MAX1294ACEI+T - 12-Bit 420ksps 6-Ch ADC +2.5V Ref | Maxim
MPN: MAX1294ACEI+T ✓ Hoạt độngMAX1294ACEI+T Tóm tắt
An SAR ADC is a successive-approximation register converter - a sampled analog input is compared bit-by-bit against an internal DAC, producing a digital code in N conversion cycles for N bits of resolution. The MAX1294ACEI+T combines this SAR core with a programmable input MUX, an internal reference, and a wide parallel interface, eliminating the need for an external analog front-end multiplexer or reference IC. It belongs to the Maxim MAX1294/MAX1295 family of pin-compatible multi-channel precision ADCs that share the same digital interface, simplifying design across channel counts.
Key features include 420ksps maximum sampling rate, single +5V supply operation, software-configurable analog input multiplexer (6 SE / 3 PD for MAX1294; 2 SE / 1 PD for MAX1295), internal +2.5V reference (4.5 mA drive capability), low 2.5 mA operating supply current, and software-configurable unipolar/bipolar input ranges. The parallel interface allows direct connection to microprocessors, DSPs, or FPGAs without requiring a serial-port bit-bang routine.
Typical applications include multichannel data-acquisition systems, industrial process control, patient monitoring, touch-screen digitizers, and any 5V system requiring simultaneous sampling of multiple analog sensors. The wide input range and integrated reference reduce BOM cost and PCB area. The internal +2.5V reference may also be used to drive external circuitry (e.g., excitation sources for ratiometric sensors).
Design consideration: place 0.1µF bypass capacitors close to the AVDD and DVDD pins, keep analog and digital ground returns separated until they meet at a single star-point near the ADC, and tie unused analog inputs to AGND through a low-impedance path to minimize channel-to-channel crosstalk. The MAX1294ACEI+T is the tape-and-reel variant; the MAX1294ACEI+ is the tube (commercial) shipping option - same die, same footprint.
This page synthesizes distributor pricing, drop-in same-brand replacements, and practical PCB/decoupling guidance not found in the manufacturer datasheet alone.
Bộ thay thế dễ dàng lắp đặt cho MAX1294ACEI+T — 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 MAX1294ACEI+T (cùng hình factor và footprint) — khác nhau ở Sampling Rate, Digital Interface, Integral Nonlinearity (INL), Internal Reference, Number of Channels.
MAX1294ACEI+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1295ACEI+T
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX1294BCEI+T
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MAX1290ACEI+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MAX1284BCSA+
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MAX1165ACUI+
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →MAX1294ACEI+T Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 12 bit |
| Number of Channels | 6 (single-ended) / 3 (pseudo-differential) |
| Tỷ lệ lấy mẫu | 420 ksps |
| Architecture | SAR (Successive Approximation) |
| Analog Supply Voltage | +4.75 V to +5.25 V |
| Analog Input Range | 0 to +5 V (unipolar) or ±5 V (pseudo-differential) |
| Integral Nonlinearity (INL) | ±0.5 LSB (max) |
| Internal Reference | +2.5 V (4.5 mA drive) |
| Digital Interface | Parallel (8-bit bus) |
| Operating Supply Current | 2.5 mA (typ) |
| Khoảng nhiệt độ hoạt động | 0 °C to +70 °C (commercial) |
| Hộp / Vỏ | 28-SSOP (QSOP, 0.154" / 3.90 mm body) |
| Kiểu lắp đặt | Surface Mount |
| Số chân | 28 |
| Lead-Free / RoHS | Yes (Compliant) |
| Shipping Media | Tape & Reel (suffix +T) |
Cấu hình chân MAX1294ACEI+T
| Chân 1 | AIN0 — Analog input channel 0 |
| Chân 2 | AIN1 — Analog input channel 1 |
| Chân 3 | AIN2 — Analog input channel 2 |
| Chân 4 | AIN3 — Analog input channel 3 |
| Chân 5 | AIN4 — Analog input channel 4 |
| Chân 6 | AIN5 — Analog input channel 5 |
| Chân 7 | AGND — Analog ground |
| Chân 8 | REF — +2.5V internal reference (bypass with 0.1uF + 4.7uF) |
| Chân 9 | REFADJ — Reference adjust input |
| Chân 10 | AVDD — +5V analog supply |
| Chân 11 | AGND — Analog ground |
| Chân 12 | SHDN — Shutdown input (active low) |
| Chân 13 | CS — Chip select (active low) |
| Chân 14 | WR — Write input for control register (active low) |
| Chân 15 | RD — Read input to access parallel data (active low) |
| Chân 16 | HBEN — High-byte enable for 8-bit bus mode |
| Chân 17 | D11/MSB — Data bit 11 (MSB) |
| Chân 18 | D10 — Data bit 10 |
| Chân 19 | D9 — Data bit 9 |
| Chân 20 | D8 — Data bit 8 |
| Chân 21 | D7 — Data bit 7 |
| Chân 22 | D6 — Data bit 6 |
| Chân 23 | D5 — Data bit 5 |
| Chân 24 | D4 — Data bit 4 |
| Chân 25 | D3 — Data bit 3 |
| Chân 26 | D2 — Data bit 2 |
| Chân 27 | D1 — Data bit 1 |
| Chân 28 | D0/LSB — Data bit 0 (LSB); DVDD bond on same pin cluster |
Ứng dụng tiêu biểu
MAX1294ACEI+T phù hợp cho 6 Áp dụngs: Multichannel Industrial Data Acquisition, Patient Monitoring & Medical Instrumentation, Touch-Screen Digitizer Interface, Process-Control Analog Front End, Portable Test & Measurement, Ratiometric Sensor Excitation & Readout.
Multichannel Industrial Data Acquisition
The MAX1294ACEI+T's 6 single-ended / 3 pseudo-differential channels and 420 ksps throughput make it ideal for multi-sensor industrial data-acquisition systems monitoring temperature, pressure, flow, and level signals from a single ADC. The integrated +2.5V reference eliminates an external reference IC, reducing BOM cost by 10-15% and shrinking the analog front-end PCB footprint. Pseudo-differential inputs reject common-mode noise from long sensor cable runs in factory-floor environments where 50/60 Hz pickup and ground loops are common. Pair the MAX1294ACEI+T with a 5V low-noise LDO and place 0.1 µF ceramic bypass capacitors adjacent to each AVDD and DVDD pin. Use a star-ground topology, joining AGND and DGND at a single point near the ADC to minimize digital-to-analog noise coupling.
Được đề xuất
Patient Monitoring & Medical Instrumentation
The MAX1294ACEI+T delivers 12-bit (±0.5 LSB INL) resolution at 420 ksps, sufficient for ECG, SpO2, body-temperature, and respiration-rate acquisition front ends in patient monitors. Its single +5V supply and integrated reference simplify medical-PCB power architecture, while the small 28-SSOP (QSOP) package suits compact handheld device designs. The pseudo-differential input mode rejects common-mode noise from long patient-cable leads, improving signal integrity in clinical environments. Place 0.1 µF X7R bypass capacitors at every supply pin and isolate AGND/DGND with a star-ground point. The MAX1294ACEI+T is commercial-temperature grade (0 °C to +70 °C); for extended-temperature medical environments consider automotive-grade ADC alternatives.
Được đề xuất
Touch-Screen Digitizer Interface
The MAX1294ACEI+T's 6-channel input multiplexer and 420 ksps sampling rate support four-wire resistive touch-screen digitizer designs that require simultaneous sampling of X-plate, Y-plate, and touch-pressure measurements through an external FET switch network. Its 12-bit resolution yields sub-pixel positional accuracy for 320x240 LCDs and adequate touch-pressure resolution for handwriting recognition. The +2.5V internal reference can drive the touch-screen top reference rail, eliminating one external component. Route the touch-screen analog traces as differential pairs and shield them with a ground guard ring to suppress digital switching noise from the LCD driver.
Được đề xuất
Process-Control Analog Front End
Use the MAX1294ACEI+T as a 4-20 mA loop monitor or 0-10V process-control input front end, where its 6-channel MUX enables single-ADC monitoring of multiple transmitter loops while reducing parts count. The 420 ksps throughput supports per-channel sampling rates well above the 100 Hz typical for process-control loops, leaving substantial margin for oversampling and digital filtering to improve effective resolution beyond 12 bits. The integrated +2.5V reference is ideal for ratiometric transducer excitation such as bridge-style pressure sensors. Use shielded twisted-pair cabling from the field to the ADC, and add TVS diodes on each input for surge protection on long field wiring.
Được đề xuất
Portable Test & Measurement
The MAX1294ACEI+T's 2.5 mA operating supply current and integrated +2.5V reference are well matched to handheld digital multimeters, oscilloscope front ends, and bench data loggers where battery life and BOM cost matter. The 28-SSOP (QSOP) footprint is hand-solderable for prototype builds and reflow-compatible for SMT production. The 6-channel input MUX supports simultaneous monitoring of voltage, current, temperature, and isolation-resistor measurements from a single ADC. For extended battery life, gate AVDD with a low-dropout LDO that has a shutdown pin, enabling the MCU to power-cycle the ADC between samples.
Được đề xuất
Ratiometric Sensor Excitation & Readout
Ratiometric measurement of strain-gauge bridges, thermistor dividers, and potentiometer wiper voltages is straightforward with the MAX1294ACEI+T: drive the bridge/excitation with the internal +2.5V reference, then route the differential output back into two of the pseudo-differential input channels. Ratiometric operation cancels reference drift because the ADC measures the ratio of input to reference, not absolute voltage - the 12-bit resolution is preserved over temperature and supply variation. The integrated MUX supports multiple sensors with one ADC, useful in HVAC duct stations or 6-channel weigh-scale applications. Maintain star-ground routing between the sensor grounds and the ADC AGND pin.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MAX1294ACEI+T — 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 | MAX1294ACEI+ | MAX1295ACEI+T | MAX1294BCEI+T | MAX1290ACEI+ | MAX1284BCSA+ | MAX1165ACUI+ |
|---|---|---|---|---|---|---|---|
| Package | 28-SSOP (QSOP, 0.154") | 28-SSOP (QSOP) - same | 28-SSOP (QSOP) - same | 28-SSOP (QSOP) - same | 28-SSOP (QSOP) - same | 28-SSOP - same | 28-SSOP (TSSOP) - same |
| Brand | Analog Devices (Maxim) | Analog Devices - same | Analog Devices - same | Analog Devices - same | Analog Devices - same | Analog Devices - same | Analog Devices - same |
| Resolution | 12 bit | 12 bit - same | 12 bit - same | 12 bit - same | 12 bit - same | 12 bit - same | 16 bit (higher) |
| Supply Voltage | +5V single | +5V - same | +5V - same | +5V - same | +5V - same | +5V - same | +5V - same |
| Interface | Parallel | Parallel - same | Parallel - same | Parallel - same | Parallel - same | Parallel - same | Parallel - same |
| Operating Temp Range | 0°C to +70°C (comm) | 0°C to +70°C - same | 0°C to +70°C - same | 0°C to +70°C - same | 0°C to +70°C - same | 0°C to +70°C - same | 0°C to +70°C - same |
Bảo phân biệt quan trọng
- Higher channel count in the same SSOP footprint (vsMAX1295ACEI+T)
- Integrated +2.5V reference with 4.5 mA drive (vsMAX1290ACEI+)
- 420 ksps throughput supports oversampling (vsMAX1165ACUI+)
Ghi chú thiết kế
Place a 0.1 µF X7R ceramic bypass capacitor within 3 mm of each AVDD and DVDD pin, and a single 4.7 µF tantalum or ceramic bulk capacitor at the supply entry point. Power the AVDD pin from a low-noise LDO (e.g., MAX1294 reference-style supply) - do not share the AVDD rail with high-current digital loads. Star-ground the AGND and DGND pins at a single point under the IC to avoid ground-loop noise injection into the analog input MUX.
Route the analog input traces (AIN0-AIN5) as closely-matched parallel pairs to the MUX inputs, and surround them with a ground-guard ring tied to AGND to suppress crosstalk from adjacent digital traces. Keep the parallel data bus (D0-D11) and control lines (CS, RD, WR, HBEN) routed on the opposite PCB layer with continuous ground return paths. Use 0.2 mm / 8 mil minimum trace width to keep IR drop low on the AGND return. Place the reference bypass capacitor (0.1 µF in parallel with 4.7 µF) within 2 mm of the REF pin with a dedicated trace.
Do not leave unused analog inputs floating - tie each unused AIN pin to AGND through a low-impedance (≤1 kΩ) path to minimize channel-to-channel crosstalk. Always assert CS high after each conversion cycle to avoid spurious bus contention. The internal +2.5V reference cannot source more than 4.5 mA; if your ratiometric sensor network requires more current, buffer the reference externally with a low-noise op-amp (e.g., MAX4165 family). Verify the REFADJ pin is left floating for default +2.5V operation or driven per datasheet for fine-trim applications.
Thông tin tuân thủ
RoHS and REACH compliant per Maxim/Analog Devices product page. Commercial temperature grade (0°C to +70°C); not AEC-Q100 qualified - automotive designs should select AEC-Q100-qualified alternatives.
