ON Semiconductor

The CAT3644 is a high efficiency fractional charge pump that can drive up to four LEDs programmable by a one wire digital interface. The inclusion of a 1.33x fractional charge pump mode increases device efficiency by up to 10% over traditional 1.5x charge pumps with no added external capacitors. Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multi-fractional charge pump supports a wide range of input voltages from 2.5 V to 5.5 V. The EN/DIM logic input functions as a chip enable and a digital dimming interface for current setting of all LEDs. Six different current ratios are available via the interface.

The CAT3648 is a high efficiency fractional charge pump that can drive up to four LEDs programmable by a one wire digital interface. The inclusion of a 1.33x fractional charge pump mode increases device efficiency by up to 10% over traditional 1.5x charge pumps with no added external capacitors.Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multi-fractional charge pump supports a wide range of input voltages from 2.4 V to 5.5 V.The EN/DIM logic input functions as a chip enable and a digital dimming interface for setting the current in all the LED channels. The 1-wire pulse-dimming interface supports 32 linear steps from full-scale down to zero current.

The CAT3649 is a high efficiency fractional charge pump that can drive up to six LEDs. The inclusion of a 1.33x fractional charge pump mode increases the device efficiency by up to 10% over traditional 1.5x charge pumps with no added external capacitors.Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multi-fractional charge pump supports a wide range of input voltages from 2.4 V to 5.5 V.The LED current can be adjusted in different ways. The full-scale LED current is set to 25 mA once the device is enabled. Analog dimming in 32 linear steps is achieved via a 1-wire pulse-dimming input (ADIM). Further adjustment of the LED current can be done by applying a pulse width modulation (PWM) signal on the PWM input. The PWM dimming control is compatible with content adaptive brightness control (CABC) for a wide range of PWM signal frequency up to 200 kHz.The CAT3649 can be shut down by holding the ADIM or PWM input in a logic low condition for greater than 30 ms.

The CAT3661 is a high efficiency low power fractional charge pump that drives one LED with up to 5 mA of current. Soft-start current limiting and short-circuit protection are optimized for use with coin cell batteries.Low noise input ripple and constant switching frequency allows the use of small external ceramic capacitors. This makes the CAT3661 ideal for EMI sensitive applications. The charge pump supports a wide range of input voltages from 2.0 V to 5.5 V.The CAT3661 has a built-in circuitry to provide feedback to a microcontroller of Open/Short LED and Low battery events. The Low battery indicator trip point is internally fixed at 2.4 V. External resistors can be added to raise or lower the trip voltage, if needed.The device is packaged in the tiny 16-lead TQFN 3 mm x 3 mm package with a max height of 0.8 mm.The inclusion of a 1.33x fractional charge pump mode increases device efficiency by up to 10% over traditional 1.5x tri-mode charge pumps with no added external capacitors.

The CAT4004 provides four matched low dropout current sources to drive LEDs. An external resistor on RSET sets the current in the LED channels. Each LED channel includes an individual control loop allowing the device to handle a wide range of LED forward voltages while still maintaining tight current matching.The EN/DIM logic inputs supports device enable and a digital dimming interface for current setting of all LEDs. Six different current dimming ratios are available.The device is aimed at 'direct drive' battery applications. It is required that the battery or voltage source have enough headroom to drive the LED forward voltage and current sink (>150 mV).

The CAT4008 is an 8 channel constant current driver for LED billboard and other general display applications. LED channel currents are programmed together via an external RSET resistor. Low output voltage operation on the LED channels as low as 0.4 V (for 2 to 100 mA LED current) allows for more power efficient designs.A high-speed 4-wire serial interface of up to 25 MHz clock frequency controls each individual channel using a shift register and latch configuration. A serial output data pin (SOUT) allows multiple devices to be cascaded and programmed via one serial interface. The device also includes a blanking control pin (BLANK) that can be used to disable all channels independently of the interface.Thermal shutdown protection is incorporated in the device to disable the LED outputs if the die temperature exceeds a set limit.

The CAT4016 is a 16 channel constant current driver for LED billboard and other general display applications. LED channel currents are programmed together via an external RSET resistor. Low output voltage operation on the LED channels as low as 0.4 V (for 2 to 100 mA LED current) allows for more power efficient designs.A high-speed 4-wire serial interface of up to 25 MHz clock frequency controls each individual channel using a shift register and latch configuration. A serial output data pin (SOUT) allows multiple devices to be cascaded and programmed via one serial interface. The device also includes a blanking control pin (BLANK) that can be used to disable all channels independently of the interface.Thermal shutdown protection is incorporated in the device to disable the LED outputs if the die temperature exceeds a set limit.