74HC423D.653 Datasheet, PDF(10/24 Page) NXP Semiconductors – Dual retriggerable monostable multivibrator with reset

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

74HC423D.653 Datasheet, PDF (10/24 Pages) NXP Semiconductors – Dual retriggerable monostable multivibrator with reset

◁

NXP Semiconductors

74HC423; 74HCT423

Dual retriggerable monostable multivibrator with reset

Table 7. Dynamic characteristics â¦continued

GND = 0 V; test circuit see Figure 12.

Symbol Parameter Conditions

CPD

power

per package; VI = GND to VCC ï 1.5 V

dissipation

capacitance

25 ï°C

ï40 ï°C to ï40 ï°C to Unit

+85 ï°C +125 ï°C

Min Typ Max Min Max Min Max

[6] -

- pF

[1] tpd is the same as tPHL and tPLH.

[2] tt is the same as tTHL and tTLH.

[3] For other REXT and CEXT combinations see Figure 8. If CEXT > 10 pF, the next formula is valid:

tW = K ï´ REXT ï´ CEXT (typ.), where:

tW = output pulse width in ns;

REXT = external resistor in kï;

CEXT = external capacitor in pF;

K = 0.55 for VCC = 2.0 V and 0.45 for VCC = 5.0 V; see Figure 9.

Inherent test jig and pin capacitance at pins 15 and 7 (nREXT/CEXT) is 7 pF.

[4] The time to retrigger the monostable multivibrator depends on the values of REXT and CEXT. The output pulse width will only be

extended when the time between the active-going edges of the trigger input pulses meets the minimum retrigger time.

If CEXT > 10 pF, the next formula (at VCC = 5.0 V) for the set-up time of a retrigger pulse is valid:

trtrig = 30 + 0.19 ï´ REXT ï´ CEXT0.9 + 13 ï´ REXT1.05 (typ.); where:

trtrig = retrigger time in ns;

CEXT = external capacitor in pF;

REXT = external resistor in kï.

Inherent test jig and pin capacitance at pins 15 and 7 (nREXT/CEXT) is 7 pF.

[5] When the device is powered-up, initiate the device via a reset pulse, when CEXT < 50 pF.

[6] CPD is used to determine the dynamic power dissipation (PD in ïW):

PD = CPD ï´ VCC2 ï´ fi ï´ N + ï(CL ï´ VCC2 ï´ fo); where:

fi = input frequency in MHz;

fo = output frequency in MHz;

CL = output load capacitance in pF;

VCC = supply voltage in V;

N = number of inputs switching;

ï(CL ï´ VCC2 ï´ fo) = sum of outputs.

74HC_HCT423

Product data sheet

All information provided in this document is subject to legal disclaimers.

Rev. 6 â 19 December 2011

10 of 24

▷