MC14516B

http://onsemi.com

7

TOGGLE FLIP–FLOP

PE

C

T

Q

Q

P

PARALLEL IN

FLIP–FLOP FUNCTIONAL TRUTH TABLE

Preset

Enable

Clock

T

1

X

X

Parallel In

0

0

0

1

0

X

X = Don’t Care

Figure 2. Switching Time Waveforms

RESET

PRESET ENABLE

CARRY IN OR

UP/DOWN

CLOCK

50%

50%

90%

10%

50%

90%

10%

CARRY OUT ONLY

1

PIN DESCRIPTIONS

INPUTS

P0, P1, P2, P3, Preset Inputs (Pins 4, 12, 13, 3) — Data

on these inputs is loaded into the counter when PE is taken

high.

Carry In, (Pin 5) — This active–low input is used when

Cascading stages. Carry In is usually connected to Carry Out

of the previous stage. While high, Clock is inhibited.

Clock, (Pin 15) — Binary data is incremented or

decremented, depending on the direction of count, on the

positive transition of this input.

OUTPUTS

Q0, Q1, Q2, Q3, Binary outputs (Pins 6, 11, 14, 2) —

Binary data is present on these outputs with Q0

corresponding to the least significant bit.

Carry Out, (Pin 7) — Used when cascading stages, Carry

Out is usually connected to Carry In of the next stage. This

synchronous output is active low and may also be used to

indicate terminal count.

CONTROLS

PE, Preset Enable, (Pin 1) — Asynchronously loads data

on the Preset Inputs. This pin is active high and inhibits the

clock when high.

R, Reset, (Pin 9) — Asynchronously resets the Q out–

puts to a low state. This pin is active high and inhibits the

clock when high.

Up/Down, (Pin 10) — Controls the direction of count,

high for up count, low for down count.

SUPPLY PINS

usually connected to ground.

connected to a positive supply voltage ranging from 3.0

volts to 18.0 volts.