ITT - Index of

__ JI[~~ __________________________
SEMICONDUCTORS
ITT5490, ITT7490
D_EC_A_D_E __ C_O_U_N_T_ER_S
DECADE COUNTERS
MSI TTL HIGH-SPEED DECADE COUNTERS
for applications in
• Digital Computer Systems
• Data-Handling Systems
• Control Systems
description and typical count configurations
o
INPUT
Rom
DUAL-IN -LINE PACKAGE
AND FLAT PACKAGE
PIN CONFIGURATION
(TOP VIEW)
A
INPUT
NC
These high-speed, monolithic decade counters consist
of four dual-rank, master-slave flip-flops internally
interconnected to provide a divide-by-two
counter and a divide-by-five counter. Gated direct
reset lines are provided to inhibit count inputs and
return all outputs to zero or to a binary coded
decimal (BCD) count of 9. As the output from flipflop
A is not internally connected to the succeeding
stages, the count may be separated in three independent
count modes:
RO(21
NC
VCC
R9Ul
R9(21
ILG~;::t.;:tL;..:JGND
1. When used as a binary coded decimal decade
counter, the BO input must be externally connected
to the A output. The A input receives
the incoming count. and a count sequence is
obtained in accordance with the BCD count
sequence truth table shown above. In additi.On
to a conventional zero reset. inputs are provided
to reset a BCD count for nine's complement
decimal applications.
2. If a symmetrical divide-by-ten count is desired
for frequency synthesizers' or other applications
requiring division of a binary count by
a power of ten, the 0 output must beex~
ternally connected to the A input. The input
count is then applied at the BO input and a
divide-by-ten square wave is obtained at output
A.
3. For operation as a divide-by-two counter and
a divide-by-five counter, no external intereon"
nections are required. Flip-flop A is used as a
binary element for the divide-by-two function.
The BO input is used to obtain binary divideby-five
operation at the B, C, and 0 outputs.
POSITIVE LOGIC:
SEE TRUTH TABLE
In this mode, the two counters operate independently:
however, all four flip-flops are reset
simultaneously.
These circuits are completely compatible with Series
54174 TTL and OTL logic families. Average
power dissipation is 160 mW.
absolute maximum ratings (over operating
temperature range unless otherwise. noted)
Supply Voltage V CC (See Note 3) ........................... 7V
InputVoltage Vin (See Notes 3 and 4) ............... 5.5V
Operating Free-Air Temperature Range:
ITT5490 Circuits ........................... -55°Cto 125°C
ITT7490 Circuits .................................... ooC to 70°C
Storage Temperature Range ......... -65°C to 150°C
Notes: 3. These voltage values are with respect to
network ground term inaf.
4. Input signals must be zero or positive with
respect to network ground terminal.