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CD4045B is a timing circuit consisting of 21 counter stages, two output-shaping flip-flops, two inverter output drivers, and input inverters for use in a crystal oscillator. The CD4045B configuration provides 21 flip-flop counting stages, and two flip-flops for shaping the output waveform for a 3.125% duty cycle. Push-pull operation is provided by the inverter output drivers.

The first inverter is intended for use as a crystal oscillator/amplifier. However, it may be used as a normal logic inverter if desired. A crystal oscillator circuit can be made less sensitive to voltage-supply variations by the user of source resistors. In this device, the sources of the p and n transistors have been brought out to package terminals. If external resistors are not required, the sources must be shorted to their respective substrates (S_p to V_DD, S_n to V_SS). See Fig. 1. The first inverter in conjunction with an outboard inverter, such as 1/6 CD4069, and R_X, C_X, and R_S can also be used to construct an RC oscillator. The following data is supplied as a guide in the selection of values for R_X, R_S, and C_X used in Fig. 11:

1. R_X max = 10 M and C_X = 50 pF
2. C_X max = 25 µF with R_S = 560 k

The CD4045B types are supplied in 16-lead dual-in-line plastic packages (E suffix), 16-lead small-outline package (NSR suffix), and 16-lead thin shrink small-outline packages (PW and PWR suffixes).