TI SN74S1056

SN74S1056
8-BIT SCHOTTKY BARRIER DIODE
BUS-TERMINATION ARRAY
SDLS019B – APRIL 1990 – REVISED JULY 1997
D
D
D
SC PACKAGE
(TOP VIEW)
Designed to Reduce Reflection Noise
Repetitive Peak Forward Current 300 mA
8-Bit Array Structure Suited for
Bus-Oriented Systems
D01
D02
D03
D04
GND
GND
D05
D06
D07
D08
description
This Schottky barrier diode bus-termination array
is designed to reduce reflection noise on memory
bus lines. This device consists of an 8-bit
high-speed Schottky diode array suitable for a
clamp to GND.
The SN74S1056 is characterized for operation
from 0°C to 70°C.
1
2
3
4
5
6
7
8
9
10
D PACKAGE
(TOP VIEW)
D01
D02
D03
D04
D05
D06
D07
D08
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
NC
GND
GND
GND
GND
GND
GND
NC
schematic diagrams
SC Package
D Package
1
1
D01
D02
D01
2
D02
2
15
D03
GND
3
3
D03
14
6
GND
4
D04
GND
4
D04
13
7
D05
D05
5
GND
D06
D07
GND
5
8
12
GND
6
D06
9
11
GND
7
D07
10
10
8
D08
GND
D08
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.
Copyright  1997, Texas Instruments Incorporated
PRODUCTION DATA information is 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
1
SN74S1056
8-BIT SCHOTTKY BARRIER DIODE
BUS-TERMINATION ARRAY
SDLS019B – APRIL 1990 – REVISED JULY 1997
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Steady-state reverse voltage, VR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Continuous forward current, IF: Any D terminal from GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 mA
Total through all GND terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 mA
Repetitive peak forward current, IFRM (see Note 1): Any D terminal from GND . . . . . . . . . . . . . . . . . . 300 mA
Total through all GND terminals . . . . . . . . . . . . . . . 1.2 A
Continuous total power dissipation at (or below) 25°C free-air temperature . . . . . . . . . . . . . . . . . . . 1000 mW
Operating free-air temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C
† 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.
NOTE 1: These values apply for tw ≤ 100 µs, duty cycle ≤ 20%.
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
single-diode operation (see Note 2)
PARAMETER
IR
Static reverse current
VF
Static forward voltage
VFM
Peak forward voltage
Ct
Total capacitance
TEST CONDITIONS
MIN
VR = 7 V
IF = 18 mA
TYP‡
MAX
10
IF = 50 mA
IF = 300 mA
0.65
0.85
0.8
1
1.41
VR = 0 V,
VR = 2 V,
UNIT
µA
V
V
f = 1 MHz
11
20
f = 1 MHz
8
16
pF
‡ All typical values are at TA = 25°C.
NOTE 2: Test conditions and limits apply separately to each of the diodes. The diodes not under test are open-circuited during the measurement
of these characteristics.
multiple-diode operation
PARAMETER
Ix
Internal crosstalk current
TEST CONDITIONS
MIN
TYP‡
MAX
Total IF current = 1.2 A,
See Note 3
0.6
2
Total IF current = 126 mA,
See Note 3
0.01
0.1
TYP
MAX
5
10
UNIT
mA
‡ All typical values are at TA = 25°C.
NOTE 3: Ix is measured under the following conditions with one diode static, all others switching:
Switching diodes: tw = 100 µs, duty cycle = 20%
Static diode: VR = 5 V
The static diode input current is the internal crosstalk current Ix.
switching characteristics, TA = 25°C (see Figures 1 and 2)
PARAMETER
trr
2
Reverse recovery time
TEST CONDITIONS
IF = 10 mA,
IRM(REC) = 10 mA,
POST OFFICE BOX 655303
IR(REC) = 1 mA,
• DALLAS, TEXAS 75265
MIN
RL = 100 Ω
UNIT
ns
SN74S1056
8-BIT SCHOTTKY BARRIER DIODE
BUS-TERMINATION ARRAY
SDLS019B – APRIL 1990 – REVISED JULY 1997
PARAMETER MEASUREMENT INFORMATION
50 Ω
(See Note A)
450 Ω
Pulse
Generator
Sampling
Oscilloscope
(See Note B)
DUT
90%
VFM
VF
Output
Waveform
(See Note B)
Input Pulse
(See Note A)
10%
tr
NOTES: A. The input pulse is supplied by a pulse generator having the following characteristics: tr = 20 ns, ZO = 50 Ω, freq = 500 Hz,
duty cycle = 0.01.
B. The output waveform is monitored by an oscilloscope having the following characteristics: tr ≤ 350 ps, Ri = 50 Ω, Ci = ≤ 5 pF.
Figure 1. Forward Recovery Voltage
DUT
(See Note A)
Pulse
Generator
IF
Sampling
Oscilloscope
If
tf
10%
(See Note B)
trr
0
Output
Waveform
(See Note B) IR(REC)
Input Pulse
(See Note A)
90%
IRM(REC)
NOTES: A. The input pulse is supplied by a pulse generator having the following characteristics: tf = 0.5 ns, ZO = 50 Ω, tw = ≥ 50 ns,
duty cycle = 0.01.
B. The output waveform is monitored by an oscilloscope having the following characteristics: tr ≤ 350 ps, Ri = 50 Ω, Ci = ≤ 5 pF.
Figure 2. Reverse Recovery Time
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
3
SN74S1056
8-BIT SCHOTTKY BARRIER DIODE
BUS-TERMINATION ARRAY
SDLS019B – APRIL 1990 – REVISED JULY 1997
APPLICATION INFORMATION
Large negative transients occurring at the inputs of memory devices (DRAMs, SRAMs, EPROMs, etc.) or on the
CLOCK lines of many clocked devices can result in improper operation of the devices. The SN74S1056 diode
termination array helps suppress negative transients caused by transmission-line reflections, crosstalk, and
switching noise.
Diode terminations have several advantages when compared to resistor termination schemes. Split resistor or
Thevenin equivalent termination can cause a substantial increase in power consumption. The use of a single resistor
to ground to terminate a line usually results in degradation of the output high level, resulting in reduced noise immunity.
Series damping resistors placed on the outputs of the driver reduce negative transients, but they also can increase
propagation delays down the line, as a series resistor reduces the output drive capability of the driving device. Diode
terminations have none of these drawbacks.
The operation of the diode arrays in reducing negative transients is explained in the following figures. The diode
conducts current when the voltage reaches a negative value large enough for the diode to turn on. Suppression of
negative transients is tracked by the current-voltage characteristic curve for that diode. A typical current versus
voltage plot for the SN74S1056 is shown in Figure 3.
To illustrate how the diode arrays act to reduce negative transients at the end of a transmission line, the test setup
in Figure 4(a) was evaluated. The resulting waveforms with and without the diode are shown in Figure 4(b).
The maximum effectiveness of the diode arrays in suppressing negative transients occurs when the diode arrays are
placed at the end of a line and/or the end of a long stub branching off a main transmission line. The diodes also can
be used to reduce the negative transients that occur due to discontinuities in the middle of a line. An example of this
is a slot in a backplane that is provided for an add-on card.
DIODE FORWARD CURRENT
vs
DIODE FORWARD VOLTAGE
–100
TA = 25°C
–90
I I – Forward Current – mA
–80
Variable 1:
VIN
–Ch 1
Linear Sweep:
Start
0.000 V
Stop
–2.000 V
Step
–0.010 V
–70
–60
–50
Constants:
VHI –Vs1
VLO –Vs2
–40
–30
–20
–10
0
0
0.2 0.4 0.6 0.8
1
1.2 1.4 1.6 1.8
2
VF – Forward Voltage – V
Figure 3. Current Versus Voltage for the SN74S1056
4
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
3.5000 V
0.0000 V
SN74S1056
8-BIT SCHOTTKY BARRIER DIODE
BUS-TERMINATION ARRAY
SDLS019B – APRIL 1990 – REVISED JULY 1997
APPLICATION INFORMATION
ZO = 50 Ω
Length = 36 in.
(a) DIODE TEST SETUP
56.500 ns
31.500 ns
End-ofLine
Without
Diode
81.500 ns
End-of-Line With Diode
Vmarker 1
Vmarker 2
Ch 1
Timebase
Memory 1
Vmarker 1
Vmarker 2
Offset = 0.000 V
Delay = 56.500 ns
Delta V = –2.293 V
= 1.880 V/div
= 5.00 ns/V
= 1.880 V/div
= –1.353 V
= –3.647 V
(b) OSCILLOSCOPE DISPLAY
Figure 4. Diode Test Setup and Oscilloscope Display
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
5
PACKAGE OPTION ADDENDUM
www.ti.com
30-Mar-2005
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
Lead/Ball Finish
MSL Peak Temp (3)
SN74S1056D
OBSOLETE
SOIC
D
16
TBD
Call TI
Call TI
SN74S1056DR
OBSOLETE
SOIC
D
16
TBD
Call TI
Call TI
SN74S1056SC
OBSOLETE
SIP
SC
10
TBD
Call TI
Call TI
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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