NSC DS3896N, DS3896MX, DS3896M Datasheet

DS3896/DS3897
BTL Trapezoidal

™

Transceivers

General Description

These advanced transceivers are specifically designed to
overcome problems associated with driving a densely popu­lated backplane,andthus provide significant improvement in
both speed and data integrity. Their low output capacitance,
low output signal swing and noise immunity features make
them ideal for driving low impedance buses with minimum
power consumption.

The DS3896 is an octal high speed schottky bus transceiver
with common control signals, whereas the DS3897 is a quad
device with independent driver input and receiver output
pins. The DS3897 has a separate driver disable for each
driver and is, therefore, suitable for arbitration lines. The
separate driver disable pins (En) feature internal pull ups
and may be left open if not required. On the other hand, the
DS3896 provides high package density for data/address
lines.

The open collector drivers generate precise trapezoidal
waveforms, which are relatively independent of capacitive
loading conditions on the outputs. This significantly reduces
noise coupling to adjacent lines. In addition, the receivers
use a low pass filter in conjunction with a high speed com­parator, to further enhance the noise immunity and provide
equal rejection to both negative and positive going noise
pulses on the bus.

To minimize bus loading, these devices also feature a schot­tky diode in series with the open collector output that isolates
the driver output capacitance in the disabled state. The out­put low voltage is typically “1V” and the output high level is
intended to be 2V. This is achieved by terminating the bus

with a pull up resistor to 2V at both ends. The device can
drive an equivalent DC load of 18.5Ω (or greater) in the
above configuration.

These signalling requirements, including a 1 volt signal
swing, low output capacitance and precise receiver thresh­olds are referred to as Bus Transceiver Logic (BTL).

Features

n 8 bit DS3896 transceiver provides high package density
n 4 bit DS3897 transceiver provides separate driver input

and receiver output pins

n BTL compatible
n Less than 5 pF output capacitance for minimal bus

loading

n 1 Volt bus signal swing reduces power consumption
n Trapezoidal driver waveforms (t

r,tf

≅

6 ns typical)

reduce noise coupling to adjacent lines

n Temperature insensitive receiver thresholds track the

bus logic high level to maximize noise immunity in both
high and low states

n Guaranteed A.C. specifications on noise immunity and

propagation delay over the specified temperature and
supply voltage range

n Open collector driver output allows wire-or connection
n Advanced low power schottky technology
n Glitch free power up/down protection on driver and

receiver outputs

n TTL compatible driver and control inputs and receiver

outputs

Logic Diagrams

Trapezoidal™is a trademark of National Semiconductor Corporation.

DS3896N, M

DS008510-1

DS3897N, M

DS008510-2

Order Numbers DS3896M, DS3896N, DS3897M or DS3897N

See NS Package Number M20B or N20A

January 1996

DS3896/DS3897 BTL Trapezoidal Transceivers

© 1999 National Semiconductor Corporation DS008510 www.national.com

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage 6V
Control Input Voltage 5.5V
Driver Input and Receiver Output 5.5V
Receiver Input and Driver Output 2.5V
Power Dissipation at 70˚C N Package 1480 mW
M Package TBD mW

Storage Temperature Range −65˚C to +150˚C
Lead Temperature (Soldering, 4 sec.) 260˚C

Recommended Operating
Conditions

Min Max Units

Supply Voltage, V

CC

4.75 5.25 V
Bus Termination Voltage 1.90 2.10 V
Operating Free Air Temperature 0 70 ˚C

Electrical Characteristics: (Notes 2, 3)

(0˚C ≤ TA≤ 70˚C, 4.75V ≤ VCC≤ 5.25V unless otherwise specified)

Symbol Parameter Conditions Min Typ Max Units

Driver and Control Inputs: (An, Dn, En, CD, T/R , RE , TE )

V

IH

Logical “1” Input Voltage 2.0 V

V

IL

Logical “0” Input Voltage 0.8 V

I

I

Logical “1” Input Current An=Dn=En=V

CC

1mA

I

IH

Logical “1” Input Current An=Dn=En=2.4V 40 µA

I

IHC

Logical “1” Input Current CD=T/R=RE=TE=2.4V 80 µA

I

IL

Logical “0” Input Current An=Dn=En=0.4V −1 −1.6 mA

I

ILC

Logical “0” Input Current CD=T/R=RE=TE=0.4V −180 −400 µA

V

CL

Input Diode Clamp Voltage Iclamp=−12 mA −0.9 −1.5 V

Driver Output/Receiver Input: (Bn)

V

OLB

Low Level Bus Voltage An=Dn=En=T/R=2V, VL=2V 0.75 1.0 1.2 V

RL=18.5Ω,CD=TE=0.8V (

Figure 1

)

I

IHB

Maximum Bus Current (Power On) An=Dn=En=0.8V, V

CC

=

5.25V 10 100 µA

Bn=2V

I

ILB

Maximum Bus Current (Power Off) An=Dn=En=0.8V, V

CC

=

0V 100 µA

Bn=2V

V

TH

Receiver Input Threshold V

CC

=

5V 1.47 1.55 1.62 V

Receiver Output: (An, Rn)

V

OH

Logical “1” Output Voltage Bn=1.2V, I

OH

=

−400 µA 2.4 3.2 V

CD=T/R=RE=0.8V

V

OL

Logical “0” Output Voltage Bn=2V, I

OL

=

16 mA 0.35 0.5 V

CD=T/R=RE=0.8V

I

OS

Output Short Circuit Current Bn=1.2V −20 −70 −100 mA

CD=T/R=RE=0.8V

I

CC

Supply Current (DS3896) V

CC

=

5.25V 90 135 mA

I

CC

Supply Current (DS3897) V

CC

=

5.25V 50 80 mA

Note 1: “Absolute maximum ratings” are those beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device should be
operated at these limits. The table of “Electrical Characteristic” provide conditions for actual device operation.

Note 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified.
Note 3: All typicals are given for V

CC

=

5V and T

a

=

25˚C.

DS3896 Switching Characteristics

(0˚C ≤ TA≤ 70˚C, 4.75V ≤ VCC≤ 5.25V unless otherwise specified)

Symbol Parameter Conditions Min Typ Max Units

Driver:

t

DLH

An to Bn CD=0.8V, T/R=2.0V, VL=2V 5 9 15 ns

t

DHL

(

Figure 2

)5 9 15 ns

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DS3896 Switching Characteristics (Continued)

(0˚C ≤ TA≤ 70˚C, 4.75V ≤ VCC≤ 5.25V unless otherwise specified)

Symbol Parameter Conditions Min Typ Max Units

Driver:

t

DLHC

CD to Bn An=T/R=2.0V, VL=2V 51018 ns

t

DHLC

(

Figure 2

) 5 12 20 ns

t

DLHT

T/R to Bn VCI=An, VC=5V, (

Figure 5

) 5 15 25 ns

t

DHLT

CD=0.8V, RC=390Ω,CL=30 pF 5 22 35 ns
RL1=18Ω, RL2=NC, VL=2V

t

R

Driver Output Rise Time CD=0.8V, T/R=2V, VL=2V 3 6 10 ns

t

F

Driver Output Fall Time (

Figure 2

)3 6 10 ns

Receiver:

t

RLH

Bn to An CD=0.8V, T/R=0.8V 51218 ns

t

RHL

(

Figure 3

) 5 10 18 ns

t

RLZC

CD to An Bn=2.0V, T/R=0.8V, CL=5pF 51018 ns

RL1=390Ω, RL2=NC, VL=5V (

Figure 4

)

t

RZLC

Bn=2.0V, T/R=0.8V, CL=30 pF 5 8 15 ns
RL1=390Ω, RL2=1.6k, VL=5V (

Figure 4

)

t

RHZC

Bn=0.8V, T/R=0.8V, VL=0V, 248ns
RL1=390Ω, RL2=NC, CL=5pF (

Figure 4

)

t

RZHC

Bn=0.8V, T/R=0.8V, VL=0V, 3 7 12 ns
RL1=NC, RL2=1.6k, CL=30 pF (

Figure 4

)

t

RLZT

T/R to An VCI=Bn, VC=2V, RC=18Ω, 5 10 18 ns

CD=0.8V, VL=5V, RL1=390Ω,
RL2=NC, CL=5pF (

Figure 5

)

t

RZLT

VCI=Bn, VC=2V, RC=18Ω, 142440 ns
CD=0.8V, VL=5V, RL1=390Ω,
RL2=1.6k, CL=30 pF (

Figure 5

)

t

RHZT

VCI=Bn, VC=0V, RC=18Ω, 248 ns
CD=0.8V, VL=0V, RL1=390Ω,
RL2=NC, CL=5pF (

Figure 5

)

t

RZHT

VCI=Bn, VC=0V, RC=18Ω,2815ns
CD=0.8V, VL=0V, RL1=NC
RL2=1.6k, CL=30 pF (

Figure 5

)

t

NR

Receiver Noise (

Figure 6

)3 6 ns

Rejection Pulse Width

Note: NC means open

DS3897 Switching Characteristics

(0˚C ≤ TA≤ 70˚C, 4.75V ≤ VCC≤ 5.25V unless otherwise specified)

Symbol Parameter Conditions Min Typ Max Units

Driver:

t

DLH

Dn, En to Bn TE=0.8V, RE=2.0V, VL=2V 5 9 15 ns

t

DHL

(

Figure 2

)5 9 15 ns

t

DLHT

TE to Bn An=RE=2.0V, VL=2V, (

Figure 2

) 51018 ns

t

DHLT

RC=390Ω, VCI=An, VC=5V, CL=30 pF 5 12 20 ns
RL1=18Ω, RL2=NC, VL=2V (

Figure 5

)

t

R

Driver Output Rise Time CD=0.8V, T/R=2V, VL=2V 3 6 10 ns

tF Driver Output Fall Time (

Figure 2

)3 6 10 ns

Receiver:

t

RLH

Bn to Rn TE=2.0V, RE=0.8V (

Figure 3

) 51018 ns

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