May 1998
DS3695/DS3695T/DS3696/DS3697
Multipoint RS485/RS422 Transceivers/Repeaters
General Description
The DS3695, DS3696, and DS3697 are high speed differential TRI-STATE® bus/line transceivers/repeaters designed to meet the requirements of EIA standard RS485 with extended common mode range (+12V to −7V), for multipoint data transmission.
The driver and receiver outputs feature TRI-STATE capability. The driver outputs remain in TRI-STATE over the entire common mode range of +12V to −7V. Bus faults that cause excessive power dissipation within the device trigger a thermal shutdown circuit, which forces the driver outputs into the high impedance state. The DS3696 provides an output pin TS (thermal shutdown) which reports the occurrence of the thermal shutdown of the device. This is an ªopen collectorº pin with an internal 10 kΩ pull-up resistor. This allows the line fault outputs of several devices to be wire OR-ed.
Both AC and DC specifications are guaranteed over the 0ÊC to 70ÊC temperature and 4.75V to 5.25V supply voltage range.
Features
nMeets EIA standard RS485 for multipoint bus transmission and is compatible with RS-422
n15 ns driver propagation delays with 2 ns skew (typical)
nSingle +5V supply
n−7V to +12V bus common mode range permits ±7V ground difference between devices on the bus
nThermal shutdown protection
nHigh impedance to bus with driver in TRI-STATE or with power off, over the entire common mode range allows the unused devices on the bus to be powered down
nCombined impedance of a driver output and receiver input is less than one RS485 unit load, allowing up to 32 transceivers on the bus
n70 mV typical receiver hysteresis
Connection and Logic Diagrams
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DS010408-1 |
DS010408-12 |
Top View |
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Top View |
DS010408-13
Top View
Order Number DS3695N, DS3695TN,
DS3696N, or DS3697N
See NS Package Number N08E
Note 1: TS pin was LF (Line Fault) in previous datasheets and reports the occurrence of a thermal shutdown of the device.
TRI-STATE® is a registered trademark of National Semiconductor Corporation.
Transceivers/Repeaters RS485/RS422 Multipoint DS3695/DS3695T/DS3696/DS3697
© 1998 National Semiconductor Corporation |
DS010408 |
www.national.com |
Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.
Supply Voltage, VCC |
7V |
Control Input Voltages |
7V |
Driver Input Voltage |
7V |
Driver Output Voltages |
+15V/−10V |
Receiver Input Voltages |
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(DS3695, DS3696) |
+15V/−10V |
Receiver Common Mode Voltage |
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(DS3697) |
±25V |
Receiver Output Voltage |
5.5V |
Continuous Power Dissipation @ 25ÊC |
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N Package |
1.07W (Note |
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4) |
Storage Temperature Range |
−65ÊC to |
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+150ÊC |
Lead Temperature (Soldering, 4 |
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sec.) |
260ÊC |
Recommended Operating
Conditions
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Min |
Max |
Units |
Supply Voltage, VCC |
4.75 |
5.25 |
V |
Bus Voltage |
−7 |
+12 |
V |
Operating Free Air Temp. (TA) |
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Commercial |
0 |
+70 |
ÊC |
Industrial |
−40 |
+85 |
ÊC |
Electrical Characteristics (Notes 3, 4)
0ÊC ≤ TA ≤ +70ÊC, 4.75V < VCC < 5.25V unless otherwise specified
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Conditions |
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Max |
Units |
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VOD1 |
Differential Driver Output |
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IO = 0 |
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5 |
V |
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Voltage (Unloaded) |
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VOD2 |
Differential Driver Output |
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(Figure 1 ) |
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R = 50Ω; (RS-422) (Note |
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V |
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Voltage (with Load) |
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R = 27Ω; (RS-485) |
1.5 |
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V |
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VOD |
Change in Magnitude of Driver |
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Differential Output Voltage for |
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0.2 |
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Complementary Output States |
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R = 27Ω |
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VOC |
Driver Common Mode Output Voltage |
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(Figure 1 ) |
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3.0 |
V |
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|VOC| |
Change in Magnitude of Driver |
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Common Mode Output Voltage |
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0.2 |
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for Complementary Output States |
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VIH |
Input High Voltage |
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VIL |
Input Low Voltage |
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DI, DE, |
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0.8 |
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VCL |
Input Clamp Voltage |
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IIN = −18 mA |
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−1.5 |
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RE |
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RE |
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IIL |
Input Low Current |
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VIL = 0.4V |
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−200 |
µA |
IIH |
Input High Current |
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VIH = 2.4V |
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20 |
µA |
IIN |
Input Current |
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DO/RI, |
DO |
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VCC = 0V or |
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VIN = 12V |
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+1.0 |
mA |
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5.25V |
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/DE or DE = |
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VIN = −7V |
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−0.8 |
mA |
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RE |
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RI, RI |
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0V |
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VCC = 0V or 5.25V, E = 0V |
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IOZD |
TRI-STATE Current |
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DO, |
DO |
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µA |
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DS3697 & DS3698 |
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−7V < VO < +12V |
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VTH |
Differential Input Threshold |
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−7V ≤ VCM ≤ +12V |
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−0.2 |
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+0.2 |
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Voltage for Receiver |
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VTH |
Receiver Input Hysteresis |
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VCM = 0V |
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VOH |
Receiver Output High Voltage |
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IOH = −400 µA |
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2.4 |
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V |
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VOL |
Output Low Voltage |
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RO |
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IOL = 16 mA (Note 6) |
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0.5 |
V |
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IOL = 8 mA |
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0.45 |
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TS |
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IOZR |
OFF-State (High Impedance) |
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VCC = Max |
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±20 |
µA |
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Output Current at Receiver |
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0.4V ≤ VO ≤ 2.4V |
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RIN |
Receiver Input Resistance |
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−7V ≤ VCM ≤ +12V |
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12 |
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kΩ |
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www.national.com |
2 |
Electrical Characteristics (Notes 3, 4) (Continued) |
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0ÊC ≤ TA ≤ +70ÊC, 4.75V < VCC < 5.25V unless otherwise specified |
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Symbol |
Parameter |
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Conditions |
Min |
Typ |
Max |
Units |
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ICC |
Supply Current |
No Load |
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Driver Outputs Enabled |
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42 |
60 |
mA |
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(Note 6) |
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Driver Outputs Disabled |
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27 |
40 |
mA |
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IOSD |
Driver Short-Circuit Output Current |
VO = −7V (Note 6) |
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−250 |
mA |
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VO = +12V (Note 6) |
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+250 |
mA |
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IOSR |
Receiver Short-Circuit Output Current |
VO = 0V |
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−15 |
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−85 |
mA |
Note 2: ªAbsolute Maximum Ratingsº are those beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device should be operated at these limits. The tables of ªElectrical Characteristicsº provide conditions for actual device operation.
Note 3: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified.
Note 4: All typicals are given for VCC = 5V and TA = 25ÊC.
Note 5: Derate linearly at 11.1 mW/ÊC to 570 mW at 70ÊC.
Note 6: All limits for which Note 5 is applied must be derated by 10% for DS3695T and DS3696T. Other parameters remain the same for this extended temperature range device (−40ÊC ≤ TA ≤ +85ÊC).
Switching Characteristics (Notes 4, 7) |
0ÊC ≤ TA ≤ +70ÊC, 4.75V < VCC < 5.25V unless otherwise specified |
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Receiver Switching Characteristics |
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(Figures 2, 3, 4) |
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Symbol |
Conditions |
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Min |
Typ |
Max |
Units |
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tPLH |
CL = 15 pF |
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15 |
25 |
37 |
ns |
tPHL |
S1 and S2 |
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15 |
25 |
37 |
ns |
|tPLH±tPHL| |
Closed |
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0 |
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ns |
tPLZ |
CL = 15 pF, S2 Open |
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5 |
12 |
16 |
ns |
tPHZ |
CL = 15 pF, S1 Open |
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5 |
12 |
16 |
ns |
tPZL |
CL = 15 pF, S2 Open |
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7 |
15 |
20 |
ns |
tPZH |
CL = 15 pF, S1 Open |
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7 |
15 |
20 |
ns |
Driver Switching Characteristics
Symbol |
Conditions |
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Min |
Typ |
Max |
Units |
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SINGLE ENDED CHARACTERISTICS (Figures 5, 6, 7) |
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tPLH |
RLDIFF = 60Ω |
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9 |
15 |
22 |
ns |
tPHL |
CL1 = CL2 = 100 pF |
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9 |
15 |
22 |
ns |
tSKEW|tPLH±tPHL| |
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8 |
ns |
tPLZ |
CL = 15 pF, S2 Open |
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15 |
30 |
ns |
tPHZ |
CL = 15 pF, S1 Open |
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7 |
15 |
30 |
ns |
tPZL |
CL = 100 pF, S2 Open |
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30 |
35 |
50 |
ns |
tPZH |
CL = 100 pF, S1 Open |
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30 |
35 |
50 |
ns |
DIFFERENTIAL CHARACTERISTICS (Figures 5, 8) |
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tr, tf |
RLDIFF = 60Ω |
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6 |
10 |
18 |
ns |
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CL1 = CL2 = 100 pF |
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Note 7: Switching Characteristics apply for DS3695, DS3695T, DS3696, DS3697 only. |
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3 |
www.national.com |
AC Test Circuits and Switching Waveforms
DS010408-15
FIGURE 1. Driver VOD and VOC
DS010408-3
FIGURE 2. Receiver Propagation Delay Test Circuit
DS010408-4
Note: Differential input voltage may be realized by grounding RI and pulsing RI between +2.5V and −2.5V.
FIGURE 3. Receiver Input-to-Output Propagation Delay Timing
DS010408-5
FIGURE 4. Receiver Enable/Disable Propagation Delay Timing
www.national.com |
4 |
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