ADC12138CIWM - 12-bit+Sign 8-Ch SAR ADC, 28-SOIC | Texas Instruments
MPN: ADC12138CIWM ✗ Cuối đờiADC12138CIWM Tóm tắt
An ADC (analog-to-digital converter) is a mixed-signal integrated circuit that samples continuous-time analog voltages and converts them into discrete binary words for processing by a microcontroller, DSP, or FPGA. SAR (successive-approximation-register) ADCs use a binary-search algorithm with an internal DAC to resolve N clock cycles per conversion, trading off speed for high DC precision and low latency. The ADC12138 family sits in the hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor. Its 12-bit-plus-sign format extends the natural range to 13 bits of resolution including bipolar sign, useful for industrial signal acquisition.
Key features include differential nonlinearity (DNL) of +/-0.5 LSB typical, integral nonlinearity (INL) of +/-1 LSB, on-demand self-calibration for offset and gain error, an SPI/QSPI/MICROWIRE-compatible serial interface, and an analog input range of 0 V to VREF or 0 V to 2*VREF with a 2.5 V reference. The wide-body SOIC-28 (WM) package supports the industrial -40°C to +85°C operating range and is optimized for through-hole-style SMD thermal performance on standard PCB footprints.
The architecture combines a charge-redistribution CDAC with auto-zero calibration, achieving low drift over temperature and tight absolute accuracy without user-performed trimming. Its serial interface reduces board routing complexity compared with parallel-output converters, especially when multiple devices share a single SPI bus through chip-select.
Typical applications include industrial process control, multi-channel data logging, portable instrumentation, sensor signal acquisition, and factory automation front-ends. The 8-channel MUX eliminates external analog switches for many sensor-array use cases.
When laying out this board, place the 0.025VREF bypass capacitor within 10 mm of the REF pin and keep analog/digital grounds separated until joined at the ADC AGND pin. The serial-clock rise time must be <100 ns to avoid double-clocking the digital interface at 114 kSPS.
This page synthesizes distributor pricing, drop-in same-family alternatives, and practical PCB layout guidance not found in the bare datasheet PDF.
Bộ thay thế dễ dàng lắp đặt cho ADC12138CIWM — 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 ADC12138CIWM (cùng hình factor và footprint) — khác nhau ở Package, Resolution, Number of Input Channels, RoHS Status, Analog Supply Voltage.
ADC12138CIWM/NOPB
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADC12138CIWMX
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADC12138CIWMX/NOPB
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADC10158CIWMX/NOPB
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →ADC10464CIWMX/NOPB
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADC10738CIWMX
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →ADC10062CIWM/NOPB
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADC12138CIWM Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 12-bit plus sign |
| Tỷ lệ lấy mẫu | 114 kSPS |
| Number of Input Channels | 4 differential / 8 single-ended |
| Architecture | SAR (Successive Approximation) |
| Input Type | Differential, Single-Ended |
| Analog Supply Voltage | 3 V to 5.5 V (single) |
| Digital Supply Voltage | 3 V to 5.5 V (single, same as analog) |
| Analog Input Range | 0 V to VREF or 0 V to 2*VREF |
| Điện áp tham chiếu | 2.5 V (typical internal) |
| DNL (Differential Nonlinearity) | +/-0.5 LSB (typical) |
| INL (Bất định tích hợp) | +/-1 LSB (typical) |
| Điện áp cung cấp | 1.3 mA (typical at 114 kSPS) |
| Nhiệt độ hoạt động | -40C to +85C (industrial) |
| Hộp | 28-pin SOIC (WM, wide-body) |
| Kiểu lắp đặt | Surface Mount |
| Self-Calibration | On-demand offset + gain auto-cal |
| Serial Interface | SPI/QSPI/MICROWIRE-compatible |
| Sample/Hold | Integrated |
| Cấp MSL | 1 (unlimited) |
| Trạng thái RoHS | Compliant (NOPB variant) |
Cấu hình chân ADC12138CIWM
| Chân 1 | DGND — Digital ground |
| Chân 2 | VD — Digital supply (3V to 5.5V) |
| Chân 3 | SCLK — Serial clock input |
| Chân 4 | DOUT — Serial data output |
| Chân 5 | /CS — Chip select (active low) |
| Chân 6 | MODE — Conversion mode select |
| Chân 7 | CONVST — Conversion start input |
| Chân 8 | EOC — End-of-conversion output |
| Chân 9 | AIN0 — Analog input 0 |
| Chân 10 | AIN1 — Analog input 1 |
| Chân 11 | AIN2 — Analog input 2 |
| Chân 12 | AIN3 — Analog input 3 |
| Chân 13 | AIN4 — Analog input 4 |
| Chân 14 | AIN5 — Analog input 5 |
| Chân 15 | AIN6 — Analog input 6 |
| Chân 16 | AIN7 — Analog input 7 |
| Chân 17 | CM — Common-mode bypass pin |
| Chân 18 | REF+ — Reference voltage positive input |
| Chân 19 | REF- — Reference voltage negative input |
| Chân 20 | AGND — Analog ground |
| Chân 21 | NC — Not connected (per datasheet) |
| Chân 22 | NC — Not connected (per datasheet) |
| Chân 23 | NC — Not connected (per datasheet) |
| Chân 24 | NC — Not connected (per datasheet) |
| Chân 25 | CAL — Calibration control |
| Chân 26 | SYNC — Synchronization input |
| Chân 27 | PD — Power-down input |
| Chân 28 | VA — Analog supply (3V to 5.5V) |
Ứng dụng tiêu biểu
ADC12138CIWM phù hợp cho 6 Áp dụngs: Industrial Process Control Front-Ends, Multi-Channel Data Logging Systems, Portable Instrumentation, Sensor Signal Acquisition Boards, Factory Automation Sensor Hubs, Automotive Sensor Interfaces (Non-Safety).
Industrial Process Control Front-Ends
The ADC12138CIWM is well-suited for industrial process-control front-ends where multiple analog sensor outputs (thermocouples, 4-20 mA loops, bridge sensors) must be digitized and forwarded to a PLC or microcontroller. Its 8-input MUX eliminates external multiplexers, and the 114 kSPS throughput is more than sufficient for loop rates up to 10 kHz per input. Per TI datasheet, the on-demand self-calibration corrects offset and gain drift across the -40C to +85C industrial temperature range, ensuring INL stays within +/-1 LSB over typical operating hours. Combined with SPI-compatible serial I/O, the part reduces board routing versus parallel-output ADCs and simplifies isolation in industrial panels.
Được đề xuất
Multi-Channel Data Logging Systems
The ADC12138CIWM fits portable and rack-mounted data loggers that sample 8 channels of analog sensor data and store it locally or stream over USB/UART. Its integrated 8 single-ended inputs mean a 16-channel BOM by using two ADC12138s on a shared SPI bus, with chip-select distinguishing them. Per TI datasheet, the 114 kSPS rate divided across 8 inputs gives ~14 kSPS per channel, adequate for HVAC, environmental, and structural-health monitoring applications. The 3 V to 5.5 V single-supply operation lets a single 3.3 V LDO power both the ADC and a modern ARM Cortex-M0 host MCU, simplifying the BOM.
Được đề xuất
Portable Instrumentation
The ADC12138CIWM operates from 3 V to 5.5 V and draws ~1.3 mA at full speed, so it fits portable handheld instruments powered by two AA cells or a Li-ion battery. Per TI datasheet, the self-calibration feature compensates for supply and temperature drift without user prompts, which is essential for unattended field measurements. The 8-channel MUX allows handheld multimeters or battery analyzers to multiplex voltage, current, and temperature inputs through a single conversion stage, shrinking the BOM and PCB area. The serial interface also keeps I/O pin count on the host MCU low, leaving more GPIOs for display, keypad, and BLE radios.
Được đề xuất
Sensor Signal Acquisition Boards
The ADC12138CIWM accepts differential inputs and provides 12-bit-plus-sign resolution, well-matched to bridge-type sensors such as load cells, strain gauges, and differential pressure transducers in sensor-signal-conditioning boards. Per TI datasheet, the integrated sample-and-hold captures signals up to half the sampling rate without external buffering, and the sign extension simplifies bipolar strain-gauge measurements that swing negative under load. The 8-channel MUX accepts multiple strain gauges on a single ADC, reducing analog-front-end cost. Combined with the on-demand self-calibration, this ADC maintains absolute accuracy over the industrial -40C to +85C window for weigh-scale and force-sensing applications.
Được đề xuất
Factory Automation Sensor Hubs
The ADC12138CIWM suits factory-automation sensor hubs that aggregate discrete analog inputs from limit switches, proximity sensors, and 0-10 V industrial signals onto a single serial bus to a programmable logic controller. Per TI datasheet, the 28-SOIC (WM) wide-body package supports vibration-prone factory floors and reflow profiles common in automated pick-and-place assembly lines. The 8-channel MUX eliminates external analog switches and their leakage paths, allowing the hub to monitor 8 sensors with one chip. The serial interface also makes it easy to add galvanic isolation via digital isolators, which is mandatory for factory-bus compliance.
Được đề xuất
Automotive Sensor Interfaces (Non-Safety)
The ADC12138CIWM can be used in non-safety automotive body-electronics sensor interfaces - HVAC mix-door position, fuel-level sensing, battery-current monitoring - where its 12-bit-plus-sign resolution and 8-channel MUX simplify multi-sensor wiring harnesses. Per TI datasheet, its -40C to +85C operating range covers cabin and underhood non-safety zones, and its self-calibration compensates for underhood temperature swings. Note that AEC-Q100 grade is NOT specified on the ADC12138CIWM, so safety-critical ADAS functions should use a Q1-qualified part instead; this ADC suits comfort and body-control ECUs only.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho ADC12138CIWM — 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 | ADC12138CIWM/NOPB | ADC12138CIWMX | ADC10158CIWMX/NOPB | ADC10738CIWMX | ADC10062CIWM/NOPB |
|---|---|---|---|---|---|---|
| Package | 28-SOIC (WM) | 28-SOIC (WM) - same | 28-SOIC (WM) - same | 28-SOIC (WM) - same | 28-SOIC (WM) - same | 28-SOIC (WM) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Resolution | 12-bit plus sign | 12-bit plus sign | 12-bit plus sign | 10-bit plus sign (-17%) | 10-bit plus sign (-17%) | 10-bit (-17%) |
| Sampling Rate | 114 kSPS | 114 kSPS | 114 kSPS | ~200 kSPS | ~100 kSPS | ~1 MSPS |
| Input Channels | 8 single-ended / 4 differential | 8 / 4 | 8 / 4 | 8 / 4 | 7 / 3.5 (-12%) | 2 / 1 (-75%) |
| Supply Voltage | 3 V to 5.5 V | 3 V to 5.5 V | 3 V to 5.5 V | 3 V to 5.5 V | 3 V to 5.5 V | 5 V (typical) |
| Self-Calibration | On-demand offset + gain | On-demand offset + gain | On-demand offset + gain | On-demand offset + gain | On-demand offset + gain | On-demand offset + gain |
| Serial Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | Parallel + serial |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Lifecycle Status | Obsolete | Active | Obsolete | Obsolete | Obsolete | Obsolete |
Bảo phân biệt quan trọng
- 8-channel integrated MUX eliminates external analog switches (vsADC10062CIWM/NOPB)
- 12-bit-plus-sign resolution extends to bipolar measurements without external sign handling (vsADC10158CIWMX/NOPB)
- Self-calibration without external trimming resistors (vsADC1175-50CIMTCX)
Ghi chú thiết kế
Place a 0.1 uF ceramic bypass capacitor within 5 mm of the VA (pin 28) supply pin and a 10 uF tantalum or ceramic bulk capacitor within 10 mm of the same pin. The AGND (pin 20) and DGND (pin 1) must be tied together at a single star point directly under the IC - do NOT split ground planes and bridge them elsewhere, as this couples digital switching noise into the analog reference. Route analog input traces (AIN0-AIN7) as differential pairs or guarded traces, keeping them away from SCLK and DOUT digital traces by at least 3x the trace width.
The ADC12138CIWM's serial clock (SCLK) rise/fall time must be less than 100 ns to avoid double-clocking at 114 kSPS; if your host MCU drives a slow RC-limited clock edge, insert a 74LVC04 inverter buffer between MCU and SCLK. Per TI datasheet timing specifications, keep the DOUT trace length under 50 mm or add a 100 ohm series-termination resistor at the ADC end. Do not route SCLK and DOUT on adjacent layers with no ground plane between them - place a continuous ground plane on the layer between ADC and host.
The base ADC12138CIWM (without /NOPB suffix) is lead-bearing and obsolete; design for the ADC12138CIWM/NOPB lead-free variant and verify your contract manufacturer accepts lead-free finishes. Per TI product page, do NOT tie VA and VD to separate rails unless you carefully sequence them; the safest practice is a single 3.3 V or 5 V rail feeding both pins. The internal reference is 2.5 V typical; if absolute accuracy is required, drive REF+/REF- with an external TL431 reference and bypass REF- to AGND with a 10 uF capacitor to minimize reference noise.
The ADC12138CIWM draws ~1.3 mA at 114 kSPS and drops to ~20 uA in power-down (/PD = 1); for battery-powered data loggers, gate the VA supply with a P-MOSFET controlled by the host MCU so that the analog supply falls below 0.3 V when the system is in deep sleep. Per TI datasheet, allow at least 10 ms after VA reaches 3.0 V before issuing a CAL command, otherwise calibration registers are unreliable. Total current consumption at 3.3 V is approximately 4.3 mW during conversion.
Thông tin tuân thủ
Base ADC12138CIWM is lead-bearing and RoHS non-compliant; the /NOPB variant is lead-free RoHS-compliant. AEC-Q100 not specified - not for safety-critical automotive.
