Features n Integrated, Logic-Seectabe 20Ω Termination esistor n 20Mbps Max Data ate n No Damage or Latchup to ESD: ±5kV HBM n High Input Impedance Supports 256 Nodes (C-, I-Grades) n Operation Up to 05 C (H) n 250kbps Low-EMI Mode n Guaranteed Faisafe eceiver Operation Over the Entire Common Mode ange n Current Limited Drivers and Therma Shutdown n Deayed Micropower Shutdown (5µA Max) n Power Up/Down Gitch-Free Driver Outputs n Low Operating Current (900µA Max in eceive Mode) n Meets A TIA/EIA-485-A Specifications n Avaiabe in 0-Pin 3mm 3mm DFN, 2-Pin 4mm 3mm DFN and 6-Pin SSOP Packages Appications n Low Power S485/S422 Transceiver n Leve Transator n Backpane Transceiver /LTC286 20Mbps S485 Transceivers with Integrated Switchabe Termination Description The LTC 2859 and LTC286 are ow power, 20Mbps S485/422 transceivers operating on 5V suppies. The receiver incudes a ogic-seectabe 20Ω termination, one-eighth unit oad supporting up to 256 nodes per bus (C-, I-grades), and a faisafe feature that guarantees a high output state under conditions of foating or shorted inputs. The driver features a ogic-seectabe ow-emi 250kbps operating mode, and maintains a high output impedance over the entire common mode range when disabed or when the suppy is removed. Excessive power dissipation caused by bus contention or a faut is prevented by current imiting a outputs and by a therma shutdown. Enhanced ESD protection aows the and LTC286 to withstand ±5kV (human body mode) on the transceiver interface pins without atchup or damage. Product Seection Guide PAT NUMBE DUPLEX PACKAGE Haf DFN-0 LTC286 Fu SSOP-6, DFN-2 L, LT, LTC, LTM, Linear Technoogy, the Linear ogo and µmodue are registered trademarks of Linear Technoogy Corporation. A other trademarks are the property of their respective owners. Typica Appication E DE D 20Ω 20Ω D E DE at 20Mbps Y Z SLO 2859/6 TA0 SLO Y Z 20Ω D 2V/V 20ns/V 28596 TA02 E DE SLO
Absoute Maximum atings Suppy Votage ( )... 0.3V to 7V Logic Input Votages (E, DE,,, SLO)... 0.3V to 7V Interface I/O: A, B, Y, Z...( 5V) to +5V (A-B) or (B-A) with Terminator Enabed...6V eceiver Output Votage ()... 0.3V to ( +0.3V) Pin Configuration (Note ) Operating Temperature (Note 4) C, LTC286C... 0 C to 70 C I, LTC286I... 40 C to 85 C H... 40 C to 05 C Storage Temperature ange... 65 C to 25 C Lead Temperature (Sodering, 0 sec) GN Package...300 C E DE TOP VIEW 0 2 3 9 8 B A 4 5 7 6 SLO GND DD PACKAGE 0-LEAD (3mm 3mm) PLASTIC DFN EXPOSED PAD (PIN ) PCB GND CONNECTION T JMAX = 25 C, θ JA = 43 C/W θ JC = 3 C/W E DE GND 2 3 4 5 6 TOP VIEW 3 2 A 0 B 9 Z 8 Y 7 SLO DE PACKAGE 2-LEAD (4mm 3mm) PLASTIC DFN EXPOSED PAD (PIN 3) PCB GND CONNECTION T JMAX = 25 C, θ JA = 43 C/W θ JC = 4.3 C/W E DE GND NC NC 2 3 4 5 6 7 8 TOP VIEW 6 5 A 4 B 3 Z 2 Y SLO 0 NC 9 NC GN PACKAGE 6-LEAD (NAW 0.50) PLASTIC SSOP T JMAX = 25 C, θ JA = 0 C/W θ JC = 40 C/W Order Information LEAD FEE FINISH TAPE AND EEL PAT MAKING* PACKAGE DESCIPTION MPEATUE ANGE LTC286CDE#PBF LTC286CDE#TPBF 286 2-Lead (4mm 3mm) Pastic DFN 0 C to 70 C LTC286IDE#PBF LTC286IDE#TPBF 286 2-Lead (4mm 3mm) Pastic DFN 40 C to 85 C LTC286CGN#PBF LTC286CGN#TPBF 286 6-Lead Pastic SSOP 0 C to 70 C LTC286IGN#PBF LTC286IGN#TPBF 286I 6-Lead Pastic SSOP 40 C to 85 C CDD#PBF CDD#TPBF LBNX 0-Lead (3mm 3mm) Pastic DFN 0 C to 70 C IDD#PBF IDD#TPBF LBNX 0-Lead (3mm 3mm) Pastic DFN 40 C to 85 C HDD#PBF HDD#TPBF LBNX 0-Lead (3mm 3mm) Pastic DFN 40 C to 05 C Consut LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a abe on the shipping container. Consut LTC Marketing for information on non-standard ead based finish parts. For more information on ead free part marking, go to: http://www.inear.com/eadfree/ For more information on tape and ree specifications, go to: http://www.inear.com/tapeandree/ 2
Eectrica Characteristics /LTC286 The denotes the specifications which appy over the fu operating temperature range, otherwise specifications are at T A = 25 C, = 5V uness otherwise noted (Note 2). SYMBOL PAAME CONTIONS MIN TYP MAX UNITS Driver V OD Differentia Driver Output Votage =, I O = 0mA, = 4.5V (Figure ) V = 27Ω (S485), = 4.5V (Figure ) = 50Ω (S422), = 4.5V (Figure ).5 2.0 V V D V OD Change in Magnitude of Driver = 27Ω or = 50Ω (Figure ) 0.2 V Differentia Output Votage for Compementary Output States V OC Driver Common Mode Output Votage = 27Ω or = 50Ω (Figure ) 3.0 V D V OC Change in Magnitude of Driver = 27Ω or = 50Ω (Figure ) 0.2 V Common Mode Output Votage for Compementary Output States I OZD Driver Three-State (High Impedance) DE = OV, V O = 7V, +2V ±0 µa Output Current on Y and Z (LTC286 Ony) I OSD Maximum Driver Short-Circuit Current 7V (Y or Z) 2 (Figure 2) ±20 ±250 ma eceiver I IN2 eceiver Input Current (A, B) DE = = 0V, = 0V or 5V, V A or V B = 2V, Other at 0V (H-Grade) 25 250 µa µa DE = = 0V, = 0V or 5V, V A or V B = 7V, Other at 0V (H-Grade) 00 45 µa µa V TH eceiver Differentia Input Threshod Votage 7V V CM 2 ±0.2 V DV TH eceiver Input Hysteresis V CM = 0V 25 mv V OH eceiver Output HIGH Votage I 0 = 4mA, V ID = 200mV, = 4.5V 2.4 V V OL eceiver Output LOW Votage I 0 = 4mA, V ID = 200mV, = 4.5V 0.4 V I OZ eceiver Three-State (High Impedance) Output Current on E = 5V, 0V V O ± µa IN eceiver Input esistance E = 5V or 0V, DE = = 0V 7V V A = V B 2V (H-Grade) 96 48 25 25 kω kω M eceiver Input Terminating esistor = 5V, V AB = 2V, V B = 7, 0, 0V 08 20 56 Ω (Figure 7) Logic V IH Logic Input High Votage DE,, E,, SLO, = 4.5V 2 V V IL Logic Input Low Votage DE,, E,, SLO, = 4.5V 0.8 V I IN Logic Input Current DE,, E,, SLO 0 ±0 µa Suppies I SHDN Suppy Current in Shutdown Mode DE = 0V, E =, = 0V 0 5 µa I CC Suppy Current in eceive Mode No Load, DE = 0V, E = 0V, = 0V 540 900 µa I CCT Suppy Current in Transmit Mode No Load, DE =, E =, SLO =, = 0V 630 000 µa I CCTS Suppy Current in Transmit SLO Mode No Load, DE =, E =, SLO = 0V, = 0V 670 00 µa I CCL Suppy Current in Loopback Mode No Load, DE =, E= 0V, SLO =, = 0V 660 00 µa (Both Driver and eceiver Enabed) I CCT Suppy Current in Termination Mode DE = 0V, E =, =, SLO = 640 80 µa 3
Switching Characteristics The denotes the specifications which appy over the fu operating temperature range, otherwise specifications are at T A = 25 C, = 5V, T E = 0 uness otherwise noted (Note 2). SYMBOL PAAME CONTIONS MIN TYP MAX UNITS Driver in Norma Mode (SLO HIGH) f MAX Maximum Data ate Note 3 20 Mbps t PLHD, t PHLD Driver Input to Output FF = 54Ω, C L = 00pF (Figure 3) 0 50 ns Dt PD Driver Input to Output Difference FF = 54Ω, C L = 00pF (Figure 3) 6 ns t PLHD -t PHLD t SKEWD Driver Output Y to Output Z FF = 54Ω, C L = 00pF (Figure 3) ±6 ns t D, t FD Driver ise or Fa Time FF = 54Ω, C L = 00pF (Figure 3) 4 2.5 ns t ZLD, t ZHD, t LZD, Driver Enabe or Disabe Time L = 500Ω, C L = 50pF, E = 0 (Figure 4) 70 ns t HZD t ZHSD, t ZLSD Driver Enabe from Shutdown L = 500Ω, C L = 50pF, E = (Figure 4) 8 µs t SHDN Time to Shutdown (DE =, E = ) or (DE = 0, E ) (Figure 4) 00 ns Driver in SLO Mode (SLO LOW) f MAXS Maximum Data ate Note 3 250 kbps t PLHDS, t PHLDS Driver Input to Output FF = 54Ω, C L = 00pF (Figure 3) 0.95.5 µs Dt PDS Driver Input to Output Difference t PLH -t PHL FF = 54Ω, C L = 00pF (Figure 3) 50 500 ns t SKEWDS Driver Output A to Output B FF = 54Ω, C L = 00pF (Figure 3) (H-Grade) t DS, t FDS Driver ise or Fa Time FF = 54Ω, C L = 00pF (Figure 3) 0.9.5 µs t ZHDS, t ZLDS Driver Enabe Time L = 500Ω, C L = 50pF, E = 0 (Figure 4) 300 ns t LZDS, t HZDS Driver Disabe Time L = 500Ω, C L = 50pF, E = 0 (Figure 4) 70 ns t ZHSDS, t ZLSDS Driver Enabe from Shutdown L = 500Ω, C L = 50pF, E = (Figure 4) 8 µs t SHDNS Time to Shutdown (DE = 0, E = ) or (DE =, E = ) (Figure 4) 500 ns eceiver t PLH, t PHL eceiver Input to Output C L = 5pF, V CM =.5V, V AB =.5V, t and t F < 50 70 ns 4ns (Figure 5) t SKEW Differentia eceiver Skew C L = 5pF (Figure 5) 6 ns t PLH -t PHL t, t F eceiver Output ise or Fa Time C L = 5pF (Figure 5) 3 2.5 ns t ZL, t ZH, t LZ, eceiver Enabe/Disabe L = kω, C L =5pF, DE = (Figure 6) 50 ns t HZ = 0 or t ZHS, t ZLS eceiver Enabe from Shutdown L = kω, C L = 5pF, DE = 0V (Figure 6) 8 µs = 0 or t N, t TZ Termination Enabe or Disabe Time V B = 0V, V AB = 2V, E =, DE = 0V (Figure 7) 00 µs 200 200 ±500 ±750 ns ns Note : Stresses beyond those isted under Absoute Maximum atings may cause permanent damage to the device. Exposure to any Absoute Maximum ating condition for extended periods may affect device reiabiity and ifetime.. Note 2: A currents into device pins are positive; a currents out of device pins are negative. A votages are referenced to device ground uness otherwise specified. Note 3: Maximum data rate is guaranteed by other measured parameters and is not tested directy. Note 4: This IC incudes overtemperature protection that is intended to protect the device during momentary overoad conditions. Junction temperature wi exceed 25 C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may resut in device degradation or faiure. 4
Test Circuits /LTC286 GND O DIVE Y Z + V OD + V OC GND O DIVE Y Z I OSD + 7V to +2V 2859/6 F0-2 Figure. Driver DC Characteristics Figure 2. Driver Output Short-Circuit Current DIVE Y Z FF C L C L Y, Z (Y-Z) OV V O t PLHD, t PHLD, t PLHDS t PHLDS /2 V O t SKEWD, t SKEWDS 90% 0% 90% 0 0 0% t D, t FD, t DS t FDS 2859/6 F03 Figure 3. Driver Timing Measurement O GND DIVE DE Y Z L C L L C L GND O O GND DE Y or Z Z or Y OV V OL V OH OV V O /2 t ZLD, t ZLDS, t ZLSD, t ZLSDS t ZHD, t ZHDS, t ZHSD, t ZHSDS /2 /2 t LZD, t LZDS 0.5V t HZD, t HZDS, t SHDN, t SHDNS 0.5V 2859/6 F04 Figure 4. Driver Enabe and Disabe Timing Measurement 5
test circuits V CM ±V AB /2 ±V AB /2 A B ECEIVE C L A-B V AB V AB 0V V O 0V 90% 0% t PLH /2 t /2 t PHL 90% 0% t F t SKEW = t PLH t PHL 2859/6 F05 Figure 5. eceiver Propagation Deay Measurements 0V O A O 0V B = 0V O ECEIVE E C L L O GND E 0V V O V OL V OH 0V t ZL, t ZLS t ZH, t ZHS /2 /2 /2 t LZ t HZ 0.5V 0.5V 2859/6 F06 Figure 6. eceiver Enabe/Disabe Time Measurements M = V AB ECEIVE A B + + V AB V B I A I A 0V /2 90% t N ttz 0% 2859/6 F07 Figure 7. Termination esistance and Timing Measurements 6
Typica Performance Characteristics /LTC286 T A = 25 C, = 5V, uness otherwise noted. eceiver Skew vs Temperature Driver Skew vs Temperature Driver Propagation Deay vs Temperature ECEIVE SKEW (ns) 2 0 V AB =.5V C L = 5pF DIVE SKEW (ns) 3 2 0 FF = 54Ω C L = 00pF SLO = DIVE PP DELAY (ns) 8 6 4 2 0 8 6 FF = 54Ω C L = 00pF SLO = 40 20 0 20 40 60 80 00 20 MPEATUE ( C) 28596 G0 40 20 0 20 40 60 80 00 20 MPEATUE ( C) 28596 G02 4 40 20 0 20 40 60 80 00 20 MPEATUE ( C) 28596 G03 35 M vs Temperature 5 Driver Output Low/High Votage vs Output Current 5 Driver Differentia Output Votage vs Temperature ESISTANCE (Ω) 30 25 20 5 0 05 00 OUTPUT VOLTAGE (V) 4 3 2 V OH V OL OUTPUT VOLTAGE (V) 4 3 2 = = 00Ω = 54Ω 95 40 20 0 20 40 60 80 00 20 MPEATUE ( C) 28596 G04 0 0 0 20 30 40 50 60 70 OUTPUT CUENT (ma) 28596 G05 0 40 20 0 20 40 60 80 00 20 MPEATUE ( C) 28596 G06 OUTPUT VOLTAGE (V) 5 4 3 2 0 0 eceiver Output Votage vs Output Current (Source and Sink) SOUCE SINK 2 3 4 5 OUTPUT CUENT (ma) 28596 G07 PP DELAY (ns) 70 65 60 55 50 45 40 35 30 40 eceiver Propagation Deay vs Temperature V AB =.5V C L = 5pF 20 0 20 40 60 80 00 MPEATUE ( C) 20 28596 G08 SUPPLY CUENT (ma) 60 50 40 30 20 0 0 0. Suppy Current vs Data ate = 54Ω = 00Ω = 0 00 DATA A (Mbps) 28596 G09 7
Pin Functions (DD/DE/GN) (Pin ): eceiver Output. If the receiver output is enabed (E ow) and A > B by 200mV, then wi be high. If A < B by 200mV, then wi be ow. If the receiver inputs are open, shorted, or terminated without a vaid signa, wi be high. E (Pin 2): eceiver Enabe. A ow enabes the receiver. A high input forces the receiver output into a high impedance state. DE (Pin 3): Driver Enabe. A high on DE enabes the driver. A ow input wi force the driver outputs into a high impedance. If E is high with DE and LOW, the part wi enter a ow power shutdown state. (Pin 4): Driver Input. If the driver outputs are enabed (DE HIGH), then a ow on forces the driver positive output LOW and negative output HIGH. A high on, with the driver outputs enabed, forces the driver positive output HIGH and negative output LOW. (Pin 5): Interna Termination esistance Enabe. A high input wi connect a termination resistor (20Ω typica) between pins A and B. GND (Pins 6,/6,3/6): Ground. Pins and 3 are backside therma pad, connected to Ground. SLO (Pins 7/7/): Driver Sew ate Contro. A ow input wi force the driver into a reduced sew rate mode. Y (Pins -/8/2): Positive Driver Output for LTC286. Z (Pins -/9/3): Negative Driver Output for LTC286. B (Pins 9/0/4): Negative eceiver Input (and Negative Driver Output for ). A (Pins 8//5): Positive eceiver Input (and Positive Driver Output for ). (Pins 0/2/6): Positive Suppy. 4.5V < < 5.5V. Bypass with 0.µF ceramic capacitor. 8
Function Tabes LTC286 LOGIC INPUTS DE E MODE A, B MINATO 0 0 0 eceive IN Enabed Off 0 0 eceive with Term IN Enabed On 0 0 Shutdown IN Hi-Z Off 0 Term Ony IN Hi-Z On 0 0 Transmit with eceive Driven Enabed Off 0 Transmit with eceive and Term Driven Enabed On 0 Transmit Driven Hi-Z Off Transmit with Term Driven Hi-Z On LOGIC INPUTS DE E MODE A, B Y, Z MINATO 0 0 0 eceive IN Hi-Z Enabed Off 0 0 eceive with Term IN Hi-Z Enabed On 0 0 Shutdown IN Hi-Z Hi-Z Off 0 Term Ony IN Hi-Z Hi-Z On 0 0 Transmit with eceive IN Driven Enabed Off 0 Transmit with eceive and Term IN Driven Enabed On 0 Transmit IN Driven Hi-Z Off Transmit with Term IN Driven Hi-Z On Bock Diagrams LTC286 E DE SLEEP/SHUTDOWN LOGIC AND DELAY 20Ω A (5kV) E DE SLEEP/SHUTDOWN LOGIC AND DELAY 20Ω A (5kV) ECEIVE ECEIVE B (5kV) B (5kV) SLO SLO DIVE DIVE Z (5kV) Y (5kV) 2859/6 BD 9
Appications Information Driver The driver provides fu S485 and S422 compatibiity. When enabed, if is high, Y-Z is positive for the fu dupex device (LTC286) and A-B is positive for the hafdupex device (). When the driver is disabed, both outputs are highimpedance. For the fu dupex LTC286, the eakage on the driver output pins is guaranteed to be ess than 0µA over the entire common mode range of 7V to +2V. On the haf-dupex, the impedance is dominated by the receiver input resistance, IN. Driver Overvotage and Overcurrent Protection The driver outputs are protected from short circuits to any votage within the Absoute Maximum range of ( 5V) to +5V. The maximum current in this condition is 250mA. If the pin votage exceeds about ±0V, current imit fods back to about haf of the peak vaue to reduce overa power dissipation and avoid damaging the part. The /LTC286 aso feature therma shutdown protection that disabes the driver, terminator, and receiver in case of excessive power dissipation. SLO Mode: Sew Limiting for EMI Emissions Contro The /LTC286 feature a ogic-seectabe reducedsew mode (SLO mode) that softens the driver output edges to contro the high frequency EMI emissions from equipment and data cabes. The reduced sew rate mode is entered by taking the SLO pin ow, where the data rate is imited to about 250kbps. Sew imiting aso mitigates the adverse effects of imperfect transmission ine termination caused by stubs or mismatched cabes. Figures 8a and 8b show the LTC286 driver outputs in norma and SLO mode with their corresponding frequency spectrums operating at 250kbps. SLO mode significanty reduces the high frequency harmonics. Y, Z Y Z Y Z V/V 2µs/V 0dB/V.25MHz/V 28596 F08a Driver Output at 25kHz into 00Ω esistor Frequency Spectrum of the Same Signa Figure 8a. Driver Output in Norma Mode Y, Z Y Z Y Z V/V 2µs/V Driver Output at 25kHz into 00Ω esistor 0dB/V.25MHz/V 28596 F08b Frequency Spectrum of the Same Signa 0 Figure 8b. Driver Output in SLO Mode
Appications Information eceiver and Faisafe With the receiver enabed, when the absoute vaue of the differentia votage between the A and B pins is greater than 200mV, the state of wi refect the poarity of (A-B). The /LTC286 have a faisafe feature that guarantees the receiver output to be in a ogic HIGH state when the inputs are either shorted, eft open, or terminated (externay or internay), but not driven for more than about 3µs. The deay prevents signa zero crossings from being interpreted as shorted inputs and causing to go high inadvertenty. This faisafe feature is guaranteed to work for inputs spanning the entire common mode range of 7V to +2V. The receiver output is internay driven high (to ) or ow (to ground) with no externa pu-up needed. When the receiver is disabed the pin becomes Hi-Z with eakage of ess than ±µa for votages within the suppy range. /LTC286 eceiver Input esistance The receiver input resistance from A or B to ground is greater than 96k permitting up to a tota of 256 receivers per system without exceeding the S485 receiver oading specification. High temperature H-Grade operation reduces the minimum input resistance to 48k permitting 28 receivers on the bus. The input resistance of the receiver is unaffected by enabing/disabing the receiver or by powering/unpowering the part. The equivaent input resistance ooking into A and B is shown in Figure 9. Switchabe Termination Proper cabe termination is very important for good signa fideity. If the cabe is not terminated with its characteristic impedance, refections wi resut in distorted waveforms. The /LTC286 are the first S485 transceivers to offer integrated switchabe termination resistors on the receiver input pins. This provides the tremendous advantage of being abe to easiy change, through ogic contro, the proper ine termination for optima performance when configuring transceiver networks. When the pin is high, the termination resistor is enabed and the differentia resistance from A to B is 20Ω. Figure 0 shows the I/V characteristics between pins A and B with the termination resistor enabed and disabed. The resistance is maintained over the entire S485 common mode range of 7V to +2V as shown in Figure. >96k 60Ω A 60Ω >96k 2859/6 F09 B Figure 9. Equivaent Input esistance into A and B (on the, Vaid if Driver is Disabed) Figure 0. Curve Trace Between A and B with Termination Enabed and Disabed
appications information The integrated termination resistor has a high frequency response which does not imit performance at the maximum specified data rate. Figure 2 shows the magnitude and phase of the termination impedance vs frequency. The termination resistor cannot be enabed by if the device is unpowered or in therma shutdown mode. Suppy Current The unoaded static suppy currents in the / LTC286 are very ow typicay under 700µA for a modes of operation without the interna terminator enabed. In appications with resistivey terminated cabes, the suppy current is dominated by the driver oad. For exampe, when using two 20Ω terminators with a differentia driver output votage of 2V, the DC current is 33mA, which is sourced by the positive votage suppy. This is true whether the terminators are externa or interna such as in the / LTC286. Power suppy current increases with togging data due to capacitive oading and this term can increase significanty at high data rates. Figure 3 shows suppy current vs data rate for two different capacitive oads (for the circuit configuration of Figure 3). ESISTANCE (Ω) MAGNITUDE (Ω) 50 40 30 20 0 0 85 70 55 40 25 0 95 5 0 5 0 5 COMMON MODE VOLTAGE (V) 28596 F Figure. Termination esistance vs Common Mode Votage MAGNITUDE PHASE 30 5 0 5 30 45 60 PHASE ( ) High Speed Considerations A ground pane ayout is recommended for the / LTC286. A 0.µF bypass capacitor ess than one quarter inch away from the pin is aso recommended. The PC board traces connected to signas A/B and Z/Y (LTC286) shoud be symmetrica and as short as possibe to maintain good differentia signa integrity. To minimize capacitive effects, the differentia signas shoud be separated by more than the width of a trace and shoud not be routed on top of each other if they are on different signa panes. Care shoud be taken to route outputs away from any sensitive inputs to reduce feedback effects that might cause noise, jitter, or even osciations. For exampe, in the fu dupex LTC286, and A/B shoud not be routed near the driver or receiver outputs. The ogic inputs of the /LTC286 have 50mV of hysteresis to provide noise immunity. Fast edges on the outputs can cause gitches in the ground and power suppies which are exacerbated by capacitive oading. If a ogic input is hed near its threshod (typicay.5v), a noise gitch 2 CUENT (ma) 80 0 0 0 75 70 65 60 55 50 45 0 2 FEQUENCY (MHz) Figure 2. Termination Magnitude and Phase vs Frequency FF = 54Ω C L = 000pF C L = 00pF 0 3 0 4 DATA A (kbps) 75 0 285455 F2 0 5 28596 F3 Figure 3. Suppy Current vs Data ate
Appications Information from a driver transition may exceed the hysteresis eves on the ogic and data inputs pins causing an unintended state change. This can be avoided by maintaining norma ogic eves on the pins and by sewing inputs through their threshods by faster than V/µs when transitioning. Good suppy decouping and proper ine termination aso reduces gitches caused by driver transitions. Cabe Length vs Data ate For a given data rate, the maximum transmission distance is bounded by the cabe properties. A typica curve of cabe ength vs data rate compiant with the S485 standard is shown in Figure 4. Three regions of this curve refect different performance imiting factors in data transmission. In the fat region of the curve, maximum distance is determined by resistive osses in the cabe. The downward soping region represents imits in distance and data rate due to AC osses in the cabe. The soid vertica ine /LTC286 represents the specified maximum data rate in the S485 standard. The dashed ines at 250kbps and 20Mbps show the maximum data rates of the /LTC286 in Low- EMI and norma modes, respectivey. CABLE LENGTH (FT) 0k k 00 LOW-EMI MODE MAX DATA A S485 MAX DATA A 0 0k 00k M 0M DATA A (bps) NOMAL MODE MAX DATA A 00M 28596 F4 Figure 4. Cabe Length vs Data ate (S485 Standard Shown in Soid Lines) Typica Appications Muti-Node Network with End Termination Using = 0V = 0V D D = 5V = 5V D D 2859/6 TA04 3
Package Description Pease refer to http://www.inear.com/designtoos/packaging/ for the most recent package drawings. DD Package 0-Lead Pastic DFN (3mm 3mm) (eference LTC DWG # 05-08-699 ev C) 0.70 ±0.05 3.55 ±0.05 2.5 ±0.05.65 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) ECOMMENDED SOLDE PAD PITCH AND MENSIONS = 0.25 TYP 6 0 0.40 ±0.0 PIN TOP MAK (SEE NO 6) 0.200 EF 3.00 ±0.0 (4 SIDES) 0.75 ±0.05 0.00 0.05.65 ±0.0 (2 SIDES) (DD) DFN EV C 030 5 0.25 ±0.05 0.50 BSC 2.38 ±0.0 (2 SIDES) BOTTOM VIEW EXPOSED PAD PIN NOTCH = 0.20 O 0.35 45 CHAMFE NO:. DAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VAIATION OF (WEED-2). CHECK THE LTC WEBSI DATA SHEET FO CUENT STATUS OF VAIATION ASSIGNMENT 2. DAWING NOT TO SCALE 3. ALL MENSIONS AE IN MILLIMES 4. MENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PESENT, SHALL NOT EXCEED 0.5mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDE PLAD 6. SHADED AEA IS ONLY A EFEENCE FO PIN LOCATION ON THE TOP AND BOTTOM OF PACKAGE 4
Package Description Pease refer to http://www.inear.com/designtoos/packaging/ for the most recent package drawings. /LTC286 DE/UE Package 2-Lead Pastic DFN (4mm 3mm) (eference LTC DWG # 05-08-695 ev D) 0.70 ±0.05 3.60 ±0.05 2.20 ±0.05.70 ±0.05 3.30 ±0.05 PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 2.50 EF ECOMMENDED SOLDE PAD PITCH AND MENSIONS APPLY SOLDE MASK TO AEAS THAT AE NOT SOLDEED 4.00 ±0.0 (2 SIDES) = 0.05 TYP 7 = 0.5 TYP 2 0.40 ±0.0 PIN TOP MAK (NO 6) 0.200 EF 3.00 ±0.0 (2 SIDES) 0.75 ±0.05 0.00 0.05 3.30 ±0.0.70 ±0.0 6 0.25 ±0.05 0.50 BSC 2.50 EF BOTTOM VIEW EXPOSED PAD PIN NOTCH = 0.20 O 0.35 45 CHAMFE (UE2/DE2) DFN 0806 EV D NO:. DAWING PPOSED TO BE A VAIATION OF VESION (WGED) IN JEDEC PACKAGE OUTLINE M0-229 2. DAWING NOT TO SCALE 3. ALL MENSIONS AE IN MILLIMES 4. MENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PESENT, SHALL NOT EXCEED 0.5mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDE PLAD 6. SHADED AEA IS ONLY A EFEENCE FO PIN LOCATION ON THE TOP AND BOTTOM OF PACKAGE 5
Package Description Pease refer to http://www.inear.com/designtoos/packaging/ for the most recent package drawings. GN Package 6-Lead Pastic SSOP (Narrow.50 Inch) (eference LTC DWG # 05-08-64).045 ±.005.89.96* (4.80 4.978) 6 5 4 3 2 0 9.009 (0.229) EF.254 MIN.50.65.229.244 (5.87 6.98).50.57** (3.80 3.988).065 ±.005 ECOMMENDED SOLDE PAD LAYOUT.0250 BSC 2 3 4 5 6 7 8.007.0098 (0.78 0.249).05 ±.004 (0.38 ±0.0) 45 0 8 TYP.0532.0688 (.35.75).004.0098 (0.02 0.249).06.050 (0.406.270) NO:. CONTLLING MENSION: INCHES INCHES 2. MENSIONS AE IN (MILLIMES) 3. DAWING NOT TO SCALE * MENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.52mm) PE SIDE ** MENSION DOES NOT INCLUDE INLEAD FLASH. INLEAD FLASH SHALL NOT EXCEED 0.00" (0.254mm) PE SIDE.008.02 (0.203 0.305) TYP.0250 (0.635) BSC GN6 (SSOP) 0204 6
evision History (evision history begins at ev C) EV DA DESCIPTION PAGE NUMBE C 3/2 Added H-grade Order Information and Eectrica Characteristics parameters evised eceiver Input esistance section epaced Figure 2 Added Termination esistor restriction information 2, 3, 4 2 2 Information furnished by Linear Technoogy Corporation is beieved to be accurate and reiabe. However, no responsibiity is assumed for its use. Linear Technoogy Corporation makes no representation that the interconnection of its circuits as described herein wi not infringe on existing patent rights. 7
Typica Appication Faisafe 0 Appication (Ide State = Logic 0 ) 00kΩ I B "A" I2 D 20Ω A "B" 2859/6 TA03 eated Parts PAT NUMBE DESCIPTION COMMENTS LTC2854/LTC2855 LTC2856/LTC2857/ LTC2858 LTC2850/LTC285/ LTC2852 LTC2862/LTC2863/ LTC2864/LTC2865 LTM288 3.3V 20Mbps S485/S422 Transceivers with Integrated Up to ±25kV HBM ESD, 25 C Operation Switchabe Termination 5V 20Mbps and Sew ate Limited 5kV S485/S422 ±5kV ESD, 25 C Operation Transceivers 3.3V 20Mbps S485/S422 Transceivers ±5kV ESD, 25 C Operation ±60V Faut Protected 3V to 5.5V S485/S422 Transceivers 20Mbps or 250kbps, ±5kV HBM ESD, ±25V Common Mode ange Compete 3.3V Isoated S485/S422 µmodue Transceiver + Power 2500V MS Isoation with Integrated Isoated DC/DC Converter and Switchabe Termination LTC485 Low Power S485 Interface Transceiver I CC = 300µA (Typ) LTC49 Differentia Driver and eceiver Pair I CC = 300µA LTC480 3.3V Utraow Power S485 Transceiver 3.3V Operation LTC483 Utraow Power S485 Low EMI Transceiver Controed Driver Sew ate LTC485 Differentia Bus Transceiver 0Mbaud Operation LTC487 Utraow Power S485 with Low EMI, Shutdown and High Up to 256 Transceivers on the Bus Input Impedance LTC520 50Mbps Precision Quad Line eceiver Channe-to-Channe Skew 400ps (Typ) LTC535 Isoated S485 Fu-Dupex Transceiver 2500V MS Isoation in Surface Mount Package LTC685 52Mbps S485 Transceiver with Precision Deay Propagation Deay Skew 500ps (Typ) LT785 ±60V Faut Protected S485 Transceiver 60V Toerant, 5kV ESD 8 LT 032 EV C PIND IN USA Linear Technoogy Corporation 630 McCarthy Bvd., Mipitas, CA 95035-747 (408) 432-900 FAX: (408) 434-0507 www.inear.com LINEA CHNOLOGY COPOATION 2006