MAX1112EPP+ - 8-Bit 8-Ch 1ksps SAR ADC, +5V | Maxim Integrated
MPN: MAX1112EPP+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.42 | $12.42 |
| 10 | $11.18 | $111.80 |
| 100 | $9.94 | $994.00 |
| 500 | $8.95 | $4,475.00 |
| 1,000 | $7.96 | $7,960.00 |
MAX1112EPP+ Overview
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+.
Drop-in alternatives for MAX1112EPP+ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1112CPP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1113EPP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1112CPP
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MAX1112EAP+
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MAX1113CPP+
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MAX1112EPP+ Maximum Ratings & Electrical Characteristics
| Resolution | 8 bits |
| Sampling Rate | 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) |
| Package | 20-pin PDIP (PDIP-20) |
| Mounting Type | Through-Hole |
| Operating Temperature | -40 °C to +85 °C |
MAX1112EPP+ Pin Configuration
| Pin 1 | VDD — +5V power supply |
| Pin 2 | REF — Reference voltage (internal 2.5V, bypass with 4.7 µF) |
| Pin 3 | AGND — Analog ground |
| Pin 4 | DGND — Digital ground |
| Pin 5 | AIN0 — Analog input channel 0 |
| Pin 6 | AIN1 — Analog input channel 1 |
| Pin 7 | AIN2 — Analog input channel 2 |
| Pin 8 | AIN3 — Analog input channel 3 |
| Pin 9 | AIN4 — Analog input channel 4 |
| Pin 10 | AIN5 — Analog input channel 5 |
| Pin 11 | AIN6 — Analog input channel 6 |
| Pin 12 | AIN7 — Analog input channel 7 |
| Pin 13 | SHDN — Shutdown (active low, tie high for always-on) |
| Pin 14 | DOUT — Serial data output |
| Pin 15 | SCLK — Serial clock input |
| Pin 16 | CS — Chip select (active low) |
| Pin 17 | DIN — Serial data input |
| Pin 18 | INT/EXT — Clock select (internal/external) |
| Pin 19 | REF- — Reference ground return |
| Pin 20 | SSTRB — Serial strobe output |
Typical Applications
MAX1112EPP+ is suitable for 6 applications: 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.
Recommended
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.
Recommended
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.
Recommended
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.
Recommended
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.
Recommended
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.
Recommended
Recommended Products Summary
Engineering reference data for MAX1112EPP+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 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 |
Key Differentiators
- 8 single-ended / 4 differential input channels in a single chip (vs MAX1113EPP+)
- Extended-industrial -40 °C to +85 °C temperature grade (vs MAX1112CPP+)
- Integrated 2.5V reference with 50 ppm/°C drift (vs External reference designs)
Design Notes
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.
Compliance Information
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.
