7-909

CD4047BMS

FIGURE 28. TYPICAL POWER DISSIPATION vs OUTPUT FREQUENCY (VDD = 15V)

ASTABLE MODE

SUPPLY VOLTAGE (VDD) = 15V

Q OR Q FREQUENCY (F) (Hz)

C = 0.1

µF

C = 0.01

µF

C =1000pF

C =100pF

C =10pF

Astable Mode Design Information

Unit-to-Unit Transfer Voltage Variations

The following analysis presents variations from unit to unit as

a function of transfer voltage (VTR) shift (33%-67% VDD) for

free running (astable) operation.

FIGURE 29. ASTABLE MODE WAVEFORMS

thus if

is used, the variation will be +5%, -0%

due to variations in transfer voltage.

Variations Due to VDD and Temperature Changes

In addition to variations from unit to unit, the astable period

varies with VDD and temperature, Typical variations are pre-

sented in graphical form in Figures 11 to 18 with 10V as ref-

for temperature variations curves.

t1 = -RC In

VTR

;

VDD + VTR

typically, t1 = 1.1RC

t2 = -RC In

VDD - VTR

;

2VDD - VTR

typically, t2 = 1.1RC

= -2RC In

(VTR)(VDD - VTR)

(VDD + VTR)(2VDD - VTR)

Typ:

Min:

Max:

VTR = 0.5VDD

VTR = 0.33VDD

VTR = 0.67VDD

t1

t2

t1

t2

TERMINAL 13

TERMINAL 10

Monostable Mode Design Information

The following analysis presents variations from unit to unit as a

function of transfer voltage (VTR) shift (33% - 67% VDD) for

one shot (monostable) operation.

FIGURE 30. MONOSTABLE WAVEFORMS

thus if

is used, the variation will be +9.3%,

-0% due to variations in transfer voltage.

NOTES:

1. In the astable mode, the first positive half cycle has a duration of

2. In addition to variations from unit to unit, the monostable pulse

width varies with VDD and temperature. These variations are

presented in graphical form in Figures 19 to 26 with 10V as ref-

temperature variation curves.

VTR

;

2VDD

tM = -RC In

(VTR)(VDD - VTR)

(2VDD - VTR)(2VDD)

where tM = Monostable mode pulse width.

Values for tM are as follows:

Typ:

Min:

Max:

VTR = 0.5VDD

VTR = 0.33VDD

VTR = 0.67VDD

tM = 2.48RC

tM = 2.71RC

tM = 2.48RC

t1´

t2

t1´

t2

tM

tM

TERMINAL 13

TERMINAL 10

TERMINAL 8

tM = 2.48RC