SE555 Datasheet PDF – Precision Timer – TI

Part Number : SE555

Function : Precision Timer

Package : PDIP, SOP, TSSOP, SOIC 8 Pin

Manufacturers : Texas Instruments

Pinouts :
SE555 datasheet

Description :

These devices are precision timing circuits capable of producing accurate time delays or oscillation. In the time-delay or monostable mode of operation, the timed interval is controlled by a single external resistor and capacitor network. In the astable mode of operation, the frequency and duty cycle can be controlled independently with two external resistors and a single external capacitor.

The threshold and trigger levels normally are two-thirds and one-third, respectively, of Vcc. These levels can be altered by use of the control-voltage terminal. When the trigger input falls below the trigger level, the flip-flop is set, and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level, the flip-flop is reset and the output is low.

The reset (RESET) input can override all other inputs and can be used to initiate a new timing cycle. When RESET goes low, the flip-flop is reset, and the output goes low. When the output is low, a low-impedance path is provided between discharge (DISCH) and ground.

The output circuit is capable of sinking or sourcing current up to 200 mA. Operation is specified for supplies of 5 V to 15 V. With a 5-V supply, output levels are compatible with TTL inputs.

Block Diagram

SE555 Block diagram

Features

1. Timing From Microseconds to Hours
2. Astable or Monostable Operation
3. Adjustable Duty Cycle
4. TTL-Compatible Output Can Sink or Source up to 200 mA

Applications

1. Fingerprint Biometrics
2. Iris Biometrics
3. RFID Reader

 

SE555 Datasheet PDF Download

SE555 pdf

Other data sheets within the file : NA555, NE555, SA555, NA555D, NA555DG4

74HC157 Datasheet – Quad 2-Input Multiplexer

Part Number : 74HC157

Function : High-Speed CMOS Logic Quad 2-Input Multiplexer

Package : DIP, SOIC 16 Pin

Manufacturers : Texas Instruments

Image

74HC157 Multiplexer

 

Description :

The ’74HC157, ’74HCT157, ’74HC158, and ’74HCT158 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select input (S).

The Enable input (E) is active Low. When (E) is High, all of the outputs in the 158, the inverting type, (1Y-4Y) are forced High and in the 157, the non-inverting type, all of the outputs (1Y-4Y) are forced Low, regardless of all other input conditions.

Pinouts :

74HC157 datasheet

Features

1. Common Select Inputs
2. Separate Enable Inputs
3. Buffered inputs and Outputs
4. Balanced Propagation Delay and Transition Times
5. Significant Power Reduction Compared to LSTTL Logic ICs

 

74HC157 Datasheet PDF

74HC157 pdf

Other data sheets within the file : 74HC157N, 74HCT157, CD54HC157F