SGS Thomson Microelectronics ST490ACN, ST490ACDR, ST490ACD, ST490ABN, ST490ABDR Datasheet

ST490A

LOW POWER HIGH SPEED RS-485/RS-422 TRANSCEIVER

■ LOW SUPPLY CURRENT: 5mA MAX

■ -7 TO 12 COMMON MODE INPUT VOLTAGE

RANGE

■ 70mV TYPICAL INPUT HYSTERESIS

■ DESIGNED FOR 25Mbps OPERATION

■ OPERATE FROM SINGLE 5 SUPPLY

■ ±4kV ESD PROTECTION

■ CURRENT LIMITING AND THERMAL

SHUTDOWN FOR DRIVER OVERLOAD
PROTECTION

DESCRIPTION

The ST490A is a low power transceiver for
RS-485 and RS-422 communications.Thedevice
contains one driver and one receiver in full dup lex
configuration. The ST490A draws 5mA (typ.) of
supply current when unl oaded or fully loaded with
disabled drivers. It operates from a single 5V
supply.

Driver is short-circuit current limited and is
protected against excessive power dissipation by
thermal shutdown circuitry that place t he driver
outputs into a high-impedance state. The rec eiver
input has a fail-safe feature that guarant ees a
logic high output if both inputs are open circuit.

DIP SOP

ORDERING CODES

Type

ST490ACN 0 to 70 °C DIP-8 50parts per tube / 40tube per box
ST490ABN -40 to 85 °C DIP-8 50parts per tube / 40tube per box
ST490ACD 0 to 70 °C SO-8 (Tube) 100parts per tube / 20tube per box

ST490ABD -40 to 85 °C SO-8 (Tube) 100parts per tube / 20tube per box
ST490ACDR 0 to 70 °C SO-8 (Tape & Reel) 2500 parts per reel
ST490ABDR -40 to 85 °C SO-8 (Tape & Reel) 2500 parts per reel

Temperature

Range

Package Comments

1/11November 2002

ST490A

PIN CONFIGURATION

PIN DESCRIPTION

PlN N° SYMBOL NAME AND FUNCTION

1

V

CC

2 RO Receiver Output.
3 DI Driver Input.
4 GND Ground
5 Z Inverting Driver Output
6 Y Non-inverting Driver Output
7 B Inverting Receiver Input
8 A Non-inverting Receiver Input

Supply Voltage

TRUTH TABLE (DRIV E R)

INPUT OUTPUTS

DI Y Z

LLH

HHL

X= Don’t Care; Z=High Impedance

TRUTH TABLE (RE CE IVER)

DIFFERENTIAL INPUT OUTPUT

A-B RO

≥ -0.2V H

between -0.2V to 0.2V ?

≤ -0.2V L

OPEN H

?= Irrelevant; Z=High Impedance

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

Y,VZ

V

A,VB

V

RO

ESD Human Boby Model 3.5 KV

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.

2/11

Supply Voltage

CC

Driver Input Voltage

DI

Driver Output Voltage
Receiver Input Voltage
Receiver Output Voltage -0.3 to (VCC+ 0.3)

7V

-0.5 to 7 V

-7.5 to 12.5 V

-7.5 to 12.5 V
V

ST490A

ELECTRICAL CHARACTERISTICS

V

=4.5Vto5.5V,TA=-40to85°C, unless otherwise specified.Typicalvaluesare referred toTA=25°C)

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

I

SUPPLY

C

TRANSMITTER E L ECTRICAL CHARACTERISTICS

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

V

V

∆V

∆V

I

No Load Supply Current 2 5 mA
Input Capacitance 1.8 pF

C

IN

Driver Output Capacitance 1.2 pF

C

YZ

Output Capacitance 2.3 pF

OUT

=4.5Vto 5.5V,TA= -40to85°C,unlessotherwisespecified.TypicalvaluesarereferredtoTa= 25°C)

Differential Drive Output

OD1

(No load)
Differential Drive Output

OD2

(With Load)
Differential Drive Output

OD3

(With Load)
Change in magnitude of

OD

Driver Differential Output

RL=54Ω(RS-422) (Figure 1) 1.5 2.6 5 V

RL= 100Ω (RS-422) (Figure 1) 2 3 V

=54Ωor 100Ω (Figure 1) 0 0.2 V

R

L

Voltage for Complementary
Output States (Note1)

Driver Common Mode

V

OC

Output Voltage
Change in magnitude of

OC

Driver Common Mode

RL=54Ω(Figure 1) 1 3 V

RL=54Ω(Figure 1) 0 0.2 V

Output Voltage (Note1)
Power Off Output Current VCC=0V VO=-7V to 12V ± 100 µA

I

OFF

Driver Short Circuit Output

OSD

Current
Input Logic Threshold Low 0.8 V

V

IL

Input Logic Threshold High 2 V

V

IH

VO=-7V to 12V ± 35 ± 250 mA

V

CC

V

3/11

ST490A

RECEIVER ELECTRICAL CHARACTERISTICS

V

=4.5Vto 5.5V,TA= -40to85°C,unlessotherwisespecified.TypicalvaluesarereferredtoTa= 25°C)

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

I

Logic Input Current ± 2.0 µA

IN1

Input Current (A, B) other input=0V

I

V

∆V

V

V

R
I

OSR

IN2

Receiver Differential

TH

Threshold Voltage
Receiver Input Hysteresis VCM=0V 70 mV

TH

Receiver Output High

OH

Voltage
Receiver Output Low

OL

Voltage
Receiver Input Resistance VCM= -7V to 12V 12 24 KΩ

RIN

Receiver Short-Circuit
Current

= 0 or 5.25V

V

CC

VCM= -7V to 12V -0.2 0.2 V

I

= -8mA, VID= 200mV 3.5 4.7 V

OUT

I

= 8mA, VID= -200mV 0.2 0.4 V

OUT

VO=0VtoV

CC

DRIVER S WITCHING CHARACTERISTICS

=4.5Vto5.5V,TA=-40to85°C,unlessotherwisespecified.Typicalvaluesareref erred to Ta=25°C)

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Maximum Data Rate Jitter <5% 25 50 Mbps

D

R

t

PLH

t

PHL

t

SKEW

t

TLH

t

THL

Propagation Delay Input to
Output

Differential Output Delay
Skew

Rise or Fall Differential
Time

RL=54Ω CL1=CL2=50pF, (Figure 1) 10 16 ns

RL=54Ω CL1=CL2=50pF, (Figure 1) 1 3 ns

RL=54Ω CL1=CL2=50pF, (Figure 1) 8 12 ns

V

=12V 0.5 1 mA

IN

=-7V -0.35 -0.8 mA

V

IN

795mA

RECEIVER SWITCHING CHARACTERISTICS

=4.5Vto5.5V,TA=-40to85°C, unless otherwise specified.Typicalvaluesareref erred to Ta=25°C)

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

Propagation Delay Input to

t

PLH

Output

t

PHL

t

SKD|tPLH -tPHL

Skew
t
t

Rise or Fall Time CL= 15pF (Figures 2,4) 8 ns

TLH
THL

4/11

|ReceiverOutput

CL= 15pF (Figures 2,4) 19 30 ns

CL= 15pF (Figures 2,4) 1 3 ns