Texas Instruments LM8325DGR8X-1/NOPB

Overview

LM8325DGR8X-1/NOPB from Texas Instruments is a dedicated mobile I/O companion IC for keypad scanning, GPIO expansion, and LED brightness control via three independent PWM channels. It operates from a single 1.8V ±10% supply, integrates an internal RC oscillator and POR, supports up to 8×12 keypad matrices plus 8 SF keys, and communicates over I²C-compatible ACCESS.bus at 100 kHz/400 kHz - deployed in cordless phones and smart handheld devices.

For engineers reviewing the LM8325DGR8X-1/NOPB datasheet, LM8325DGR8X-1/NOPB pinout, LM8325DGR8X-1/NOPB application, or LM8325DGR8X-1/NOPB equivalent, key selection considerations include its 25-pin csBGA package, programmable IRQN-driven interrupt handling, 15-byte key event FIFO, HALT mode power management, and register-based PWM scripting capability for autonomous LED control.

Technical Context

The LM8325DGR8X-1/NOPB implements a register-mapped command interpreter accessed exclusively via its I²C-compatible ACCESS.bus slave interface (default address 0x88), with auto-increment addressing support for efficient multi-byte register access. Its keyscan engine performs full matrix evaluation every 4 ms, storing press/release events in a 15-byte FIFO and asserting IRQN on configurable edge-triggered interrupts.

Three independent slow-clock PWM units (driven by 32.768 kHz input) each feature a 64-byte script buffer supporting RAMP, SET_PWM, BRANCH, TRIGGER, and END commands - enabling self-sustaining LED modulation sequences without host intervention. The device enters HALT mode after 1020 ms of inactivity, reducing current draw to minimum while retaining wake-up capability on bus activity or IRQN edge detection.

Key Specifications

Pinout & Package

LM8325DGR8X-1/NOPB uses a 25-ball chip-scale BGA (csBGA) package with 0.5 mm pitch and 3.0 mm × 3.0 mm body size. Pin functions are multiplexed across keypad I/O, PWM outputs, and system interface signals.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I/O companion applications.

Compared with TCA6424A and PCA9557, the LM8325DGR8X-1/NOPB delivers integrated keyscan, autonomous PWM scripting, and HALT-mode power optimization - eliminating host-side firmware overhead for human-interface tasks while maintaining pin efficiency and thermal robustness.

Availability

LM8325DGR8X-1/NOPB is available at Aetrix Electronics and suitable for cordless phone interfaces, smart handheld device I/O expansion, keyboard applications with low-power wake-up, and industrial control panel keypad systems requiring stable component supply and long-term manufacturability.

Supply support for LM8325DGR8X-1/NOPB 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in precision timing, power management, and human-interface solutions.

The LM8325DGR8X-1/NOPB belongs to TI's Mobile I/O Companion product line, engineered specifically to offload keypad scanning, GPIO expansion, and LED control from application processors in space- and power-constrained portable electronics.

FAQ

What is the default I²C address of the LM8325DGR8X-1/NOPB?

The LM8325DGR8X-1/NOPB ships with a default I²C-compatible ACCESS.bus slave address of 0x88. This address can be changed via software configuration, and a Global Call Reset (write 0x06 to address 0x00) restores it to 0x88. The LM8325DGR8X-1/NOPB does not support hardware address pins, so all devices on a shared bus must be individually addressed in firmware.

How does the LM8325DGR8X-1/NOPB handle multiple simultaneous key presses?

The LM8325DGR8X-1/NOPB supports up to four concurrent key presses. It stores them in KBDCODE0–KBDCODE3 registers, setting the MULTIKEY flag in KBDCODE0 when additional keys are pressed. All events are also logged in the 15-byte EVTCODE FIFO with press/release status. The LM8325DGR8X-1/NOPB reports these synchronously via IRQN and maintains ordering integrity even during rapid multi-key actuation.

Can the LM8325DGR8X-1/NOPB operate without an external crystal?

Yes, the LM8325DGR8X-1/NOPB includes an internal RC oscillator and requires no external clock for basic operation. The CLKIN pin accepts a 32 kHz–2 MHz external source only when higher PWM timing accuracy is needed; otherwise, the internal oscillator drives keyscan, HALT mode, and PWM timing. The LM8325DGR8X-1/NOPB initializes reliably using POR and internal clocking.

What happens to the IRQN pin after power-on reset?

After power-on reset, the LM8325DGR8X-1/NOPB drives IRQN low due to the PORIRQ signal. To release the pin and enable normal interrupt operation, the host must write 0x01 to register 0x84 (RSTINTCLR). Until this write occurs, IRQN remains asserted low regardless of key events or other interrupt sources - a mandatory initialization step for the LM8325DGR8X-1/NOPB to function correctly.

Does the LM8325DGR8X-1/NOPB support wake-up from HALT mode on keypad activity alone?

Yes, the LM8325DGR8X-1/NOPB wakes from HALT mode on any keypad activity - including key press, key release, or error condition - by asserting IRQN. The wake-up is edge-triggered and configurable for rising, falling, or pulse detection. No ACCESS.bus traffic is required; the internal keyscan engine remains active in HALT mode to monitor matrix transitions, making the LM8325DGR8X-1/NOPB ideal for battery-sensitive applications.