Samsung HT-DL200, Service Manual

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Samsung Electronics 8-3
74VHCT244A
Octal Buffer/Line Driver with 3-STATE Outputs
General Description
The VHCT244A is an advanced high speed CMOS octal
bus transceiver fabricated with silicon gate CMOS technol-
ogy. It achieves high speed operation similar to equivalent
Bipolar Schottky TTL while maintaining the CMOS low
power dissipation. The VHCT244A is a non-inverting 3-
STATE buffer having two active-LOW output enables. This
device is designed to be used as 3-STATE memory
address drivers, clock drivers, and bus oriented transmitter/
receivers.
Protection circuits ensure that 0V to 7V can be applied to
the input and output (Note 1) pins without regard to the
supply voltage. These circuits prevent device destruction
due to mismatched supply and input/output voltages. This
device can be used to interface 5V to 3V systems and two
supply systems such as battery back up.
Note 1: Outputs in OFF-State
Features
■
High Speed: t
PD
=
5.9 ns (typ) at V
CC
=
5V
■
Power down protection is provided on inputs and
outputs
■
Low power dissipation: I
CC
=
4
µ
A (max) @ T
A
=
25
°
C
■
Pin and function compatible with 74HCT244
Ordering Code:
Surface mount packages are also available on Tape and Reel. Specify by appending the suffix letter ìXî to the ordering code.
Logic Symbol Connection Diagram
Pin Descriptions
Order Number Package Number Package Description
74VHCT244AM M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
74VHCT244ASJ M20D 20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74VHCT244AMTC MTC20 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
74VHCT244AN N20A 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Pin Names Description
OE
1
, OE
2
3-STATE Output Enable Inputs
I
0
ñI
7
Inputs
O
0
ñO
7
3-STATE Outputs
3. 74VHCT244A