鈥?/div>
DESCRIPTION
A Dynamic Output Control (DOC鈩? circuit is implemented, which, during the transition, initially lowers the output
impedance to effectively drive the load and, subsequently, raises the impedance to reduce noise.
Figure 1
shows
typical V
OL
vs I
OL
and V
OH
vs I
OH
curves to illustrate the output impedance and drive capability of the circuit. At
the beginning of the signal transition, the DOC circuit provides a maximum dynamic drive that is equivalent to a
high-drive standard-output device. For more information, refer to the TI application reports,
AVC Logic Family
Technology and Applications,
literature number SCEA006, and
Dynamic Output Control (DOC鈩? Circuitry
Technology and Applications,
literature number SCEA009.
3.2
2.8
V - Output Voltage - V
OL
2.4
2.0
1.6
V
CC
= 2.5 V
1.2
V
CC
= 1.8 V
0.8
0.4
0
17
34
51
68
85 102 119
I
OL
- Output Current - mA
136
153
170
V
CC
= 3.3 V
T
A
= 25擄C
Process = Nominal
- Output Voltage - V
2.8
2.4
2.0
1.6
1.2
0.8
V
CC
= 3.3 V
0.4
V
CC
= 2.5 V
V
CC
= 1.8 V
-32
-16
0
T
A
= 25擄C
Process = Nominal
V
OH
-160 -144 -128 -112 -96 -80 -64 -48
I
OH
- Output Current - mA
Figure 1. Output Voltage vs Output Current
This 16-bit bus transceiver and register is operational at 1.2-V to 3.6-V V
CC
, but is designed specifically for
1.65-V to 3.6-V V
CC
operation.
The SN74AVC16646 can be used as two 8-bit transceivers or one 16-bit transceiver. Data on the A or B bus is
clocked into the registers on the low-to-high transition of the appropriate clock (CLKAB or CLKBA) input.
Figure 2
illustrates the four fundamental bus-management functions that can be performed with the SN74AVC16646.
Output-enable (OE) and direction-control (DIR) inputs are provided to control the transceiver functions. In the
transceiver mode, data present at the high-impedance port may be stored in either register or in both. The
select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Widebus, EPIC, DOC are trademarks of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright 漏 1998鈥?005, Texas Instruments Incorporated