MAX1240BEPA+ - 12-Bit 73ksps SPI ADC, External Ref | Maxim
MPN: MAX1240BEPA+ ✓ Hoạt độngMAX1240BEPA+ Tóm tắt
An SAR (Successive Approximation Register) ADC is a type of analog-to-digital converter that uses a binary search algorithm against a precision reference to determine the digital code for an analog input. In the system hierarchy, the MAX1240BEPA+ sits below instrumentation-class SAR ADCs and above 8-bit successive-approximation parts, with 12 bits representing a widely-used resolution for sensor readout, process control, and portable instrumentation where 8 bits is too coarse and 14/16 bits is unnecessary.
Key features include a 73 ksample/s sampling rate, 1 analog input channel, single-ended input range of 0V to Vref with Vref up to 3.6V, an internal track/hold, and a serial data output clocked by an external SCLK. The MAX1240 draws very low supply current during conversion and drops to microamp-level quiescent current in shutdown, which is enabled via a dedicated hardware pin. The 8-pin PDIP footprint allows easy breadboarding and through-hole prototyping.
The device is built on a BiCMOS process to combine low-noise analog input buffering with low-power CMOS digital logic. Because it uses an external reference (rather than the internal 2.5V reference of the MAX1240A/MAX1241A variants), designers can connect any precision low-drift reference - such as the MAX6126 - to optimize noise, scale the input range, or ratiometrically track a sensor bridge excitation voltage.
Typical applications include portable data logging, hand-held instrumentation, sensor signal conditioning (thermocouple, RTD, strain gauge), process control analog front-ends, battery-powered measurement equipment, and 4 mA to 20 mA loop-powered industrial sensors. The low power-down current makes it especially suitable for duty-cycled, battery-powered designs.
When designing with this part, choose a low-noise reference and place the input bypass capacitor close to AVDD. Ensure SCLK runs no faster than the datasheet-specified maximum and allow tCONV between CNVST rising edge and the first SCLK-driven bit clock-out. Refer to the manufacturer datasheet for full timing and absolute maximum ratings.
This page synthesizes distributor pricing, parametric drop-in alternatives, and practical design notes not found in the manufacturer datasheet - giving procurement and design engineers a single reference for evaluation, sourcing, and second-source decisions.
Bộ thay thế dễ dàng lắp đặt cho MAX1240BEPA+ — 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 MAX1240BEPA+ (cùng hình factor và footprint) — khác nhau ở Conversion Time, Package, Input Type, Number of Channels, Operating Temperature Range.
MAX1240BCPA+
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MAX1241BEPA+
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MAX1240BEPA+
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →MAX1240BEPA
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MAX1240EEPA+
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
MAX1240BEPA+ Tỷ lệ tối đa & tính chất điện
| Độ phân giải | 12 bits |
| Architecture | SAR (Successive Approximation) |
| Tỷ lệ lấy mẫu | 73 ksamples/sec |
| Number of Input Channels | 1 (single-ended) |
| Input Type | Single-ended, pseudo-differential (AIN vs. GND) |
| Analog Supply Voltage | +2.7 V to +3.6 V (single supply) |
| Digital Supply Voltage | +2.7 V to +3.6 V (single supply) |
| Reference Type | External (MAX1240; MAX1241 has internal 2.5 V) |
| Reference Input Range | 0 V to +3.6 V (VREF ≤ AVDD) |
| Analog Input Range | 0 V to VREF |
| Data Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Track-and-Hold | Internal, 1:1 S/H:ADC ratio |
| Power-Down Current | 5 µW (power-down mode) |
| Nhiệt độ hoạt động | 0 °C to +70 °C (commercial, 'E' grade) |
| Hộp | 8-pin PDIP (E suffix) |
| Kiểu lắp đặt | Through-Hole (DIP) |
| Process Technology | BiCMOS |
| Trạng thái RoHS | Compliant |
Cấu hình chân MAX1240BEPA+
| Chân 1 | VDD — Positive supply voltage, +2.7V to +3.6V |
| Chân 2 | AIN — Analog input, single-ended, 0V to VREF |
| Chân 3 | GND — Ground, 0V return for both analog and digital supplies |
| Chân 4 | SCLK — Serial clock input from SPI master |
| Chân 5 | DOUT — Serial data output, MSB first |
| Chân 6 | SSTRB — Serial strobe / active-low chip-select |
| Chân 7 | VREF — External reference voltage input, 0V to +3.6V |
| Chân 8 | CNVST — Conversion start, active-low; tie high for power-down |
Ứng dụng tiêu biểu
MAX1240BEPA+ phù hợp cho 6 Áp dụngs: Portable Data Logger, Handheld Multimeter / DMM, Thermocouple / RTD Signal Conditioning Front-End, Process-Control Analog Front-End, Battery-Powered Measurement Instrument, Industrial Sensor Readout Module.
Portable Data Logger
The MAX1240BEPA+'s 73 ksps sampling rate and 5 µW power-down current make it an ideal ADC core for handheld battery-powered data loggers that sample slowly and spend most of their time asleep. Position the part between a precision low-drift reference (such as MAX6126) and a small microcontroller hosting an SPI master; duty-cycle conversions to extend battery life from days into weeks. Single-ended 0V-VREF input is well-matched to 0-3V sensor outputs without active signal conditioning.
Được đề xuất
Handheld Multimeter / DMM
In a handheld digital multimeter, the MAX1240BEPA+ digitizes voltage, current-derived voltage, and resistance measurements with 12-bit precision (1 mV count at 3.3V full scale, ideal for 2000-count or 4000-count DMM displays). The 8-PDIP package is breadboard-friendly and supports the through-hole PCB assembly typical of low-volume test instruments. Its SPI interface ties directly into common microcontroller GPIO without external logic.
Được đề xuất
Thermocouple / RTD Signal Conditioning Front-End
Pairing the MAX1240BEPA+ with a precision op-amp driven thermocouple or 4-wire RTD front-end yields a 12-bit temperature readout suitable for industrial process monitoring, HVAC controls, and laboratory instrumentation. Ratiometric measurement against a low-drift reference keeps the cold-junction compensation error inside a few LSB over the 0°C to +70°C commercial range. The shutdown pin enables millisecond-duration conversions only when needed, keeping quiescent draw at the microamp level.
Được đề xuất
Process-Control Analog Front-End
Within a 4-20 mA current loop receiver or a 0-10V process-control input module, the MAX1240BEPA+ provides 12-bit digital conversion of a single-ended analog signal that has been level-shifted and filtered to the 0V to 3.6V input range. The external-reference architecture supports ratiometric scaling, where the same reference that excites the sensor also biases the ADC, eliminating gain error caused by reference drift in temperature.
Được đề xuất
Battery-Powered Measurement Instrument
Field-deployable measurement devices - whether an environmental sensor, agricultural telemetry node, or portable gas analyzer - benefit from the MAX1240BEPA+'s 5 µW shutdown draw, which lets a host microcontroller wake once per minute, take a single conversion, and return to sleep without measurable battery impact. A single 3V CR2032 lithium cell can power the ADC and a low-energy MCU for years in typical duty cycles.
Được đề xuất
Industrial Sensor Readout Module
In an industrial sensor readout module - such as a load-cell digitizer, bridge-sensor interface, or strain-gauge signal chain - the MAX1240BEPA+ provides the ADC slice of a small, low-cost sensing node. The external reference allows direct ratiometric scaling of the bridge excitation voltage, so bridge sensitivity error cancels out. Combined with a low-noise op-amp gain stage, the full signal chain delivers 12-bit precision across the 0°C to +70°C commercial range.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho MAX1240BEPA+ — 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 | MAX1240BCPA+ | MAX1241BEPA+ | MAX1240BEPA | MAX1240EEPA+ |
|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 8-PDIP | 8-PDIP - same | 8-PDIP - same | 8-PDIP - same | 8-PDIP - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Sampling Rate | 73 ksps | 73 ksps | 73 ksps | 73 ksps | 73 ksps |
| Supply Voltage | +2.7V to +3.6V | +2.7V to +3.6V | +2.7V to +5.25V (wider) | +2.7V to +3.6V | +2.7V to +3.6V |
| Reference Type | External | External | Internal 2.5V | External | External |
| Power-Down Current | 5 µW | 5 µW | 5 µW | 5 µW | 5 µW |
| Operating Temperature | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C | 0°C to +70°C (extended screening) |
Bảo phân biệt quan trọng
- External reference allows ratiometric sensor bridge measurement (vsMAX1241BEPA+)
- Lower supply voltage ceiling suits 3.3V digital systems (vsMAX1241BEPA+)
- Through-hole PDIP supports prototyping and legacy assembly (vsMAX1240BCSA+ (SOIC-8))
Ghi chú thiết kế
Place a 0.1µF X7R ceramic bypass capacitor as close as possible to the VDD pin (pin 1) with a 1µF or larger bulk capacitor on the same node. Tie CNVST/active-low high between conversions to enter power-down mode (5 µW), reducing average supply current to microamp levels in duty-cycled designs. AVDD and DVDD should share a single well-decoupled supply rail.
Route the analog input trace (AIN, pin 2) directly to the source sensor with a guard trace tied to GND or with the surrounding copper plane grounded. Keep digital traces (SCLK, DOUT, SSTRB, CNVST) physically separated from the analog input trace to avoid digital noise coupling into the ADC input. Place the external reference (such as a MAX6126) close to the VREF pin (pin 7) and add a 0.1µF bypass on its output.
Do not apply VREF greater than AVDD or above +3.6V - this will damage or saturate the ADC's reference input. Ensure SCLK does not exceed the datasheet maximum frequency and respect tCONV timing between CNVST falling edge and the first SCLK rising edge that clocks data out. Single-ended input assumes the signal reference is at GND; using a pseudo-differential input requires tying the negative terminal to a quiet mid-rail such as VREF/2.
Thông tin tuân thủ
RoHS compliant per Maxim Integrated product page. Commercial 0°C to +70°C operating range - not AEC-Q100 qualified (industrial -40°C to +85°C variants are not available in this PDIP version; see MAX1240AESA+ in SOIC-8 for extended temperature).
