 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SP3249 Datasheet(PDF) 6 Page - Sipex Corporation |
|
||||||||||||||||||||||||||||||
SP3249 Datasheet(HTML) 6 Page - Sipex Corporation |
|
|
6 / 14 page  Rev.4/08/02 SP3249E Intelligent +3.0V to +5.5V RS-232 Transceivers © Copyright 2002 Sipex Corporation 6 DESCRIPTION The SP3249E device meets the EIA/TIA-232 and ITU-T V.28/V.24 communication protocols and can be implemented in battery-powered, por- table, or hand-held applications such as notebook or palmtop computers. The SP3249E device features 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 SP3249E device can operate at a data rate of 250kbps fully loaded. The SP3249E is a 5-driver/3-receiver device, ideal for portable or hand-held applications. The SP3249E device is an ideal choice for power sensitive designs. THEORY OF OPERATION The SP3249E device is made up of three basic circuit blocks: 1. Drivers, 2. Receivers, and 3. the Sipex proprietary charge pump. 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-232F and all previous RS-232 versions. Unused driver inputs should be connected to GND or V CC. The drivers can guarantee a data rate of 250kbps fully loaded with 3k Ω in parallel with 1000pF, ensuring compatibility with PC-to-PC commu- nication 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 7 shows a loopback test circuit used to test the RS-232 Drivers. Figure 8 shows the test results of the loopback circuit with all five driv- ers active at 120kbps with typical RS-232 loads in parallel with 1000pF capacitors. Figure 6 shows the test results where one driver was active at 250kbps and all five drivers loaded with an RS- 232 receiver in parallel with a 1000pF capacitor. A solid RS-232 data transmission rate of 120kbps provides compatibility with many designs in personal computer peripherals and LAN appli- cations. Receivers The receivers convert ±5.0V EIA/TIA-232 levels to TTL or CMOS logic output levels. Since receiver input is usually from a transmission line where long cable lengths and system interference can degrade the signal, the inputs have a typical hysteresis margin of 500mV. This ensures that the receiver is virtually immune to noisy transmission lines. Should an input be left unconnected, an internal 5k Ω pulldown resistor to ground will commit the output of the receiver to a HIGH state. Figure 6. Interface Circuitry Controlled by Microprocessor Supervisory Circuit SP3249E 3 1 4 GND C1+ C1- C2+ C2- V+ V- VCC 0.1 µF 0.1 µF 0.1 µF + C2 C5 C1 + + C3 C4 + + 0.1 µF 0.1 µF VCC 2 5k Ω 5k Ω 5k Ω 24 23 22 21 20 18 5 6 7 8 9 11 RS-232 OUTPUTS RS-232 INPUTS T 1IN R 1OUT R 1IN T 2OUT T 2IN T 3IN T 3OUT T 1OUT R 2IN R 3IN R 2OUT R 3OUT UART or Serial µC TxD RTS DTR RxD CTS DSR DCD RI 19 17 10 12 T 4OUT T 4IN T 5IN T 5OUT 13 15 14 16 |
Similar Part No. - SP3249 |
|
Similar Description - SP3249 |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
