Description
The ATS675 is the next generation of the Allegro® True Power-On State (TPOS) sensor family, offering improved accuracy compared to prior generations, gradual TPOS to Running Mode adjustment for accuracy-shift reduction, and longer output fall time for improved radiated emissions performance. The ATS675 provides absolute zero-speed performance and TPOS information.
The sensor incorporates a single-element Hall IC with an optimized custom magnetic circuit that switches in response to magnetic signals created by a ferromagnetic target. The IC
contains a sophisticated digital circuit designed to eliminate the detrimental effects of magnet and system offsets. Signal processing is used to provide device performance at zero target
speed, independent of air gap, and which adapts dynamically to the typical operating conditions found in automotive applications, particularly camshaft-sensing applications.
High resolution peak-detecting DACs are used to set the adaptive switching thresholds of the device, ensuring high accuracy despite target eccentricity. Internal hysteresis in the thresholds
reduces the negative effects of anomalies in the magnetic signal (such as magnetic overshoot) associated with targets used in many automotive applications. The resulting output of the
device is a digital representation of the ferromagnetic target profile. The ATS675 also includes a low bandwidth filter that increases the noise immunity and the signal-to-noise ratio of the sensor.
The device package is lead (Pb) free, with 100% matte tin leadframe plating.

Features and Benefits
*Chopper stabilized; optimized for automotive cam sensing applications
*Optimized absolute timing accuracy step size through gradual transition from TPOS to Running Mode
*High immunity to signal anomalies resulting from magnetic overshoot and peak-to-peak field variation
*Tight timing accuracy over full operating temperature range
*True zero-speed operation
*Automatic Gain Control circuitry for air gap independent switchpoints
*Operation at supply voltages down to 3.3 V
*Digital output representing target profile
*Undervoltage lockout (UVLO)
*Patented Hall IC-magnet system
*Increased output fall time for improved radiated emissions performance

ATS675LSETN-LT-T, ATS675LSETN-HT-T  

ATS675LSE - Self-Calibrating TPOS Speed Sensor Optimized for Automotive Cam Sensing Applications

Description
The A6281 is a 3-channel constant current LED driver that has a wide range of output currents. The A6281 controls LED brightness with a Pulse Width Modulation (PWM) scheme that gives the application the capability of displaying a billion colors in an RGB cluster. The maximum current is set by an external resistor.
The LED brightness is controlled by performing PWM control on the outputs. The brightness data of the PWM signal for each LED is stored in three 10-bit registers. The peak value for each LED can be adjusted (dot-corrected) to compensate for mismatch, aging, and temperature effects. All the internal latched registers are loaded by a 32-bit shift register. One address bit controls whether dot correction/clock divider ratio or brightness data is loaded into the registers. The remaining bits are used for the data.
The A6281 is designed to minimize the number of components needed to drive LEDs with large pixel spacing. A large number of A6281s can be daisy chained together and controlled by just four control signals (clock, serial data, latch, and output enable). Each of these inputs is buffered to drive the next chip in the chain. Also, VIN can be tied to the LED voltage supply bus, thus eliminating the need for a separate chip supply bus or an external regulator.

Features and Benefits
*3 × 10-bit PWM brightness settings
*3 × 7-bit dot correction current settings
*5 to 17 V operation
*Wide output current range, 10 to 150 mA per channel
*Internally generated PWM clock
*Serial port operates at up to 5 MHz
*Data and clock logic architecture allows single microcontroller control of large quantities of seriallyconnected A6281s at fast data transfer rate
*Buffered logic outputs to drive cables
*Thermal shutdown and UVLO protection
*Power-On Reset

Applications
*Colored, large-character LED signs
*Scrolling, colored marquees
*Architectural lighting
*High intensity monochrome displays
*Large video and graphic displays

A6281EESTR-T  

A6281 - 3-Channel Constant Current LED Driver with Programmable PWM Control

Description
The A3955 is designed to drive one winding of a bipolar stepper motor in a microstepping mode. The outputs are rated for continuous output currents to ±1.5 A and operating voltages to 50 V. Internal pulse width modulated (PWM) current control combined with an internal three-bit nonlinear digitalto-analog converter allows the motor current to be controlled in full-, half-, quarter-, or eighth-step (microstepping) modes. Nonlinear increments minimize the number of control lines necessary for microstepping. Microstepping provides increased step resolution, and reduces torque variations and resonance problems at low speed.
Internal circuitry determines whether the PWM current-control circuitry operates in a slow (recirculating) current-decay mode, fast (regenerative) current-decay mode, or in a mixed
current-decay mode in which the off-time is divided into a period of fast current decay and with the remainder of the fixed off-time spent in slow current decay. The combination of
user-selectable current-sensing resistor and reference voltage, digitally selected output current ratio; and slow, fast, or mixed current-decay modes provides users with a broad, variable
range of motor control.
Internal circuit protection includes thermal shutdown with hysteresis, transient-suppression diodes, and crossover-current protection. Special power-up sequencing is not required.
The A3955 is supplied in a choice of two power packages; a 16-pin dual-in-line plastic package with copper heat-sink tabs (suffix ‘B’), and a 16-lead plastic SOIC with internally fused pins (suffix ‘LB’). For both package styles, the thermally enhanced pins are at ground
potential and need no electrical isolation. Both packages are lead (Pb) free, with leadframe plating 100% matte tin.

Features and Benefits
*±1.5 A continuous output current
*50 V output voltage rating
*Internal PWM current control
*3-bit nonlinear DAC
*Fast, mixed fast/slow, and slow current-decay modes
*Internal transient-suppression diodes
*Internal thermal shutdown circuitry
*Crossover-current and UVLO protection

A3955SB-T, A3955SLB-T, A3955SLBTR-T  

A3955 - Full-Bridge PWM Microstepping Motor Driver

Description
The Series STR-F6600 is specifically designed to satisfy the requirements for increased integration and reliability in off-line quasi-resonant flyback converters.
The series incorporates a primary control and drive circuit with discrete avalanche-rated power MOSFETs.
Covering the power range from below 25 watts up to 300 watts for 100/115/230 VAC inputs, and up to 150 watts for 85 to 265 VAC universal input, these devices can be used in a range of applications, from battery chargers and set top boxes, to televisions, monitors, and industrial power supply units.
Cycle-by-cycle current limiting, under-voltage lockout with hysteresis, over-voltage protection, and thermal shutdown protects the power supply during the normal overload and fault conditions.
Over-voltage protection and thermal shutdown are latched after a short delay.
The latch may be reset by cycling the input supply.
Low-current startup and a low-power standby mode selected from the secondary circuit completes a comprehensive suite of features.
The series is provided in a five-pin overmolded TO-3P style package, affording dielectric isolation without compromising thermal characteristics.

FEATURES
*Flyback Operation with Quasi-Resonant Soft Switching
for Low Power Dissipation and EMI
*Rugged Avalanche-Rated MOSFET
*Choice of MOSFET Voltage and rDS(on)
*Full Over-Current Protection (no blanking)
*Under-Voltage Lockout with Hysteresis
*Over-Voltage Protection
*Direct Voltage Feedback
*Low Start-up Current (<400 μA)
*Low-Frequency, Low-Power Standby Operation
*Overmolded 5-Pin Package

 

STR-F6600-OFF-LINE QUASI-RESONANT FLYBACK SWITCHING REGULATORS

Description
The A6285 is designed for LED display applications.
This BiCMOS device includes an On/Off shift register, a Dot Correction (DC) shift register, accompanying data latches, and 16 MOS constant-current sink drivers with active pull-ups that
can be enabled or disabled as required by the application.
The CMOS shift registers and latches allow direct interfacing with microprocessor-based systems.
With a 3.3 or 5 V logic supply, typical serial data input rates can reach up to 30 MHz.
The LED drive current level can be set by a single external resistor, selected by the application designer.
A CMOS serial data output permits cascading of multiple devices in applications requiring additional drive lines.
Individual LED light intensity can be adjusted to correct for light intensity variations by using the Dot Correction feature.
Open LED connections can be detected, and then signaled back to the host microprocessor through the serial data output (SDO pin).
The FAULT output flags an LED open circuit (LOD) condition or a thermal shutdown (TSD) condition.
A staggering delay on the load outputs during ON/OFF transitions helps to reduce ground bounce.

Features and Benefits
* 3.0 to 5.5 V logic supply range
* Schmitt trigger inputs for improved noise immunity
* Power-On Reset (POR)
* Up to 80 mA constant-current sinking outputs
* LED open circuit detection (LOD)
* Dot correction (DC) for adjusting LED light intensity on each channel with 7-bit resolution
* Low-power CMOS logic and latches
* High data input rate up to 30 MHz
* Active output pull-ups with enable/disable
* 20 ns typical staggering delay between outputs
* Internal UVLO and thermal shutdown (TSD) circuitry
* Fault output flags for an LED open circuit (LOD) or a thermal shutdown (TSD) condition

A6285EET-T
A6285EETTR-T  

A6285 - 16-Channel Constant-Current Latched LED Driver with Open LED Detection and Dot Correction