Datasheet MC1488D, MC1488P Datasheet (SGS Thomson Microelectronics)



■ CURRENTLIMITEDOUTPUT±10mATYP.

■ POWER-OFF SOURCE IMPEDANCE 300Ω

MIN.

■ SIMPLESLEWRATE CONTROL WITH

EXTERNALCAPACITOR

■ FLEXIBLEOPERATINGSUPPLYRANGE

■ INPUTSARETTLANDµPCOMPATIBLE

DESCRIPTION

The MC1488 is a monolithic quad line driver
designed to interface data terminal equipment
with data communications equipment in
conformance with the specifications of EIA
StandardNo. RS232C.

MC1488

RS232C QUAD LINE DRIVER

P

DIP14

(Plastic Package)

(Plastic Micropackage)

D

SO14

(topview)

ORDERCODES:

MC1488P (PlasticDIP)

MC1488D(SO14)

LOGICDIAGRAMPIN CONNECTIONS

March 2000

1/9

MC1488

ABSOLUTEMAXIMUM RATINGS

Symb ol Parameter Test C o n dit io ns Unit

Power Supply Voltage 15 V

V

S

V

Power Supply Voltage –15 V

EE

V

Input Voltage Range –15≤V

IR

V

Output Signal Voltage

O

T

Operating Ambient Temperature 0 to 75

amb

T

Storage Temperature Range –65 to 150

stg

THERMALDATA

Symb o l Parameter Plasti c DI P14 Cera mi c D I P 1 4 SO14

R

th j-amb

Thermal Resistance Junction-ambientMax. 200oC/W 165oC/W 165oC/W

ELECTRICAL CHARACTERISTICS

= 9 ±10%V,VEE=–9±10%V ,T

V

S

Symbol Parameter Test Conditions Min. Typ. M ax. Un it F ig.

Input Current Low Logic StateVIL= 0V 1 1.6 mA 1

I

IL

I

Input Current High Logic StateVIH=5V 10µA1

IH

= 0to75oC, unlessotherwise specified

amb

7V

≤

IR

15 V

±

o

C

o

C

V

Output Voltage

OH

V

Output Voltage Low Logic State

OL

+

I

* Positive Output Short-circuit

OS

Current 6 10 12

–

I

* Negative Output Short-circuit

OS

Current -6 -10 -12

R

Output Resistance

O

I

Positive Supply Current

s

I

EE

P

c

=∞)

(R

i

Negative Supply Current

=∞)

(R

L

Power Consumption VS=9V VEE= -9V

High Logic StateR

=0.8V,VS= 9V, VEE=–9V

V

IL

=0.8V,VS= 13.2V, VEE= –13.2V

V

IL

= 1.9V, VEE= –9V, VS=9V

V

IH

= 1.9V, VEE= –13.2V, VS=13.2V

V

IH

V

S=VEE

V

IH

V

IL

V

IH

V

IL

V

IH

V

IL

V

IH

V

IL

V

IH

V

IL

V

IH

V

IL

V

S

=0Vol=±2V

=1.9V Vs=9V

=0.8V Vs=9V

=1.9V Vs= 12V

=0.8V Vs=12V

=1.9V Vs= 15V

=0.8V Vs=15V

=1.9V Vs= -9V

=0.8V Vs=-9V

=1.9V Vs= -12V

=0.8V Vs=-12V

=1.9V Vs= -15V

=0.8V Vs=-15V

=12V VEE= -12V

L

=3k

Ω

6

9710.5

-6-9-7

-10.5

300

15

4.5
19

5.5

-13

-18

20

6

25

7
34
12

-17

-15

-23

-15

-34

-2.5
333

567

V

V

mA 3

mA 3

Ω

mA 5

mA

A

µ

mA

A

µ

mA
mA

mW

2
2

2
2

4

5

SWITCHING CHARACTERISTICS

=

V

S

±9 ±1V,V

EE

=–

9±1%V,T

amb

o

=

C

25

Symbol Parameter Test Conditions Min. T yp. Max. Uni t Fig.

t

Propagation Delay Time

PHL

Fall Time

t

THL

Propagation Delay Time

t

PHL

Rise Time

t

THL

* Maximum package power dissipation may be exceeded if all outputs are shorted simultaneously.

=3kΩand 15pF

Z

i

=3kΩand 15pF

Z

i

=3kΩand 15pF

Z

i

=3kΩand 15pF

Z

i

275 350 ns 6

45 75 ns 6

110 175 ns 6

55 100 ns 6

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TESTCIRCUITS

MC1488

Figure1 : Input Current

Figure3 : OutputShort-Circuit Current

Figure2 : Output Voltage

Figure4 : Output Resistance (poweroff)

Figure5 : Power SupplyCurrents

Figure6 : SwitchingResponse

3/9

MC1488

Figure7 : Transfer Characteristicsversus Figure8 : Short-CircuitOutput Current versus

Temperature

Figure9 : OutputSlew-Rate Load Capacitance Figure 10: OutputVoltage and CurrentLimiting

Characteristics

4/9

Figure11 :

MaximumOperatingTemperature

versusPower SupplyVoltage

TYPICALAPPLICATION: RS232CData Transmission

MC1488

APPLICATION INFORMATION

The Electronic Industries Association (EIA) has
released the RS232C specification detailing the
requirements for the interface between data
processing equipment. This standard specifies
not only the number and type of interface leads,
but also the voltage levels to be used. The
MC1488 quad driver and its companion circuit,
the MC1489 quad receiver, provide a complete
interfacesystem between DTL or TTL logic levels
and the RS232C defined levels. The RS232C
requirements as applied to drivers are discussed
herein.

The required driver voltages are defined as
between 5 and 15 V in magnitude and are
positivefor a logic ”0” andnegativefor a logic ”1”.
These voltages are so defined when the drivers
are terminated with a 3000 to 7000Ω resistor.
The MC1488 meets this voltage requirement by
converting a DTL/TTL logic level into RS232C
levelswith one stageof inversion.

The RS232C specification further requires that
during transitions, the driver output slew rate
must not exceed 30 V per µs. The inherent slew
rate of the MC1488 is much too fast for this
requirement. The current limited output of the
device can be used to control this slew rate by
connecting a capacitor to each driver output. The
required capacitor can be easily determined by
using the relationship C = I

x ∆T/ ∆V from

OS

which Figure 12 is derived. Accordingly, a 330 pF
capacitor on each output will guarantee a worst
case slew rate of 30 V perµs.

The interface driver is also required to withstand
an accidental short to any other conductor in an
interconnecting cable. The worst possible signal
on any conductor would be another driverusing a
plus or minus 15 V,500 mA source.The MC1488
is designed to indefinitely withstand such a short
to all four outputs in a package as long as the
power-supply voltages are greater than 9.0 V
(i.e., VS

≥ 9.0 V ; VEE≤ - 9.0 V). In some
power-supply designs, a loss of system power
causes a low impedance on the power-supply
outputs. When this occurs, a low impedance to
ground would exist at the power inputs to the
MC1488 effectively shorting the 300Ω output
resistor to ground. If all four outputs were then
shorted to plus or minus 15 V, the power
dissipation in these resistors would be excessive.
Therefore, if the systemis designed to permit low
impedances to ground at the power-suppies of
the drivers, a diode should be placed in each
power-supply lead to prevent over-heating in this
fault condition. These two diodes, as shown in
Figure 13, could be used to decouple all the
driverpackages ina system.(Thesesame diodes
will allow the MC1488 to withstand momentary
shorts to the ±15 V limits specified in the earlier

5/9

MC1488

Standard RS232B). The addition of the diodes
also permits the MC1488 to withstand faults with
power-supplies of less than the 9.0 V stated
above.

The maximum short-circuit current allowable
under faultconditions is more thanguaranteed by
the previously mentioned 10 mA output current
limiting.

The MC1488 is an extremely versatile line driver
with a miriad of possible applications. Several
featuresof the driversenhancethis versatility:

1. Output Current Limiting - this enables the
circuitdesignerto define the ouptut voltagelevels
independent of power-supplies and can be
accomplished by diode clamping of the output
pins.

2. Power-Supply Range - as can be seen from
the schematic drawing of the drivers, the positive

Figure12 : Slew Rateversus Capacitancefor
I

= 10mA

sc

and negative driving elements of the device are
essentially independent and do not require
matching power-supplies. In fact, the positive
supply can very from a minimum seven volts
(required for driving the negative pulldown
section) to the maximum specified 15 V. The
negative supply can vary from approximately -

2.5 V to the minimum specified - 15 V. The
MC1488 will drive the ouptut to within 2 V of the
positive or negative supplies as long as the
current output limits are not exceeded. The
combination of the current-limiting and
supply-voltagefeatures allow a wide combination
of possible outputs within the same quad
package.

Figure13 : Power SupplyProtectionto Meet
Power-offFault Conditions

6/9

Plastic DIP-14 MECHANICAL DATA

MC1488

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

a1 0.51 0.020

B 1.39 1.65 0.055 0.065
b 0.5 0.020

b1 0.25 0.010

D 20 0.787
E 8.5 0.335
e 2.54 0.100

e3 15.24 0.600

F 7.1 0.280

I 5.1 0.201
L 3.3 0.130
Z 1.27 2.54 0.050 0.100

mm inch

P001A

7/9

MC1488

SO-14 MECHANICALDATA

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 1.75 0.068
a1 0.1 0.2 0.003 0.007
a2 1.65 0.064

b 0.35 0.46 0.013 0.018
b1 0.19 0.25 0.007 0.010

C 0.5 0.019
c1 45 (typ.)

D 8.55 8.75 0.336 0.344

E 5.8 6.2 0.228 0.244

e 1.27 0.050
e3 7.62 0.300

F 3.8 4.0 0.149 0.157

G 4.6 5.3 0.181 0.208

L 0.5 1.27 0.019 0.050

M 0.68 0.026

S 8 (max.)

mm inch

8/9

P013G

MC1488

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