1FEATURES
2• 8 × 8 Standard Keys
• 8 Special Function Keys (SF Keys) Providing a
Total of 72 Keys for the Maximum Keyboard
Matrix
• ACCESS.Bus (I2C-compatible) Communication
Interface to the Host
• Four General Purpose Host Programmable I/O
Pins with Two Optional (Slow) External
Interrupts
• 15-byte FIFO Buffer to Store Key Pressed and
Key Released Events
• Error Control with Error Reports on (FIFO
Overrun, Keypad Overrun, Invalid Command)
• Host Programmable PWM
• Host Programmable Active Time and
Debounce Time

APPLICATIONS
• Mobile Phones
• Personal Digital Assistants (PDAs)
• Smart Handheld Devices
• Personal Media Players

DESCRIPTION
The LM8333 Mobile I/O Companion offloads the
burden of keyboard scanning from the host, while
providing extremely low power consumption in both
operational and standby modes. It supports keypad
matrices up to 8 × 8 in size (plus another 8 special-
function keys), for portable applications such as
cellphones, PDAs, games, and other handheld
applications.
Key press and release events are encoded into a
byte format and loaded into a FIFO buffer for retrieval
by the host processor. An interrupt output (IRQ) is
used to signal events such as keypad activity, a state change on either of two interrupt-capable general-
purpose I/O pins, or an error condition. Interrupt and
error codes are available to the host by reading
dedicated registers.
Four general-purpose I/O pins are available, two of
which have interrupt capability. A pulse-width
modulated output based on a host-programmable
internal timer is also available, which can be used as
a general-purpose output if the PWM function is not
required.
To minimize power, the LM8333 automatically enters
a low-power standby mode when there is no keypad,
I/O, or host activity.
The device is packaged in a 32–pin WQFN and a
49-pin csBGA. Both are chip-scale packages.