MC14516B
http://onsemi.com
6
TOGGLE FLIP−FLOP
PE
C
T
Q
Q
P
PARALLEL IN
FLIP−FLOP FUNCTIONAL TRUTH TABLE
Preset
Enable
Clock T Q
n+1
1 X X Parallel In
0 0 Q
n
0 1 Q
n
0 X Q
n
X = Don’t Care
Figure 2. Switching Time Waveforms
V
DD
V
SS
V
DD
V
SS
V
DD
V
SS
V
DD
V
SS
V
OL
V
OH
RESET
PRESET ENABLE
CARRY IN OR
UP/DOWN
CLOCK
Q
0
OR CARRY OUT
t
rem
t
su
t
rem
t
h
t
TLH
t
PLH
t
PHL
t
PLH
t
THL
50%
50%
90%
10%
50%
90%
10%
CARRY OUT
ONLY
t
w(H)
t
w(H)
t
w
1
f
cl
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
V
SS
, Negative Supply Voltage, (Pin 8) — This pin is
usually connected to ground.
V
DD
, Positive Supply Voltage, (Pin 16) — This pin is
connected to a positive supply voltage ranging from 3.0 V
to 18 V.
