NTE955MC
Integrated Circuit
CMOS Timing Circuit
Description:
The NTE955MC is a monolithic timing circuit in an 8鈥揕ead DIP type package fabricated using CMOS
process. This timer is fully compatible with CMOS, TTL, and MOS logic and operates at frequencies
up to 2MHz. Because of its high impedance, this device uses smaller timing capacitors than those
used by the NE555. As a result, more accurate time delays and oscillations are possible. Power con-
sumption is low across the full range of power supply voltage.
Like the NE555, the NTE955MC has a trigger level equal to approximately one鈥搕hird of the supply
voltage and a threshold level equal to approximately two鈥搕hirds of the supply voltage. These levels
can be altered by use of the control voltage terminal (Pin5). When the trigger input (Pin2) falls below
the trigger level, the flip鈥揻lop is set and the output goes high. If Pin2 is above the trigger level and the
threshold input (Pin6) is above the threshold level, the flip鈥揻lop is reset and the output is low. The reset
input (Pin4) can override all other inputs and can be used to initiate a new timing cycle. If Pin4 is low,
the flip鈥揻lop is reset and the output is low. Whenever the output is low, a low鈥搃mpedance path is pro-
vided between the discharge terminal (Pin7) and GND. All unused inputs should be tied to an ap-
propriate logic level to prevent false triggering.
While the CMOS output is capable of sinking over 100mA and sourcing over 10mA, the NTE955MC
exhibits greatly reduced supply鈥揷urrent spikes during output transitions. This minimizes the need for
the large decoupling capacitors required by the NE555.
Features:
D
Direct Replacement for 555 Timers
D
Very Low Power Consumption: 1mW Typ at V
DD
= 5V
D
Operates in Both Astable and Monostable Modes
D
CMOS Output Capable of Swinging Rail to Rail
D
High Output Current Capability:
Sink 100mA Typ
Source 10mA Typ
D
Output Fully Compatible with CMOS, TTL, and MOS
D
Low Supply Current Reduces Spikes During Output Transitions
D
Single Supply Operation from 2V to 15V
Applications:
D
Precision Timing
D
Pulse Generation
D
Sequential Timing
D
Time Delay Generation
D
Pulse Width Modulation
D
Pulse Position Modulation
D
Linear Ramp Generator
1
2
3
4
5
