ON Semiconductor

The CAT4240 is a DC-DC step-up converter that delivers an accurate constant current ideal for driving LEDs. Operation at a fixed switching frequency of 1 MHz allows the device to be used with small value external ceramic capacitors and inductor. LEDs connected in series are driven with a regulated current set by the external resistor R1. The CAT4240 high-voltage output stage is perfect for driving mid-size and large panel displays containing up to ten white LEDs in series.LED dimming can be done by using a DC voltage, a logic signal, or a pulse width modulation (PWM) signal. The shutdown input pin allows the device to be placed in power-down mode with 'zero' quiescent current.In addition to thermal protection and overload current limiting, the device also enters a very low power operating mode during 'Open LED' fault conditions.

The CAT5110 linear-taper digital POT performs the same function as a mechanical potentiometer or a variable resistor. This device consists of a fixed resistor and a wiper contact with 32 tap points that are digitally controlled through a 2-wire up/down serial interface.The CAT5110 is configured as a potentiometer.Three resistance values are available: 10kΩ, 50kΩ and 100kΩ.

The CAT5112 is a single digital POT designed as an electronic replacement for mechanical potentiometers. Ideal for automated adjustments on high volume production lines, they are also well suited for applications where equipment requiring periodic adjustment is either difficult to access or located in a hazardous or remote environment.The CAT5112 contains a 32-tap series resistor array connected between two terminals RH and RL. An up/down counter and decoder that are controlled by three input pins, determines which tap is connected to the wiper, RWB. The CAT5112 wiper is buffered by an op amp that operates rail to rail. The wiper setting, stored in non-volatile memory, is not lost when the device is powered down and is automatically recalled when power is returned. The wiper can be adjusted to test new system values without effecting the stored setting. Wiper-control of the CAT5112 is accomplished with three input control pins,CS, U/D, andINC. TheINCinput increments the wiper in the direction which is determined by the logic state of the U/Dinput. TheCSinput is used to select the device and also store the wiper position prior to power down.The digital POT can be used as a buffered voltage divider. For applications where the potentiometer is used as a 2-terminal variable resistor, please refer to the CAT5114. The buffered wiper of the CAT5112 is not compatible with that application.

The CAT5113 is a single digital POT designed as an electronic replacement for mechanical potentiometers. Ideal for automated adjustments on high volume production lines, they are also well suited for applications where equipment requiring periodic adjustment is either difficult to access or located in a hazardous or remote environment.The CAT5113 contains a 100-tap series resistor array connected between two terminals RHand RL. An up/down counter and decoder that are controlled by three input pins, determines which tap is connected to the wiper, RW. The CAT5113 wiper is buffered by an op amp that operates rail to rail. The wiper setting, stored in non-volatile NVRAM memory, is not lost when the device is powered down and is automatically recalled when power is returned. The wiper can be adjusted to test new system values without affecting the stored setting. Wiper-control of the CAT5113 is accomplished with three input control pins,CS, U/D, andINC. TheINCinput increments the wiper in the direction which is determined by the logic state of the U/Dinput. TheCSinput is used to select the device and also store the wiper position prior to power down.The digital POT can be used as a three-terminal resistive divider or as a two-terminal variable resistor.

The CAT5115 is a single digital POT designed as an electronic replacement for mechanical potentiometers and trim pots. Ideal for automated adjustments on high volume production lines, they are also well suited for applications where equipment requiring periodic adjustment is either difficult to access or located in a hazardous or remote environment.The CAT5115 contains a 32-tap series resistor array connected between two terminals RHand RL. An up/down counter and decoder that are controlled by three input pins, determines which tap is connected to the wiper, RW. The wiper is always set to the mid point, tap 15 at power up. The tap position is not stored in memory. Wiper-control of the CAT5115 is accomplished with three input control pins,CS, U/D, andINC. TheINCinput increments the wiper in the direction which is determined by the logic state of the U/Dinput. TheCSinput is used to select the device.The digital POT can be used as a three-terminal resistive divider or as a two-terminal variable resistor. Digital POTs bring variability and programmability to a wide variety of applications including control, parameter adjustments, and signal processing.