15

Rev: B Date:7/7/04

SP526 Multi–Mode Serial Transceiver

© Copyright 2004 Sipex Corporation

THEORY OF OPERATION

The SP526 device is made up of 1) the drivers,

2) the receivers, and 3) a charge pump.

Drivers

The SP526 has four enhanced independent

drivers. Control for the mode selection is done

via a two–bit control word into DP0 and DP1.

The drivers are prearranged such that for each

mode of operation, the relative position and

functionality of the drivers are set up to

accommodate the selected interface mode. As

the mode of the drivers is changed, the electrical

characteristics will change to support the

required signal levels. The mode of each driver

in the different interface modes that can be

selected is shown in Table 1.

There are four basic types of driver circuits —

RS-232 (V.28), RS-423 (V.10), RS-422 (V.11),

and RS-485.

The RS-232 (V.28) drivers output single–ended

signals with a minimum of

±5V (with 3KΩ &

2500pF loading), and can operate to at least

120Kbps. Since the SP526 uses a charge pump

to generate the RS-232 output rails, the driver

outputs will never exceed

±10V.

The RS-423 (V.10) drivers are also single–

ended signals which produce open circuit V

OL

and V

When terminated with a 450

Ω load to ground,

the driver output will not deviate more than 10%

of the open circuit value. This is in compliance

FEATURES

The SP526 contains highly integrated serial

transceivers that offer programmability between

interface modes through software control. The

SP526 offers the hardware interface modes for

RS-232 (V.28), RS-423 (V.10), RS-422 (V.11),

and RS-485. The interface mode selection is

done via two control pins.

The SP526 has four drivers, four receivers, and

an on-board charge pump that is ideally suited

for low-cost wide area network connectivity

and other multi-protocol applications. Based on

our multi-mode SP500 family, Sipex has

allocated specific transceiver cells, or "building

blocks," from this product series and created the

SP526.

Sipex's "building blocks" concept

allows these small transceiver cells to be

packaged to offer a simple low-cost solution to

networking applications that need only 4

interface modes. For example, an 8-channel

applications requiring eight serial transceivers

can be achieved implementing two SP526

devices. The SP526 can be implemented in

series with other devices in our SP500 family.

A 9-channel network application can be achieved

implementing the SP505 which contains seven

transceivers in conjunction with the SP526.

1

D0

D

S

R

E

V

I

R

DS

R

E

V

I

E

C

E

R

1

T2

T3

T4

T1

R2

R3

R4

R

00

e

d

o

M

e

t

a

t

S

-

i

r

T

n

i

s

t

u

p

t

u

O

x

R

d

n

a

x

T

-

N

W

O

D

T

U

H

S

01

1

1

.

V1

1

.

V1

1

.

V0

1

.

V1

1

.

V1

1

.

V1

1

.

V1

1

.

V

10

1

1

.

V1

1

.

V0

1

.

V0

1

.

V1

1

.

V1

1

.

V1

1

.

V1

1

.

V

11

8

2

.

V8

2

.

V8

2

.

V8

2

.

V8

2

.

V8

2

.

V8

2

.

V8

2

.

V

Table 1. SP526 Driver and Receiver Mode Selection with the Control Lines D1 and D0