UM3352E UNIONSEMI | Alldatasheet
Document overview
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Technical content
Features
z Industrial-Control Local Area Networks z Transceivers for EMI-Sensitive
Applications
z ESD Protection for RS-485 I/O Pins ±12kV—IEC61000-4-2, Air-Gap Discharge z True Fail-Safe Receiver while Maintaining EIA/TIA-485 Compatibility z Enhanced Slew-Rate Limiting Facilitates Error-Free Data Transmission z 2nA Low-Current Shutdown Mode z –7V to +12V Common-Mode Input Voltage Range z Allows up to 256 Transceivers on the Bus z Thermal Shutdown z Current-Limiting for Driver Overload Protection
Ordering Information
Part Number Operating Temperature Mark Code Package Type UM3352EESA -40°C to +85°C UM3352EESA SOP8 UM3352EEPA -40°C to +85°C UM3352EEPA DIP8 Selection Guide Part Number Guaranteed Date Rate (Mbps) Low-Power Shutdown Slew-Rate Limited Driver/ Receiver Enable Shutdown Current (nA) Transceivers On Bus ±12kV ESD Protection UM3352E 0.5 Yes Yes Yes 2 256 Yes
http://www.union-ic.com Rev.02Jun.2013 3 / 1 1 UM3352E (VCC = +5V ± 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC= +5V and TA = +25°C.) (Note 1) Parameter Symbol Test Conditions Min Typ Max Unit RECEIVER Receiver Differential Threshold Voltage VTH -7V≤VCM≤12V -200 -50 mV Receiver Input Hysteresis Δ VTH VCM=0V 25 mV Receiver Input Resistance RIN -7V≤VCM≤12V 96 K Ω VIN = 12V 1.0 Input Current (A and B) IIN2 DE = GND, VCC = GND or 5V VIN = -7V -0.8 mA Receiver Output High Voltage VOH IO = -1.5mA, VID = 200mV VCC -1.5 V Receiver Output Low Voltage VOL IO = 2.5mA, VID = 200mV 0.4 V Three-State Output Current at Receiver IOZR VCC = 5V, 0V ≤ VO ≤ VCC ±1 µA Receiver Output Short Circuit Current IOSR 0V≤VRO ≤VCC ±8 ±60 mA ESD Protection ESD Protection for A, B IEC61000-4-2 Air Discharge ±12 kV Note 1: All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device ground unless otherwise noted. Note 2: ΔVOD and ΔVOC are the changes in V OD and V OC, respectively, when the DI input changes state. Note 3: Maximum current level applies to peak cu rrent just prior to fold back current limiting; minimum current level applies during current limiting.
http://www.union-ic.com Rev.02Jun.2013 4 / 1 1 UM3352E Switching Characteristics (VCC = +5V ± 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.) Parameter Symbol Test Conditions Min Typ Max Unit Maximum Data Rate fMAX 500 kbps tDPLH 250 720 1000 Driver Input-to-Output tDPHL Figures 3 and 7, RDIFF = 54Ω, CL1 = CL2 = 100pF 250 720 1000 ns Driver Output Skew | tDPLH - tDPHL | tDSKEW Figures 3 and 7, RDIFF = 54Ω, CL1 = CL2 = 100pF 3 100 ns Driver Rise or Fall Time tDR, tDF Figures 3 and 7, RDIFF = 54Ω, CL1 = CL2 = 100pF 200 530 750 ns Driver Enable to Output High tDZH Figures 4 and 8, CL = 100pF, S2 closed 2500 ns Driver Enable to Output Low tDZL Figures 4 and 8, CL = 100pF, S1 closed 2500 ns Driver Disable Time from Low tDLZ Figures 4 and 8, CL = 15pF, S1 closed 100 ns Driver Disable Time from High tDHZ Figures 4 and 8, CL = 15pF, S2 closed 100 ns Receiver Input to Output tRPLH, tRPHL | VID | ≥2.0V; rise and fall time of VID≤15ns 127 200 ns Differential Receiver Skew | tRPLH - tRPHL | tRSKD Figures 6 and 9; | VID | ≥2.0V; rise and fall time of VID≤15ns 3 30 ns Receiver Enable to Output Low tRZL Figures 5 and 10, CL = 100pF, S1 closed 20 50 ns Receiver Enable to Output High tRZH Figures 5 and 10, CL = 100pF, S2 closed 20 50 ns Receiver Disable Time from Low tRLZ Figures 5 and 10, CL = 100pF, S1 closed 20 50 ns Receiver Disable Time from High tRHZ Figures 5 and 10, CL = 100pF, S2 closed 20 50 ns Time to Shutdown tSHDN (Note 4) 50 200 600 ns Driver Enable from Shutdown to Output High tDZH(SHDN) Figures 4 and 8, CL = 15pF, S2 closed 4500 ns Driver Enable from Shutdown to Output Low tDZL(SHDN) Figures 4 and 8, CL = 15pF, S1 closed 4500 ns Receiver Enable from Shutdown to Output High tRZH(SHDN) Figures 5 and 10, CL = 100pF, S2 closed 3500 ns Receiver Enable from Shutdown to Output Low tRZL(SHDN) Figures 5 and 10, CL = 100pF, S1 closed 3500 ns Note 4: The device is put into shutdown by bringing R E high and DE low. If the enable inputs are in this state for less than 50ns, the device is guaranteed not to enter shutdown. If the enable inputs are in this state for at least 600ns, the device is guaranteed to have entered shutdown.
http://www.union-ic.com Rev.02Jun.2013 5 / 1 1 UM3352E Pin Description Pin Number Symbol Function 1 RO Receiver Output. If A ＞B by -50mV, RO will be high; if A ＜B by 200mV, RO will be low. 2 RE Receiver Output Enable. Drive RE low to enable Receiver, RO is high impedance when RE is high. Drive RE high and DE low to enter low-power shutdown mode. 3 DE Driver Enable. Drive DE high to enable drivers. The outputs are high impedance when DE is low. Drive RE high and DE low to enter low-power shutdown mode. 4 DI Driver Input. A low on DI forces output A low and output B high. Similarly, a high on DI forces output A high and output B low.
5 GND Ground
6 A Non-inverting Receiver Input and Non-inverting Driver Output
7 B Inverting Receiver Input and Inverting Driver Output,
8 V CC Power Supply for RS-485 transceiver
RS-485 Communication Function Table Table1. Transmitting INPUTS OUTPUTS RE DE DI B A MODE X 1 1 0 1 Normal X 1 0 1 0 Normal 0 0 X High-Z High-Z Normal 1 0 X High-Z High-Z Shutdown X=Don’t care; High-Z=High impedance Table2. Receiving INPUTS OUTPUTS RE DE A, B RO MODE
0 X >-50mV 1 Normal
0 X <-200mV 0 Normal
0 X Inputs Open 1 Normal
X=Don’t care; High-Z=High impedance
http://www.union-ic.com Rev.02Jun.2013 8 / 1 1 UM3352E Applications Information
256 Transceivers on the Bus
The standard RS-485 receiver input impedance is 12k Ω (one unit load), and the standard driver can drive up to 32 unit loads. The Union family of transceivers have a 1/8 unit load receiver input impedance (96k Ω), allowing up to 256 transceivers to be connected in parallel on one communication line. Any combination of these devices and/or other RS-485 transceivers with a total of 32 unit loads or less can be connected to the line. Reduced EMI and Reflections The UM3352E is slew-rate limited, minimi zing EMI and reducing reflections caused by improperly terminated cables. In general, a transm itter’s rise time relates directly to the length of an unterminated stub, which can be driven with only minor waveform reflections. The following equation expresses this relationship conservatively: Length=t RISE/(10×1.5ns/ft) Where tRISE is the transmitter’s rise time. A system can work well with longer unterminate d stubs, even with severe reflections, if the waveform settles out before the UART samples them. Low-Power Shutdown Mode Low-power shutdown mode is initiated by bringing both RE high and DE low. In shutdown, the device typically draws only 2nA of supply current. RE and DE may be driven simultaneously; the parts are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, th e parts are guaranteed to enter shutdown. Enable times tZH and t ZL in the Switching Characteristics tables assume the part was not in a low-power shutdown state. Enable times t ZH(SHDN) and t ZL(SHDN) assume the parts were shut down. It takes drivers and receivers longer to become enabled from low-power shutdown mode (t ZH(SHDN), tZL(SHDN)) than from driver/receiver-disable mode (tZH, tZL). Driver Output Protection Two mechanisms prevent excessive output current and power dissipation caused by faults or by bus contention. The first, a foldback current limit on the output stage, provides immediate protection against short circuits over the w hole common-mode voltage range. The second, a thermal shutdown circuit, forces the driver outputs into a high-impedance state if the die temperature becomes excessive. Line Length vs. Data Rate The RS-485/RS-422 standard covers line lengths up to 4000 feet. For line lengths greater than 4000 feet, repeater is required. Typical Applications The UM3352E transceivers are designed for bidirectional data communications on multipoint bus transmission lines. To minimize reflections, the lin e should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possible.
http://www.union-ic.com Rev.02Jun.2013 9 / 1 1 UM3352E
Package Information
MILLIMETERS INCHES Symbol Min Max Min Max A 1.350 1.750 0.053 0.069 A1 0.100 0.250 0.004 0.010 A2 1.350 1.550 0.053 0.061 b 0.33 0.51 0.013 0.020 c 0.170 0.250 0.006 0.010 D 4.700 5.100 0.185 0.200 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 e 1.270 (BSC) 0.050 (BSC) L 0.400 1.270 0.016 0.050 θ 0° 8° 0° 8° Land Pattern NOTES: 1. Compound dimension: 4.90×3.90 ; 2. Unit: mm; 3. General tolerance ±0.05mm unless otherwise specified; 4. The layout is just for reference. Tape and Reel Orientation
http://www.union-ic.com Rev.02Jun.2013 1 0 / 1 1 UM3352E DIP8 Outline Drawing AL DIMENSIONS MILLIMETERS INCHES Symbol Min Max Min Max A - 5.08 - 0.200 A1 0.38 - 0.015 - A2 3.18 4.45 0.125 0.175 A3 1.40 2.03 0.055 0.080 b 0.41 0.56 0.016 0.022 b1 1.14 1.65 0.045 0.065 C 0.20 0.30 0.008 0.012 D (8 PIN) 8.84 9.91 0.348 0.390 D1 0.13 2.03 0.005 0.080 E 7.62 8.26 0.300 0.325 E1 6.10 7.87 0.240 0.310 e 2.54 - 0.100 - eA 7.62 - 0.300 - eB - 10.16 - 0.400 L 2.92 3.81 0.115 0.150
http://www.union-ic.com Rev.02Jun.2013 1 1 / 1 1 UM3352E IMPORTANT NOTICE The information in this document has been ca refully reviewed and is believed to be accurate. Nonetheless, this document is subjec t to change without notice. Union assumes no responsibility for any inaccuracies that may be contained in this document, and makes no commitment to update or to keep current the contained information, or to notify a person or organization of any update. Union rese rves the right to make changes, at any time, in order to improve reliability, function or design and to attempt to supply the best product possible. Union Semiconductor, Inc Add: 2F, Building 3, Lane 647, Songtao Road, Shanghai 201203 Tel: 021-51093966 Fax: 021-51026018 Website: www.union-ic.com