NSC DS75176BN, DS75176BMX, DS75176BM Datasheet

DS75176B/DS75176BT
Multipoint RS-485/RS-422 Transceivers

General Description

The DS75176B is a high speed differential TRI-STATE

®

bus/line transceiver designed to meet the requirements of
EIA standard RS485 with extended common mode range
(+12V to −7V), for multipoint data transmission. In addition, it
is compatible with RS-422.

The driver and receiver outputs feature TRI-STATE capabil­ity, for the driver outputs over the entire common mode
range of +12V to −7V. Bus contention or fault situations that
cause excessive power dissipation within the device are
handled by a thermal shutdown circuit, which forces the
driver outputs into the high impedance state.

DC specifications are guaranteed over the 0 to 70˚C tem­perature and 4.75V to 5.25V supply voltage range.

Features

n Meets EIA standard RS485 for multipoint bus

transmission and is compatible with RS-422.

n Small Outline (SO) Package option available for

minimum board space.

n 22 ns driver propagation delays.
n Single +5V supply.
n −7V to +12V bus common mode range permits

±

7V

ground difference between devices on the bus.

n Thermal shutdown protection.
n High impedance to bus with driver in TRI-STATE or with

power off, over the entire common mode range allows
the unused devices on the bus to be powered down.

n Pin out compatible with DS3695/A and SN75176A/B.
n Combined impedance of a driver output and receiver

input is less than one RS485 unit load, allowing up to 32
transceivers on the bus.

n 70 mV typical receiver hysteresis.

Connection and Logic Diagram

TRI-STATE®is a registered trademark of National Semiconductor Corp.

DS008759-1

Top View

Order Number DS75176BN, DS75176BTN, DS75176BM or DS75176BTM

See NS Package Number N08E or M08A

July 1998

DS75176B/DS75176BT Multipoint RS-485/RS-422 Transceivers

© 1999 National Semiconductor Corporation DS008759 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, V

CC

7V
Control Input Voltages 7V
Driver Input Voltage 7V
Driver Output Voltages +15V/ −10V
Receiver Input Voltages (DS75176B) +15V/ −10V
Receiver Output Voltage 5.5V
Continuous Power Dissipation

@

25˚C
for M Package 675 mW (Note 5)
for N Package 900 mW (Note 4)

Storage Temperature Range −65˚C to +150˚C
Lead Temperature

(Soldering, 4 seconds) 260˚C

Recommended Operating
Conditions

Min Max Units

Supply Voltage, V

CC

4.75 5.25 V

Voltage at Any Bus Terminal −7 +12 V

(Separate or Common Mode)

Operating Free Air Temperature T

A

DS75176B 0 +70 ˚C
DS75176BT −40 +85 ˚C

Differential Input Voltage,

VID (Note 6) −12 +12 V

Electrical Characteristics (Notes 2, 3)

0˚C ≤ TA≤ 70˚C, 4.75V<V

CC

<

5.25V unless otherwise specified

Symbol Parameter Conditions Min Typ Max Units

V

OD1

Differential Driver Output IO=0 5 V
Voltage (Unloaded)

V

OD2

Differential Driver Output (

Figure 1

) R=50Ω; (RS-422) (Note 7) 2 V

Voltage (with Load) R = 27Ω; (RS-485) 1.5 V

∆V

OD

Change in Magnitude of Driver
Differential Output Voltage For 0.2 V
Complementary Output States

V

OC

Driver Common Mode Output (

Figure 1

) R=27Ω 3.0 V

Voltage

∆|V

OC

| Change in Magnitude of Driver

Common Mode Output Voltage 0.2 V
For Complementary Output
States

V

IH

Input High Voltage 2V

V

IL

Input Low Voltage DI, DE, 0.8

V

CL

Input Clamp Voltage RE , E IIN= −18 mA −1.5

I

IL

Input Low Current VIL= 0.4V −200 µA

I

IH

Input High Current VIH= 2.4V 20 µA

I

IN

Input DO/RI, DO/RI VCC= 0V or 5.25V VIN= 12V +1.0 mA
Current DE = 0V V

IN

= −7V −0.8 mA

V

TH

Differential Input Threshold −7V ≤ VCM≤ + 12V −0.2 +0.2 V
Voltage for Receiver

∆V

TH

Receiver Input Hysteresis VCM=0V 70 mV

V

OH

Receiver Output High Voltage IOH= −400 µA 2.7 V

V

OL

Output Low Voltage RO IOL= 16 mA (Note 7) 0.5 V

I

OZR

OFF-State (High Impedance) VCC= Max

±

20 µA

Output Current at Receiver 0.4V ≤ V

O

≤ 2.4V

R

IN

Receiver Input Resistance −7V ≤ VCM≤ +12V 12 kΩ

I

CC

Supply Current No Load Driver Outputs Enabled 55 mA

(Note 7) Driver Outputs Disabled 35 mA

I

OSD

Driver Short-Circuit VO= −7V (Note 7) −250 mA
Output Current V

O

= +12V (Note 7) +250 mA

www.national.com 2

Electrical Characteristics (Notes 2, 3) (Continued)

0˚C ≤ TA≤ 70˚C, 4.75V<V

CC

<

5.25V unless otherwise specified

Symbol Parameter Conditions Min Typ Max Units

I

OSR

Receiver Short-Circuit VO= 0V −15 −85 mA
Output Current

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 tables of “Electrical Characteristics” 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 TA= 25˚C.

Note 4: Derate linearly at 5.56 mW/˚C to 650 mW at 70˚C.
Note 5: Derate linearly 6.11 mW/˚C to 400 mW at 70˚C.
Note 6: Differential - Input/Output bus voltage is measured at the noninverting terminal A with respect to the inverting terminal B.
Note 7: All worst case parameters for which note 7 is applied, must be increased by 10%for DS75176BT. The other parameters remain valid for −40˚C

<

T

A

<

+85˚C.

Switching Characteristics

VCC= 5.0V, TA= 25˚C

Symbol Parameter Conditions Min Typ Max Units

t

PLH

Driver Input to Output R

LDIFF

=60Ω 12 22 ns

t

PHL

Driver Input to Output CL1=CL2= 100 pF 17 22 ns

t

r

Driver Rise Time R

LDIFF

=60Ω 18 ns

t

f

Driver Fall Time CL1=CL2= 100 pF 18 ns

(

Figure 3

and

Figure 5

)

t

ZH

Driver Enable to Output High CL= 100 pF (

Figure 4

and

Figure 6

)S1

Open

29 100 ns

t

ZL

Driver Enable to Output Low CL= 100 pF (

Figure 4

and

Figure 6

)S2

Open

31 60 ns

t

LZ

Driver Disable Time from Low CL=15pF(

Figure 4

and

Figure 6

)S2

Open

13 30 ns

t

HZ

Driver Disable Time from High CL=15pF(

Figure 4

and

Figure 6

)S1

Open

19 200 ns

t

PLH

Receiver Input to Output CL=15pF(

Figure 2

and

Figure 7

)3037ns

t

PHL

Receiver Input to Output S1 and S2 Closed 32 37 ns

t

ZL

Receiver Enable to Output Low CL=15pF(

Figure 2

and

Figure 8

)S2

Open

15 20 ns

t

ZH

Receiver Enable to Output High CL=15pF(

Figure 2

and

Figure 8

)S1

Open

11 20 ns

t

LZ

Receiver Disable from Low CL=15pF(

Figure 2

and

Figure 8

)S2

Open

28 32 ns

t

HZ

Receiver Disable from High CL=15pF(

Figure 2

and

Figure 8

)S1

Open

13 35 ns

www.national.com3