MAX1112EPP+ - 8-Bit 8-Ch 1ksps SAR ADC, +5V | Maxim Integrated
MPN： MAX1112EPP+ ✓ 啟用中MAX1112EPP+ 概覽
An SAR (Successive Approximation Register) ADC is a precision converter architecture that performs one bit decision per clock cycle using a comparator and a binary-weighted capacitive DAC. SAR ADCs sit within the broader ADC family alongside flash, sigma-delta, and pipeline converters, and they are favored when applications need a balance of low power consumption, moderate speed (ksps range), excellent DC accuracy, and small package size - making them ubiquitous in industrial process control, instrumentation, and portable data-acquisition front ends.
Key differentiating specifications include 1 ksps sampling rate, an 8-channel single-ended or 4-channel differential input MUX (MAX1112), hardware- and software-configurable unipolar/bipolar input ranges (0 to +5V, 0 to +2.5V, ±5V, ±2.5V via external resistors), an internal 2.5V reference with 50 ppm/°C drift, and a low 1 mA (typ) supply current. The 20-pin PDIP through-hole footprint simplifies prototyping and breadboard evaluation versus surface-mount equivalents.
Typical applications include portable patient monitors, panel meters and digital multimeters, isolated data acquisition systems, and battery-powered instrumentation where the part's combination of low power, internal reference, and small footprint reduces external BOM. When paired with an optocoupler on the SPI lines the MAX1112EPP+ enables isolated industrial sensing.
A practical design tip: place a 0.1 µF ceramic bypass capacitor within 5 mm of the VDD pin and a 4.7 µF tantalum bulk capacitor at the supply entry point; the internal reference requires at least a 4.7 µF external bypass on REF for specified noise performance. The shutdown (SHDN) pin reduces supply current to under 10 µA between conversions, which is essential for battery-powered designs that must wake periodically to take a measurement.
This page synthesizes distributor pricing, drop-in alternative listings, pin-level design notes, and application-circuit recommendations not found in the manufacturer datasheet alone - providing engineers a single source for procurement and design validation of the MAX1112EPP+.
直接替換替代品，適用於 MAX1112EPP+ — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
MAX1112CPP+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1113EPP+
✅ 直接替換📋 參考替代品（不在目錄中）
MAX1112CPP
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
MAX1112EAP+
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
MAX1113CPP+
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
MAX1112EPP+ 最大額定值與電氣特性
| 解析度 | 8 bits |
| 取樣率 | 1 ksps (max) |
| Number of Input Channels | 8 single-ended / 4 differential (MAX1112) |
| Input Configuration | Single-Ended or Pseudo-Differential |
| Architecture | SAR (Successive Approximation) |
| Supply Voltage (VDD) | +5 V ±5% (4.5 V to 5.5 V) |
| Supply Current (Active) | 1 mA (typ) |
| Supply Current (Shutdown) | <10 µA (typ) |
| Internal Reference Voltage | 2.5 V (bandgap) |
| Reference Drift | 50 ppm/°C (typ) |
| Input Voltage Range (Software Configured) | 0 to +5V, 0 to +2.5V, ±5V, ±2.5V |
| Serial Interface | SPI / QSPI / MICROWIRE compatible |
| Integral Non-Linearity (INL) | ±1 LSB (max) |
| 封裝 | 20-pin PDIP (PDIP-20) |
| 安裝類型 | Through-Hole |
| 工作溫度 | -40 °C to +85 °C |
MAX1112EPP+ 腳位配置
| 腳位 1 | VDD — +5V power supply |
| 腳位 2 | REF — Reference voltage (internal 2.5V, bypass with 4.7 µF) |
| 腳位 3 | AGND — Analog ground |
| 腳位 4 | DGND — Digital ground |
| 腳位 5 | AIN0 — Analog input channel 0 |
| 腳位 6 | AIN1 — Analog input channel 1 |
| 腳位 7 | AIN2 — Analog input channel 2 |
| 腳位 8 | AIN3 — Analog input channel 3 |
| 腳位 9 | AIN4 — Analog input channel 4 |
| 腳位 10 | AIN5 — Analog input channel 5 |
| 腳位 11 | AIN6 — Analog input channel 6 |
| 腳位 12 | AIN7 — Analog input channel 7 |
| 腳位 13 | SHDN — Shutdown (active low, tie high for always-on) |
| 腳位 14 | DOUT — Serial data output |
| 腳位 15 | SCLK — Serial clock input |
| 腳位 16 | CS — Chip select (active low) |
| 腳位 17 | DIN — Serial data input |
| 腳位 18 | INT/EXT — Clock select (internal/external) |
| 腳位 19 | REF- — Reference ground return |
| 腳位 20 | SSTRB — Serial strobe output |
典型應用
MAX1112EPP+ 適用於 6 應用s: Portable Patient Monitoring Devices, Digital Panel Meters and Multimeters, Isolated Industrial Data Acquisition Systems, Battery-Powered Field Instrumentation, Process Control Loop Monitoring, Remote Sensor Signal Conditioning.
Portable Patient Monitoring Devices
The MAX1112EPP+ is a strong fit for portable patient monitoring devices such as pulse oximeters, handheld ECG front-ends, and bedside vital-sign monitors where multi-channel sensing and low power are mandatory. Its 8 single-ended input channels digitize up to four differential vital-sign signals (lead I/II ECG, SpO2 photodiode current, respiration impedance) at 1 ksps - sufficient for heart-rate and respiration bandwidths under 500 Hz. The internal 2.5V reference removes the need for a precision external reference, shrinking BOM for cost-sensitive medical disposables. Power budget is dominated by sensor excitation; the ADC contributes only 1 mA active and under 10 µA in shutdown, allowing intermittent sampling to extend battery life beyond 100 hours. Pair with the MAX11120ATI+T (a 12-bit upgrade) for higher-precision designs.
推薦
Digital Panel Meters and Multimeters
Handheld digital multimeters (DMMs) and panel meters use the MAX1112EPP+ to digitize voltage, current, and resistance measurements with autoranging input scaling. The 8-channel input mux enables simultaneous measurement of V, I, and temperature-compensation signals without external analog switches. The ±1 LSB INL provides 3½-digit DMM accuracy (1 part in 2000), and the SPI interface lets the meter's microcontroller read conversion results and switch ranges on a single bus. Through-hole PDIP packaging simplifies hand-soldered prototyping common in metrology designs. Reference temperature drift of 50 ppm/°C keeps gain error below 0.1% over commercial operating range.
推薦
Isolated Industrial Data Acquisition Systems
Isolated industrial data acquisition modules (4-20 mA loop digitizers, PLC analog input cards) benefit from the MAX1112EPP+'s through-hole PDIP package and SPI interface. The serial interface easily passes through digital optocouplers or iCouplers, allowing the field-side ADC to be galvanically isolated from the backplane controller for high common-mode voltages up to 5 kV. The 8 input channels share a single ground-referenced mux, so all input signals must be referenced to the same isolated common. The internal reference eliminates a separate isolated supply rail for REF, simplifying isolated power design. For higher-channel-count systems, two MAX1112EPP+ parts can share a single SPI bus via distinct CS lines.
推薦
Battery-Powered Field Instrumentation
Battery-powered data loggers, soil-moisture probes, and remote weather stations use the MAX1112EPP+ for periodic sensor sampling with extreme sleep current. The SHDN pin drops active supply current from 1 mA to under 10 µA between conversions, so a 2.4 Ah lithium AA pack can sustain hourly readings for several years. The 8 single-ended inputs accommodate multiple environmental sensors (temperature, humidity, light, soil moisture, rain gauge) on a single chip, eliminating analog mux ICs. Wide -40 to +85 °C operating temperature handles outdoor deployment from arctic to desert conditions. Internal 2.5V reference avoids precision analog supply rails, critical when the only available rail is the battery itself.
推薦
Process Control Loop Monitoring
Industrial process control loops (temperature, pressure, flow) are commonly monitored with the MAX1112EPP+ in 4-20 mA current-loop digitizers and supervisory control systems. The 8-channel mux digitizes multiple sensor inputs simultaneously without external analog switches, while the SPI bus connects directly to a host microcontroller or PLC analog input card. The ±1 LSB INL gives 0.4% accuracy on full-scale readings, well within the 1% error budget typical of process monitoring. The internal 2.5V reference can be overdriven by an external precision reference (e.g., MAX6070) when calibration-grade accuracy is required. The through-hole PDIP simplifies field-serviceable designs and conforms to legacy PLC module footprints.
推薦
Remote Sensor Signal Conditioning
Remote sensor signal conditioning modules - strain gauge bridges, RTD amplifiers, and thermocouple cold-junction compensation - use the MAX1112EPP+ as a low-cost multi-channel digitizer with on-chip reference. The pseudo-differential input mode rejects common-mode noise on long sensor cables, while the 8 single-ended channels accommodate up to four full-bridge strain gauges with excitation. SPI output couples easily to isolated transceivers for high-voltage or safety-critical applications. The 1 ksps throughput supports vibration monitoring and shock-sensor applications where bandwidth up to 500 Hz is required. Through-hole PDIP simplifies hand-reworkable designs in test fixtures and laboratory instrumentation.
推薦
推薦產品摘要
工程參考資料，適用於 MAX1112EPP+ — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | MAX1112CPP+ | MAX1113EPP+ | MAX1112CPP | MAX1112EAP+ |
|---|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | PDIP-20 | PDIP-20 | PDIP-20 | PDIP-20 | PDIP-20 |
| Resolution | 8 bits | 8 bits | 8 bits | 8 bits | 8 bits |
| Sampling Rate | 1 ksps | 1 ksps | 1 ksps | 1 ksps | 1 ksps |
| Input Channels (Single-Ended / Differential) | 8 / 4 | 8 / 4 | 4 / 2 | 8 / 4 | 8 / 4 |
| Operating Temperature Range | -40 °C to +85 °C | 0 °C to +70 °C | -40 °C to +85 °C | 0 °C to +70 °C | -40 °C to +125 °C (automotive) |
| Supply Current (Active) | 1 mA | 1 mA | 1 mA | 1 mA | 1 mA |
| Internal Reference | 2.5V (50 ppm/°C) | 2.5V (50 ppm/°C) | 2.5V (50 ppm/°C) | 2.5V (50 ppm/°C) | 2.5V (50 ppm/°C) |
| Serial Interface | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE | SPI/QSPI/MICROWIRE |
主要差異化特點
- 8 single-ended / 4 differential input channels in a single chip (對比MAX1113EPP+)
- Extended-industrial -40 °C to +85 °C temperature grade (對比MAX1112CPP+)
- Integrated 2.5V reference with 50 ppm/°C drift (對比External reference designs)
設計說明
Place a 0.1 µF ceramic bypass capacitor within 5 mm of the VDD pin and a 4.7 µF tantalum bulk capacitor at the supply entry point. The internal 2.5V reference (REF pin) requires a minimum 4.7 µF external bypass for specified noise performance; values below 1 µF degrade effective resolution by 1-2 LSB. The SHDN pin reduces supply current to under 10 µA between conversions and should be driven from a microcontroller GPIO for battery-powered designs.
Use a star-ground topology with separate analog (AGND) and digital (DGND) ground pins joined only at the PCB ground plane. Route the SPI bus traces (DOUT, DIN, SCLK, CS) away from analog input traces and clock signals to minimize digital coupling into the analog frontend. Place the REF bypass capacitor as close as possible to the REF pin and use a guard trace tied to AGND around sensitive analog input traces (AIN0-AIN7) on the PCB.
Do not leave the SHDN pin floating; tie it to VDD through a 100 kΩ pull-up if unused, otherwise the ADC may intermittently fail to power up. Avoid driving AIN inputs beyond VDD + 0.3V or below AGND - 0.3V - the absolute maximum ratings are 6V on AIN and VDD pins. For bipolar input ranges (±5V, ±2.5V), use external resistor dividers per datasheet Figure 4; attempting to directly apply bipolar signals without scaling can damage the input mux.
合規資訊
Specific RoHS / REACH compliance status not stated in the verified web data; check manufacturer product page for confirmation. PDIP-20 through-hole package is generally lead-free compatible but verify lot-level documentation.
