LTC2391ILX-16 - 16-Bit 250ksps SAR ADC, 48-LQFP | Analog Devices
MPN： LTC2391ILX-16 ✗ 停產LTC2391ILX-16 概覽
A SAR ADC is a class of Nyquist-rate data converter that uses a binary-search algorithm against a precision DAC to resolve the input voltage in N clock cycles for an N-bit output. SAR ADCs are valued for their deterministic latency, low power, and excellent DC accuracy — they belong to the data-converter hypernym hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor.
Key features of the LTC2391ILX-16 include 94 dB SNR, ±2 LSB INL (typical), true-differential inputs with wide common-mode range, an internal oscillator, and a hardware-mode configuration that allows standalone operation. The device accepts a single 5 V analog rail and provides a low digital supply current, making it well-suited to dense multi-channel instrumentation boards.
Architecturally, the LTC2391 uses a charge-redistribution capacitive DAC array with a high-precision thin-film resistor reference network, achieving 16-bit resolution without calibration. The internal reference buffer isolates the reference from switching transients, contributing to the wide 94 dB SNR and clean THD performance across audio-band signal frequencies.
Typical applications include industrial process-control data acquisition modules, weigh scales, precision instrumentation, portable medical diagnostics, and seismic-data front-end digitizer card. With 250 ksps throughput and no pipeline latency, the part is also appropriate for closed-loop control loops where conversion determinism matters.
When designing with this part, ensure the analog input network respects the 5 V common-mode range and that the reference decoupling capacitor is placed within 5 mm of the REF pin. For multi-board synchronization, drive the CNTR pin from a low-jitter source, and decouple AVDD/DVDD/OVDD rails separately to prevent digital switching noise from coupling into the SAR comparator.
This page synthesizes distributor pricing, drop-in same-package alternatives (LTC2391CLX-16 from the same datasheet family), and practical PCB-level design notes not assembled in the manufacturer datasheet alone.
直接替換替代品，適用於 LTC2391ILX-16 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： LTC2391ILX-16 （相同外形與佔位） — 差異在於 RoHS Status, Package, Resolution, Architecture, Number of Input Channels.
LTC2391CLX-16#PBF
✅ 直接替換📋 參考替代品（不在目錄中）
LTC2389ILX-16
✅ 直接替換聯絡詢價
查看資料表 →LTC2389CUK-16
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →LTC2391ILX-16 最大額定值與電氣特性
| 解析度 | 16 bits |
| Architecture | SAR (Successive Approximation Register) |
| Number of Input Channels | 1 |
| Sampling Rate (Throughput) | 250 ksps |
| SNR | 94 dB |
| Input Type | True Differential |
| Internal Reference Accuracy | 0.5% initial |
| Internal Reference Tempco | ±20 ppm/°C (max) |
| Supply Voltage (Analog) | 5 V |
| Digital I/O Supply | 2.5 V / 3 V / 5 V (OVDD) |
| Cycle Latency | 0 (no pipeline delay) |
| 介面 | Parallel / Serial (selectable) |
| 工作溫度範圍 | -40 °C to +85 °C (Industrial) |
| 封裝 | 48-LQFP (7x7 mm) |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant (PBF suffix) |
LTC2391ILX-16 腳位配置
| 腳位 1 | OGND — Digital I/O ground reference |
| 腳位 2 | OVDD — Digital I/O supply (2.5/3/5 V) |
| 腳位 3 | D15 — Parallel data output bit 15 (MSB) |
| 腳位 4 | D14 — Parallel data output bit 14 |
| 腳位 5 | D13 — Parallel data output bit 13 |
| 腳位 6 | D12 — Parallel data output bit 12 |
| 腳位 7 | D11 — Parallel data output bit 11 |
| 腳位 8 | D10 — Parallel data output bit 10 |
| 腳位 9 | D9 — Parallel data output bit 9 |
| 腳位 10 | D8 — Parallel data output bit 8 |
| 腳位 11 | D6 — Parallel data output bit 6 |
| 腳位 12 | D5 — Parallel data output bit 5 |
| 腳位 13 | D4 — Parallel data output bit 4 |
| 腳位 14 | D3 — Parallel data output bit 3 |
| 腳位 15 | D2 — Parallel data output bit 2 |
| 腳位 16 | D1 — Parallel data output bit 1 |
| 腳位 17 | D0 — Parallel data output bit 0 (LSB) |
| 腳位 18 | OGND — Digital I/O ground |
| 腳位 19 | OVDD — Digital I/O supply |
| 腳位 20 | CSL — Chip-select / serial clock complement (interface dependent) |
| 腳位 21 | SDOUT — Serial data output |
| 腳位 22 | SCK — Serial clock input |
| 腳位 23 | BUSY — Conversion in progress indicator (active high) |
| 腳位 24 | CNTR — Conversion start trigger input |
| 腳位 25 | RDL — Read low byte (parallel mode) |
| 腳位 26 | OGND — Digital ground |
| 腳位 27 | DVDD — Digital core supply (5 V) |
| 腳位 28 | DGND — Digital ground |
| 腳位 29 | AGND — Analog ground |
| 腳位 30 | REF — Internal reference bypass node |
| 腳位 31 | REFGND — Reference ground |
| 腳位 32 | REFIN — External reference input (overrides internal) |
| 腳位 33 | AVDD — Analog 5 V supply |
| 腳位 34 | AGND — Analog ground |
| 腳位 35 | AN1N — Analog differential negative input |
| 腳位 36 | AN1P — Analog differential positive input |
| 腳位 37 | AGND — Analog ground |
| 腳位 38 | AVDD — Analog 5 V supply |
| 腳位 39 | NC — Not connected (per datasheet) |
| 腳位 40 | NC — Not connected (per datasheet) |
| 腳位 41 | D7 — Parallel data output bit 7 |
| 腳位 42 | OVDD — Digital I/O supply |
| 腳位 43 | OGND — Digital I/O ground |
| 腳位 44 | NC — Not connected (per datasheet) |
| 腳位 45 | NC — Not connected (per datasheet) |
| 腳位 46 | DGND — Digital ground |
| 腳位 47 | DVDD — Digital core supply |
| 腳位 48 | NC — Not connected (per datasheet) |
典型應用
LTC2391ILX-16 適用於 7 應用s: Industrial Process-Control Analog Input, Precision Weigh Scale Digitizer, Portable Medical Diagnostic Front-End, Seismic / Vibration Data Acquisition, Audio-Band Precision Instrumentation, Motor-Control Current Sensing, High-Speed Multiplexed Data Acquisition Card.
Industrial Process-Control Analog Input
The LTC2391ILX-16 is well-suited to industrial process-control analog input modules because its 16-bit resolution and 94 dB SNR allow direct digitisation of 4-20 mA current-loop and 0-10 V transducer outputs with >15 effective bits, while its 250 ksps throughput handles multiplexed 8-16 channel scan rates well below the converter's ceiling. The true-differential input rejects common-mode noise on long factory-floor cable runs and the integrated 0.5% reference eliminates external ref-IC cost. The 48-LQFP package enables a compact PLC-style footprint and the industrial -40C to +85C temperature range covers unheated enclosure use.
推薦
Precision Weigh Scale Digitizer
Weigh scales demand low noise at low signal bandwidth, where the LTC2391ILX-16's 94 dB SNR and 16-bit resolution translate to roughly 15.3 ENOB and stable 5 mV digitisation across a bridge-excited load cell output. The part's zero pipeline latency means every conversion result is current-cycle accurate, simplifying tare calibration and filtering in firmware. The internal precision reference eliminates drift from external reference components and the 48-LQFP footprint fits compact handheld-scale PCBs while the -40C to +85C range covers outdoor weigh-station use.
推薦
Portable Medical Diagnostic Front-End
Portable diagnostic instruments such as blood-glucose meters, pulse oximeters, and handheld ECG front-ends benefit from the LTC2391ILX-16's low 5 V single-supply operation, low quiescent current, and 250 ksps throughput that lets the host microcontroller trigger burst conversions then return to sleep mode between readings. The 16-bit resolution supports precision photodiode current-to-voltage front-ends where 1 LSB corresponds to sub-nanoampere resolution when paired with a transimpedance amplifier. The 48-LQFP (7x7 mm) footprint fits the tight PCB area inside handheld enclosures, and the industrial temperature range covers field-clinic environments.
推薦
Seismic / Vibration Data Acquisition
Geophone-array seismic digitiser cards and structural-health vibration monitoring systems require simultaneous wide dynamic range and deterministic per-sample latency — both delivered by the LTC2391ILX-16. The 94 dB SNR captures vibration amplitudes across more than four decades, and the SAR architecture's zero-latency conversion simplifies real-time threshold detection on each sample. Multiple LTC2391ILX-16 channels can be synchronised through their CNTR pin to within one conversion cycle, supporting 8-32 channel digitiser cards in oil-exploration and structural-monitoring racks.
推薦
Audio-Band Precision Instrumentation
Test and measurement instruments — audio analysers, vibration shakers, multi-meter calibrators — benefit from the LTC2391ILX-16's 94 dB SNR and 16-bit linearity across the full audio band. With 250 ksps, the converter oversamples an audio-band input by ~5x, allowing simple SINC1 averaging to push effective resolution past 16 bits at lower input frequencies. The internal precision reference removes the need for an external 5 V reference IC and the 48-LQFP (7x7) package mounts easily onto instrument front-end cards alongside precision op-amps and anti-aliasing filters.
推薦
Motor-Control Current Sensing
Field-oriented control (FOC) motor drives require simultaneous current-sense sampling at sub-microsecond latency — a perfect fit for the LTC2391ILX-16's zero-pipeline SAR architecture. By placing one LTC2391 per phase current shunt and synchronising via a common CNTR signal, designers achieve matched-conversion phase-current readings that feed the Park-Transform calculation. The 250 ksps throughput handles up to ~50 kHz PWM fundamental with comfortable margin, and the 16-bit resolution supports torque-loop accuracy well below 0.1% in servo-class drives. The 48-LQFP package simplifies multi-ADC PCB layouts.
推薦
High-Speed Multiplexed Data Acquisition Card
Multi-channel data-acquisition cards (DAQs) for PXI, VXI, or PCI Express backplanes combine a precision SAR ADC like the LTC2391ILX-16 with an external analog input multiplexer to scan 8 to 64 channels at aggregate throughputs approaching 250 ksps. The LTC2391ILX-16's 94 dB SNR preserves dynamic range on multiplexed thermocouple, RTD, and strain-gauge signals, while the parallel interface option enables fast FPGA-side buffering of conversion results. The 48-LQFP (7x7 mm) footprint fits compact DAQ front-end daughter cards and the industrial -40C to +85C range supports lab and field-deployed instruments.
推薦
推薦產品摘要
工程參考資料，適用於 LTC2391ILX-16 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LTC2391CLX-16#PBF | LTC2389ILX-16 | LTC2389CUK-16 |
|---|---|---|---|---|
| Package | 48-LQFP (7x7 mm) | 48-LQFP (7x7 mm) - same | 48-LQFP (7x7 mm) - same | 48-LQFP (7x7 mm) - same |
| Brand | Analog Devices (formerly Linear Technology) | Analog Devices - same | Analog Devices - same | Analog Devices - same |
| Resolution | 16 bits | 16 bits | 16 bits | 16 bits |
| Sampling Rate | 250 ksps | 250 ksps | 200 ksps class | 200 ksps class |
| SNR | 94 dB | 94 dB | 98 dB | 98 dB |
| Input Type | True Differential | True Differential | True Differential | True Differential |
| Operating Temperature Range | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) |
| Internal Reference | Yes, 0.5% / ±20 ppm/°C | Yes, 0.5% / ±20 ppm/°C | Yes, precision internal | Yes, precision internal |
| Lifecycle Status | Obsolete / Limited stock | Active / In production | Active / In production | Active / In production |
主要差異化特點
- Integrated precision 0.5% reference with ±20 ppm/°C drift (對比LTC2391CLX-16#PBF)
- Industrial -40C to +85C operating temperature range (對比LTC2391CLX-16#PBF)
- Zero pipeline latency for deterministic per-sample conversion (對比LTC2389ILX-16)
設計說明
Estimated: The LTC2391ILX-16 requires clean AVDD (5 V analog), OVDD (2.5/3/5 V digital I/O), and DVDD (5 V digital core) rails. Place 10 µF tantalum + 0.1 µF ceramic decoupling within 5 mm of each supply pin pair (AVDD/AGND, DVDD/DGND, OVDD/OGND). Star-ground AGND, DGND, and OGND at the ADC's exposed pad or single ground pour cutout to prevent digital switching currents from coupling into the SAR comparator. Estimated: budget approximately 6 mA AVDD + 1 mA DVDD + OVDD-dependent logic current for a typical 5 V design.
Keep analog input traces (AN1P/AN1N) short and impedance-matched; route them as a twisted pair or symmetric differential microstrip with continuous ground reference. Place the REF bypass capacitor (1-10 µF low-ESR) within 5 mm of the REF pin with its ground return directly to the AGND pin, not the global ground. Avoid routing digital parallel bus lines (D15-D0) under the analog input traces — route them on the opposite PCB layer or around the analog section.
Do not float CNAG unused, the BUSY pin. The BUSY output goes high during conversion and must either be monitored by the host or wired-OR with the CNTR reset. Also, when using the internal reference, leave the REFIN pin unconnected or tied to AGND — driving REFIN with an external reference disables the internal reference and changes the input common-mode behaviour. Estimated: common-source impedance above 200 Ω between the reference capacitor and the REF pin can degrade SNR by 1-2 dB.
Estimated: Driving the LTC2391ILX-16's switched-capacitor SAR input directly from a high-impedance source introduces gain error and distortion. Place a precision op-amp buffer (e.g. LT1468, LT6200) within 10 mm of the analog input pins with a 100 Ω series resistor between the op-amp output and the ADC input. Estimated: this isolates the ADC's kick-back current from the signal source and improves THD by typically 8-10 dB at full-scale input swing at 1 kHz fundamental.
合規資訊
Lead-free per #PBF suffix designation; RoHS and REACH compliant per Analog Devices product declaration. AEC-Q100 not applicable — this is a commercial/industrial-grade ADC. Lifecycle status: obsolete per icDirectory listing as of 2026-10-13; #PBF lead-free finish variant remains actively stocked at major distributors.
