TL/F/11658
VME02 Control Transceiver with Incident Wave Switching
PRELIMINARY
May 1994
VME02 Control Transceiver
with Incident Wave Switching
General Description
The VME02 is designed for two-way synchronous communi-
cations between data buses with minimal external timing
requirements.
The VME02 consists of three non-inverting bidirectional
buffers with TRI-STATEÉoutputs designed with incident
wave switching, live insertion support and enhanced noise
margin optimized for VME backplane applications. In addi-
tion the VME02 contains eight bidirectional buffers with
open collector driver with enhanced noise margin and live
insertion support.
AV
CC bias pin provides for the precharging of the A side
outputs during live insertion. When set at 5.0V, this pin will
establish a voltage of 1.5V on the A port before VCC is
connected. This precharge will minimize the capacitive dis-
charge, and associated discontinuity, onto the active back-
plane during board insertion.
The B port includes a bus hold circuit to latch the output to
the value last forced on that pin.
The B port of this device includes 25Xseries output resis-
tors, which minimize undershoot and ringing.
Features
YSupports the VME64 ETL specification
YFunctionally and pin compatible with
TI SN74ABTE16246
YImproved TTL-compatible input threshold range
YEight outputs support VME open collector functions
YSupports 25Xincident wave switching on the A port
YVCC Bias pin minimizes signal distortion during live
insertion
YBiCMOS design significantly reduces power dissipation
YDistributed VCC and GND pin configuration minimizes
high-speed switching noise
Y25Xseries-dampening resistor on B-port
YAvailable in 48-pin SSOP and ceramic flatpak
YGuaranteed output skew
YGuaranteed simultaneous switching noise level and
dynamic threshold performance
YGuaranteed latchup protection
Pin Description
Pin Names Description
9DIR11DIR Transmit/Receive Inputs
OE Output Enable Input (Active LOW)
1A8A Backplane Bus Inputs or Open
Collector Outputs, with Live Insertion
9A11A Backplane Bus Inputs or
TRI-STATE Outputs, with Live Insertion
1BI8BI Local Bus Input Pins
1BO8BO Local Bus Output Pins, with Bus Hold
9B11B Local Bus Inputs, with Bus Hold or
TRI-STATE Outputs
VCC Bias Live Insertion Power Supply
Connection Diagram
Pin Assignment for
SSOP and Flatpak
TL/F/116581
TRI-STATEÉis a registered trademark of National Semiconductor Corporation.
C1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.
Functional Description
The device uses Direction (DIR) control and Output Enable (OE) control. The DIR inputs determine the direction of data flow
through the device.
The part contains active circuitry which keeps all outputs disabled when VCC is less than 2.2V to aid in live insertion applications.
Truth Table
Inputs Operation
OE 9DIR 10DIR 11DIR 11OEA
H X X X X Isolation
L X X X X 1BI8BI Data to 1A8A Bus(*OC)
1A8A Data to 1BO8BO Bus
L L X X X 9A Data to 9B Bus
L H X X X 9B Data to 9A Bus
L X L X X 10A Data to 10B Bus
L X H X X 10B Data to 10A Bus
L X X L L 11A Data to 11B Bus
L X X L H 11A, 11B Isolation
L X X H X 11B Data to 11A Bus
Note: *OC eOpen Collector Outputs
Logic Diagram (Positive Logic)
TL/F/11658 2
2
ETL’s Improved Noise Immunity
TTL input thresholds are typically determined by temperature-dependent junction voltages which result in worst case input
thresholds between 0.8V and 2.0V. By contrast, ETL provides greater noise immunity because its input thresholds are deter-
mined by current mode input circuits similar to those used for ECL or BTL. ETL’s worst case input thresholds, between 1.4V and
1.6V, are compensated for temperature, voltage and process variations.
Improved Input Threshold Characteristics of ETL
TL/F/11658 11
TTL Worst Case VOUT–VIN
TL/F/11658 12
ETL Worst Case VOUT–VIN
3
Incident Wave Switching
When TTL logic is used to drive fully loaded backplanes, the combination of low backplane bus characteristic impedance, wide
TTL input threshold range and limited TTL drive generally require multiple waveform reflections before a valid signal can be
received across the backplane. The VME International Trade Association (VITA) defined ETL to provide incident wave switching
which increases the data transfer rate of a VME backplane and extends the life of VME applications. TTL compatibility with
existing VME backplanes and modules was maintained.
To demonstrate the incident wave switching capability, consider a VME application. A VME bus must be terminated to a2.94V
with 190Xat each end of its 21 card backplane. The surge impedance presented by a fully loaded VME backplane is approxi-
mately 25X. If the output voltage/current of an ABTC driver is plotted with this load, the intersection at 1.2V for a falling edge
and at 1.6V for a rising edge does not reach the worst case input threshold of a second ABTC circuit. This is shown in the two
figures below. However, an ETL driver located at one end of the backplane is able to provide incident wave switching because it
has a higher drive and a tighter input threshold.
Estimated ETL/ABTC Initial Falling Edge Step
TL/F/11658 3
Estimated ETL/ABTC Initial Rising Edge Step
TL/F/11658 4
Because ETL has a much more precise input threshold region, an ETL receiver will interpret its predicted falling input of 0.85V as
a logic ZERO and the initial rising edge of 1.9V as a logic ONE. This comparison is for the case of a 25Xsurge impedance
backplane driven from one end.
4
Incident Wave Switching (Continued)
The resulting ABTC and ETL waveform predictions and their input thresholds are compared below. This shows how ETL can
achieve backplane speeds not always possible with conventional TTL compatible logic families.
Comparing the Incident Wave Switching of ETL with ABTC
TL/F/11658 5
5
Live Insertion Module Replacement
To allow a system module to be replaced without disturbing
signals passing between other operating modules requires
careful design of operating systems, applications software
and hardware. ETL supports live insertion module replace-
ment with features that minimize backplane signal distur-
bance while a module is inserted. As specified by VITA, live
insertion requires several backward-compatible system en-
hancements including: an improved backplane connector
with an embedded ground plane and differential length con-
nector pins. The differential length connector pins allow
power sequencing to the module so that the signal pins can
be controlled to a biased high impedance before they make
contact with the backplane.
VITA’s ETL modules will use an early VCC power input,
called VCC Bias, to control the ETL transceivers to a high
impedance to minimize insertion disturbance. In addition,
VCC Bias is used to precharge the backplane driver output
capacitance including the module connector pin and mod-
ule etch. The precharge voltage is to 1.5V using a switched
40 kXresistor. This precharge will minimize the capacitive
discharge onto an active backplane as the signal connec-
tion is made. To allow designers to maintain this condition until
after a module is fully powered and initialized, the OE pin
can be used to maintain outputs in the high impedance,
precharged state. Contact bounce during live insertion will
charge each output pin to a logic ONE or ZERO. If the con-
tact bounces open, the 40 kXresistor will reestablish the
1.5V level in a few microseconds.
When applying power to a PCB containing ETL transceivers,
the system VCC can be connected to VCC Bias without dam-
age to the device.
If the advantages of Live Insertion are to be included in the
system, then VCC Bias should be allowed to reach normal
operating levels before VCC becomes higher than 2.2 volts.
In addition, when removing a module, or turning off system
power, VCC should be reduced below 2.2 volts before
VCC Bias is allowed to drop below normal operating limits.
This sequencing is shown below.
The figure VCC Power-up Critical Voltages shows the rela-
tionship between OE and VCC while power is being applied
and removed. This relationship holds if VCC Bias is within
normal operating conditions or if VCC Bias is equal to VCC.
TL/F/11658 13
Power Sequencing to Achieve Live Insertion Precharging
TL/F/11658 6
VCC and OE Power-Up Critical Relations
6
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Storage Temperature b65§Ctoa
150§C
Ambient Temperature under Bias b55§Ctoa
125§C
Junction Temperature under Bias
Ceramic b55§Ctoa
175§C
Plastic b55§Ctoa
150§C
VCC Pin Potential to
Ground Pin b0.5V to a7.0V
Input Voltage (Note 2) b0.5V to a7.0V
Input Current (Note 2) b50 mA to a5.0 mA
Voltage Applied to Any Output
in the Disabled or
Power-off State b0.5V to 5.5V
in the HIGH State b0.5V to VCC
Current Applied to Output
in LOW State (Max) 128 mA
DC Latchup Source Current b500 mA
Over Voltage Latchup (I/O) 10V
Note 1: Absolute maximum ratings are values beyond which the device may
be damaged or have its useful life impaired. Functional operation under
these conditions is not implied.
Note 2: Either voltage limit or current limit is sufficient to protect inputs.
Recommended Operating
Conditions
Free Air Ambient Temperature
Military b55§Ctoa
125§C
Commercial b40§Ctoa
85§C
Supply Voltage
Military a4.5V to a5.5V
Commercial a4.5V to a5.5V
Minimum Input Edge Rate (Dt/DV)
Data Input 20 ns/V
Enable Input 50 ns/V
DC Electrical Characteristics
Symbol Parameter VME02 Units VCC Conditions
Min Typ Max
VIH Input HIGH Voltage OE 2.0 VRecognized HIGH Signal
Other Inputs 1.6
VIL Input LOW Voltage OE 0.8 VRecognized LOW Signal
Other Inputs 1.4
VCD Input Clamp Diode Voltage b1.2 V Min IIN eb
18 mA (OEn, DIR)
VOH Output HIGH Voltage VCC b1V I
OH eb
100 mA
B Port 2.4 V Min IOH eb
1mA
2.0 V IOH eb
12 mA
VCC b1V I
OH eb
1mA
9A11A 2.4 V Min IOH eb
32 mA
2.0 V IOH eb
60 mA
VOL Output LOW Voltage B Port 0.4 V Min IOL e1mA
0.8 V IOL e12 mA
A Port 0.55 V Min IOL e64 mA
0.9 V IOL e90 mA
IHOLD Bus Hold Current
B Port
100
mA Min
OE eHIGH,
VOe0.8V
b100 OE eHIGH,
VOe2.0V
ICC VCC Bias Supply Current VCC esVCC Bias
10 mA VCC Bias e0 to 5.5V
IOe0
IOFF Output Current, Power Down 100 mA 0.0 VCC Bias e0V
VIor VOs4.5V
IIInput Current Control Pins Military g10 mA 5.5 VIN e0orV
CC
Commercial g5mA 5.5 VIN e0orV
CC
IIH aOutput Leakage Current 9A11A 50 mA 5.5 VOUT e2.7V, OE e2.0V
IOZH
IIL aOutput Leakage Current 9A11A b50 mA 5.5 VOUT e0.5V, OE e2.0V
IOZL
7
DC Electrical Characteristics (Continued)
Symbol Parameter VME02 Units VCC Conditions
Min Typ Max
ICCH Power Supply Current 40 mA Max All Outputs HIGH,
OE eLOW, DIR eHIGH or LOW
ICCL Power Supply Current 80 mA Max All Outputs LOW,
OE eLOW, DIR eHIGH or LOW
ICCZ Power Supply Current
40
OE eHIGH
mA Max All Others at VCC or GND
DIR eHIGH or LOW
ICCD Dynamic ICC
0.15 MHz
mA/ Max
Outputs Open
No Load OEneGND, DIR eHIGH
(Note 1) One Bit Toggling, 50% Duty Cycle
VLI Output Live A Port 1.3 1.7 V 5.0 IOUT e0 mA, OE eHIGH
Insertion Voltage VCC Bias e5.0V
IPRE Precharge Current b20 b100 mA 5.0 OE eHIGH, VOe0V,
A-Port VCC Bias e5.0V
20 100 mA 5.0 VOe3V, VCC Bias e5.0V,
OE eHigh
VOLP Quiet Output Maximum 1.0 V 5.0 TAe25§C (Note 2)
Dynamic VOL CLe50 pF; RLe500X
VOLV Quiet Output Minimum b1.4 V 5.0 TAe25§C (Note 2)
Dynamic VOL CLe50 pF; RLe500X
VOHV Minimum High Level Dynamic 2.7 V 5.0 TAe25§C (Note 4)
Output Voltage (Note 1) CLe50 pF; RLe500X
VIHD Minimum High Level Dynamic 2.0 1.5 V 5.0 TAe25§C (Note 3)
Input Voltage (Note 1) CLe50 pF; RLe500X
VILD Maximum Low Level Dynamic 1.2 0.8 V 5.0 TAe25§C (Note 3)
Input Voltage (Note 1) CLe50 pF; RLe500X
Note 1: Guaranteed, but not tested.
Note 2: Max. number of outputs defined as (n). n b1 data inputs are driven 0V to 3V. One output at LOW. Guaranteed, but not tested.
Note 3: Max. number of data inputs (n) switching. n b1 inputs switching 0V to 3V. Input-under-test switching: 3V to threshold (VILD), 0V to threshold (VIHD).
Guaranteed, but not tested.
Note 4: Max. number of outputs defined as (n). n b1 data inputs are driven 0V to 3V. One output HIGH. Guaranteed, but not tested.
8
AC Electrical Characteristics
Symbol Parameter
Commercial Military Commercial
Units Fig.
No.
TAea
25§CT
A
eb
55§Ctoa
125§CT
A
eb
40§Ctoa
85§C
VCC ea
5V VCC e4.5V5.5V VCC e4.5V5.5V
Min Typ Max Min Max Min Max
tPLH Propagation 1.5 7.0 1.5 7.0 1.5 7.0 ns 1, 2, 4
tPHL Delay 9A11A to 9B11B 1.5 7.0 1.5 7.0 1.5 7.0
tPLH Propagation 1.5 7.0 1.5 7.0 1.5 7.0 ns 1, 2, 4
tPHL Delay 9B11B to 9A11A 1.5 7.0 1.5 7.0 1.5 7.0
tPHL Propagation Delay 7 7 7 ns 1,2,3
1BI8BI to 1A8A
tPLH Propagation Delay 15 15 15 ns 1, 2, 3
1BI8BI to 1A8A
tPZH Output Enable 1.0 7.0 1.0 7.0 1.0 7.0 ns 1, 2, 3
tPZL Time 9B11B and 9A11A 1.0 7.0 1.0 7.0 1.0 7.0
tPHZ Output Disable 1.0 7.0 1.0 7.0 1.0 7.0 ns 1, 2, 3
tPLZ Time 9B11B and 9A11A 1.0 7.0 1.0 7.0 1.0 7.0
trRise Time 1V
x
2V, 1.2 3.0 0.8 4.0 1.2 3.0 ns 1, 2, 4
9A11A Outputs
tfFall Time 2V
x
1V, 1.2 3.0 0.8 4.0 1.2 3.0 ns 1, 2, 4
9A11A Outputs
9
Skew
Symbol Parameter
Commercial Military
Units Conditions
TAeb
40§Ctoa
85§CT
A
eb
55§Ctoa
125§C
VCC e4.5V5.5V VCC e4.5V5.5V
16 Outputs Switching 16 Outputs Switching
Max Max
tOHS Pin-to-Pin Skew 1.3 1.3 ns
Figures 1, 2, 4
(Notes 1, 2) LH/HL A-Port to B-Port
tOHS Pin-to-Pin Skew 1.3 1.3 ns
Figures 1, 2, 4
(Notes 1, 2) LH/HL B-Port to A-Port
tPS Duty Cycle Skew 2.0 2.0 ns
Figures 1, 2, 4
(Notes 1, 2) B-Port to A-Port
tPS Duty Cycle Skew 2.0 2.0 ns
Figures 1, 2, 4
(Notes 1, 2) A-Port to B-Port
VME Extended Skew
Symbol Parameter
Commercial Military
Units Conditions
TAeb
40§Ctoa
85§CT
A
eb
55§Ctoa
125§C
VCC e4.5V5.5V VCC e4.5V5.5V
16 Outputs Switching 16 Outputs Switching
Max Max
tPV Device-to-Device Skew LH/HL 4.0 4.5 ns
Figures 1, 2, 4
(Notes 1, 2) Transitions 9B 11B to 9A 11A
tPV Device-to-Device Skew LH/HL 2.5 3.0 ns
Figures 1, 2, 4
(Notes 1, 2) Transitions 9A 11A to 9B 11B
tCP Change in Propagation Delay 4.0 4.5 ns
Figures 1, 2, 4
(Note 3) with Load 9B11B to 9A11A
tCPV Device-to-Device, Change
(Notes 1, 2, 3) in Propagation Delay with 6.0 7.0 ns
Figures 1, 2, 4
Load 9B11B to 9A11A
Note 1: Skew is defined as the absolute difference in delay between two outputs. The specification applies to any outputs switching HIGH to LOW, LOW to HIGH,
or any combination switching HIGH-to-LOW or LOW-to-HIGH. This specification is guaranteed but not tested.
Note 2: This is measured with both devices at the same value of VCC g1% and with package temperature differences of 20§C from each other.
Note 3: This is measured with Rx in
Figure 1
at 13Xfor one unit and at 56Xfor the other unit.
Capacitance
Symbol Parameter Typ Max Units Conditions, TAe25§C
CIN Input Capacitance 5 8 pF VCC e0.0V (OEn, DIR)
CI/O (Note 1) Output Capacitance 9 12 pF VCC e5.0V (An)
Note 1: CI/O is measured at frequency f e1 MHz, per MIL-STD-883B, Method 3012.
10
AC Loading
TL/F/11658 7
*Includes jig and probe capacitance
FIGURE 1. Standard AC Test Load
Note 1: Defined to emulate the range of VME bus transmission line loading
as a function of board population and driver location. Rx e13X,26Xor
56Xdepending on test.
Test Port SW1 SW2 Rx
tPHZ,t
PZH 9A11A, B Open Open
tPLZ,t
PZL 9A11A, B a7 Open
tPHL/tPLH 1A–8A a7 Open
tPLH/tPHL 9A11A Open Closed 26
tPLH/tPHL B Open Open
tr,t
f9A11A Open Closed 26
tPV 9A11A Open Closed 26
tPV B Open Open
tCP 9A11A Open Closed 13 then 56
tCPV 9A11A Open Closed 13 and 56
FIGURE 1a
TL/F/11658 8
FIGURE 2. Input Pulse Requirements
Amplitude Rep. Rate tWtrtf
3.0V 1 MHz 500 ns 2.5 ns 2.5 ns
FIGURE 2a. Test Input Signal Requirements
TL/F/11658 9
FIGURE 3. TRI-STATE Output HIGH
and LOW Enable and Disable Times
TL/F/11658 10
FIGURE 4. Rise, Fall Time and Propagation Delay Waveforms
11
Ordering Information
The device number is used to form part of a simplified purchasing code where the package type and temperature range are
defined as follows:
VME02 SS C X
Device Type Special Variations
XeDevices shipped in 13×reels
Package Code QB eMilitary grade device with
SS eSmall Outline (SSOP) environmental and burn-in
FPFP eFine Pitch Flatpak processing shipped in tubes.
Temperature Range
CeCommercial (b40§Ctoa
85§C)
MeMilitary (b55§Ctoa
125§C)
12
Physical Dimensions inches (millimeters)
48-Lead SSOP (0.300×Wide) (SS)
NS Package Number MS48A
13
VME02 Control Transceiver with Incident Wave Switching
Physical Dimensions inches (millimeters) (Continued)
48-Pin Ceramic Flatpak (FPFP)
NS Package Number WA48A
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systems which, (a) are intended for surgical implant support device or system whose failure to perform can
into the body, or (b) support or sustain life, and whose be reasonably expected to cause the failure of the life
failure to perform, when properly used in accordance support device or system, or to affect its safety or
with instructions for use provided in the labeling, can effectiveness.
be reasonably expected to result in a significant injury
to the user.
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