10-Port Constant-Current LED Drivers and I/O Expanders with PWM Intensity Control

 

Part Number	Replacement	Explanation

Description

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The MAX6966/MAX6967 serial-interfaced peripherals provide microprocessors with 10 I/O ports rated to 7V.

Each port can be individually configured as either:

• A 20mA constant-current LED driver (static or pulsewidth modulated (PWM)).
• A 10mA constant-current LED driver (static or PWM).
• An open-drain logic output.
• An overvoltage-protected Schmitt logic input.

Analog and switching LED intensity control is built in:

• Individual 8-bit PWM control per output.
• Individual 1-bit analog control (half/full) per output.
• Global 3-bit analog control applies to all LED outputs.

PWM timing of the 10 port outputs may be optionally staggered, consecutively phased in 45° increments. This spreads the PWM load currents over time in eight steps, helping to even out the power-supply current and reduce the RMS current.

The MAX6966/MAX6967 can be configured to awake from shutdown on receipt of a minimum 3ms pulse on the active-low CS input. This hardware-wakeup feature allows a power-management controller or similar ASIC to enable the MAX6966/MAX6967 with preconfigured LED intensity settings.

Shutdown can be programmed to wait up to 4s, fade down the sink currents to zero for a period of 1/16s to 4s, and then shut down. A similar ramp-up from shutdown can be programmed for 1/16s to 4s.

The MAX6966/MAX6967 support hot insertion. All port pins remain high impedance in power-down (V+ = 0V) with up to 8V asserted on them.

The DOUT/OSC pin can be configured as either the serial interface data output or optional PWM clock input. The MAX6966 powers up defaulting as DOUT output. The MAX6967 defaults as OSC input.

For a similar part without the constant-current controls, refer to the MAX7317 data sheet.

MAX6966, MAX6967: Block Diagram Enlarge+

Key Features

• High-Speed 26MHz SPI™-/QSPI™-/MICROWIRE™-Compatible Serial Interface
• 2.25V to 3.6V Operation
• I/O Ports Default to High-Z (LEDs Off) on Power-Up
• I/O Port Inputs Are Overvoltage Protected to 7V
• I/O Port Outputs Are 7V-Rated Open Drain
• I/O Port Outputs Are 10mA or 20mA Constant-Current Static/PWM LED Drivers, or Open-Drain Logic Outputs
• I/O Ports Support Hot Insertion
• Individual 8-Bit PWM Intensity Control for Each LED
• Any Output May Use or Not Use PWM Control
• Exit Shutdown (Warm Start) with Simple Active-Low CS Pulse
• Auto Ramp-Down into Shutdown
• Auto Ramp-Up Out from Shutdown
• 0.8µA (typ), 2µA (max) Shutdown Current
• Tiny 3mm x 3mm, 0.8mm High Thin QFN Package
• -40°C to +125°C Temperature Range

Applications/Uses

• Cell Phones
• Keypad Backlights
• LCD Backlights
• LED Status Indication
• Portable Equipment
• RGB LED Drivers