Analog Devices Inc./Maxim Integrated MAX6957AAX/GG8

Overview

MAX6957AAX/GG8 from Maxim Integrated is a 28-port, SPI-compatible LED display driver and GPIO expander with individually configurable ports for constant-current LED sinking (1.5–24mA), push-pull logic output (10mA sink/4.5mA source), or Schmitt-trigger input with optional pullup. It operates from 2.5V to 5.5V across –40°C to +125°C and supports transition detection on seven ports (P24–P30) for interrupt-driven system monitoring in industrial panel meters and set-top boxes.

For engineers reviewing the MAX6957AAX/GG8 datasheet, MAX6957AAX/GG8 pinout, MAX6957AAX/GG8 application, or MAX6957AAX/GG8 equivalent, key selection considerations include per-port current programmability (16-step), 26MHz SPI/QSPI/MICROWIRE interface timing compliance, ISET resistor-based global current scaling, and P31-interrupt signaling for port-level logic transitions - all within a 36-pin SSOP package.

Technical Context

The MAX6957AAX/GG8 implements a 4-wire SPI-compatible serial interface with strict timing: 38.4ns minimum clock period, 19ns min high/low pulse width, and zero hold time for CS-to-SCLK. Its 28 I/O ports (P4–P31) are fully software-configurable via register-mapped control (0x09–0x0F), supporting mixed-mode operation - e.g., simultaneous LED segment driving (open-drain sink), GPIO output (active-high/low), and Schmitt inputs (with/without 12–180µA pullup).

Transition detection logic monitors P24–P30 against a snapshot register; a change triggers active-high interrupt on P31, cleared only by reading/writing the mask register (0x06). Shutdown mode reduces supply current to ≤11µA while preserving register state, and LED current is set globally (0x02) or per-port (0x12–0x1F), each nibble controlling one segment's 16-step current level.

Key Specifications

Pinout & Package

MAX6957AAX/GG8 is housed in a 36-pin SSOP (Small Outline Package) with 0.635mm pitch, exposed pad not internally connected, and thermal performance rated for 941mW continuous dissipation at +70°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6957AAX/GG8, MAX6956ATL+ trades SPI speed for I²C simplicity and reduced pin count, while MAX7301ATG+ sacrifices LED integration for lower unit cost and higher GPIO drive strength - making each suitable for distinct subsystem architectures.

Availability

MAX6957AAX/GG8 is available at Aetrix Electronics and suitable for industrial panel meters, set-top box front panels, and white goods control interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6957AAX/GG8 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 and mixed-signal ICs for industrial, automotive, and communications applications, emphasizing robustness, integration, and wide operating conditions.

The MAX6957 product line delivers highly integrated LED display drivers with GPIO expansion, targeting space-constrained human-machine interfaces where reliability across –40°C to +125°C is mandatory.

FAQ

What is the exact package type and pin count for MAX6957AAX/GG8?

MAX6957AAX/GG8 uses a 36-pin SSOP (Shrink Small Outline Package) with 0.635mm lead pitch. The "AAX" suffix explicitly denotes the 36-pin SSOP variant, distinct from the 28-pin SSOP (AAI), 28-pin DIP (ANI), and 40-pin TQFN (ATL) versions. Pin 1 is ISET; pins 2 and 3 are GND; pin 28 is V+; and pins 37–40 correspond to P28–P31.

How does MAX6957AAX/GG8 configure its 28 I/O ports, and what are the valid modes?

MAX6957AAX/GG8 configures each of its 28 ports (P4–P31) via four-bit pairs in registers 0x09 through 0x0F. Valid modes are: LED segment driver (open-drain sink, 1.5–24mA), push-pull logic output (10mA sink/4.5mA source), Schmitt logic input (no pullup), or Schmitt logic input with internal pullup (12–180µA depending on V+). All ports default to Schmitt inputs at power-up.

What is the role of the ISET pin on MAX6957AAX/GG8, and how is it used?

The ISET pin (Pin 1) on MAX6957AAX/GG8 sets the full-scale LED segment current by connecting an external resistor (RISET) to GND. With RISET = 39kΩ, maximum current is 24mA per segment at V+ = 5.5V. Current scales linearly with V+/RISET, enabling precise, resistor-based global brightness control without digital register writes.

Does MAX6957AAX/GG8 support daisy-chaining, and how is it implemented?

Yes, MAX6957AAX/GG8 supports daisy-chaining via its DOUT pin (Pin 4), which outputs data shifted in 15.5 clocks earlier. Multiple devices are connected DIN→DOUT in series, with shared SCLK and CS lines. Each 16-bit command propagates through the chain; updating one device requires sending No-Op (0x00) commands to others in the chain.

How does the transition detection feature work on MAX6957AAX/GG8, and which pins support it?

MAX6957AAX/GG8 provides hardware transition detection on ports P24 through P30. When enabled via the M bit in the configuration register (0x04), it compares current port states against a snapshot register. Any change on a masked port asserts INT on P31 (configured as output). The interrupt is latched and cleared only by accessing the mask register (0x06).