SGS Thomson Microelectronics ST3485EBD, ST3485ECN, ST3485ECDR, ST3485EBDR Datasheet

3.3V POWERED, 15KV ESD PROTECTED, TRASMIT AT
UP T O 12MBPS TRUE RS-485/RS-422 TRANSCEIVER

■ ESD PROTECTION:

±15KV HUMAN BODY MODEL
±8KV IEC 1000-4-2 CONTACT DISCHARGE

■ OPERATE FROM A SINGLE 3.3V SUPPLY-

NO CHARGE PUMP REQUIRED

■ INTEROPERABLEWITH 5 V LOGIC

■ 1µA LOW CURRENT SHUTDOWN MODE

MAX

■ GUARANTEED 12 Mbps DATA R ATE

■ -7 TO 12 COMMON MO DE INPUT VOLTAGE

RANGE

■ HALF DUPLEX VERSIONS AVAILABLE

■ INDUSTRY STANDA RD 75176 PINOUT

■ CURRENT LIMITING AND THERMAL

SHUTDOWN FOR DRIVER OVERLOAD
PROTECTION

■ GUARANTEED HIGH RECEIVER OUTPUT

STATE FOR FLOATING INPUTS WITH NO
SIGNAL PRESENT

■ ALLOW UP TO 64 TRANSCEIVERS ON T HE

BUS

DESCRIPTION

The ST3485E is ±15kV ESD protected, 3.3V low
power transceiver for R S - 485 and RS-422
communications. The device contains one driver

ST3485E

DIP SOP

and one receiver in hal f duplex configuration. The
ST3485E transmit and receive at guaranteed data
rate at least to 12Mbps.
All transmitter outputs and receiver inputs are
protected to ±15kV using Human Body Mo del.
Driver is short-circuit current limited and is
protected against excessive p ower dissipation by
thermal shutdown circuitry that place the driver
outputs into a high-impedance state.
The S T3485E input has a t ru e fail-safe feature
that guarantees a logic high output if both inputs
are open circuit, shorted together or in presence of
the termination with no signal on the bus.

ORDERING CODES

Type

ST3485ECN 0 to 70 °C DIP-8 50parts per tube / 40tube per box
ST3485EBN -40 to 85 °C DIP-8 50parts per tube / 40tube per box
ST3485ECD 0 to 70 °C SO-8 (Tube) 100parts per tube / 20tube per box

ST3485EBD -40 to 85 °C SO-8 (Tube) 100parts per tube / 20tube per box
ST3485ECDR 0 to 70 °C SO-8 (Tape & Reel) 2500 parts per reel
ST3485EBDR -40 to 85 °C SO-8 (Tape & Reel) 2500 parts per reel

Temperature

Range

Package Comments

1/16October 2002

ST3485E

PIN CONFIGURATION

PIN DESCRIPTION

PlN N° SYMBOL NAME AND FUNCTION

1RO

2RE

3DE

4DI
5 GND Ground

6 A Non-inverting Receiver Input and Non-inverting Driver Output
7 B Inverting Receiver Input and Inverting Driver Output
8

V

CC

Receiver Output. If A>B by 200mV, RO will be high; if A<B by 200mV, RO will be
low

Receiver Output Enable. RO is enabled when RE is low; RO is high impedance
when RE is high. If RE is high and DE is low, the device will enter a low power
shutdown mode.

Driver Output Enable. The driver outputs are enabled by bringing DE high. They
are high impedance when DE is low. If RE is high DE is low,thedevice will enter a
low-power shutdown mode. If the driver outputs are enabled, the part functions as
line driver, while they are high impedance, it functions as line receivers if RE is
low.

Driver Input. A low on DI forces output A low and output B high. Similarly, a high
on DI forces output A high and output B low

Supply Voltage: VCC= 3V to 3.6V

TRUTH TABLE (DRIVE R)

INPUTS OUTPUTS

RE

X= Don’t Care; Z=High Impedance

2/16

DE DI B A

X H H L H Normal
X H L H L Normal
L L X Z Z Normal
H L X Z Z Shutdown

MODE

TRUTH TABLE (RECE IVER)

INPUTS OUTPUT

DE A-B RO

RE

LL ≥ -0.015V H Normal
LL ≤ -0.2V L Normal
L L Inputs Open H Normal
L L Inputs Shorted H Normal

H L X Z Shutdown

X= Don’t Care; Z=High Impedance

MODE

ST3485E

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

V

DO

V

V

RO

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

ESD PERFORMANCE: TRANSMITTER O UTPUTS, RECEIVER INPUTS

Symbol Parameter Test Conditions Min. Typ. Max. Unit

ESD ESD Protection Voltage Human Body Model ± 15 KV

ESD ESD Protection Voltage IEC-1000-4-2 Contact Disharge ± 8KV

ELECTRICAL CHARACTERISTICS

=3Vto3.6V,TA= -40 to 85°C, unless otherwise specified. Typical values are referred to TA= 25°C)

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

I

SUPPLYVCC

I

SHDN

Supply Voltage

CC

Control Input Voltage (RE,DE)

I

Driver Input Voltage (DI)

DI

Driver Output Voltage (A, B)
Receiver Input Voltage (A, B)

RI

Receiver Output Voltage (RO) -0.3 to (VCC+ 0.3)

Power Supply Current No Load, DI=0V or V

CC

DE=VCC,

=0V or V

RE

CC

DE=0V,

=0V

RE

Shutdown Supply Current DE=0V, RE=VCC, DI=0V or V

CC

7V

-0.3 to 7 V

-0.3 to 7 V

-7.5 to 12.5 V

-7.5 to 12.5 V
V

1.3 2.2 mA

1.2 1.9 mA

0.002 1 µA

LOGIC INPUT EL ECTRICAL CHARACTERISTICS

=3Vto3.6V,TA= -40 to 85°C, unless otherwise specified. Typical values are referred to TA= 25°C)

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

Input Logic Threshold Low DE, DI, RE 1.3 0.8 V

IL

Input Logic Threshold High DE, DI, RE 2 V

V

IH

Logic Input Current DE, DI, RE ± 2.0 µA

I

IN1

I

Input Current (A, B) DE=0V, VCC= 0 or 3.6V VIN=12V 1 mA

IN2

=-7V -0.8 mA

V

IN

3/16

ST3485E

TRANSMITTER ELECTRICAL CHARACTERISTICS

=3Vto3.6V,TA= -40 to 85°C, unless otherwise specified. T yp ical values are r efe rred to Ta=25°C)

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

∆V

V

∆V

I

RECEIVER ELECTRICAL CHARACTERISTICS

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

∆V

V

I

R

I

Differential Drive Output RL= 100Ω (RS-422) (Figure 1) 2 V

OD

=54Ω(RS-485) (Figure 1) 1.5 V

R

L

=60Ω(RS-485) (Figure 2) 1.5 V

R

L

Change in magnitude of

OD

Driver Differential Output

=54Ωor 100Ω (Figure 1) 0.2 V

R

L

Voltage for Complementary
Output States (Note1)

Driver Common Mode

OC

Output Voltage
Change in magnitude of

OC

Driver Common Mode

RL=54Ωor 100Ω (Figure 1) 3 V

=54Ωor 100Ω (Figure 1) 0.2 V

R

L

Output Voltage (Note1)
Driver Short Circuit Output

OSD

Current

± 250 mA

=3Vto3.6V,TA= -40 to 85°C, unless otherwise specified. T yp ical values are r efe rred to Ta=25°C)

Receiver Differential

V

TH

Threshold Voltage
Receiver Input Hysteresis VCM=0V 30 V

TH

Receiver Output High

OH

Voltage
Receiver Output Low

V

OL

Voltage
3-State (High Impedance)

OZR

Output Current at Receiver
Receiver Input Resistance VCM= -7V to 12V 24 KΩ

RIN

Receiver Short-Circuit

OSR

Current

VCM= -7V to 12V, DE = 0 -0.2 -0.015 V

I

= -4mA, VID= 200mV, (Figures 8,9) 2 V

OUT

I

= 4mA, VID= -200mV, (Figure 3) 0.4 V

OUT

VCC= 3.6V VO=0VtoV

VRO=0VtoV

CC

CC

760mA

± 1 µA

4/16

ST3485E

DRIVER SWITCHING CHARACTERISTICS

V

=3Vto3.6V,TA= -40 to 85°C, unless otherwise specified. T yp ical values are r efe rred to Ta=25°C)

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

D

Maximum Data Rate 12 15 Mbps

R

Differential Output Delay RL=60Ω CL= 15pF, (Figures 4,5) 18 30 ns

t

DD

Differential Output

t

TD

Transition Time
t
t

t

Propagation Delay RL=27Ω CL= 15pF, (Figures 8,9) 18 30 ns

PLH
PHL

PDS|tPLH -tPHL

Delay Skew (Note2)

Output Enable Time RL=110Ω (Figures 10,11) 19 35 ns

t

PZL

t
t

t

SKEW

t

ZH(SHDN)

t

ZL(SHDN)

Output Enable Time RL=110Ω (Figures 6,7) 30 50 ns

PZH

Output Disable Time RL=110Ω (Figures 6,7) 19 35 ns

PHZ

Output Disable Time RL=110Ω (Figures 10,11) 30 50 ns

t

PLZ

Differential Output Delay

Skew

Driver Enable from

Shutdown to Output High

Driver Enable from

Shutdown to Output Low

| Propagation

RL=60Ω CL= 15pF, (Figures 4,5) 12 20 ns

RL=27Ω CL= 15pF, (Figures 8,9) 2 5 ns

13ns

30 50 ns

19 35 ns

RECEIVER SWITCHING CHARACTERISTICS

=3Vto3.6V,TA= -40 to 85°C, unless otherwise specified . Typicalvalues are referred toTa= 25°C)

V

CC

Symbol Parameter Test Conditions Min. Typ. Max. Unit

t
t

t

RPDS|tPLH -tPHL

t
t

t

ZH(SHDN)

t

ZL(SHDN)

Note 1:∆VODand ∆VOCare the changes in VODand VOC, respectively, when the DI input changes state.
Note 2:measuredon |t
Note 3: The transceivers are put into shutdown by bring RE high and DE low. If the input are in state for less than 80ns, the part are guaren­teed not to enter shutdown. If the inputs are in this state for at least 300ns, the parts are guarenteed to have entered shutdown.

Propagation Delay VID=0V to 3V CL1= 15pF, (Figures 12,13) 30 50 ns

PLH
PHL

| Propagation

VID=0V to 3V CL1= 15pF, (Figures 12,13) 1 3 ns
Delay Skew
Output Enable Time CRL= 15pF (Figures 14-18) 10 20 ns

t

PZL

Output Enable Time CRL= 15pF (Figures 14-18) 10 20 ns

PZH

Output Disable Time CRL= 15pF (Figures 14-18) 10 20 ns

PHZ

Output Disable Time CRL= 15pF (Figures 14-18) 10 20 ns

t

PLZ

Receiver Enable from

CRL= 15pF (Figures 14-18) 10 20 ns
Shutdown to Output High

Receiver Enable from

CRL= 15pF (Figures 14-18) 20 40 ns
Shutdown to Output Low

(A)-t

PLH

(A)| and |t

PHL

PLH

(B)-t

PHL

(B)|

5/16