ADC121S021CISDX - 12-Bit 50-200ksps SAR ADC | Texas Instruments
MPN: ADC121S021CISDX ✗ Cuối đờiADC121S021CISDX Tóm tắt
A SAR ADC is a type of data converter that uses a binary-search successive-approximation algorithm to convert an analog input to a digital code in a fixed number of clock cycles, delivering deterministic latency and excellent dynamic performance without the pipeline delay of higher-speed flash or pipelined converters. SAR ADCs sit within the broader data-converter hierarchy as low-latency, low-power, medium-resolution samplers used in sensor, instrumentation, and control loops, and they form a key subclass of precision analog-to-digital converters in modern mixed-signal systems.
Key features of the ADC121S021 include ±1 LSB INL/DNL (max), a true no-missing-codes 12-bit output, an SINAD of 72 dB (typical at 200 ksps), a single-ended analog input span of 0 V to VREF (with VREF = V_A), an external reference or V_A supply, a 3-wire serial interface (CS, SCLK, DOUT), and a power-down mode that drops supply current to microampere levels between conversions. The wide supply range (2.7 V-5.25 V) makes the part compatible with both 3.3 V and 5 V microcontrollers.
The device uses a charge-redistribution DAC array and a high-speed comparator inside the SAR loop, clocked by the external SCLK input up to 20 MHz. Throughput scales linearly with SCLK frequency across the 50-200 ksps window, and the digital interface is independent of analog sampling rate, which simplifies host MCU firmware.
Typical applications include portable/battery-powered sensor digitizers, industrial process-control front ends, optical-module monitoring, low-cost instrumentation, and consumer audio/video signal monitoring. Designers pick this part for its tiny 6-pin WSON footprint, single-supply operation, and deterministic SPI behavior.
When designing with this device, place a 1 µF decoupling capacitor as close as possible to V_A and use the exposed thermal pad to lower θJA. A clean, low-impedance VREF (or simply tying REF to V_A) is essential to realizing full 12-bit performance. The original ADC121S021CISDX is now obsolete; the /NOPB lead-free and CISDX/NOPB reel-packaged variant is the recommended active replacement.
This page synthesizes distributor pricing, pin-compatible drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, helping engineers select a 12-bit SAR ADC quickly and confidently.
Bộ thay thế dễ dàng lắp đặt cho ADC121S021CISDX — 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 ADC121S021CISDX (cùng hình factor và footprint) — khác nhau ở Package, Resolution, RoHS Status, Architecture, Operating Temperature Range.
ADC121S021CISDX/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC121S021CIMFX/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC121S021CISD/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADC121S021CISDX
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADC121S021CISDX Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 12 bit |
| Number of Channels | 1 |
| Converter Type | SAR (Successive Approximation Register) |
| Sample Rate Range | 50 ksps to 200 ksps |
| Supply Voltage (V_A) | 2.7 V to 5.25 V |
| Supply Current (200 ksps, 3 V) | 1.4 mW typical |
| Analog Input Type | Single-ended (pseudo-differential) |
| Phạm vi điện áp đầu vào | 0 V to V_REF |
| Điện áp tham chiếu | V_REF (external) or V_A |
| INL (max) | ±1 LSB |
| DNL (max) | +1.5 / -1 LSB |
| SINAD | 72 dB typical at 200 ksps |
| Serial Interface | SPI / QSPI / MICROWIRE-compatible (3-wire: CS, SCLK, DOUT) |
| SCLK Frequency (max) | 20 MHz |
| Hộp | 6-pin WSON (2.2 x 2.5 mm) with exposed thermal pad |
| Nhiệt độ hoạt động | -40C to +85C (industrial) |
| Power-Down Current | Microampere-level (see datasheet) |
| Trạng thái RoHS | Compliant (/NOPB variant) |
Cấu hình chân ADC121S021CISDX
| Chân 1 | VIN — Analog input (single-ended, 0 V to V_REF) |
| Chân 2 | GND — Ground return |
| Chân 3 | DOUT — Serial data output (SPI/QSPI/MICROWIRE) |
| Chân 4 | SCLK — Serial clock input (up to 20 MHz) |
| Chân 5 | CS — Active-low chip select |
| Chân 6 | V_A — Analog/digital supply (2.7 V to 5.25 V) |
| Chân EP | EPAD — Exposed thermal pad - tie to GND for thermal dissipation |
Ứng dụng tiêu biểu
ADC121S021CISDX phù hợp cho 6 Áp dụngs: Portable Battery-Powered Sensor Digitizer, Industrial Process-Control Input Module, Optical Module Monitor (SFP/QSFP DOM), Low-Cost Handheld Instrumentation, Consumer Audio/Video Signal Monitoring, Automotive Sensor-Cluster Digitizer (non-safety).
Portable Battery-Powered Sensor Digitizer
The ADC121S021CISDX is well matched to portable sensor digitizers where 12-bit resolution at low sample rates is sufficient. With 1.4 mW typical power dissipation at 3 V and 200 ksps, plus a microampere power-down mode between conversions, it can run from a single Li-ion cell for months in duty-cycled temperature, pressure, or gas-sensor front ends. The 6-pin WSON (2.2 x 2.5 mm) footprint leaves room for surrounding analog signal conditioning on a tiny PCB.
Được đề xuất
Industrial Process-Control Input Module
In 4-20 mA or 0-10 V industrial input modules, the ADC121S021CISDX provides 12-bit (±1 LSB INL) digitizing of a single-ended analog signal with deterministic latency from its SAR architecture. The 2.7-5.25 V supply range accepts 3.3 V and 5 V backplanes, while the 50-200 ksps throughput handles multiplexed thermocouple, RTD, or strain-gauge bridges. The exposed thermal pad and 6-pin WSON simplify thermal management in sealed IP65 enclosures.
Được đề xuất
Optical Module Monitor (SFP/QSFP DOM)
Digital Diagnostic Monitoring (DOM) inside SFP and QSFP optical transceivers requires a low-power, small-footprint ADC for bias current, TX power, and received-power measurements. The ADC121S021CISDX's 6-pin WSON (2.2 x 2.5 mm) package, 12-bit resolution, and SPI interface up to 20 MHz match typical microcontroller companion chips in these modules. Power-down mode enables sub-mA standby between host polls.
Được đề xuất
Low-Cost Handheld Instrumentation
Handheld multimeters, data loggers, and bench instruments use the ADC121S021CISDX to digitize a single high-impedance analog channel with 12-bit accuracy at sample rates up to 200 ksps. The 3-wire SPI interface attaches directly to a low-cost MCU such as an MSP430 or Cortex-M0 without glue logic. The 1.4 mW power budget at 3 V permits battery-only designs running from two AA cells in series.
Được đề xuất
Consumer Audio/Video Signal Monitoring
In set-top boxes, A/V receivers, and TV-side monitoring ports, the ADC121S021CISDX samples audio-level, video-sync, or backlight-current sense nodes for housekeeping and protection. The 50-200 ksps window comfortably digitizes audio-band signals, while 12-bit resolution provides sufficient dynamic range for level meters. The WSON package and 1.4 mW power keep thermal and PCB real estate negligible inside space-constrained consumer enclosures.
Được đề xuất
Automotive Sensor-Cluster Digitizer (non-safety)
For non-safety body and chassis functions (e.g., seat-position, HVAC flap position, ambient light), the ADC121S021CISDX delivers 12-bit digitizing on a 6-pin WSON footprint that drops into cluster PCBs alongside a 3.3 V MCU. The -40 °C to +85 °C industrial temperature range covers cabin environments. Note: for ASIL-rated applications use the AEC-Q100-qualified ADC121S021-Q1 family variant instead.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho ADC121S021CISDX — 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 | ADC121S021CISDX/NOPB | ADC121S021CISD/NOPB | ADC121S021CIMFX/NOPB |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 6-WSON (2.2x2.5) | 6-WSON (2.2x2.5) - same | 6-WSON (2.2x2.5) - same | 6-SOT-23 - different footprint |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit |
| Sample Rate | 50-200 ksps | 50-200 ksps | 50-200 ksps | 50-200 ksps |
| Supply Voltage | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V |
| Interface | SPI up to 20 MHz | SPI up to 20 MHz | SPI up to 20 MHz | SPI up to 20 MHz |
| RoHS / Lead-Free | Non-RoHS (tin-lead, obsolete) | RoHS / lead-free (active) | RoHS / lead-free (active) | RoHS / lead-free (active) |
| Lifecycle | Obsolete | Active | Active | Active |
Bảo phân biệt quan trọng
- WSON (2.2 x 2.5 mm) is the smallest 12-bit 200 ksps SAR footprint in TI's S021 family (vsADC121S021CIMFX/NOPB (SOT-23))
- Lead-free /NOPB finish enables modern RoHS-compliant builds (vsADC121S021CISDX (obsolete tin-lead base part))
- Single-channel SAR with deterministic latency vs sigma-delta settling delays (vsHigher-channel-count pipelined ADCs)
Ghi chú thiết kế
Place a 1 µF X7R/X5R ceramic decoupling capacitor as close as possible to the V_A pin (Pin 6) with a short, wide trace to ground. The exposed thermal pad (EP) must be soldered to a grounded copper pour of at least 10 mm² to keep θJA within the datasheet spec. Avoid routing digital SCLK/DOUT traces parallel to the analog VIN trace to minimize digital-to-analog coupling.
Do not leave CS floating - it must be driven low to enable the serial interface and high to put the part in power-down. A floating CS can cause continuous conversion and elevated supply current. Use a 10 kΩ pull-up to V_A if the host MCU does not drive CS between conversions. Also ensure the SCLK line idles low, since the ADC samples on the SCLK rising edge.
For full 12-bit no-missing-codes performance, drive V_REF from a low-noise source. Tie V_REF to V_A when a 5 V supply is used, or use a dedicated shunt reference (e.g., TL431) when V_A is 3.3 V and the analog input swing must reach 3.3 V. Adding a 0.1 µF ceramic bypass right at the V_A pin suppresses high-frequency V_A ripple that would otherwise appear as conversion noise.
Thông tin tuân thủ
Base part ADC121S021CISDX is non-RoHS (tin-lead finish) and obsolete. The /NOPB variants are RoHS compliant and lead-free. Not AEC-Q100 qualified; use ADC121S021-Q1 family for automotive.
