Analog Devices Inc./Maxim Integrated MAX6956AAX/V+T

Overview

The MAX6956AAX/V+T from Maxim Integrated is a 28-port, I²C-compatible LED display driver and GPIO expander operating from 2.5V to 5.5V across –40°C to +125°C. It supports per-port configuration as constant-current LED sink (1.5–24mA, 16-step), push-pull output (10mA sink/4.5mA source), or Schmitt input with optional pullup. Seven ports feature transition detection for interrupt-driven monitoring - used in automotive instrument clusters and industrial panel meters.

For engineers reviewing the MAX6956AAX/V+T datasheet, MAX6956AAX/V+T pinout, MAX6956AAX/V+T application, or MAX6956AAX/V+T equivalent, key selection criteria include its 36-pin SSOP automotive-qualified package, 400kbps I²C interface with 16-address capability via AD0/AD1, shutdown current ≤11µA, and dual-role port flexibility for mixed LED/GPIO systems.

Technical Context

The MAX6956AAX/V+T implements a two-wire I²C slave interface with auto-incrementing register addressing, supporting both single-bit and 8-bit port writes. Its port configuration logic uses two bits per port (in registers 0x09–0x0F) to select among four modes: LED driver, GPIO output, Schmitt input, or Schmitt input with internal pullup.

LED current is set globally via external resistor RISET on ISET pin, enabling 16 discrete current steps per segment up to 24mA at V+ = 5.5V. Transition detection is hardware-assisted on ports P24–P30, with maskable status reporting and interrupt assertion on P31 - no software polling required.

Key Specifications

Pinout & Package

MAX6956AAX/V+T is housed in a 36-pin SSOP package (body size 10.2mm × 5.3mm, 0.65mm pitch), rated for automotive temperature range and RoHS-compliant (+ suffix). Pin 1 is ISET; pins 2–3 and 36 are GND; pin 28 is V+; pins 25 and 26 are SDA and SCL; pins 4 and 27 are AD0 and AD1; pins 5–24 map to ports P12–P31; pins 29–35 are unused (N.C.).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED driver and I/O expander applications.

Compared with MAX6956AAX/V+T, MAX6957ATL+ trades I²C flexibility for SPI determinism and higher throughput, while MAX7300ATG+ reduces cost and complexity by removing LED-specific circuitry - making it unsuitable for direct display integration but viable for pure GPIO extension.

Availability

MAX6956AAX/V+T is available at Aetrix Electronics and suitable for automotive instrument clusters, industrial panel meters, and white goods control panels requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6956AAX/V+T 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 demanding industrial, automotive, and communications applications.

The MAX6956 product line delivers integrated LED driving and GPIO expansion for space-constrained, high-reliability human-machine interfaces - targeting applications where display clarity, input responsiveness, and thermal robustness are critical.

FAQ

What is the maximum LED sink current per port on the MAX6956AAX/V+T?

The MAX6956AAX/V+T supports up to 24mA per port when configured as an LED driver, with 16 discrete current steps from 1.5mA to 24mA. This maximum is achieved at V+ = 5.5V and is set globally by the external ISET resistor (e.g., 39kΩ to GND). The MAX6956AAX/V+T maintains this current accuracy across its full –40°C to +125°C operating range.

Does the MAX6956AAX/V+T support true I²C bus arbitration and multi-master operation?

Yes, the MAX6956AAX/V+T fully complies with I²C specification timing requirements including tBUF, tHD,STA, and tSU,STA, enabling reliable multi-master operation. When used in such systems, read operations require a repeated START condition after setting the command byte to prevent address pointer corruption by other masters - a behavior explicitly documented in the MAX6956AAX/V+T datasheet.

How many ports on the MAX6956AAX/V+T support hardware interrupt generation?

Seven ports - P24 through P30 - support configurable transition detection logic that can generate an interrupt on logic-level change. This function is controlled via the Transition Detect Mask register (0x06), and the resulting interrupt is asserted on port P31 as an active-low open-drain signal. The MAX6956AAX/V+T does not support interrupt generation on any other ports.

Can the MAX6956AAX/V+T drive common-cathode (CC) LED displays?

No, the MAX6956AAX/V+T is designed exclusively for common-anode (CA) LED configurations. Its LED driver ports operate as constant-current sinks - connecting to LED anodes via V+, with cathodes tied to port pins. Driving common-cathode displays would require external high-side switching, which is not supported by the MAX6956AAX/V+T architecture or specified in its electrical characteristics.

What is the purpose of the virtual ports P0–P3 in the MAX6956AAX/V+T register map?

Virtual ports P0–P3 exist solely to simplify software handling of LED segments spanning two MAX6956AAX/V+T devices - for example, when a 16-segment digit is split across adjacent drivers. Writing to P0–P3 aliases to physical ports P28–P31 of the second device, allowing identical byte writes to update overlapping segments without custom bit-masking logic. These virtual ports have no physical pin assignment on the MAX6956AAX/V+T.