chân 46 | NC — Not connected (per datasheet) |
| Chân 47 | NC — Not connected (per datasheet) |
| Chân 48 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
ADS8481IRGZR phù hợp cho 6 Áp dụngs: Industrial Process Control & Data Acquisition, Multi-Axis Motor Control with Position Feedback, Test & Measurement Instrumentation, Weigh Scales & Strain-Gauge Digitizers, Medical Instrumentation Signal Chains, Audio Signal Path Digitization & Metering.
Industrial Process Control & Data Acquisition
The ADS8481IRGZR's 18-bit NMC and pseudo-differential unipolar 0-4.096 V input map directly onto current-loop / 4-20 mA-sourced process signals after a resistor-sense stage. The 1 MSPS throughput digitizes multiplexed thermocouple, RTD, and load-cell transducer channels with deterministic latency, while the internal 4.096 V reference eliminates a BOM item and keeps gain error below the resolution step. Placed behind an input MUX and front-end op-amp, the converter produces one settled 18-bit conversion per CONVST pulse, simplifying galvanically-isolated multi-channel DAQ designs that must reject 50/60 Hz mains noise.
Được đề xuất
Multi-Axis Motor Control with Position Feedback
For servo and stepper drive systems, the ADS8481IRGZR digitizes encoder analog signals and current-sense shunts with 18-bit precision and deterministic SAR latency, enabling tight PI/DM-control loops. The 1 MSPS sample rate exceeds typical 8 kHz current-loop bandwidth by 125x, so loop controllers can oversample for dithered averaging without compromising throughput. The internal reference and exposed thermal pad keep the converter footprint inside the motor-drive PCB, while the parallel digital bus avoids SPI bit-banging in deterministic safety-rated firmware update paths.
Được đề xuất
Test & Measurement Instrumentation
Bench-top DMMs and bench-scale digitizers benefit from the ADS8481IRGZR's 18-bit NMC and low +/-0.1 mV offset error, achieving sub-1 LSB measurement uncertainty after calibration. The 1 MSPS throughput supports wideband sensor capture while the internal 4.096 V reference provides traceability for accurate voltage measurements. The parallel bus allows rapid data streaming to an FPGA-based DSP back-end for FFT, statistical, or post-processing of raw samples.
Được đề xuất
Weigh Scales & Strain-Gauge Digitizers
Load-cell digitizers exploit the ADS8481IRGZR's pseudo-differential 0-4.096 V range that matches the full-scale output of typical bridge sensors excited at 5 V with low common-mode bias. 18-bit NMC and low drift give 5+ digit stable weight readings, while the internal reference reduces warm-up drift and calibration recompute. Multiple channels can be time-multiplexed on a single converter to keep multi-axis force-plate systems compact.
Được đề xuất
Medical Instrumentation Signal Chains
Patient monitoring devices (ECG, pulse-ox front-ends, infusion pump flow-rate) leverage the ADS8481IRGZR's deterministic SAR latency to align conversion with the mains-line rejection cycle. The 18-bit resolution resolves the small dynamic range of physiological signals, and the internal reference reduces power and board area - critical for battery-powered portable instruments. The exposed thermal pad supports the strict thermal budget of wearable designs.
Được đề xuất
Audio Signal Path Digitization & Metering
Studio metering bridges, VU/peak program meters, and digital crossover systems use the ADS8481IRGZR to digitize audio-taper levels after a precision detector. With 18-bit precision across the 0-4.096 V audio-tapered range, the converter provides more than 100 dB dynamic range useful for digital trim controls. The internal reference simplifies power-rail design, while the 1 MSPS throughput is more than adequate for the bandwidth-limited audio path.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho ADS8481IRGZR — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | ADS8481IBRGZR | ADS8481IRGZT | ADS8472IRGZR | ADS8472IBRGZR |
|---|---|---|---|---|---|
| Package | 48-VQFN Exposed Pad (RGZ) | 48-VQFN Exposed Pad (RGZ) - same | 48-VQFN Exposed Pad (RGZ) - same | 48-VQFN Exposed Pad (RGZ) - same | 48-VQFN Exposed Pad (RGZ) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 18 bit | 18 bit | 18 bit | 16 bit | 16 bit |
| Sampling Rate | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS |
| Internal Reference | 4.096 V | 4.096 V | 4.096 V | 4.096 V | 4.096 V |
| Input Type | Pseudo-differential, unipolar | Pseudo-differential, unipolar | Pseudo-differential, unipolar | Pseudo-differential, unipolar | Pseudo-differential, unipolar |
| Data Interface | Parallel (18/16/8-bit) | Parallel (18/16/8-bit) | Parallel (18/16/8-bit) | Parallel (18/16/8-bit) | Parallel (18/16/8-bit) |
| Performance Grade | Standard (I- grade) | Tight bin (IB- grade) | Standard | Standard (16-bit) | Tight bin (16-bit IB) |
| 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 |
Bảo phân biệt quan trọng
- Internal 4.096 V reference - no external REF IC required (vsADS8482IRGZR (true-differential, 16-bit variant))
- Higher resolution (18-bit) versus the 16-bit family (vsADS8472IRGZR)
- Tight B-grade bin available in the same package (vsADS8481IRGZR (standard grade))
Ghi chú thiết kế
Solder the exposed thermal pad (EP) of the VQFN-48 RGZ package to a continuous analog-ground copper pour directly underneath the IC. Place the REFCAP and AVDD decoupling 1 uF/100 nF pair within 2 mm of pins. Use a star-ground topology with AVDD, DVDD, and the analog input shield all returning to the EP pad - this reduces ground bounce during bus transitions and keeps reference noise from coupling into the CDAC charge balancing.
Route the parallel data bus (DB0-DB17), CONVST, RD, and BUSY signals away from analog traces - place a ground guard on both sides. For CONVST-driven modes, hold CONVST pulse width > 20 ns and keep ground impedance low for the digital return current. Use a slow-edge rate on CONVST if ringing is observed; SAR converters tolerate slower edges within their timing margins.
Do not leave the BYTE pin floating - the 18/16/8-bit bus-width mode is selected at power-up based on BYTE pin state; a floating pin will yield an unpredictable bus mode. Avoid using REFIO as an output when an external reference is being driven into the same node - either drive externally OR let REFIO be the buffered internal reference output, never both. Avoid layouts with AINM tied directly to ground before pin-strap; for true pseudo-differential performance, AINM should track the sensor reference, not PCB ground.
Thông tin tuân thủ
RoHS and lead-free compliant per TI product page. No AEC-Q100 variant for this part family.
