SN75ALS171, SN75ALS171A

TRIPLE DIFFERENTIAL BUS TRANSCEIVERS

SLLS056D – AUGUST 1987 – REVISED SEPTEMBER 1995

6

POST OFFICE BOX 655303

switching characteristics over recommended ranges of supply voltage and operating free-air

temperature (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP†

MAX

UNIT

ALS171

RL = 54 Ω,

See Figure 3,

3

13

ALS171A

L

,

CL = 50 pF

g,

6

11

td(OD)

Differential output delay time

ALS171

RL1 = RL3 = 165 Ω,

CL =60 pF

VTERM = 5 V,

See Figure 6

3

13

ns

ALS171A

CL = 60 pF,

RL2 = 75 Ω,

See Figure 6

6

11

t k( )

Pulse skew‡

RL = 54 Ω,

See Figure 3

CL = 50 pF,

1

5

ns

tsk(p)

Pulse skew‡

RL1 = RL3 = 165 Ω,

CL = 60 pF,

RL2 = 75 Ω,

See Figure 6

1

5

ns

§

ALS171

RL = 54 Ω,

CL = 50 pF,

10

t k(li )

Skew limit§

ALS171A

L

,

See Figure 3

L

,

5

ns

tsk(lim)

Skew limit§

ALS171

RL1 = RL3 = 165 Ω,

RL2 = 75 Ω,

10

ns

ALS171A

L1

L3

,

CL = 60 pF,

L2

,

See Figure 6

5

RL = 54 Ω,

See Figure 3

CL = 50 pF,

3

8

13

tt(OD)

Differential-output transition time

RL1 = RL3 = 165 Ω,

CL = 60 pF,

See Figure 6

RL2 = 75 Ω,

VTERM = 5 V,

3

8

13

ns

tPZH

Output enable time to high level

RL = 110 Ω,

See Figure 4

30

50

ns

tPZL

Output enable time to low level

RL = 110 Ω,

See Figure 5

30

50

ns

tPHZ

Output disable time from high level

RL = 110 Ω,

See Figure 4

3

8

13

ns

tPLZ

Output disable time from low level

RL = 110 Ω,

See Figure 5

3

8

13

ns

tPDE

Differential-output enable time

RL1 = RL3 = 165 Ω,

RL2 = 75 Ω,

8

30

45

ns

tPDZ

Differential-output disable time

L1

L3

CL = 60 pF,

L2

See Figure 7

5

10

45

ns

† All typical values are at VCC = 5 V and TA = 25°C.

‡ Pulse skew is defined as the | td(ODH) – td(ODL)| of each channel.

§ Skew limit is the maximum difference in propagation delay times between any two channels of one device and between any two devices. This

parameter is applicable at one VCC and operating temperature within the recommended operating conditions.

SYMBOL EQUIVALENTS

DATA-SHEET PARAMETER

EIA/TIA-422-B

RS-485

VO

Voa, Vob

Voa, Vob

|VOD1 |

Vo

Vo

|VOD2 |

Vt (RL = 100 Ω)

Vt (RL = 54 Ω)

|VOD3 |

Vt (Test Termination

Measurement 2)

Vtest

Vtst

∆|VOD|

||V t |– |V t ||

||V t |– |V t ||

VOC

|Vos |

|Vos |

∆|VOC|

|Vos –Vos |

|Vos –Vos |

IOS

|I sa |, | Isb |

IO

|I xa |, | Ixb |

Iia, Iib