Switching characteristics, Parameter measurement information – National DS36C278 User Manual

Page 4

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Switching Characteristics

(Continued)

Over Supply Voltage and Operating Temperature ranges unless otherwise specified (Notes 3 and 8)

Symbol

Parameter

Conditions

Reference

Min

Typ

Max

Units

RECEIVER CHARACTERISTICS

t

PHL

Propagation Delay

C

L

e

15 pF

Figures 12 13

30

210

400

ns

High to Low

t

PLH

Propagation Delay

30

190

400

ns

Low to High

t

SK

Skew

l

t

PHL

b

t

PLH

l

0

20

50

ns

t

PLZ

Output Disable Time

C

L

e

15 pF

Figures 14 15 16

50

150

ns

t

PHZ

55

150

ns

t

PZL

Output Enable Time

40

150

ns

t

PZH

45

150

ns

Note 1

‘‘Absolute Maximum Ratings’’ are those values beyond which the safety of the device cannot be guaranteed They are not meant to imply that the devices

should be operated at these limits The table of ‘‘Electrical Characteristics’’ specifies conditions of device operation

Note 2

Current into device pins is defined as positive Current out of device pins is defined as negative All voltages are referenced to ground except V

OD1

and

V

OD2

Note 3

All typicals are given for V

CC

e a

5 0V T

A

e a

25 C

Note 4

Delta

l

V

OD2

l

and Delta

l

V

OC

l

are changes in magnitude of V

OD2

and V

OC

respectively that occur when input changes state

Note 5

Threshold parameter limits specified as an algebraic value rather than by magnitude

Note 6

Hysteresis defined as V

HST

e

V

TH

b

V

TL

Note 7

I

IN

includes the receiver input current and driver TRI-STATE leakage current

Note 8

C

L

includes probe and jig capacitance

Note 9

For complete details of test see RS-485

Parameter Measurement Information

TL F 12040 – 2

FIGURE 1 Driver V

OD2

and V

OC

TL F 12040 – 18

FIGURE 2 Driver V

OD3

TL F 12040 – 3

FIGURE 3 Driver V

OH

and V

OL

TL F 12040 – 4

Vtest e b7V to a12V

FIGURE 4 Driver I

OSD

TL F 12040 – 5

FIGURE 5 Driver Differential Propagation Delay Test Circuit

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