Distributed VCC and GND Pin Configuration
Minimizes High-Speed Switching Noise
D
Flow-Through Architecture Optimizes PCB
Layout
D
High-Impedance State During Power Up
and Power Down
D
High-Drive Outputs (–32-mA IOH, 64-mA IOL)
D
Package Options Include Plastic Thin
Shrink Small-Outline (DGG), 300-mil Shrink
Small-Outline (DL) Packages and 380-mil
Fine-Pitch Ceramic Flat (WD) Package
Using 25-mil Center-to-Center Spacings
description
The ’ABT16843 18-bit bus-interface D-type
latches are designed specifically for driving highly
capacitive or relatively low-impedance loads.
They are particularly suitable for implementing
buffer registers, I/O ports, bidirectional bus
drivers, and working registers.
The ’ABT16843 can be used as two 9-bit latches
or one 18-bit latch. The 18 latches are transparent
D-type latches. The device provides true data at
its outputs.
A buffered output-enable (OE) input can be used
to place the nine outputs in either a normal logic
state (high or low logic levels) or a
high-impedance state. The outputs are in the
high-impedance state during power up and power
down. The outputs remain in the high-impedance
state while the device is powered down. In the
high-impedance state, the outputs neither load
nor drive the bus lines significantly. The
high-impedance state and increased drive
provide the capability to drive bus lines without
need for interface or pullup components.
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 and EPIC-ΙΙB are trademarks of Texas Instruments Incorporated.
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information current as of publication date. Products conform to
specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all
parameters.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Copyright 1997, Texas Instruments Incorporated
1
SN54ABT16843, SN74ABT16843
18-BIT BUS-INTERFACE D-TYPE LATCHES
WITH 3-STATE OUTPUTS
SCBS223E – OCTOBER 1992 – REVISED MA Y 1997
description (continued)
OE does not affect the internal operations of the latch. Previously stored data can be retained or new data can
be entered while the outputs are in the high-impedance state.
When VCC is between 0 and 2.1 V , the device is in the high-impedance state during power up or power down.
However, to ensure the high-impedance state above 2.1 V, OE
the minimum value of the resistor is determined by the current-sinking capability of the driver.
The SN54ABT16843 is characterized for operation over the full military temperature range of –55°C to 125°C.
The SN74ABT16843 is characterized for operation from –40°C to 85°C.
FUNCTION TABLE
(each 9-bit latch)
INPUTS
PRECLROE
LXLXXH
HLLXX L
HHLHL L
HHLHH H
HHLLX Q
XXHXXZ
LED
should be tied to VCC through a pullup resistor;
OUTPUT
Q
0
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
logic diagram (positive logic)
2
1OE
SN54ABT16843, SN74ABT16843
18-BIT BUS-INTERFACE D-TYPE LATCHES
WITH 3-STATE OUTPUTS
SCBS223E – OCTOBER 1992 – REVISED MA Y 1997
1PRE
1CLR
1LE
1D1
2OE
2PRE
2CLR
55
1
56
54
27
30
28
S2
C1
1D
R
To Eight Other Channels
3
1Q1
2LE
2D1
29
42
S2
C1
1D
R
To Eight Other Channels
15
2Q1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
3
SN54ABT16843, SN74ABT16843
UNIT
18-BIT BUS-INTERFACE D-TYPE LATCHES
WITH 3-STATE OUTPUTS
SCBS223E – OCTOBER 1992 – REVISED MA Y 1997
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTES: 1. The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.
2. The package thermal impedance is calculated in accordance with EIA/JEDEC Std JESD51.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER
TEST CONDITIONS
UNIT
V
V
V
4.5 V
VOLV
V
V
V
I
V
CC
GND
SN54ABT16843, SN74ABT16843
18-BIT BUS-INTERFACE D-TYPE LATCHES
WITH 3-STATE OUTPUTS
SCBS223E – OCTOBER 1992 – REVISED MA Y 1997
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
TA = 25°CSN54ABT16843SN74ABT16843
MINTYP†MAXMINMAXMINMAX
V
IK
OH
V
hys
I
I
‡
I
OZPU
‡
I
OZPD
I
OZH
I
OZL
I
off
I
Outputs highVCC = 5.5 V,VO = 5.5 V505050µA
CEX
§
I
O
Outputs high
I
Outputs low
CC
Outputs disabled
¶
∆I
CC
C
i
C
o
* On products compliant to MIL-PRF-38535, this parameter does not apply.
†
All typical values are at VCC = 5 V.
‡
This parameter is characterized, but not production tested.
§
Not more than one output should be tested at a time, and the duration of the test should not exceed one second.
¶
This is the increase in supply current for each input that is at the specified TTL voltage level rather than VCC or GND.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
5
SN54ABT16843, SN74ABT16843
tsuSetup time, data before LE↓
ns
thHold time, data after LE↓
ns
(INPUT)
(OUTPUT)
D
Q
ns
LE
Q
ns
PRE
Q
ns
CLR
Q
ns
OE
Q
ns
OE
Q
ns
18-BIT BUS-INTERFACE D-TYPE LATCHES
WITH 3-STATE OUTPUTS
SCBS223E – OCTOBER 1992 – REVISED MA Y 1997
timing requirements over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted) (see Figure 1)
VCC = 5 V,
TA = 25°C
MINMAXMINMAXMINMAX
CLR low3.33.33.3
t
w
Pulse duration
p
PRE
low3.33.33.3
LE high3.33.33.3
High0.90.90.9
Low0.60.60.6
High1.71.71.7
Low1.81.81.8
switching characteristics over recommended ranges of supply voltage and operating free-air
temperature, C
PARAMETER
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
= 50 pF (unless otherwise noted) (see Figure 1)
L
FROM
TO
VCC = 5 V,
TA = 25°C
MINTYPMAXMINMAXMINMAX
1.63.14.21.65.11.64.8
1.63.24.21.651.64.8
2.3452.36.32.35.9
2.53.94.82.55.62.55.3
2.145.12.16.32.16.1
2.23.74.62.25.32.25
1.93.74.81.95.71.95.4
2.24.25.32.26.12.26
1.63.34.31.65.51.65.4
23.24.625.925.8
1.745.51.76.41.76.3
1.73.74.41.75.31.75.2
SN54ABT16843SN74ABT16843
SN54ABT16843SN74ABT16843
UNIT
ns
UNIT
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
From Output
Under Test
Input
CL = 50 pF
(see Note A)
1.5 V1.5 V
VOLTAGE WAVEFORMS
PULSE DURATION
500 Ω
LOAD CIRCUIT
t
w
SN54ABT16843, SN74ABT16843
18-BIT BUS-INTERFACE D-TYPE LATCHES
SCBS223E – OCTOBER 1992 – REVISED MA Y 1997
PARAMETER MEASUREMENT INFORMATION
7 V
500 Ω
S1
Open
GND
3 V
0 V
Timing Input
Data Input
TESTS1
t
PLH/tPHL
t
PLZ/tPZL
t
PHZ/tPZH
t
1.5 V1.5 V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
WITH 3-STATE OUTPUTS
Open
7 V
Open
3 V
1.5 V
0 V
t
su
h
3 V
0 V
Input
t
PLH
Output
t
PHL
Output
INVERTING AND NONINVERTING OUTPUTS
NOTES: A. CL includes probe and jig capacitance.
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. All input pulses are supplied by generators having the following characteristics: PRR ≤ 10 MHz, ZO = 50 Ω, tr ≤ 2.5 ns, tf≤ 2.5 ns.
D. The outputs are measured one at a time with one transition per measurement.
1.5 V1.5 V
1.5 V
1.5 V1.5 V
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
Figure 1. Load Circuit and Voltage Waveforms
t
PHL
1.5 V
t
PLH
3 V
0 V
V
V
V
V
OH
OL
OH
OL
Output
Control
Output
Waveform 1
S1 at 7 V
(see Note B)
Output
Waveform 2
S1 at Open
(see Note B)
1.5 V
t
PZL
t
PLZ
1.5 V
t
t
PZH
ENABLE AND DISABLE TIMES
LOW- AND HIGH-LEVEL ENABLING
PHZ
1.5 V
VOLTAGE WAVEFORMS
1.5 V
VOL + 0.3 V
VOH – 0.3 V
3 V
0 V
3.5 V
V
OL
V
OH
≈ 0 V
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
7
IMPORTANT NOTICE
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any product or service without notice, and advise customers to obtain the latest version of relevant information
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pertaining to warranty, patent infringement, and limitation of liability.
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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
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BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1998, Texas Instruments Incorporated
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