M54995FP 8-BIT SERIAL-INPUT LATCHED DRIVER
DESCRIPTION
The M54995 is a semiconductor integrated circuit consisting of 8 stages of CMOS shift registers and latches with serial inputs and serial or parallel outputs. It is based on Bi-CMOS process technology, and has 8 bipolar drivers at the parallel outputs.
FEATURES
l Serial input and serial or parallel output
l Serial output enables cascade connection
l Built-in latch for each stage
l Enable input provides output control
l Low supply current (standby current ICC=10mA)
l Serial I/O level is compatible with typical CMOS devices
l Driver features: High withstand voltage (BVCEO=30V)
l Wide operating temperature range Ta=-20 – +75°C
FUNCTION
The M54995 consists of 8 stages of D-type flip flops connected to 8 latches. Data is input to serial input S-IN, and clock pulses are input to clock input T. When the clock changes from low to high, the input data enters the first shift register and data already in the shift registers is shifted sequentially. The serial output S-OUT is used to connect multiple M54995 to expand the number of parallel outputs. S-OUT is connected to S-IN of the next stage. For parallel output. When the clock pulse changes from low to high, latch input (LATCH) is high and output enable input (EN) is low the serial input data at S-IN appears at output O1 and the other data already present is shifted sequentially to outputs O2 through O8. The parallel outputs are inverted. When the latch input is held low, the latch retains the stored data. When the EN input is high, outputs O1 through O8 all turn off. As the internal logic is unstable when the power is turned on, the EN input should be kept high (setting outputs O1 through O8 off) until input data is set and the internal logic is initialized. L-GND is the GND of CMOS logic circuit and P-GND is the GND of output driver circuits O1 through O8 which employ bipolar transistors capable of large drive currents.
Pin
Name
Description IC405 in President George
1
T
2
S-IN
3
L-GND
4
Vcc
5
S-OUT
6
LATCH
7
/EN
8
P-GND
9
/O8
S/RF
10
/O7
SWR
11
/O6
CAL
12
/O5
MUTE
13
/O4
PA
14
/O3
T/R
15
/O2
DIM
16
/O1
Pin
Name
Description IC406 in President George
1
T
2
S-IN
3
L-GND
4
Vcc
5
S-OUT
6
LATCH
7
/EN
8
P-GND
9
/O8
ECHO
10
/O7
HI CUT
11
/O6
NB/ANL
12
/O5
USB
13
/O4
LSB
14
/O3
AM
15
/O2
FM
16
/O1
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