Electronic Components Datasheet Search |
|
SP3244EEY-L Datasheet(PDF) 10 Page - Sipex Corporation |
|
SP3244EEY-L Datasheet(HTML) 10 Page - Sipex Corporation |
10 / 22 page Rev M 10/9/06 SP3244E-SP3245E, 3.0V to 5.5V RS-232 Transceivers with Auto On-Line® Plus © Copyright 2006 Sipex Corporation 10 DESCRIPTION The SP3244E and SP3245E are 3-driver/5-re- ceiver devices ideal for serial ports in battery- powered, portable, or handheld applications such as notebook or handheld computers. SP3244E/3245E transceivers meet the EIA/ TIA-232 and ITU-T V.28/V.24 communication protocols for reliable serial communication. The SP3244E/3245E devices feature 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 SP3244E/3245E is an ideal choice for power sensitive designs. With the Auto On-line® Plus enabled the SP3244E/3245E reduces power consumption to a 1µA supply current whenever the transceivers are idle. In shutdown, the internal charge pump and the drivers will shut down. Receivers remain active unless the device is put into manual shutdown using the SHUTDOWN pin. This feature allows design engineers to address power saving concerns without major design changes. Theory Of Operation The SP3244E/3245E is made up of four basic circuit blocks: 1. Drivers, 2. Receivers, 3. the Sipex propri- etary charge pump, and 4. Auto On-line® Plus circuitry. 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-232-F and all previous RS-232 versions. Unused driver inputs should be connected to GND or VCC. The SP3244E/3245E devices operate at this typical data rate when fully loaded. The drivers can guarantee output data rates fully loaded with 3KΩ in parallel with 1000pF (SP3244E), or 250pF (SP3245E) ensuring compatibility with popular PC-to-PC communication software. The slew rate of the driver output on the SP3244E 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 slew rate of SP3245E is not limited to enable higher speed data transfers. The transition of the loaded output from HIGH to LOW also meets the monotonic signal transition requirements of the standard. Receivers The receivers convert EIA/TIA-232 signal levels to TTL or CMOS logic output levels. Re- ceivers remain active unless the device is put into manual shutdown using the SHUTDOWN pin. The non-inverted output of Receiver 2 (R2OUT) will continue to be active in all modes, including shutdown. Since receiver input is usually from a transmis- sion 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 im- mune to noisy transmission lines. Should an input be left unconnected, an internal 5KΩ pull- down resistor to ground will commit the output of the receiver to a HIGH state. Highly Efficient Charge Pump The charge pump is used to generate positive and negative signal voltages for the RS-232 drivers. This enables fully compliant RS-232 and V.28 signals from a single 3.0 or 5.5V power supply. The charge pumps use four external capaci- tors to hold and transfer electrical charge. The Sipex patented design (US Patent #5,306,954) uses a unique approach compared to older less efficient designs. The pumps use a four–phase voltage shifting technique to attain symmetrical V+ and V- power supplies. An intelligent control oscillator regulates the operation of the charge pump to maintain the proper voltages at maxi- mum efficiency. Phase 1 VSS charge store and double. The positive terminals of capacitors C1 and C2 are charged from VCC with their negative terminals initially connected to ground. C1+ is then connected to ground and the stored charge from C1– is superimposed onto C2– . Since C2+ is still connected to VCC the voltage potential across capacitor C2 is now 2 x VCC. |
Similar Part No. - SP3244EEY-L |
|
Similar Description - SP3244EEY-L |
|
|
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 |