Programmable Dual RS-232/RS-485 Transceiver

Transcription

1 SP331 Programmable Dual RS-3/ Transceiver Only Operation Software Programmable RS-3 or Selection Four RS-3 Transceivers in RS-3 Mode Two Full-Duplex Transceivers in Mode Two RS-3 Transceivers and One Transceiver in Dual Mode Self-Testing Loopback Mode Full Driver Tri-State (Hi-Z) Control Ideal for RS-3 to conversion TI4 SEL_B TX4 TX3 VCC TX1 TX GND C1 V (VDD) C C1 C V (VSS) SP TI3 TI TI1 SEL_C SEL_A SEL_D RX4 RX3 RX RX1 RI4 RI3 RI RI1 DESCRIPTION The SP331 is a programmable RS-3 and/or transceiver IC. The SP331 contains four drivers and four receivers when selected in RS-3 mode; and two drivers and two receivers when selected in mode. The SP331 also contains a dual mode which has two RS-3 drivers/receivers plus one differential driver/receiver. The RS-3 transceivers can typically operate at 30kbps while adhering to the RS-3 specifications. The transceivers can operate up to 10Mbps while adhering to the specifications. The SP331 includes a self-test loopback mode where the driver outputs are internally configured to the receiver inputs. This allows for easy diagnostic serial port testing without using an external loopback plug. The RS-3 and drivers can be disabled (High-Z output) by controlling a set of four select pins. TYPICAL APPLICATIONS CIRCUIT C1 C1- C C- SEL A SEL B Vcc TI1 TI Vcc TI3 TI4 RX1 RX RX3 RX4 5 VCC 10 V 14 V- SP331 3 SEL D TX 7 TX1 6 RI 16 5 GND SEL C Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

2 ABSOLUTE MAXIMUM RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. V CC...7V Input Voltages Logic V to (Vcc0.5V) Drivers V to (Vcc0.5V) 100mA Driver Outputs.../-15V Maximum Data Rate...8Mbps (Note 1) Storage Temperature C to 150 C Power Dissipation 8-pin WSOIC mW Package Derating: 8-pin WSOIC ø JA...40 C/W SPECIFICATIONS Limits are specified at T A = 5 C and V CC = 5. unless otherwise noted. PARAMETER MIN. TYP. MAX. UNITS CONDITIONS Logic Inputs V IL 0.8 Volts V IH.0 Volts LOGIC OUTPUTS V OL 0.4 Volts I OUT = -3.mA V OH.4 Volts I OUT = 1.0mA RS-3 DRIVER DC Characteristics HIGH Level Output Volts R L = 3kΩ, V IN = 0.8V LOW Level Output Volts R L = 3kΩ, V IN =. Open Circuit Voltage Volts Short Circuit Current /-100 ma V OUT = Power Off Impedance 300 Ω V CC =, V OUT = /-. AC Characteristics Slew Rate 30 V/µs R L = 3kΩ, C L = 50pF; V CC = 5., T 5 C Transistion Time 1.5 µs R L = 3kΩ, C L = 500pF; between /-3V, T 5 C Maximum Data Rate kbps R L = 3kΩ, C L = 500pF Propagation Delay t PHL 8 µs Measured from 1.5V of V IN to 50% Propagation Delay t PLH 8 µs of V OUT ; R L = 3kΩ RS-3 RECEIVER DC Characteristics HIGH Threshold Volts LOW Threshold Volts Receiver Open Circuit Bias.0 Volts Input Impedance kω V IN = 15V to -15V Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

3 SPECIFICATIONS Limits are specified at T A = 5 C and V CC = 5. unless otherwise noted. PARAMETER MIN. TYP. MAX. UNITS CONDITIONS RS-3 RECEIVER (continued) AC Characteristics Maximum Data Rate kbps Propagation Delay t PHL µs Measured from 50% of V IN to 1.5V Propagation Delay t PLH µs of V OUT DRIVER DC Characteristics Open Circuit Voltage 6.0 Volts Differential Output Volts R L = 54Ω, C L = 50pF Balance /-0. Volts V T - V T Common-Mode Output 3.0 Volts Output Current 8.0 ma R L = 54Ω Short Circuit Current /-50 ma Terminated in -7V to 1 AC Characteristics Maximum Data Rate 10 Mbps R L = 54Ω Maximum Data Rate 8 Mbps T A = 85 C, Note 1 Output Transition Time ns Rise/Fall time, 10%-90% Propagation Delay t PHL ns See Figures & 4, R DIFF = 54Ω, Propagation Delay t PLH ns C L1 = C L = 100pF Driver Output Skew 10 0 ns Per Figure 4, t SKEW = t PHL - t PLH RECEIVER DC Characteristics Common Mode Range Volts Receiver Sensitivity /-0. /-0.3 Volts -7V V CM 1V Input Impedance 1 15 kω -7V V CM 1V AC Characteristics Maximum Data Rate 10 Mbps Maximum Data Rate 8 Mbps T A = 85 C, Note 1 Propagation Delay t PHL ns See Figures & 6, R DIFF = 54Ω, Propagation Delay t PLH ns C L1 = C L = 100pF Differential Receiver Skew 10 0 ns t SKEW = t PHL - t PLH, R DIFF = 54Ω, C L1 = C L = 100pF ENABLE TIMING DRIVER Enable Time (see Figures 3 and 5) Enable to LOW ns C L = 15pF, S 1 Closed Enable to HIGH ns C L = 15pF, S Closed Disable Time (see Figures 3 and 5) Disable from LOW ns C L = 15pF, S 1 Closed Disable from HIGH ns C L = 15pF, S Closed Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

4 SPECIFICATIONS Limits are specified at T A = 5 C and V CC = 5. unless otherwise noted. PARAMETER MIN. TYP. MAX. UNITS CONDITIONS POWER REQUIREMENTS Supply Voltage V CC Volts Supply Current I CC No Load (T X Disabled) ma SEL_A SEL_D = "0001" No Load (RS-3 Mode) ma SEL_A SEL_D = "0000" No Load ( Mode) 7 0 ma SEL_A SEL_D = "1100" ENVIRONMENTAL Operating Temperature Commercial (_C_) 0 70 ºC Industrial (_E_) ºC Storage Temperature ºC Note 1: Exceeding the maximum data rate of 8Mbps at T A = 85 C may permanently damage the device RECEIVER INPUT GRAPH RECEIVER 1.0mA -7V -3V 6V 1V -0.6mA 1 Unit Load Maximum Input Current Versus Voltage Test Circuits A V OD R DI A B R L C L1 A B RO R V OC C L 15pF B Figure 1. Driver DC Test Load Circuit Figure. Driver/Receiver Timing Test Circuit Output Under Test C L 500Ω S 1 V CC S Figure 3. Driver Timing Test Load # Circuit Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

5 SWITCHING WAVEFORMS DRIVER INPUT DRIVER OUTPUT DIFFERENTIAL OUTPUT V A V B 3V B A V O V O V O 1/V O f 1MHz; t R 10ns; t F 10ns 1.5V 1.5V t PLH t PHL t DPLH t DPHL t R t F 1/V O t SKEW = t DPLH - t DPHL Figure 4. Driver Propagation Delays 3V DE 5V A, B.3V V OL f = 1MHz; t R < 10ns; t F < 10ns 1.5V 1.5V t ZL t LZ Output normally LOW 0.5V A, B V OH.3V t ZH Output normally HIGH 0.5V t HZ Figure 5. Driver Enable and Disable Times f = 1MHz; t R 10ns; t V F 10ns OD A B V INPUT OD V OH RECEIVER OUT 1.5V OUTPUT 1.5V V OL t PHL t PLH Figure 6. Receiver Propagation Delays Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

6 TTL Input TTL INPUT Driver Output A Driver Output B DRIVER OUTPUT Differential Output VA - VB Figure 7. Typical RS-3 Driver Output Figure 8. Typical Driver Output TI4 SEL_B TX4 TX3 VCC TX1 TX GND C1 V (VDD) C C1 C V (VSS) Figure 9. SP331 Pinout SP TI3 TI TI1 SEL_C SEL_A SEL_D RX4 RX3 RX RX1 RI4 RI3 RI RI1 Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

7 9 C1 1 C1-11 C 13 C- 4 SEL A SEL B Vcc 1 C1-11 C 13 C- 4 SEL A SEL B Vcc 6 TI1 7 TI 8 TI3 VCC T V 10 V- 14 TX1 6 TX 7 1 TI4 T4 0 RX 1 RX3 5 SP331 Vcc Vcc Vcc R 3 SEL D 5KΩ 5KΩ 5KΩ RI 16 RS-3 RS-3 RS-3 RS-3 RS-3 RS-3 RS-3 9 C1 6 TI1 7 TI 8 TI3 1 TI4 0 RX 1 RX3 RX4 8 GND Vcc 5 VCC SP V V SEL D TX 7 TX1 6 RI 16 5 SEL C RX4 R4 5KΩ RS-3 8 GND SEL C 5 Figure 10. Typical Operating Circuit Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

8 Function Table for Select Pins A B C D MODE FUNCTION RS-3 All four RS-3 drivers active RS-3 All four RS-3 drivers tri-state RS-3 All four RS-3 drivers tri-state RS-3 RS-3 (4ch) Loopback RS-3/ and T active RS-3; tri-state RS-3/ and T tri-state RS-3; active RS-3/ and T active RS-3; tri-state RS-3/ RS-3 (ch) / (1ch) Loopback /RS-3 active ; and T4 active RS /RS-3 tr-state ; active RS-3; T4 active RS /RS-3 All and RS-3 drivers tri-state /RS-3 (1ch) / RS-3 (ch) Loopback and active tri-state ; active active ; tri-state (ch) Loopback Table 1. Mode Function Table. (Refer to Control Logic Confirmations for Block Diagrams) Theory of Operation The SP331 is made up of four separate circuit blocks the charge pump, drivers, receivers, and decoder. Each of these circuit blocks is described in more detail below. ChargePump The charge pump is a Exarpatented design (U.S. 5,306,954) and uses a unique approach compared to older less efficient designs. The charge pump still requires four external capacitors, but uses a fourphase voltage shifting technique to attain symmetrical 1 power supplies. Figure 15(a) shows the waveform found on the positive side of capcitor C, and Figure 15(b) shows the negative side of capcitor C. There is a freerunning oscillator that controls the four phases of the voltage shifting. A description of each phase follows. Phase 1 V SS charge storage During this phase of the clock cycle, the positive side of capacitors C 1 and C are initially charged to. C l is then switched to ground and charge transferred to C. Since C is connected to, the voltage potential across capacitor C is now 1. Phase V SS transfer Phase two of the clock connects the negative terminal of C to the V SS storage capacitor and the positive terminal of C to ground, and transfers the generated l to C 3. Simultaneously, the positive side of capacitor C 1 is switched to and the negative side is connected to ground. Phase 3 V DD charge storage The third phase of the clock is identical to the first phase the charge transferred in C 1 produces 5V in the negative terminal of C 1, which is applied to the negative side of capacitor C. Since C is at, the voltage potential across C is l. Phase 4 V DD transfer The fourth phase of the clock connects the negative terminal of C Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

9 V CC = C 1 C 5V 5V V CC = 1 C 4 Figure 11. Charge Pump Phase 1. C 1 C C 3 C 4 Figure 1. Charge Pump Phase. V CC = C 1 C 5V 5V C 3 C 4 Figure 13. Charge Pump Phase 3. V CC = C 1 C 1 C 3 C 4 V DD Storage Capacitor V SS Storage Capacitor V DD Storage Capacitor V SS Storage Capacitor V DD Storage Capacitor V SS Storage Capacitor V DD Storage Capacitor V SS Storage Capacitor to ground and transfers the generated l across C to C 4, the V DD storage capacitor. Again, simultaneously with this, the positive side of capacitor C 1 is switched to and the negative side is connected to ground, and the cycle begins again. Since both V and V are separately generated from V CC in a noload condition, V and V will be symmetrical. Older charge pump approaches that generate V from V will show a decrease in the magnitude of V compared to V due to the inherent inefficiencies in the design. The clock rate for the charge pump typically operates at 15kHz. The external capacitors must be with a 16V breakdown rating. External Power Supplies For applications that do not require only, external supplies can be applied at the V and V pins. The value of the external supply voltages must be no greater than ±l. The current drain for the ±1 supplies is used for RS-3. For the RS-3 driver the current requirement will be 3.5mA per driver. The external power supplies should provide a power supply sequence of :l, then, followed by l. C 3 Figure 14. Charge Pump Phase 4. 1 a) C GND GND b) C- -1 Figure 15. Charge Pump Waveforms Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

10 Drivers The SP331 has four independent RS-3 single-ended drivers and two differential drivers. Control for the mode selection is done via a fourbit control word. The drivers are pre-arranged such that for each mode of operation the relative position and functionality of the drivers are set up to accommodate the selected interface mode. As the mode of the drivers is changed, the electrical characteristics will change to support the requirements of clock, data, and control line signal levels. Unused driver inputs can be left floating; however, to ensure a desired state with no input signal, pullup resistors to or pulldown resistors to ground are suggested. Since the driver inputs are both TTL or CMOS compatible, any value resistor less than 100kΩ will suffice. When in RS-3 mode, the single-ended RS-3 drivers produce compliant RS-3E and ITU V.8 signals. Each of the four drivers output single-ended bipolar signals in access of ±5V with a full load of 3kΩ and 500pF applied as specified. These drivers can also operate at least 10kbps. When programmed to mode, the differential drivers produce complaint signals. Each driver outputs a unipolar signal on each output pin with a magnitude of at least 1.5V while loaded with a worst case of 54Ω between the driver's two output pins. The signal levels and drive capability of the drivers allow the drivers to also comply with RS-4 levels. The transmission rate for the differential drivers is 10Mbps. output, a pullup resistor of 100kΩ to should be connected to the inverting input for a logic low, or the noninverting input for a logic high. For single-ended receivers, a pulldown resistor to ground of 5kΩ is internally connected, which will ensure a logic high output. The RS-3 receiver has a singleended input with a threshold of 0.8V to.4v. The RS-3 receiver has an operating voltage range of ±15V and can receive signals up to 10kbps. RS-3 receivers are used in RS-3 mode for all signal types include data, clock, and control lines of the RS-3 serial port. The differential receiver has an input impedance of 15kΩ and a differential threshold of ±00mV. Since the characteristics of an RS-4 receiver are actually subsets of, the receivers for RS-4 requirements are identical to the receivers. All of the differential receivers can receive data up to 10Mbps. Select Mode Pins Similar to our SP500 family of multiprotocol products, the SP331 has the ability to change the configuration of the drivers and receivers via a 4bit switch. Referring to Table 1; RS-3 mode, mode, or two different combinations of RS-3/ can be configured using the SEL_A and SEL_B pins. The drivers can be put into tri-state mode by using the SEL_C and SEL_D pins. All receivers remain active during any tri-state condition of the drivers. Receivers The SP331 has four single-ended receivers when programmed for RS-3 mode and two differential receivers when programmed for mode. Control for the mode selection is done via a 4bit control word, as in the drivers. As the operating mode of the receivers is changed, the electrical characteristics will change to support the requirements of the appropriate serial standard. Unused receiver inputs can be left floating without causing oscillation. To ensure a desired state of the receiver Exar Corporation 4870 Kato Road, Fremont CA, Loopback Mode Loopback is invoked by asserting "xx11" into the select pins. In RS-3/ or /RS-3 loopback mode, the RS-3 driver outputs loop back into the RS-3 receiver inputs and the differential driver loops back into the receiver. During loopback, the driver outputs and receiver inputs are disconnected from the outside world. The driver outputs are in tristate and the receiver inputs are disabled. The input impedance of the receivers during loopback is approximately 15kΩ to ground. SP331_100_01610

11 SP331 CONTROL LOGIC CONFIGURATION (Refer to Table 1) SEL A SEL B SEL C SEL D TI1 7 TI T TX1 TX TI1 7 TI T TX1 TX TI1 TX1 6 TX 7 6 TI1 TX1 6 TX TI3 TI4 T4 8 TI3 TX3 TX TI3 1 TI4 T4 8 TI3 0 RX RI 16 R 1 RX3 RX4 R4 0 RX RI 16 R 1 RX3 RI 16 1 RX3 RX4 R4 1 RX3 RI 16 SP331 LOOPBACK (Refer to Table 1) SEL A SEL B SEL C SEL D TI1 7 TI T TX1 6 TX TI1 TI T TX1 TX TI1 TX1 TX TI1 TX1 6 TX 7 8 TI3 1 TI4 T4 8 TI3 TX3 TX TI3 1 TI4 T4 TX3 TX TI3 0 RX RI 16 R 1 RX3 RX4 R4 0 RX RI 16 R 1 RX3 RI 16 1 RX3 RX4 R4 1 RX3 RI 16 Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

12 Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

13 ORDERING INFORMATION Model Temperature Range Package Types SP331CT-L... 0 C to 70 C...8-pin WSOIC SP331CT-L/TR... 0 C to 70 C...8-pin WSOIC SP331ET-L C to 85 C...8-pin WSOIC SP331ET-L/TR C to 85 C...8-pin WSOIC Note: /TR = Tape and Reel DATE REVISION DESCRIPTION Legacy Sipex Datasheet revision history 01/6/ Convert to Exar Format. Add Revision History table. Change revision to Add Note 1 and change maximum data rate at 85C. Update ABS Max Rating table. Notice EXAR Corporation reserves the right to make changes to any products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no representation that the circuits are free of patent infringement. Charts and schedules contained herein are only for illustration purposes and may vary depending upon a user's specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writting, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized ; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Copyright 010 EXAR Corporation Datasheet January 010 Send your Interface technical inquiry with technical details to: uarttechsupport@exar.com Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. Exar Corporation 4870 Kato Road, Fremont CA, SP331_100_01610

14 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Exar: SP331CT-L SP331CT-L/TR SP331ET-L/TR