EXAR Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com • uarttechsupport@exar.com

DATA COMMUNICATIONS APPLICATION NOTE

DAN124

June 2002

EXAR’S XR88C92/192 COMPARED WITH PHILIPS’S SC26C92

Author: PY

1.0

INTRODUCTION

This application note describes the major difference between Exar’s XR88C92/192 with Philips’s SC26C92.

These devices are very similar, with a few hardware, firmware-related and bus timing differences.

1.1

• The Philips SC26C92 and Exar XR88C92/192 are both available in three footprints: 44-pin PLCC, 44-pin

QFP and 40-pin DIP. The Exar and Philips DUARTs are pin-to-pin compatible in all three footprints.

• The Exar’s 44-pin TQFP package is the same size and has the same pitch as the Philips’ 44-pin QFP pack-

age. But they differ in the package thickness and the lead length. See the list below:

Exar

Philips

Thickness:

1.4mm

1.75mm

Lead Length, Lp:

0.45mm < Lp < 0.75mm

0.55mm < Lp < 0.95mm

1.2

All the internal registers in the SC26C92 and XR88C92/192 are identical with only one exception:

• Since the XR88C192 has a 16-byte FIFO as compared to a 8-byte FIFO in the SC26C92, the selectable

transmit and receive trigger levels are different.

1.3

• The XR88C92/192 is faster than the SC26C92. For example, the data access time (from -CS low to data

valid) during a read is a maximum of 32 ns for the XR88C92/192, whereas it is a maximum of 55 ns for the

SC26C92.