Advanced Linear Devices ALD7555SAL

The ALD7555/ALD7556 timers are high performance single/dual monolithic analog RC timing circuits. They offer significantly upgraded performance in speed, leakage currents, supply current, stability, temperature voltage stability, and discharge output drive when compared to SE555/ NE555, ICL7555, TLC555, and ICM7555. The ALD7555/ALD7556 offer the benefits of high input impedance, thereby allowing smaller timing capacitors and a longer timing cycle; high speed; low power dissipation for battery operated environment; reduced supply current spikes, allowing smaller and lower cost decoupling capacitors. Each timer is capable of producing accurate time delays and oscillations in both monostable and astable operation, and operates in the one-shot (monostable) mode or 50% duty cycle free running oscillation mode with a single resistor R and one capacitor C. The inputs and outputs are fully compatible with CMOS, NMOS or TTL logic. There are three matched internal resistors (approximately 200KΩ each) that set the threshold and trigger levels at two-thirds and one-third respectively of V+. These levels can be adjusted by using the control terminal. When the trigger input is below the trigger level, the output is in the high state and sourcing 2mA. When the threshold input is above the threshold level at the same time the trigger input is above the trigger level, the internal flip-flop is reset, the output goes to the low state and sinks up to 10mA. The reset input overrides all other inputs and when it is active (reset voltage less than 1V), the output is in the low state. The discarge output has been signifcantly enhanced to eliminate the need for a separate external driver.

• Improved accuracy and temperature stability
• High speed operation -- 2.5MHz typical oscillation at 5V
• High Discharge Sinking Current of 80mA at 5V
• Guaranteed low operating supply voltage of 2V to 10V
• Functional equivalent to and same pin-out as NE555/NE556, SE555, TLC555, ICM7555/ICM7556
• Greatly expanded high and low frequency ranges
• High speed, low power, monolithic CMOS technology
• Low supply current, typically: 50μA for ALD7555, 100μA for ALD7556
• Extremely low trigger, threshold and reset currents 10pA typical
• Operates in both monostable and astable modes
• Fixed 50% duty cycle or adjustable duty cycle
• CMOS, NMOS and TTL compatible input/output
• Low supply current spikes
• Rail to rail output

• High speed one-shot (monostable)
• Precision sequential timing
• Long delay timer
• Pulse width and pulse position modulation
• Missing pulse detector
• Frequency divider
• Synchronized timer