CD4047BMS

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

Typical Performance Characteristics (Continued)

ASTABLE MODE

SUPPLY VOLTAGE (VDD) = 15V

105

104

103

102

10-1

100

101

102

103

104

105

106

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-

erence for voltage variations curves and +25oC as reference

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

tA = 2(t1 + t2)

= -2RC In

(VTR)(VDD - VTR)

(VDD + VTR)(2VDD - VTR)

Typ:

Min:

Max:

VTR = 0.5VDD

VTR = 0.33VDD

VTR = 0.67VDD

tA = 4.40RC

tA = 4.62RC

tA = 4.62RC

t1

t2

t1

t2

tA/2

tA/2

tA

TERMINAL 13

TERMINAL 10

tA = 4.40RC

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

tM; succeeding durations are tA/s.

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-

erence for voltage variation curves and +25oC as reference for

temperature variation curves.

t1´ = -RC In

VTR

;

2VDD

typically, t1´ = 1.38RC

tM = (t1´ + t2)

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

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