Analog Devices Inc./Maxim Integrated MAX1178ACUP+

Overview

The MAX1178ACUP+ from Maxim Integrated is a 16-bit, 135ksps successive-approximation ADC with ±5V bipolar analog input range, single +4.75V to +5.25V analog supply, and byte-wide parallel interface. It features ±2 LSB INL, -100dB THD, and AutoShutdown™ reducing current to 0.4mA at 10ksps - ideal for precision industrial data-acquisition systems requiring high DC accuracy and low power.

For engineers reviewing the MAX1178ACUP+ datasheet, MAX1178ACUP+ pinout, MAX1178ACUP+ application, or MAX1178ACUP+ equivalent, key selection criteria include its TSSOP-20 package, internal +4.096V reference option, ±5V input scaling, and compatibility with +2.7V to +5.25V digital logic interfaces in battery-powered instrumentation.

Technical Context

The MAX1178ACUP+ implements a SAR architecture with integrated track-and-hold and factory-trimmed internal clock, eliminating external timing components. Its input scaler enables true bipolar ±5V operation from a single +5V analog supply while limiting input current to ±1.8mA.

Power management is controlled via R/C pin sequencing: second CS falling edge selects standby (reference active, 3.7mA) or shutdown (reference off, 0.5µA), with 12ms wake-up required for full 16-bit accuracy when exiting shutdown using internal reference.

Key Specifications

Pinout & Package

MAX1178ACUP+ is housed in a 20-pin TSSOP package (4.4mm × 6.5mm, 0.65mm pitch), optimized for compact industrial PCB layouts and compatible with standard reflow processes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit SAR ADC applications.

Compared with ADS8860IDRCT and AD7682BCPZ-RL7, the MAX1178ACUP+ uniquely integrates ±5V bipolar input scaling and a trimmed +4.096V reference in TSSOP-20, reducing component count and board area for industrial analog input modules - at the trade-off of lower maximum throughput than the ADS8860.

Availability

MAX1178ACUP+ is available at Aetrix Electronics and suitable for industrial process control, precision instrumentation, and portable data-acquisition systems requiring stable component supply and long-term lifecycle support.

Supply support for MAX1178ACUP+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.

The MAX1178ACUP+ belongs to Maxim's high-accuracy SAR ADC product line, engineered specifically for battery-powered and space-constrained data-acquisition systems demanding ±5V bipolar input handling and low-quiescent-power operation.

FAQ

What is the maximum sampling rate of the MAX1178ACUP+ and how does it affect system timing?

The MAX1178ACUP+ achieves a maximum sampling rate of 135ksps, with a fixed conversion time of 4.7µs after the second CS falling edge. This defines the minimum inter-sample interval and constrains real-time processing latency. At full rate, acquisition time is 2µs, so total cycle time per sample is ~6.7µs - critical for synchronizing with µP bus handshaking via EOC and HBEN signals. The internal clock eliminates external timing dependencies.

Does the MAX1178ACUP+ require external components to operate with its internal reference?

Yes, the MAX1178ACUP+ requires two mandatory bypass capacitors when using the internal +4.096V reference: a 10µF low-ESR capacitor from REF to AGND and a 0.1µF capacitor from REFADJ to AGND. These stabilize the reference buffer and suppress noise; omitting them degrades INL and increases THD. No resistors or trimming components are needed - the reference is factory-trimmed.

How does the R/C pin control power modes in the MAX1178ACUP+?

The R/C pin sequences power states across three CS edges: first edge powers up, second edge selects standby (R/C low → reference stays on, 3.7mA) or shutdown (R/C high → reference off, 0.5µA), third edge latches data. In shutdown mode, 12ms wake-up is required before next conversion achieves full 16-bit accuracy - a critical timing constraint for burst-sampling applications.

Can the MAX1178ACUP+ interface directly with a 3.3V microcontroller?

Yes, the MAX1178ACUP+ supports DVDD from +2.7V to +5.25V, making it fully compatible with 3.3V logic. Its digital outputs meet VOH ≥ DVDD–0.4V and VOL ≤ 0.4V at 1.6mA sink, and inputs accept VIH ≥ 0.7×DVDD and VIL ≤ 0.3×DVDD. No level shifters are needed - simply tie DVDD to the µP's 3.3V rail and use shared DGND.

What is the significance of the ±5V input range specification for the MAX1178ACUP+?

Unlike most 16-bit ADCs requiring external op-amps to condition bipolar signals, the MAX1178ACUP+'s ±5V input range means it accepts true bipolar voltages directly - e.g., from ±5V-output industrial sensors - while operating from a single +5V analog supply. This is achieved via an internal input scaler that attenuates and offsets the signal, eliminating level-shifting circuitry and reducing BOM cost and board area.