SP3223EH 데이터 시트보기 (PDF) - Signal Processing Technologies

부품명

상세내역

제조사

SP3223EH

High Speed Intelligent +3.0V to +5.5V RS-232 Transceivers

Signal Processing Technologies 

DESCRIPTION

The SP3223EH and SP3243EH transceivers

meet the EIA/TIA-232 and ITU-T V.28/V.24

communication protocols and can be

implemented in battery-powered, portable, or

hand-held applications such as notebook or

palmtop computers. The SP3223EH and

SP3243EH devices feature Sipex's proprietary

and patented (U.S.-- 5,306,954) on-board charge

pump circuitry that generates +5.5V RS-232

voltage levels from a single +3.0V to +5.5V

power supply. The SP3223EH and SP3243EH

devices can operate at a data rate of 460Kbps

fully loaded.

The SP3223EH is a 2-driver/2-receiver device,

and the SP3243EH is a 3-driver/5-receiver device,

ideal for portable or hand-held applications. The

SP3243EH includes one complementary

always-active receiver that can monitor an

external device (such as a modem) in shutdown.

This aids in protecting the UART or serial

controller IC by preventing forward biasing

of the protection diodes where V may be

CC

disconnected.

VCC

UART

or

Serial µC

+

C5 0.1µF

28 C1+

+

C1 0.1µF

24 C1-

+

C2 0.1µF

1 C2+

2 C2-

TxD

14 T1IN

RTS

13 T2IN

DTR

12 T3IN

26

VCC

V+ 27

SP3243EH V- 3

T1OUT 9

T2OUT 10

T3OUT 11

+

C3 0.1µF

C4 0.1µF

+

RS-232

OUTPUTS

RxD

CTS

DSR

DCD

RI

VCC

20 R2OUT

19 R1OUT

18 R2OUT

17 R3OUT

16 R4OUT

R1IN 4

5KΩ

R2IN 5

5KΩ

R3IN 6

5KΩ

R4IN 7

15 R5OUT

22

SHUTDOWN

23 ONLINE

5KΩ

R5IN 8

5KΩ

21 STATUS

GND

25

RS-232

INPUTS

RESET

µP

Supervisor

VIN

IC

The SP3223EH and SP3243EH series is an

ideal choice for power sensitive designs. The

SP3223EH and SP3243EH devices feature

Auto-Online circuitry which reduces the power

supply drain to a 1µA supply current. In many

portable or hand-held applications, an RS-232

cable can be disconnected or a connected periph-

eral can be turned off. Under these conditions,

the internal charge pump and the drivers will be

shut down. Otherwise, the system automatically

comes online. This feature allows design

engineers to address power saving concerns

without major design changes.

THEORY OF OPERATION

The SP3223EH and SP3243EH series is made

up of four basic circuit blocks: 1. Drivers,

2. Receivers, 3. the Sipex proprietary charge

pump, and 4. Auto-Online circuitry.

Drivers

The drivers are inverting level transmitters that

convert TTL or CMOS logic levels to 5.0V EIA/

TIA-232 levels with an inverted sense relative to

the input logic levels. Typically, the RS-232

output voltage swing is +5.4V with no load and

+5V minimum fully loaded. The driver outputs

are protected against infinite short-circuits to

ground without degradation in reliability. These

drivers comply with the EIA-TIA-232-F and all

previous RS-232 versions.

The drivers can guarantee a data rate over

460Kbps fully loaded with 3KΩ in parallel with

1000pF, ensuring compatibility with PC-to-PC

communication software.

The slew rate of the driver output is internally

limited to a maximum of 30V/µs in order to

meet the EIA standards (EIA RS-232D 2.1.7,

Paragraph 5). The transition of the loaded

output from HIGH to LOW also meets the

monotonicity requirements of the standard.

Figure 11. Interface Circuitry Controlled by Micropro-

cessor Supervisory Circuit

SP3223EHDS/11

SP3223EH +3.0V to +5.5V RS-232 Transceivers

10

© Copyright 2000 Sipex Corporation

Share Link: