SN75177B, SN75178B

DIFFERENTIAL BUS REPEATERS

SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993

POST OFFICE BOX 655303

2–5

SYMBOL EQUIVALENTS

DATA SHEET PARAMETER

RS-422-A

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)

∆|VOD|

| |Vt| – |Vt||

| |Vt| – |Vt||

VOC

|VOS|

|VOS|

∆|VOC|

|VOS – VOS|

|VOS – VOS|

IOS

|Isa|,|Isb|

IO

|Ixa|,|Ixb|

Iia,Iib

RECEIVER SECTION

electrical characteristics over recommended ranges of common-mode input voltage, supply

voltage, and operating free-air temperature (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP†

MAX

UNIT

VT+

Positive-going input threshold voltage

VO = 2.7 V,

IO = – 0.4 mA

0.2

V

VT–

Negative-going input threshold voltage

VO = 0.5 V,

IO = 8 mA

– 0.2‡

V

Vhys

Input hysteresis (VT+ – VT–)

50

mV

VIK

Input clamp voltage at EN

II = – 18 mA

– 1.5

V

VOH

High-level output voltage

VID = 200 mV,

See Figure 2

IOH = – 400 µA,

2.7

V

VOL

Low-level output voltage

VID = – 200 mV,

See Figure 2

IOL = 8 mA,

0.45

V

IOZ

High impedance state output current

VO =0 4Vto2 4V

20

µA

IOZ

High-impedance-state output current

VO = 0.4 V to 2.4 V

– 400

µA

II

Line input current

Other input at 0 V,

VI = 12 V

1

mA

II

Line input current

See Note 4

VI = – 7 V

– 0.8

mA

IIH

High-level enable-input current

VIH = 2.7 V

20

µA

IIL

Low-level enable-input current

VIL = 0.4 V

– 200

µA

ri

Input resistance

12

k

Ω

IOS

Short-circuit output current

–15

–85

mA

ICC

Supply current (total package)

No load

Outputs enabled

57

70

mA

ICC

Su

ly current (total ackage)

No load

Outputs disabled

26

35

mA

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

‡ The algebraic convention, where the less-positive (more-negative) limit is designated minimum, is used in this data sheet for common-mode input

voltage and threshold voltage levels only.

NOTE 4: Refer to EIA Standard RS-422 for exact conditions.

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

tPLH

Propagation delay time, low-to-high level output

VID = – 1.5 V to 1.5 V,

19

35

ns

tPHL

Propagation delay time, high-to-low level output

ID

,

CL = 15 pF,

See Figure 6

30

40

ns

tPZH

Output enable time to high level

CL =15 pF

See Figure 7

10

20

ns

tPZL

Output enable time to high level

CL = 15 pF,

See Figure 7

12

20

ns

tPHZ

Output disable time from high level

CL =15 pF

See Figure 8

25

35

ns

tPLZ

Output disable time from low level

CL = 15 pF,

See Figure 8

17

25

ns