APPLICATIONS INFORMATION Description

Quad Low Power Line Receiver

The MC14CB9AB and MC14CB9B are designed to be direct replacements for the MC14B9A and MC14B9. Both devices meet all the EIA-232 specifications and also the faster EIA-562 and CCITT V.28 specifications. Noise pulse rejection circuitry eliminates the need for most response control filter capacitors but does not exclude the possibility as filtering is still possible at the Response Control (RC) pins.

Also, the Response Control pins allow for a user defined selection of the threshold voltages. The MC14CB9AB and MC14CB9B are manufactured with a bipolar technology using low power techniques and consume at most 700

/lA,

plus load currents with a +5.0 V supply.

Outputs

The output low or high voltage depends on the state of the inputs, the load current, the bias of the Response Control pins, and the supply voltage. Table 1 applies to each receiver, regardless of how many other receivers within the package are supplying load current.

Table 1. Function Table Receivers

Receiver Inputs and Response Control

The receiver inputs determine the state of the outputs in accordance with Table 1. The nominal VIL and VIH thresholds are 0.95 V and 1.90 V respectively for the MC14CB9AB. For the MC14C89B, the nominal VIL and VIH thresholds are 0.95 and 1.30, respectively. The inputs are able to withstand

± 30 V referenced to ground. Should the input voltage exceed ground by more than ± 30 V, excessive currents will flow at the input pin. Open input pins will generate a logic high output, but good design practices dictate that Inputs should never be left open.

The Response Control (RC) pins are coupled to the inputs through a resistor string. The RC pins provide for adjustment of the threshold voltages of the IC while preserving the amount of hysteresis. Figure 10 shows a typical application to adjust the threshold voltages. The RC pins also provide access to an internal resistor string which permits low pass filtering of the input signal within the IC. Like the input pins, the RC pins should not be taken above or below ground by more than ± 30 V or excessive currents will flow at these pins. The dependence of the low level threshold voltage (VIL) upon RRC and Vbat can be described by the following equation,

VIL '" {VO.09 - Vba{ RRC (1

~~5

^+n2.02^{kn ] }}⁽¹⁾

(5.32 kn + 6.67

~~~6

^{n 2 )}

~

^{505 n}

VIH can be found by calculating for VIL using equation (1) then adding the hystereSiS for each device (0.35 for the

MOTOROLA COMMUNICATIONS DEVICE DATA

MC14CB9B or 0.95 V for the MC14CB9AB). Figure 7 plots

where f-3 dB represents the desired-3 dB roll-off frequency of the low pass filter.

Figure 10. Application to Adjust Thresholds

Input Pin}:esponse Control Pin RRC

i-

^Vbat

Another feature of the MC14CB9AB and MC14CB9B is input noise rejection. The inputs have the ability to ignore pulses which exceed the VIH and VIL thresholds but are less than 1.0 !1S in duration. As the duration of the pulse exceeds 1.0 Ils, the noise pulse may still be ignored depending on its amplitude. Figure 8 is a graph showing typical input noise rejection as a function of pulse amplitude and pulse duration.

Figure B reflects data taken for an input with an unconnected RC pin and applied to the MC14C89AB and MC14C89B.

Operating Temperature Range

The ambient operating temperature range is listed as -40°C to +85°C, and the devices are designed to meet the EIA-232-E, EIA-562 and CCITT V.28 specifications over this temperature range. The Timing Characteristics are guaranteed to meet the specifications at +25°C. The maximum ambient operating temperature is listed as +85°C.

However, a lower ambient may be required depending on system use, (i.e."specifically how many receivers within a package are used) and at what current levels they are

thermal resistance (typ., 1 OO°CIW for the DIP and 125°CIW for the SOIC packages);

maximum operating junction temperature (150°C); and

ambient temperature.

=

{[(VCC - VOH) • ilOHI] or

[(VoLl • ilOUneach receiver +(VCC • ICC) where: VCC

=

positive supply voltage;

VOH, VOL

=

measured or estimated from Figure 2 and 3;

ICC

=

measured quiescent supply current.

As indicated, the first term (in brackets) must be calculated and summed for each of the four receivers, while the last term is common to the entire package.

MC14C89B.MC14C89AB 2-13

MOTOROLA

- SEMICONDUCTOR

TECHNICAL DATA

QUAD LINE DRIVER

The MC1488 is a monolithic quad line driver designed to inter-face data terminal equipment with data communications equipment in conformance with the specifications of EIA Standard No. RS·232C.

Features:

• Current Limited Output

±10 rnA typ

• Power-Off Source Impedance 300 Ohms min

• Simple Slew Rate Control with External Capacitor

• Flexible Operating Supply Range

• Compatible with All Motorola MDTL and MTTL Logic Families

LINE DRIVER MCI488

..r--,

"----i

"1.. _ _ "

TYPICAL APPLICATION

INTERCONNECTING

CABLE LINE RECEIVER

MCI489

~ _'NTERCONNECTING I

MOlL LOGIC INPUT~"-- CABLE ~MDTl LOGIC OUTPUT

CIRCUIT SCHEMATIC (1/40F CIRCUIT SHOWN)

MC1488

QUAD MDTL LINE DRIVER R8-232C

SILICON MONOLITHIC INTEGRATED CIRCUIT

L SUFFIX CERAMIC PACKAGE

CASE 632

P SUFFIX PLASTIC PACKAGE

CASE 646

DSUFFIX

#

PLASTIC PACKAGE CASE 751A 14 .

(SO-14) 1 ' : ' PIN CONNECTIONS

VCC 1 4 0 - - - -... - - - -... - - -... - - - - , - - - , PINS 4, 9, 12 OR 2

INPUT INPUT

PINS5, 10, 13

B.2t

10k

lk 70

300

OUTPUT PINSS,B,l1 OR 3

VEE 10---~---~----~--4---4---~

MDTL and MTTL are trademarks of Motorola Inc.

MC1488 2-14

MOTOROLA COMMUNICATIONS DEVICE DATA

MAXIMUM RATINGS (T A = + 25"C unless otherwise noted.)

Power Derating (Package Limitation, Ceramic

and Plastic Dual-ln·Line Package) Po 1000 mW

Derate above TA = + 25"C 1/R9JA 6.7 mWI"C

Operating Ambient Temperature Range TA

o

to +75 "C

Storage Temperature Range Tstl'l -65 to + 175 "C

ELECTRICAL CHARACTERISTICS (VCC = +9.0 ± 1% Vdc, VEE = -9.0 ± 1% Vdc, TA = 0 to 75"C unless otherwise noted.)

Characteristic Figure Symbol Min

Input Current - Low Logic State (VIL = 0) 1 IlL

Negative Output Short-Circuit Current (1) 3 10S- -6.0

Output Resistance (VCC = VEE = 0, IVol = ±2.0 V) 4 ro 300

-Power Consumption Pc

(VCC = 9.0 Vdc, VEE = -9.0 Vdc)

-(1) Maximum Package Power Dissipation may be exceeded if all outputs are shorted simultaneously.

MOTOROLA COMMUNICATIONS DEVICE DATA

Typ

CHARACTERISTIC DEFINITIONS

FIGURE 1 - INPUT CURRENT +9 V -9 V

FIGURE 3 - OUTPUT SHORT-CIRCUIT CURRENT

+1.9 V 105+

I

105-+0.8 V

+1.9 V

V1J

V,l

+0.8 V

MC1488 2-16

FIGURE 5 - POWER-SUPPLY CURRENTS Vee

VEE

FIGURE 2 - OUTPUT VOLTAGE +9 V -9 V

FIGURE 4 - OUTPUT RESISTANCE (POWER-OFFI

±2 Vdc

±6.6 mA Max

FIGURE 6 - SWITCHING RESPONSE

ein-D---I"'-:--3-k --l..---evo

r

^'5PF

+3V,...--_ _ _ --,

~

^1.5V

ein

. lPHL - - - 0 V

Vo··-- - - .

ITHL--'--_ _ _ --J"--ITLH ITHl and ITLH Measured 10% 10 90%

MOTOROLA COMMUNICATIONS DEVICE DATA

~ FIGURE 7 - TRANSFER CHARACTERISTICS

versus POWER-SUPPLY VOLTAGE

VCC~VEE}'12V

^{-;; +12}_~

+S.O

FIGURE B - SHORT-CIRCUIT OUTPUT CURRENT versus TEMPERATURE

Vin.INPUT VOLTAGE IVOLTS)

FIGURE 9 - OUTPUT SLEW RATE versus LOAD CAPACITANCE

+20 +16

-;; +12

T. TEMPERATURE IDC)

FIGURE 10 - OUTPUT VOLTAGE AND CURRENT-LIMITING CHARACTERISTICS

~

CL. CAPACITANCE IpF) • VO.OUTPUTVOLTAGEIVOLTS)

~

16 ₁₄

FIGURE 11 - MAXIMUM OPERATING TEMPERATURE versus POWER-SUPPLY VOLTAGE

--...

T. TEMPERATURE IDC)

MOTOROLA COMMUNICATIONS DEVICE DATA

+125

MC1488 2-17

Dans le document Device Data (Page 38-42)