Is there a specification for the input-signal rise time and fall time of the general-purpose logic ICs?

In the datasheet, the rise and fall times of general-purpose general-purpose logic ICs are specified in the operating ranges in which their functional operation is guaranteed. Use general-purpose logic ICs within the operating ranges to prevent a malfunction due to output oscillation etc.

If a slowly rising or falling signal (a low slew rate signal) is applied to an input, a current spike occurs during switching, causing VCC and GND bounce, which might result in output oscillation or a malfunction.

Use ICs with a Schmitt-trigger input for slowly changing inputs. However, in the case of excessively slowly changing inputs, even ICs with a Schmitt-trigger input might not be able to suppress noise on power supply or signal lines, resulting in output oscillation or instability.

The table-1 shows the rise and fall times of a typical IC*1 in each series.

Table-1 Rise and fall time by series of general-purpose logic IC

Type

Series Name

 CMOS Logic IC
Series No.

One-Gate Logic (L-MOS) Equivalents

 Operating Voltage Range
VCC（V)

Propagation Delay time *1  tpLH, tpHL (ns)

Output Current*2, IOUT (mA)

 Rise and fall time
＠3.3 V		 Rise and fall time
@5 V

For 5-V Systems

Standard

TC40xxB
TC45xxB

TC4S
TC4W

3 to 18

200
(at 5.0 V)

±0.51
(at 5.0 V)

0~10 [μs/V]*4

0~5 [μs/V]*4

High Speed

TC74HC

TC7S
TC7W

2 to 6

23
(at 4.5 V)

±4.0 or 6.0
(at 4.5 V)
(±2.0 in the case of TC7S）

0~1 [μs/V]

0~500 [ns/V]

TC74HCT

TC7WT

4.5 to 5.5

31
(at 4.5 V)

  

0~500 [ns/V]

Advanced

TC74AC

  

2 to 5.5

8.5
(at 4.5 V)

±24
(at 4.5 V)

0~100 [ns/V]

0~20 [ns/V]

TC74ACT

  

4.5 to 5.5

9.0
(at 5.0 V)

  

0~10 [ns/V]

Very High Speed

TC74VHC
74VHC

TC7SH
TC7WH

2 to 5.5

8.5
(at 5.0 V)

±8.0
(at 4.5 V)

0~100 [ns/V]

0~20 [ns/V]

TC74VHC9
74VHC9

10
(at 5.0 V)

　　－　*3

　－　*3

TC74VHCT
74VHCT

TC7SET

4.5 to 5.5

9.5
(at 5.0 V)

  

0~20 [ns/V]

TC74VHCV
74VHCV

  

1.8 to 5.5

8.5
(at 5.0 V)

± 16
(at 4.5 V)

0~20 [ms/V]

0~1 [ms/V]

For low-voltage Systems

Low Voltage

TC74LCX
74LCX

TC7SZ
TC7PZ
TC7WZ

1.65 to 3.6
(1.65 to 5.5 in the case of TC7SZ/PZ/WZ)

6.5
(at 3.3 V)

± 24
(at 3.0 V)

0~10 [ns/V]

  
Very Low
Voltage

TC74VCX

7UL

1.2 to 3.6
(0.9 to 3.6 in the case of 7UL)

4.2
(at 2.3 V)

± 24
(at 3.0 V)
(±8.0 in the case of 7UL）

0~10 [ns/V]

  

*1: Maximum propagation delay time of typical ICs (TC4001, TC74HC244, TC74HCT244, TC74AC244, TC74ACT244, 74VHC244, 74VHC9541 (An-Yn), VHCT244, VHCV244, 74LCX244, and TC74VCX244) at -40 to 85°C, except for the TC4001 for which the maximum propagation delay time at 25°C is shown.
*2: Those output current values are from DC Characteristics table of the datasheet. In addition, absolute maximum ratings also specify the current.
*3: Rise and fall times are not specified because the TC74VHC9 and 74VHC9 series provide Schmitt-trigger inputs.　
*4:Rise and fall times are not specified in the datasheet. The values shown above should be considered only as a guide for creating a design.

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