HP 5340A Service Manual

Model 5340A
Theory of Operation
4 - 41. Dual NAND Schmitt Triggers 1820 - 0537
4 - 42. This IC (Figure 4 - 18) functions as a four - input NAND gate with Schmitt trigger action.
The Schmitt action gives different input threshold levels for positive
- and negative - going
signals. This difference between the threshold levels
is called hysteresis and is typically 800
millivolts. Built in temperature compensation is included to ensure high stability of the threshold
levels and hysteresis. These characteristics allow triggering on slow input ramps and ensure
clean, jitter
- free outputs.
Figure
4 - 18. Dual NAND Schmitt Triggers 1820 - 0537
'CC 2D 2C NC 26 2A 2Y
positive logic:
Y = ABCD
NC - No internal connection.
tPin assignments for these circuits are the same for all packages.
4 - 43. EECL High - speed D - Binary 1820 - 0557
4 - 44. The 1820 - 0557 is a 350 MHz binary counter using the dual rank master - slave design. The
truth table for synchronous or asynchronous operation is shown in Figure
4 - 19.
Figure 4 - 19. EECL High - speed D - Binary 1820 - 0557
(8)
SYNCHRONOUS: Clocks on positive transition
of
C1 or C2 (C1 + C2)
X H
ASYNCHRONOUS:
Sets or resets on positive transition
Normal set operation
Normal reset operation
Set dominant
H = OV Nominal L = -0.6V Nominal X = Either L or H
NOTE:
must transfer
low not later than t sd after set transfers
low to ensure latching in set condition.
(C1 + C2) must be low during set operation or
4 - 13

HP 5340A Specifications

General

Brand	HP
Model	5340A
Category	Cash Counter
Language	English