XR16L2550 LOW VOLTAGE DUART WITH 16-BYTE FIFO SEPTEMBER 2010 REV. 1.1.3 FEATURES GENERAL DESCRIPTION 2.25 to 5.5 Volt operation 1 The XR16L2550 (L2550) is a dual universal asynchronous receiver and transmitter (UART). The 5 Volt tolerant inputs XR16L2550 is an improved version of the Pin-to-pin compatible to Exars ST16C2450, ST16C2550 UART with lower operating voltages and ST16C2550 and XR16L2750 in 44-PLCC and 48- 5 volt tolerant inputs. The L2550 provides enhanced TQFP packages UART functions with 16 byte FIFOs, a modem control interface and data rates up to 4 Mbps. Onboard Pin-to-pin compatible to XR16C2850 in 44-PLCC status registers provide the user with error indications Pin alike XR16L2551, XR16L2751 and and operational status. System interrupts and modem XR16C2850 in 48-TQFP package control features may be tailored by external software to meet specific user requirements. Independent Two independent UART channels programmable baud rate generators are provided to Up to 3.125Mbps with external clock of 50 MHz select transmit and receive clock rates up to 3.125 Register Set compatible to 16C550 Mbps. The Baud Rate Generator can be configured 16 byte Transmit FIFO to reduce the bandwidth for either crystal or external clock input. An internal requirement of the external CPU loopback capability allows onboard diagnostics. The L2550 is available in a 44-pin PLCC, 48-pin TQFP 16 byte Receive FIFO with error tags to reduce and 32-pin QFN packages. The L2550 is fabricated in the bandwidth requirement of the external CPU an advanced CMOS process. 4 selectable Receive FIFO interrupt trigger NOTE: 1 Covered by U.S. Patent 5,649,122. levels Automatic RTS/CTS hardware flow control APPLICATIONS Automatic Xon/Xoff software flow control Portable Appliances Wireless infrared encoder/decoder Medical Monitors Full Modem Interface (CTS , RTS , DSR , Base Stations DTR , RI , CD ) Programmable character lengths (5, 6, 7, 8) Micro Servers with even, odd, or no parity Telecommunication Network Routers Tiny 32-QFN, no lead package (5x5x0.9mm) Industrial Automation Controls 44-PLCC and 48-TQFP packages also available FIGURE 1. XR16L2550 BLOCK DIAGRAM 2.25 to 5.5 Volt VCC * 5 Volt Tolerant Inputs A2:A0 GND D7:D0 IOR UART Channel A IOW TXA, RXA, DTRA , 16 Byte TX FIFO CSA UART DSRA , RTSA , Regs DTSA , CDA , RIA , CSB TX & RX OP2A 8-bit Data INTA BRG Bus 16 Byte RX FIFO INTB Interface TXRDYA TXB, RXB, DTRB , TXRDYB UART Channel B DSRB , RTSB , RXRDYA (same as Channel A) CTSB , CDB , RIB , RDRXYB OP2B Reset XTAL1 Crystal Osc/Buffer XTAL2 Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com XR16L2550 LOW VOLTAGE DUART WITH 16-BYTE FIFO REV. 1.1.3 FIGURE 2. PIN OUT ASSIGNMENT D5 1 36 RESET 2 35 DTRB D6 D7 3 34 DTRA RTSA RXB 4 33 RXA 5 32 OP2A XR16L2550 6 31 RXRDYA TXRDYB 48-pin TQFP TXA 7 30 INTA INTB TXB 8 29 OP2B 9 28 A0 A1 CSA 10 27 CSB 11 26 A2 NC NC 12 25 1 24 RESET D6 2 23 RTSA D7 INTA 3 22 RXB XR16L2550 4 21 INTB RXA 32-pin QFN A0 5 20 TXA 6 19 A1 TXB A2 7 18 CSA CSB 8 17 NC D5 7 39 RESET D6 8 38 DTRB D7 9 37 DTRA RXB 10 36 RTSA 11 35 OP2A RXA XR16L2550 TXRDYB 12 34 RXRDYA 44-pin PLCC TXA 13 33 INTA TXB 14 32 INTB OP2B 15 31 A0 16 A1 CSA 30 CSB 17 29 A2 ORDERING INFORMATION PART NUMBER PACKAGE OPERATING TEMPERATURE RANGE DEVICE STATUS XR16L2550IL 32-Lead QFN -40C to +85C Active XR16L2550IJ 44-Lead PLCC -40C to +85C Active XR16L2550IM 48-Lead TQFP -40C to +85C Active 2 XTAL1 13 48 D4 18 6 XTAL1 D4 XTAL2 14 47 D3 XTAL2 19 5 D3 IOW 15 46 D2 IOW 20 4 D2 CDB 16 45 D1 CDB 21 3 D1 GND 17 44 D0 GND 22 2 D0 RXRDYB 18 43 TXRDYA 23 RXRDYB 1 TXRDYA IOR 19 42 VCC IOR 24 44 VCC DSRB 41 20 RIA 25 DSRB 43 RIA RIB 21 40 CDA RTSB RIB 26 42 CDA 22 39 DSRA CTSB 38 RTSB 27 41 DSRA 23 CTSA NC 24 37 NC CTSB 28 40 CTSA 32 NC 9 D5 XTAL1 31 D4 10 XTAL2 11 30 D3 IOW 12 29 D2 28 GND 13 D1 IOR 14 27 D0 RTSB 15 26 VCC CTSA CTSB 16 25