Digital Equipment 21BM18, Service Manual

Page: 28 / 51

SERVICE MANUAL
2
6
Fig. 10 Pinning Diagram
HEF4053P(N): 16-lead DIL; plastic
(SOT38-1)
HEF4053D(F): 16-lead DIL; ceramic
(cerdip)
(SOT74)
HEF4053T(D): 16-lead S0; plastic
(SOT109-1)
(): Package Designator North America
Pinning
Y
0A
to Y
0C
Independent inputs/outputs
Y
1A to
Y
1C
Independent inputs/outputs
S
A
to S
c
Select inputs
E Enable input (active LOW)
Z
A
to Z
C
Common inputs/outputs
3. Function Table
Inputs Channel
E Sn On
L L Y
0n
-Z
n
L H Y
1n
-Z
n
H X none
Notes
H=HIGH state (the more positive voltage)
L=LOW state (the less positive voltage)
X=STATE is immaterial
Fig. 21 Schematic Diagram (One Switch)
Fig 11
Ratings
Limiting values in accordance with the Absolute Maximum System (IEC 134)
Supply voltage (with reference to V
DD
) V
EE
-18 to + 0,5 V
Note
To avoid drawing V
DD
current out of terminal Z, when switch current flows into terminals Y, the voltage
drop across the bidirecctional switch must not exceed 0, 4 V. If the switch current flows into terminal
Z, no V
DD
current will flow out of terminals Y, in this case there is no limit for the voltage drop across
the switch, but the voltages at Y and Z may not exceed V
DD
or V
EE.