Analog Devices Inc./Maxim Integrated MAX156BCNG

Overview

The MAX156BCNG from Maxim Integrated is a high-speed, 4-channel, 8-bit analog-to-digital converter (ADC) with simultaneous track-and-hold (T/H) inputs, 3.6µs per-channel conversion time, internal 2.5V reference, and support for unipolar/bipolar and single-ended/differential input configurations - used in vibration analysis, AC power metering, and DSP front-end acquisition systems.

For engineers reviewing the MAX156BCNG datasheet, MAX156BCNG pinout, MAX156BCNG application, or MAX156BCNG equivalent, this page delivers verified technical context, real-world interface timing behavior, RAM-based data access mechanics, hard-wired vs. I/O mode trade-offs, and validated alternative options for multichannel sampling systems requiring synchronized analog capture.

Technical Context

The MAX156BCNG implements a successive-approximation ADC core with four independent track-and-hold amplifiers that sample all enabled channels simultaneously on the falling edge of WR. Its internal 8×4 RAM stores conversion results sequentially by channel address, accessed via RD pulses with automatic address incrementing.

Configuration is handled either in hard-wired mode (MODE pin tied low/high with VSS grounded or at –5V) or I/O mode (MODE open), where D0–D7 double as bidirectional configuration/data lines controlling BIP, DIFF, INH, PD, and ALL bits - with one-conversion latency for polarity and input-mode changes.

Key Specifications

Pinout & Package

MAX156BCNG is housed in a 24-pin narrow-body plastic DIP (PDIP) package with 0.3-inch width, lead finish Sn/Pb, and RoHS-compliant option available (MAX156BCNG+). Pin functions are electrically identical to the 28-pin wide SO variant but omit AIN4–AIN7 and associated pins (25–28).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel simultaneous-sampling ADC applications.

Compared with MAX156BCNG, AD7864-1ARUZ offers higher resolution and faster conversion but demands external reference design and lacks integrated T/H matching; ADS8325IPW delivers superior noise performance but cannot replace MAX156BCNG in any multichannel synchronized acquisition role due to single-channel architecture.

Availability

MAX156BCNG is available at Aetrix Electronics and suitable for AC power metering, industrial vibration monitoring, motor drive signal acquisition, and portable data logger designs requiring stable component supply and long-term production continuity.

Supply support for MAX156BCNG 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, automotive, and communications applications.

The MAX155/MAX156 family was engineered specifically for high-fidelity, multichannel data acquisition systems demanding simultaneous sampling, flexible input configuration, and integrated reference - targeting test equipment, power analytics, and real-time signal conditioning.

FAQ

What is the maximum sampling rate achievable with the MAX156BCNG in 4-channel mode?

The MAX156BCNG completes each channel conversion in 3.6 µs. In full 4-channel sequential readout, total acquisition + readout time is dominated by conversion latency. With external 5 MHz CLK and optimized RD/WR timing, sustained throughput reaches ~220 kSPS aggregate - sufficient for 50 kHz small-signal bandwidth applications per channel as specified in SINAD testing.

Does the MAX156BCNG support differential input mode, and how is it configured?

Yes, the MAX156BCNG supports differential input mode via the DIFF bit (D6) in its configuration register. When DIFF = 1 and MODE is open-circuit, pairs AIN0–AIN1, AIN2–AIN3 are interpreted as differential inputs. Configuration occurs on WR rising edge; the setting takes effect on the next conversion cycle - requiring careful sequencing if dynamically switching modes during operation.

Can the MAX156BCNG operate without an external crystal or oscillator?

Yes - the MAX156BCNG requires only an external TTL/CMOS-compatible clock signal applied to the CLK pin (0.5–5 MHz), not a crystal. It contains no internal oscillator; timing is fully synchronous to the externally supplied clock, allowing precise control of sampling intervals and easy integration with FPGA or microcontroller clock trees.

How does power-down mode affect the configuration register and RAM contents in the MAX156BCNG?

In power-down mode (PD = 1), the MAX156BCNG reduces supply current to ≤100 µA while retaining all configuration register values and RAM data. The internal reference is disabled, and no conversions or reads are possible. Upon exit (PD = 0), the register state remains intact - eliminating need for reinitialization - though internal reference requires up to 5 ms to stabilize before first conversion.

Is the MAX156BCNG pin-compatible with the MAX155, and what are the key physical differences?

No - the MAX156BCNG uses a 24-pin narrow PDIP package, while the MAX155 uses 28-pin PDIP or wide SO. Pins 25–28 on MAX155 (AIN4–AIN7) are absent on MAX156BCNG, and internal routing excludes those channels entirely. Signal pin functions (e.g., AIN0–AIN3, WR, RD, BUSY) align, but PCB layout is not interchangeable without redesign.