XR19L402 TWO CHANNEL INTEGRATED UART AND RS-485 TRANSCEIVER JULY 2009 REV. 1.0.3 APPLICATIONS GENERAL DESCRIPTION Battery-Powered Equipment The XR19L402 (L402) is a highly integrated device that combines a full-featured two channel Universal Handheld and Mobile Devices Asynchronous Receiver and Transmitter (UART) and RS- Handheld Terminals 485 transceivers. The L402 is designed to operate with a Industrial Peripheral Interfaces single 3.3V or 5V power supply. The L402 is fully compliant with RS-485 Standards. Point-of-Sale (POS) Systems The L402 operates in four different modes: Active, Partial FEATURES Sleep, Full Sleep and Power-Save. Each mode can be invoked via hardware or software. Upon power-up, the Meets true RS-485 Standards at 3.3V or 5V operation L402 is in the Active mode where the UART and RS-485 transceiver function normally. In the Partial Sleep mode, the Up to 8 Mbps data transmission rate internal crystal oscillator of the UART or charge pump of the 45us sleep mode exit (charge pump to full power) RS-485 transceiver is turned off. In Full Sleep mode, both ESD protection for RS-485 I/O pins at the crystal oscillator and the charge pump are turned off. +/-15kV - Human Body Model While the UART is in the Sleep mode, the Power-Save +/- 8kV - IEC 61000-4-2, Contact Discharge mode isolates the core logic from the control signals (chip select, read/write strobes, address and data bus lines) to +/- 15kV - IEC 61000-4-2, Air-Gap Discharge minimize the power consumption. The RS-485 receivers Software compatible with industry standard 16550 UART remain active in any of these four modes. Intel/Motorola bus select Complete modem interface Sleep and Power-save modes to conserve battery power Wake-up interrupt upon exiting low power modes FIGURE 1. BLOCK DIAGRAM *5 V Tolerant Inputs Crystal PwrSave Charge Pump BRG Osc/Buffer A2:A0 D7:D0 64 Byte TXA+ IOR TXA TX FIFO TXA- IOW (R/W ) RXA+ 64 Byte CSA (CS ) RXA RX FIFO RXA- CSB VCC33 INTA (IRQ ) CTSA INTB Modem DSRA RS-485 Transceiver RESET (RESET ) I/Os RIA I/M CDA TEST EN Channel A TXB+ TXB HALF/FULLA TXB- Channel B HALF/FULLB RXB+ ( Similar to RXB ChannelA ) RXB- TXB UART RXB RXBSEL XR19L402 Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com Intel or Motorola Bus Interface UART Registers XTAL1 XTAL2 GND VCC33 R EN VCC50 ACP C1+ C1-XR19L402 TWO CHANNEL INTEGRATED UART AND RS-485 TRANSCEIVER REV. 1.0.3 FIGURE 2. PIN OUT OF THE DEVICE A0 1 36 TXA- D0 2 35 NC D1 3 34 RXA+ D2 4 33 RXA- XR19L402 D3 5 32 NC D4 6 31 C1+ 48- pin QFN D5 7 30 C1- Intel Bus Mode D6 8 29 NC D7 9 28 RXB- CSA 10 27 RXB+ CSB 11 26 NC 12 PWRSAVE 25 TXB- VCC 36 TXA- A0 1 D0 2 35 NC D1 3 34 RXA+ D2 4 33 RXA- XR19L402 D3 5 32 NC D4 6 31 48- pin QFN C1+ D5 7 30 C1- Motorola Bus Mode D6 29 8 NC D7 9 28 RXB- CS 10 27 RXB+ A3 26 NC 11 12 PWRSAVE 25 TXB- GND ORDERING INFORMATION PART NUMBER PACKAGE OPERATING TEMPERATURE RANGE DEVICE STATUS XR19L402IL48 48-pin QFN -40C to +85C Active 2 A1 48 13 XTAL1 A2 47 XTAL2 14 46 INTA IOW 15 45 INTB 16 IOR RXBSEL 44 TXB 17 43 RXB I/M 18 TEST EN 42 RESET 19 20 41 HALF/FULLA ACP R EN 40 HALF/FULLB 21 VDD50 22 39 VDD33 TXB+ 23 38 TXA+ GND 37 GND 24 48 A1 XTAL1 13 A2 47 XTAL2 14 46 IRQ 15 R/W 45 NC NC 16 RXBSEL 44 17 TXB 43 RXB I/M 18 TEST EN 42 19 RESET 41 HALF/FULLA 20 ACP R EN 40 HALF/FULLB 21 22 VCC50 VCC33 39 TXB+ 23 38 TXA+ GND GND 24 37