HCF4527B_02 Datasheet, PDF (8/12 Pages) STMicroelectronics – BCD RATE MULTIPLEXER

HCF4527B
Symbol
Parameter
V_DD (V)
t_R Inhibit Input Removal Time
5
10
15
t_R Set Removal Time
5
10
15
t_R Clear Removal Time
5
10
15
(*) Typical temperature coefficient for all V_DD value is 0.3 %/°C.
Test Condition
Value (*)
Unit
Min. Typ. Max.
240 120
130 65
ns
110 55
150 75
80 40
ns
50 25
60 30
40 20
ns
30 15
APPLICATION NOTE :
For fractional multipliers with more than one digit,
HCF4527B may be cascaded in two different
modes: The ADD mode and the MULTIPLY mode
(see figure 1 and 2).
When two units are cascaded in ADD mode and
programmed to 9 and 4 respectively, the more
significant unit will have 9 output pulses for every
10 input pulses and the other will have 4 output
pulses for every 100 input pulses for a total of :
 ₁₉₀ + ₁₀₄₀ = ₁⁹⁰⁴₀
In the multiply mode, the fraction programmed into
the first rate multiplier is multiplied by the fraction
programmed into the second one :
If N₁ = 9 and N₂ =4
f_OUT2 = ₁₄₀ f_OUT1
f_OUT1 = ₁₉₀ f_CLOCK
f_OUT2 = ₁⁴⁰ x ( ₁⁹⁰ f_CLOCK ) = ₁₃₀⁶⁰ f_CLOCK
Therefore 36 output pulses for every 100 clock
input pulses
Two HCF4527B Cascaded in the ADD mode with a Preset Number
8/12