SP232ACT-L/TR - EXAR - Datasheet.Live

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)668-7000 • Fax (510)668-7017 • www.exar.com SP232A_100_051308

DESCRIPTION

FEATURES

SP232A

Enhanced RS-232 Line Drivers/Receivers

• Operates from a Single +5V Power Supply

• Meets all RS-232F and ITU V.28 Specications

• Operates with 0.1μF Ceramic Capacitors

• High Data rate - 120kbps under load

• Low power CMOS Operation

• +/-2kV Human Body Model ESD Protection

• Lead Free packaging available

The SP232A is a line driver and receiver pair that meets the specications of RS-232 and V.28 serial

protocols. This device is pin-to-pin compatible with popular industry standard pinouts. The SP232A

offers 120kbps data rate under load, small ceramic type 0.1μF charge pump capacitors and overall

ruggedness for comercial applications. The SP232A features Exar's BiCMOS design allowing for low

power operation without sacricing performance. This device is avaialble in plastic DIP, SOICW and

nSOIC packages operating over the commercial and industrial temperature ranges.

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)668-7000 • Fax (510)668-7017 • www.exar.com SP232A_100_051308

AbSoLUTE MAxiMUM RATingS

These are stress ratings only and functional opera-

tion of the device at these ratings or any other above

those indicated in the operation sections of the speci-

cations below are not implied. Exposure to absolute

maximum ratings conditions for extended periods of

time may affect reliability.

Supply Voltage (VCC)...............................................+ 6V

V+........................................................................... (Vcc-0.3V) to +11.0V

V- .............................................................................-11.0V

Input Voltages

Tin.....................................................-0.3V to (Vcc + 0.3V)

Rin............................................................................+/-15V

Output Voltages

Tout...............................................(V+, +0.3V) to (V-, -0.3V

Rout...................................................-0.3V to (Vcc + 0.3V)

Vcc=5V ±10%, 0.1μF charge pump capacitors, Tmin to Tmax, unless otherwise noted, Typical values are Vcc=5V

and Ta=25°C

Short Circuit duration

Tout.....................................................Continuous

Package Power Dissipation:

Plastic DIP...............................................375mW

(derate 7mW/°C above +70°C)

Small Outline...........................................375mW

(derate 7mW/°C above +70°C)

Storage Temperature..................-65°C to +150°C

Lead Temperature (soldering, 10s).......... +300°C

ELECTRiCAL CHARACTERiSTiCS

PARAMETER TEST ConDiTionS Min TYP MAx UniT

TTL inPUT

Logic Threshold LOW Tin 0.8 Volts

Logic Threshold HIGH Tin 2.0 Volts

Logic Pull-Up Current Tin = 0V 15 200 μA

TTL oUTPUT

Output Voltge LOW iouT = 3.2 mA: Vcc = +5V 0.4 Volts

Output Voltage HIGH iouT = -1.0 mA 3.5 Volts

RS-232 oUTPUT

output Voltage Swing all Transmitter outputs loaded

with 3k ohms to GND +/-5.0 +/-6.5V Volts

Output Resistance Vcc = 0V, Vout = +/-2V 300 Ohms

Output Short Circuit Current Innite Duration +/-18 mA

Maximum Data Rate CL = 2500pF, RL = 3kΩ 120 240 kbps

RS-232 inPUT

Voltage Range -15 +15 Volts

Voltage Threshold LOW Vcc = 5V, Ta=25°C 0.8 1.2 Volts

Voltage Threshold HIGH Vcc = 5V, Ta=25°C 1.7 2.4 Volts

Hysteresis Vcc = 5V, Ta=25°C 0.2 0.5 1.0 Volts

Resistance Ta=25°C, -15V ≤ Vin ≤ +15V 3 5 7 kΩ

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)668-7000 • Fax (510)668-7017 • www.exar.com SP232A_100_051308

DYnAMiC CHARACTERiSTiCS

Driver Propagation Delay TTL to RS_232; CL = 50pF 1.5 3.0 μs

Receiver Propagation Delay RS-232 to TTL, 0.1 1.0 μs

Instantaneous Slew Rate CL = 10pF, RL = 3-7kΩ 30 V/ μs

Transition Region Slew Rate CL = 2500pF, RL = 3kΩ;

Measured from +3V to -3V or

-3V to +3V 10 V/ μs

PoWER REQUiREMEnTS

Vcc Power Supply Current No Load, Vcc = 5V, Ta=25°C 1.5 5 mA

Vcc Power Supply Current, Loaded All Transmitters RL = 3kΩ,

Ta=25°C 11 mA

ELECTRiCAL CHARACTERiSTiCS

Vcc=5V ±10%, 0.1μF charge pump capacitors, Tmin to Tmax, unless otherwise noted, Typical values are Vcc=5V

and Ta=25°C

Pin ASSignMEnTS

Pin number Pin name Pin Function

1 C1+ Positive terminal of the voltage doubler charge pump

capacitor

2 V+ +6.5V generated by the charge pump

3C1- Negative terminal of the voltage doubler charge pump

capacitor

4 C2+ Positive terminal of the inverting charge pump capacitor

5 C2- Negative terminal of the inverting charge pump capacitor

6 V- -6.7V generated by the charge pump

7 T2OUT RS-232 driver output

8 R2IN RS-232 receiver input

9R2OUT TTL/CMOS receiver output

10 T2IN TTL/CMOS driver input

11 T1IN TTL/CMOS driver input

12 R1OUT TTL/CMOS receiver output

13 R1IN RS-232 receiver input

14 T1OUT RS-232 driver output

15 GND Ground

16 Vcc 5V supply voltage

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)668-7000 • Fax (510)668-7017 • www.exar.com SP232A_100_051308

DESCRiPTion

DETAiLED DESCRiPTion

The SP232A transceiver is a two driver and two

receiver device that meets the EIA/TIA- 232 and

V.28 serial communication protocol. The device

is pin-to-pin compatible with popular industry

standard pinouts. The SP232A offers 120kbps

data rate, 10V/μs slew rate and a regulated

charge pump that operates from a single 5V

supply. The proprietary on-board charge pump

generates a regulated output of +/-6.5V for RS-

232 compliant voltage levels.

Theory of operation

The SP232A is made up of three basic circuit

blocks: 1. Driver, 2. Receiver, and 3. charge

pump.

Drivers

The drivers are inverting level transmitters that

convert TTL or CMOS logic levels to EIA/TIA-

232 levels with an inverted sense relative to the

input logic levels. Typically, the RS-232 output

voltage swing is +/-6.5V with no load and +/-

5.0V minimum when fully loaded. The driver out-

puts are protected against innite short-circuits

to ground without degradation in reliability.

The drivers can guarantee output data rates of

120Kbps under worst case loading of 3k ohms

and 2500pF.

The driver output Slew Rate is internally limited

to 30V/μs in order to meet the EIA standards

(EIA-232F). Additionally, the driver output LOW

to HIGH transition meet the monotonicity output

requirements of the standard.

Receivers

The receivers convert EIA/TIA-232 signal levels

to TTL or CMOS logic output levels. Since the

input is usually from a transmission line, where

long cable length and system interference can

degrade the signal, the receiver inputs have a

typical hysteresis margin of 500mV. This en-

sures that the receiver is virtually immune to

noisy transmission lines. Should a input be left

unconnected, an internal 5Kohm pull-down re-

sistor to ground will commit the output of the re-

ceiver to a logic HIGH state. The input voltage

range for the SP232A Receiver is +/-15V.

Charge pump

The charge pump is a patented design and

uses a unique approach compared to older less

efcient designs. The charge pump requires 4

external capacitors and uses a four phase volt-

age shifting technique. The internal power sup-

ply consists of a regulated dual charge pump

that provides output voltages of +/-6.5V. This

is important to maintain compliant RS-232 lev-

els regardless of power supply uctuations.

The charge pump operates in a discontinous

mode using an internal oscillator. If the voltages

are less than a magnitude of 6.5V, the charge

pump is enabled. If the output voltage exceed

a magnitude of 6.5V then the charge pump is

disabled. The internal oscillator controls the four

phases of the voltage shifting. A description of

each phase follows:

Phase 1

Vss charge store and double: The positive ter-

minals of capacitors C1 and C2 are charged

from Vcc with their negative terminals initially

connected to ground. C1+ is then connected

to ground and the stored charge from C1- is

superimposed onto C2-. Since C2+ is still con-

nected to Vcc the voltage potential across C2 is

now 2 x Vcc.

Phase 2

Vss transfer and invert: Phase two connects

the negative terminal of C2 to the Vss storage

capacitor and the positive terminal of C2 to

ground. This transfers the doubled and inverted

(V-) voltage onto C4. Meanwhile, capacitor C1

is charged from Vcc in order to prepare it for its

next phase.

Phase 3

Vdd charge store and double: Phase three is

identical to the rst phase. The positive termi-

nals of C1 and C2 are charged from Vcc with

their negative terminals initially connected to

ground. C1+ is then connected to ground and

the stored charge from C1- is superimposed

onto C2-. Since C2+ is still connected to Vcc

the voltage potential across capacitor C2 is now

2 x Vcc.

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)668-7000 • Fax (510)668-7017 • www.exar.com SP232A_100_051308

DESCRiPTion

Phase 4

Vdd transfer. The fourth phase connects the

negative terminal of C2 to ground and the posi-

tive terminal of C2 to the Vdd storage capacitor .

This transfers the doubled (V+) voltage onto C3.

Meanwhile, capacitor C1 is charged from Vcc to

prepare it for its next phase.

Under lightly loaded conditions, the intelligent

pump oscillator maximizes efciency by running

only as needed to maintain V+ and V- voltage

levels. Since interface transceivers spend most

of their time at idle, this power-efcient innova-

tion can greatly reduce total power consump-

tion. This improvement is made possible by

the independent phase sequences of the Exar

charge pump design.

The clock rate of the charge pump typically op-

erates greater than 70kHz allowing the pump to

operate efciently with small 0.1uF capacitors.

Efcient operation depends on rapid charging

and discharging of C1 and C2. Therefore, the

capacitors should be mounted as close as pos-

sible to the IC and have a low ESR (equivalent

series resistance). Inexpensive, surface mount

ceramic capacitors are ideal for use on charge

pump. If polarized capacitors are used the posi-

tive and negative terminals should be connect-

ed as shown on the typical operating circuit. A

diagram of the 4 individual phases is shown in

Figure 1.

+ +

Phases 1 and 3: Store/Double.

Double charge from C 1 onto C2.

C 2 is now charged to -2xVcc

+ +

Phase 2 – Vss transfer from C2 to C4.

Meanwhile C 1 is charged to Vcc

Vss

transfer from C2 to C3.

Meanwhile C1 is charged to Vcc

V-

V+

V-

V+

Patented 5,306,954

Phase 4 VDD

Figure 1. Charge pump phases

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (5

0)668-7000 • Fax (5

0)668-70

7 • www.exar.com SP232A_

00_05

3 0 8

TYP

CAL PERF

RMA

CE CHARACTER

Figure 2, Charge pump waveforms with no

load (

= C

+, 2 = C2+, 3 = V+, 4 = V-).

Figure 3, Charge pump waveforms when

fully loaded with 3k ohms (

= C

+, 2 = C2+,

3 = V+, 4 = V-).

Figure 4, Loopback results at 60kHZ and

2500pF load (

= TXin, 2 = TXout/RXin, 3 =

RXout).

Figure 5, Charge pump outputs at

start up (

= Vcc, 2 = V+, 3 = V-).

Figure 6, Typical Application circuit

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)668-7000 • Fax (510)668-7017 • www.exar.com SP232A_100_051308

Notice

EXAR Corporation reserves the right to make changes to any products contained in this publication in order to improve design, performance or reliabil-

ity. EXAR Corporation assumes no representation that the circuits are free of patent infringement. Charts and schedules contained herein are only for

illustration purposes and may vary depending upon a user's specic application. While the information in this publication has been carefully checked;

no responsibility, however, is assumed for inaccuracies.

EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can

reasonably be expected to cause failure of the life support system or to signicantly affect its safety or effectiveness. Products are not authorized for

use in such applications unless EXAR Corporation receives, in writting, assurances to its satisfaction that: (a) the risk of injury or damage has been

minimized ; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances.

Datasheet May 2008

Send your Interface technical inquiry with technical details to: customersupport@exar.com

Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.

ORDERING INFORMATION

Part number LEAD FREE Tape & Reel Temperature range Package Type

SP232ACN -L /TR From 0 to +700C 16 pin nSOIC

SP232ACT -L /TR From 0 to +700C16 pin WSOIC

SP232ACP -L /TR From 0 to +700C 16 pin PDIP

SP232AEN -L /TR From -40 to +850C 16 pin nSOIC

SP232AET -L /TR From -40 to +850C16 pin WSOIC

SP232AEP -L /TR From -40 to +850C 16 pin PDIP

All packages are available as lead free (RoHS compliant). To order add “-L” sufx to part number.

For Tape and Reel add “/TR”. Reel quantity is 2,500 for NSOIC.

Example: SP232ACN-L/TR = lead free and Tape and Reel. SP232ACN/TR = standard with Tape

and Reel.