MAX1294ACEI+T - 12-Bit 420ksps 6-Ch ADC +2.5V Ref | Maxim
MPN: MAX1294ACEI+T ✓ فعالMAX1294ACEI+T نمای کلی
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.
جایگزین‌های drop-in برای MAX1294ACEI+T — همان پکیج، سازگار پین‌به‌پین. قطعات با پکیج متفاوت که نیاز به تغییر PCB دارند مستثنی هستند.
گونه‌ها در این سری
مدل‌های هم‌سری که جایگزین مستقیم هستند برای MAX1294ACEI+T (همان فرم‌فاکتور و فوت‌پرینت) — متفاوت در Sampling Rate, Digital Interface, Integral Nonlinearity (INL), Internal Reference, Number of Channels.
MAX1294ACEI+
✅ جایگزین مستقیم📋 جایگزین مرجع (خارج از کاتالوگ)
MAX1295ACEI+T
✅ جایگزین مستقیمبرای قیمت تماس بگیرید
مشاهده دیتاشیت ←MAX1294BCEI+T
✅ جایگزین مستقیم ⚠️ مشخصات تأییدنشده📋 جایگزین مرجع (خارج از کاتالوگ)
MAX1290ACEI+
✅ جایگزین مستقیم📋 جایگزین مرجع (خارج از کاتالوگ)
MAX1284BCSA+
✅ جایگزین مستقیم ⚠️ مشخصات تأییدنشده📋 جایگزین مرجع (خارج از کاتالوگ)
MAX1165ACUI+
✅ جایگزین مستقیمبرای قیمت تماس بگیرید
مشاهده دیتاشیت ←MAX1294ACEI+T حداکثر مقادیر مجاز و مشخصات الکتریکی
| رزولوشن | 12 bit |
| Number of Channels | 6 (single-ended) / 3 (pseudo-differential) |
| نرخ نمونه‌برداری | 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) |
| محدوده دمای کاری | 0 °C to +70 °C (commercial) |
| بسته‌بندی / کیس | 28-SSOP (QSOP, 0.154" / 3.90 mm body) |
| نوع نصب | Surface Mount |
| تعداد پایه | 28 |
| Lead-Free / RoHS | Yes (Compliant) |
| Shipping Media | Tape & Reel (suffix +T) |
پیکربندی پین MAX1294ACEI+T
| پین 1 | AIN0 — Analog input channel 0 |
| پین 2 | AIN1 — Analog input channel 1 |
| پین 3 | AIN2 — Analog input channel 2 |
| پین 4 | AIN3 — Analog input channel 3 |
| پین 5 | AIN4 — Analog input channel 4 |
| پین 6 | AIN5 — Analog input channel 5 |
| پین 7 | AGND — Analog ground |
| پین 8 | REF — +2.5V internal reference (bypass with 0.1uF + 4.7uF) |
| پین 9 | REFADJ — Reference adjust input |
| پین 10 | AVDD — +5V analog supply |
| پین 11 | AGND — Analog ground |
| پین 12 | SHDN — Shutdown input (active low) |
| پین 13 | CS — Chip select (active low) |
| پین 14 | WR — Write input for control register (active low) |
| پین 15 | RD — Read input to access parallel data (active low) |
| پین 16 | HBEN — High-byte enable for 8-bit bus mode |
| پین 17 | D11/MSB — Data bit 11 (MSB) |
| پین 18 | D10 — Data bit 10 |
| پین 19 | D9 — Data bit 9 |
| پین 20 | D8 — Data bit 8 |
| پین 21 | D7 — Data bit 7 |
| پین 22 | D6 — Data bit 6 |
| پین 23 | D5 — Data bit 5 |
| پین 24 | D4 — Data bit 4 |
| پین 25 | D3 — Data bit 3 |
| پین 26 | D2 — Data bit 2 |
| پین 27 | D1 — Data bit 1 |
| پین 28 | D0/LSB — Data bit 0 (LSB); DVDD bond on same pin cluster |
کاربردهای معمول
MAX1294ACEI+T مناسب است برای 6 کاربردs: 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.
پیشنهادی
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.
پیشنهادی
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.
پیشنهادی
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.
پیشنهادی
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.
پیشنهادی
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.
پیشنهادی
خلاصه محصولات پیشنهادی
داده‌های مرجع مهندسی برای MAX1294ACEI+T — مقایسه، راهنمای طراحی و اطلاعات انطباق.
راهنمای انتخاب
مقایسه با جایگزین‌ها
| پارامتر | این محصول | 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 |
تفاوت‌های کلیدی
- Higher channel count in the same SSOP footprint (در مقابلMAX1295ACEI+T)
- Integrated +2.5V reference with 4.5 mA drive (در مقابلMAX1290ACEI+)
- 420 ksps throughput supports oversampling (در مقابلMAX1165ACUI+)
یادداشت‌های طراحی
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.
اطلاعات انطباق
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.
