NSC DS3896N, DS3896MX, DS3896M Datasheet

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January 1996

DS3896/DS3897

BTL Trapezoidal™ Transceivers

General Description

These advanced transceivers are specifically designed to overcome problems associated with driving a densely populated backplane, and thus 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 ª1Vº 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

n8 bit DS3896 transceiver provides high package density

n4 bit DS3897 transceiver provides separate driver input and receiver output pins

nBTL compatible

nLess than 5 pF output capacitance for minimal bus loading

n1 Volt bus signal swing reduces power consumption

nTrapezoidal driver waveforms (tr, tf 6 ns typical) reduce noise coupling to adjacent lines

nTemperature insensitive receiver thresholds track the bus logic high level to maximize noise immunity in both high and low states

nGuaranteed A.C. specifications on noise immunity and propagation delay over the specified temperature and supply voltage range

nOpen collector driver output allows wire-or connection

nAdvanced low power schottky technology

nGlitch free power up/down protection on driver and receiver outputs

nTTL compatible driver and control inputs and receiver outputs

Logic Diagrams

DS3896N, M

DS3897N, M

DS008510-1

DS008510-2

Order Numbers DS3896M, DS3896N, DS3897M or DS3897N

See NS Package Number M20B or N20A

Trapezoidal™ is a trademark of National Semiconductor Corporation.

Transceivers Trapezoidal BTL DS3896/DS3897

DS008510

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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 70ÊC N Package	1480 mW
M Package	TBD mW

Electrical Characteristics: (Notes 2, 3)

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

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

Recommended Operating

Conditions

	Min	Max	Units
Supply Voltage, VCC	4.75	5.25	V
Bus Termination Voltage	1.90	2.10	V
Operating Free Air Temperature	0	70	ÊC

Symbol

Parameter

Conditions

Min

Typ

Max

Units

)

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

VIH

Logical ª1º Input Voltage

2.0

VIL

Logical ª0º Input Voltage

0.8

Logical ª1º Input Current

An= Dn = En = VCC

IIH

Logical ª1º Input Current

An= Dn = En = 2.4V

µA

IIHC

Logical ª1º Input Current

CD= T/R

= RE = TE = 2.4V

µA

IIL

Logical ª0º Input Current

An= Dn = En = 0.4V

−1

−1.6

IILC

Logical ª0º Input Current

CD= T/R

= RE = TE = 0.4V

−180

−400

µA

VCL

Input Diode Clamp Voltage

Iclamp = −12 mA

−0.9

−1.5

Driver Output/Receiver Input: (Bn)

VOLB

Low Level Bus Voltage

An = Dn = En = T/R

= 2V, VL = 2V

0.75

1.0

1.2

RL = 18.5Ω, CD =

= 0.8V (Figure 1)

IIHB

Maximum Bus Current (Power On)

An = Dn = En = 0.8V, VCC = 5.25V

100

µA

Bn = 2V

IILB

Maximum Bus Current (Power Off)

An = Dn = En = 0.8V, VCC = 0V

100

µA

Bn = 2V

VTH

Receiver Input Threshold

VCC = 5V

1.47

1.55

1.62

Receiver Output: (An, Rn)

VOH

Logical ª1º Output Voltage

Bn= 1.2V, IOH = −400 µA

2.4

3.2

= 0.8V

CD = T/R

VOL

Logical ª0º Output Voltage

Bn= 2V, IOL = 16 mA

0.35

0.5

CD = T/R

= RE = 0.8V

IOS

Output Short Circuit Current

Bn = 1.2V

−20

−70

−100

= 0.8V

CD = T/R

ICC

Supply Current (DS3896)

VCC = 5.25V

135

ICC

Supply Current (DS3897)

VCC = 5.25V

Note 1: ªAbsolute maximum ratingsº 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 ªElectrical Characteristicº 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 VCC = 5V and Ta = 25ÊC.

DS3896 Switching Characteristics

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

Symbol	Parameter		Conditions	Min	Typ	Max	Units

Driver:

tDLH	An to Bn	CD = 0.8V, T/R	= 2.0V, VL = 2V	5	9	15	ns
tDHL			(Figure 2)	5	9	15	ns

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DS3896 Switching Characteristics (Continued)

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

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Driver:

tDLHC

CD to Bn

An = T/R

= 2.0V, VL = 2V

tDHLC

(Figure 2)

tDLHT

VCI = An, VC = 5V, (Figure 5)

T/R

to Bn

tDHLT

CD = 0.8V, RC = 390Ω, CL = 30 pF

RL1 = 18Ω, RL2 = NC, VL = 2V

Driver Output Rise Time

CD = 0.8V, T/R

= 2V, VL = 2V

Driver Output Fall Time

(Figure 2)

Receiver:

tRLH

Bn to An

CD = 0.8V, T/R

= 0.8V

tRHL

(Figure 3)

tRLZC

CD to An

= 0.8V, CL = 5 pF

Bn = 2.0V, T/R

RL1 = 390Ω, RL2 = NC, VL = 5V ( Figure 4)

tRZLC

= 0.8V, CL = 30 pF

Bn = 2.0V, T/R

RL1 = 390Ω, RL2 = 1.6k, VL = 5V

(Figure 4)

tRHZC

= 0.8V, VL = 0V,

Bn = 0.8V, T/R

RL1 = 390Ω, RL2 = NC, CL = 5 pF (Figure 4)

tRZHC

= 0.8V, VL = 0V,

Bn = 0.8V, T/R

RL1 = NC, RL2 = 1.6k, CL = 30 pF

(Figure 4)

tRLZT

VCI = Bn, VC = 2V, RC = 18Ω,

T/R

to An

CD = 0.8V, VL = 5V, RL1 = 390Ω,

RL2 = NC, CL = 5 pF

(Figure 5)

tRZLT

VCI = Bn, VC = 2V, RC = 18Ω,

CD = 0.8V, VL = 5V, RL1 = 390Ω,

RL2 = 1.6k, CL = 30 pF

(Figure 5)

tRHZT

VCI = Bn, VC = 0V, RC = 18Ω,

CD = 0.8V, VL = 0V, RL1 = 390Ω,

RL2 = NC, CL = 5 pF

(Figure 5)

tRZHT

VCI = Bn, VC = 0V, RC = 18Ω,

CD = 0.8V, VL = 0V, RL1 = NC

RL2 = 1.6k, CL = 30 pF

(Figure 5)

tNR

Receiver Noise

(Figure 6)

Rejection Pulse Width

Note: NC means open

DS3897 Switching Characteristics

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

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Driver:

tDLH

Dn, En to Bn

= 0.8V,

= 2.0V, VL = 2V

tDHL

(Figure 2)

tDLHT

An =

= 2.0V, VL = 2V, (Figure 2)

to Bn

tDHLT

RC = 390Ω, VCI = An, VC = 5V, CL = 30 pF

RL1 = 18Ω, RL2 = NC, VL = 2V (Figure 5)

Driver Output Rise Time

= 2V, VL = 2V

CD = 0.8V, T/R

Driver Output Fall Time

(Figure 2)

Receiver:

tRLH

Bn to Rn

= 2.0V,

= 0.8V (Figure 3)

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