View MAX3483_112270.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-0333; Rev 0; 12/94
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
_______________General Description
The MAX3483, MAX3485, MAX3486, MAX3488, MAX3490, and MAX3491 are 3.3V, low-power transceivers for RS-485 and RS-422 communication. Each part contains one driver and one receiver. The MAX3483 and MAX3488 feature slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission at data rates up to 250kbps. The partially slew-rate-limited MAX3486 transmits up to 2.5Mbps. The MAX3485, MAX3490, and MAX3491 transmit at up to 10Mbps. Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if both inputs are open circuit. The MAX3488, MAX3490, and MAX3491 feature fullduplex communication, while the MAX3483, MAX3485, and MAX3486 are designed for half-duplex communication.
____________________________Features
o Operate from a Single 3.3V Supply-- No Charge Pump! o Interoperable with +5V Logic o 8ns Max Skew (MAX3485/MAX3490/MAX3491) o Slew-Rate Limited for Errorless Data Transmission (MAX3483/MAX3488) o 2nA Low-Current Shutdown Mode (MAX3483/MAX3485/MAX3486/MAX3491) o -7V to +12V Common-Mode Input Voltage Range o Allows up to 32 Transceivers on the Bus o Full-Duplex and Half-Duplex Versions Available o Industry Standard 75176 Pinout (MAX3483/MAX3485/MAX3486) o Current-Limiting and Thermal Shutdown for Driver Overload Protection
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
______________Ordering Information
PART MAX3483CPA MAX3483CSA MAX3483C/D MAX3483EPA MAX3483ESA MAX3485CPA MAX3485CSA MAX3485C/D MAX3485EPA MAX3485ESA TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO
________________________Applications
Low-Power RS-485/RS-422 Transceivers Telecommunications Transceivers for EMI-Sensitive Applications Industrial-Control Local Area Networks
Ordering Information continued at end of data sheet. * Contact factory for for dice specifications.
______________________________________________________________Selection Table
PART NUMBER MAX3483 MAX3485 MAX3486 MAX3488 MAX3490 MAX3491 GUARANTEED DATA RATE (Mbps) 0.25 10 2.5 0.25 10 10 3.0 to 3.6 SUPPLY VOLTAGE (V) HALF/FULL DUPLEX Half Half Half Full Full Full SLEW-RATE LIMITED Yes No Yes Yes No No DRIVER/ RECEIVER ENABLE Yes Yes Yes No No Yes SHUTDOWN CURRENT (nA) 2 2 2 -- -- 2 PIN COUNT 8 8 8 8 8 14 1
________________________________________________________________ Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC) ...............................................................7V Control Input Voltage (RE, DE) ...................................-0.3V to 7V Driver Input Voltage (DI) .............................................-0.3V to 7V Driver Output Voltage (A, B, Y, Z)..........................-7.5V to 12.5V Receiver Input Voltage (A, B) ................................-7.5V to 12.5V Receiver Output Voltage (RO)....................-0.3V to (VCC + 0.3V) Continuous Power Dissipation (TA = +70C) 8-Pin Plastic DIP (derate 9.09mW/C above +70C) .....727mW 8-Pin SO (derate 5.88mW/C above +70C)..................471mW 14-Pin Plastic DIP (derate 10mW/C above +70C) ......800mW 14-Pin SO (derate 8.33mW/C above +70C)................667mW Operating Temperature Ranges MAX34_ _C_ _.......................................................0C to +70C MAX34_ _E_ _ ....................................................-40C to +85C Storage Temperature Range .............................-65C to +160C Lead Temperature (soldering, 10sec) .............................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(VCC = 3.3V 0.3V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C) PARAMETER Differential Driver Output Change in Magnitude of Driver Differential Output Voltage for Complementary Output States (Note 1) Driver Common-Mode Output Voltage Change in Magnitude of Common-Mode Output Voltage (Note 1) Input High Voltage Input Low Voltage Logic Input Current Input Current (A, B) Output Leakage (Y, Z) Output Leakage (Y, Z) in Shutdown Mode Receiver Differential Threshold Voltage Receiver Input Hysteresis Receiver Output High Voltage Receiver Output Low Voltage Three-State (High Impedance) Output Current at Receiver Receiver Input Resistance SYMBOL VOD CONDITIONS RL = 100 (RS-422), Figure 4 RL = 54 (RS-485), Figure 4 RL = 60 (RS-485), VCC = 3.3V, Figure 5 VOD MIN 2.0 1.5 1.5 V TYP MAX UNITS
RL = 54 or 100, Figure 4
0.2
V
VOC
RL = 54 or 100, Figure 4
3
V
VOC VIH VIL IIN1 IIN2 IO IO VTH VTH VOH VOL IOZR RIN
RL = 54 or 100, Figure 4 DE, DI, RE DE, DI, RE DE, DI, RE DE = 0V, VCC = 0V or 3.6V VIN = 12V VIN = -7V 2.0
0.2
V V
0.8 2 1.0 -0.8 20 -20 1 -1 -0.2 50 VCC - 0.4 0.4 1 12 0.2
V A mA A A V mV V V A k
VOUT = 12V DE = 0V, RE = 0V, VCC = 0V or 3.6V, MAX3491 VOUT = -7V VOUT = 12V DE = 0V, RE = VCC, VCC = 0V or 3.6V, MAX3491 VOUT = -7V -7V VCM 12V VCM = 0V IOUT = -1.5mA, VID = 200mV, Figure 6 IOUT = 2.5mA, VID = 200mV, Figure 6 VCC = 3.6V, 0V VOUT VCC -7V VCM 12V
2
_______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 3.3V 0.3V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C) PARAMETER SYMBOL No load, DI = 0V or VCC CONDITIONS DE = VCC, RE = 0V or VCC DE = 0V, RE = 0V MIN TYP 1.1 0.95 0.002 MAX 2.2 mA 1.9 1 -250 250 8 60 A mA mA UNITS
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
Supply Current
ICC
Supply Current in Shutdown Mode Driver Short-Circuit Output Current Receiver Short-Circuit Output Current
ISHDN IOSD IOSR
DE = 0V, RE = VCC, DI = VCC or 0V VOUT = -7V VOUT = 12V 0V VRO VCC
DRIVER SWITCHING CHARACTERISTICS--MAX3485, MAX3490, and MAX3491
(VCC = 3.3V, TA = +25C) PARAMETER Driver Differential Output Delay Driver Differential Output Transition Time Driver Propagation Delay, Low-to-High Level Driver Propagation Delay, High-to-Low Level SYMBOL tDD tTD tPLH tPHL CONDITIONS RL = 60, Figure 7 RL = 60, Figure 7 RL = 27, Figure 8 RL = 27, Figure 8 MIN 1 3 7 7 TYP 22 8 22 22 MAX 35 25 35 35 8 45 45 40 40 650 650 90 90 80 80 900 900 UNITS ns ns ns ns ns ns ns ns ns ns ns
tPDS RL = 27, Figure 8 |tPLH - tPHL| Driver Propagation Delay Skew (Note 2) DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3485/MAX3491 only) Driver Output Enable Time to Low Level Driver Output Enable Time to High Level Driver Output Disable Time from High Level Driver Output Disable Time from Low Level Driver Output Enable Time from Shutdown to Low Level Driver Output Enable Time from Shutdown to High Level tPZL tPZH tPHZ tPLZ tPSL tPSH RL = 110, Figure 10 RL = 110, Figure 9 RL = 110, Figure 9 RL = 110, Figure 10 RL = 110, Figure 10 RL = 110, Figure 9
DRIVER SWITCHING CHARACTERISTICS--MAX3486
(VCC = 3.3V, TA = +25C) PARAMETER Driver Differential Output Delay Driver Differential Output Transition Time Driver Propagation Delay, Low-to-High Level Driver Propagation Delay, High-to-Low Level SYMBOL tDD tTD tPLH tPHL tPDS tPZL tPZH tPHZ tPLZ tPSL tPSH CONDITIONS RL = 60, Figure 7 RL = 60, Figure 7 RL = 27, Figure 8 RL = 27, Figure 8 RL = 27, Figure 8 RL = 110, Figure 10 RL = 110, Figure 9 RL = 110, Figure 9 RL = 110, Figure 10 RL = 110, Figure 10 RL = 110, Figure 9 55 55 45 45 700 700 MIN 24 15 20 20 TYP 48 35 48 48 MAX 70 60 70 70 11 100 100 80 80 1000 1000 UNITS ns ns ns ns ns ns ns ns ns ns ns 3
|tPLH - tPHL| Driver Propagation Delay Skew (Note 2)
Driver Output Enable Time to Low Level Driver Output Enable Time to High Level Driver Output Disable Time from High Level Driver Output Disable Time from Low Level Driver Output Enable Time from Shutdown to Low Level Driver Output Enable Time from Shutdown to High Level
_______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
DRIVER SWITCHING CHARACTERISTICS--MAX3483 and MAX3488
(VCC = 3.3V, TA = +25C) PARAMETER Driver Differential Output Delay Driver Differential Output Transition Time Driver Propagation Delay, Low-to-High Level Driver Propagation Delay, High-to-Low Level SYMBOL tDD tTD tPLH tPHL CONDITIONS RL = 60, Figure 7 RL = 60, Figure 7 RL = 27, Figure 8 RL = 27, Figure 8 RL = 27, Figure 8 RL = 110, Figure 10 RL = 110, Figure 9 RL = 110, Figure 9 RL = 110, Figure 10 RL = 110, Figure 10 RL = 110, Figure 9 MIN 600 400 700 700 TYP 900 700 1000 1000 100 900 600 50 50 1.9 2.2 1300 800 80 80 2.7 3.0 MAX 1400 1200 1500 1500 UNITS ns ns ns ns ns ns ns ns ns s s
tPDS |tPLH - tPHL| Driver Propagation Delay Skew (Note 2) DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3483 only) Driver Output Enable Time to Low Level Driver Output Enable Time to High Level Driver Output Disable Time from High Level Driver Output Disable Time from Low Level Driver Output Enable Time from Shutdown to Low Level Driver Output Enable Time from Shutdown to High Level tPZL tPZH tPHZ tPLZ tPSL tPSH
RECEIVER SWITCHING CHARACTERISTICS
(VCC = 3.3V, TA = +25C) PARAMETER Time to Shutdown Receiver Propagation Delay, Low-to-High Level Receiver Propagation Delay, High-to-Low Level SYMBOL tSHDN tRPLH tRPHL tRPDS tPRZL tPRZH tPRHZ tPRLZ tPRSL tPRSH CONDITIONS MAX3483/MAX3485/MAX3486/MAX3491 only (Note 3) VID = 0V to 3.0V, CL = 15pF, Figure 11 MAX3483/MAX3488 VID = 0V to 3.0V, CL = 15pF, Figure 11 MAX3483/MAX3488 VID = 0V to 3.0V, CL = 15pF, Figure 11 MAX3483/MAX3488 CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only CL = 15pF, Figure 12, MAX3483/MAX3485/MAX3486/MAX3491 only 25 25 25 25 720 720 MIN 80 25 25 25 25 TYP 190 65 75 65 75 MAX 300 90 120 90 120 10 20 50 50 45 45 1400 1400 UNITS ns ns ns ns ns ns ns ns ns ns
|tPLH - tPHL| Receiver Propagation Delay Skew
Receiver Output Enable Time to Low Level Receiver Output Enable Time to High Level Receiver Output Disable Time from High Level Receiver Output Disable Time from Low Level Receiver Output Enable Time from Shutdown to Low Level Receiver Output Enable Time from Shutdown to High Level
Note 1: VOD and VOC are the changes in VOD and VOC, respectively, when the DI input changes state. Note 2: Measured on |tPLH (Y) - tPHL (Y)| and |tPLH (Z) - tPHL (Z)|. Note 3: The transceivers are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 80ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 300ns, the parts are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section. 4 _______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
__________________________________________Typical Operating Characteristics
(VCC = 3.3V, TA = +25C, unless otherwise noted.)
OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE
MAX3483-01
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE
MAX3483-02
RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE
IRO = 1.5mA
MAX3483-03 MAX3483-06
25
-20 -18 OUTPUT CURRENT (mA) -16 -14 -12 -10 -8 -6 -4 -2
3.30 OUTPUT HIGH VOLTAGE (V) 3.25 3.20 3.15 3.10 3.05 3.00
OUTPUT CURRENT (mA)
20
15
10
5
0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 OUTPUT LOW VOLTAGE (V)
0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 OUTPUT HIGH VOLTAGE (V)
-40
-20
0
20
40
60
80
100
TEMPERATURE (C)
RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE
MAX3483-04
DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX3483-05
DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs.TEMPERATURE
2.6 DIFFERENTIAL OUTPUT VOLTAGE (V) 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8 1.7 1.6 -40 -20 0 20 40 60 80 100 R = 54
0.8 0.7 OUTPUT LOW VOLTAGE (V) 0.6 0.5 0.4 0.3 0.2 0.1 0 -40 -20 0 20 40
100 90 OUTPUT CURRENT (mA) 80 70 60 50 40 30 20 10 0
IRO = 2.5mA
60
80
100
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
TEMPERATURE (C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
TEMPERATURE (C)
OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGE
MAX3483-07
OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE
MAX3483-08
175 150 OUTPUT CURRENT (mA) 125 100 75 50 25 0 0 2 4 6 8 10
-100
OUTPUT CURRENT (mA) 12
-80
-60
-40
-20
0 OUTPUT LOW VOLTAGE (V) -7 -6 -5 -4 -3 -2 -1 0 1 2 3 OUTPUT HIGH VOLTAGE (V) 4 5
_______________________________________________________________________________________
5
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
_____________________________Typical Operating Characteristics (continued)
SUPPLY CURRENT vs. TEMPERATURE
X = DON'T CARE SUPPLY CURRENT (mA) 1.1 DE = VCC, RE = X DE = 0, RE = 0 0.9
MAX3483-09
SHUTDOWN CURRENT vs. TEMPERATURE
90 SHUTDOWN CURRENT (nA) 80 70 60 50 40 30 20 10
MAX3483-10
1.2
100
1.0
0.8 0.7 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
______________________________________________________________Pin Description
PIN MAX3483/ MAX3485/ MAX3486 1 MAX3488/ MAX3490 2 NAME MAX3491 Receiver Output. If A > B by 200mV, RO will be high; if A < B by 200mV, RO will be low. Receiver Output Enable. RO is enabled when RE is low; RO is high impedance when RE is high. If RE is high and DE is low, the device will enter a low-power shutdown mode. Driver Output Enable. The driver outputs are enabled by bringing DE high. They are high impedance when DE is low. If RE is high and DE is low, the device will enter a low-power shutdown mode. If the driver outputs are enabled, the parts function as line drivers. While they are high impedance, they function as line receivers if RE is low. Driver Input. A low on DI forces output Y low and output Z high. Similarly, a high on DI forces output Y high and output Z low. Ground Noninverting Driver Output Inverting Driver Output Noninverting Receiver Input and Noninverting Driver Output Noninverting Receiver Input Inverting Receiver Input and Inverting Driver Output Inverting Receiver Input Positive Supply: 3.0V VCC 3.6V No Connect--not internally connected FUNCTION
2
RO - RE
2
--
3
3
--
4
DE
4 5 -- -- 6 -- 7 -- 8 -- 6
3 4 5 6 -- 8 -- 7 1 --
5 6, 7 9 10 -- 12 -- 11 13, 14 1, 8
DI GND Y Z A A B B VCC N.C.
_______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
TOP VIEW
RO
1
R
8 7 6
VCC B A GND
RO
1
R
RE 2 DE 3 DI 4 D
RE 2 DE 3 DI 4 D
5
8 VCC 7B Rt 6 A 5 GND
MAX3483 MAX3485 MAX3486
B Rt A R
DE D DI
RO RE
DIP/SO
NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.
Figure 1. MAX3483/MAX3485/MAX3486 Pin Configuration and Typical Operating Circuit
TOP VIEW
VCC 1 5Y
VCC
MAX3488 MAX3490
Rt 6Z
VCC 1 RO 2 DI 3 GND 4
R
8 7 6
A B Z Y
DI
3
D
R
RO
8A RO 2
D
5
R
Rt 7 B
D
DI
DIP/SO
4 GND GND
Figure 2. MAX3488/MAX3490 Pin Configuration and Typical Operating Circuit
TOP VIEW
DE 4 1 2 3 4 5 6 7 D R 14 V CC 13 V CC 12 A 11 B 10 Z 9Y 8 N.C. N.C. 1, 8 3 RO 2 DI 5
VCC 13, 14 9 Y
VCC RE
MAX3491
N.C. RO RE DE DI GND GND
D
Rt 10 Z 12 A Rt 11 B
R
RO
R
D
DI
DIP/SO
6, 7 RE GND
GND
DE
Figure 3. MAX3491 Pin Configuration and Typical Operating Circuit
_______________________________________________________________________________________ 7
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
375 RL 2 D VOD RL 2 D VOC VCC 375 VOD RL VCM = -7V to +12V
VCC
Figure 4. Driver VOD and VOC
Figure 5. Driver VOD with Varying Common-Mode Voltage
VID
R
0V VOL IOL (+) VOH IOH (-)
Figure 6. Receiver VOH and VOL
3V IN CL D GENERATOR (NOTE 4) 50 VCC CL CL = 15pF (NOTE 5) 90% OUT 50% 10% tTD 90% 50% 10% tTD RL = 60 OUT tDO tDO 1.5V 1.5V 0V
2.0V
-2.0V
Figure 7. Driver Differential Output Delay and Transition Times
8
_______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
3V VOM IN RL = 27 S1 D GENERATOR (NOTE 4) 50 VCC VOH + VOL 2 OUT CL = 15pF (NOTE 5) Y OUT tPLH tPHL VOH VOM VOM VOL 1.5V 1.5V 0V
VOM =
1.5V
Z OUT
tPHL
tPLH VOH VOM VOM VOL
Figure 8. Driver Propagation Times
S1 0V OR 3V D OUT RL = 110 tPZH tPHZ 0.25V VOM IN 1.5V 1.5V
3V
0V GENERATOR (NOTE 4) CL = 50pF (NOTE 5) 50 OUT VOH + VOL VOM = 2
VOH
1.5V
0V
Figure 9. Driver Enable and Disable Times (tPZH, tPSH, tPHZ)
VCC 3V RL = 110 S1 0V OR 3V D CL = 50pF (NOTE 5) 50 OUT tPSL GENERATOR (NOTE 4) tPLZ VCC OUT VOM 0.25V VOL IN 1.5V 1.5V 0V
Figure 10. Driver Enable and Disable Times (tPZL, tPSL, tPLZ)
_______________________________________________________________________________________
9
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
3.0V GENERATOR (NOTE 4) VID 50 R OUT IN CL = 15pF (NOTE 5) tRPLH tRPHL VCC 1.5V 0V VOM = VCC 2 OUT VOM VOM 0V 1.5V 1.5V 0V
Figure 11. Receiver Propagation Delay
S1 1k VID R S2 VCC
1.5V -1.5V
S3
CL (NOTE 5) GENERATOR (NOTE 4) 50
3V IN tPRZH tPRSH VOH OUT 1.5V 0V OUT 1.5V 1.5V 0V S1 OPEN S2 CLOSED S3 = 1.5V IN tPRZL tPRSL 1.5V
3V S1 CLOSED S2 OPEN S3 = -1.5V
0V
VCC
VOL
3V IN 1.5V 0V tPRHZ OUT 0.25V VOH OUT 0V tPRLZ 0.25V S1 OPEN S2 CLOSED S3 = 1.5V IN 1.5V
3V S1 CLOSED S2 OPEN S3 = -1.5V
0V
VCC
VOL
Figure 12. Receiver Enable and Disable Times
Note 4: The input pulse is supplied by a generator with the following characteristics: PRR = 250kHz, 50% duty cycle, tr 6.0ns, ZO = 50. Note 5: CL includes probe and stray capacitance. 10 ______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
____________________Function Tables
Devices with Receiver/Driver Enable (MAX3483/MAX3485/MAX3486/MAX3491)
__________Applications Information
The MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/ MAX3491 are low-power transceivers for RS-485 and RS-422 communications. The MAX3483 and MAX3488 can transmit and receive at data rates up to 250kbps, the MAX3486 at up to 2.5Mbps, and the MAX3485/ MAX3490/MAX3491 at up to 10Mbps. The MAX3488/ MAX3490/MAX3491 are full-duplex transceivers, while the MAX3483/MAX3485/MAX3486 are half-duplex. Driver Enable (DE) and Receiver Enable (RE) pins are included on the MAX3483/MAX3485/MAX3486/ MAX3491. When disabled, the driver and receiver outputs are high impedance.
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
Table 1. Transmitting
INPUTS RE X X 0 1 DE 1 1 0 0 DI 1 0 X X OUTPUTS B* 0 1 High-Z High-Z A* 1 0 High-Z High-Z MODE Normal Normal Normal Shutdown
* B and A outputs are Z and Y, respectively, for full-duplex part (MAX3491). X = Don't care; High-Z = High impedance
Reduced EMI and Reflections (MAX3483/MAX3486/MAX3488)
The MAX3483/MAX3488 are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 13 shows both the driver output waveform of a MAX3485/MAX3490/MAX3491 transmitting a 125kHz signal and the Fourier analysis of that waveform. High-frequency harmonics with large amplitudes are evident. Figure 14 shows the same information, but for the slew-rate-limited MAX3483/MAX3488 transmitting the same signal. The high-frequency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced.
Table 2. Receiving
INPUTS RE 0 0 0 1 DE 0* 0* 0* 0 A, B +0.2V -0.2V Inputs Open X OUTPUTS RO 1 0 1 High-Z MODE Normal Normal Normal Shutdown
* DE is a "don't care" (x) for the full-duplex part (MAX3491). X = Don't care; High-Z = High impedance
Devices without Receiver/Driver Enable (MAX3488/MAX3490)
Low-Power Shutdown Mode (MAX3483/MAX3485/MAX3486/MAX3491)
A low-power shutdown mode is initiated by bringing both RE high and DE low. The devices will not shut down unless both the driver and receiver are disabled (high impedance). In shutdown, the devices typically draw only 2nA of supply current. For these devices, the t PSH and t PSL enable times assume the part was in the low-power shutdown mode; the tPZH and tPZL enable times assume the receiver or driver was disabled, but the part was not shut down.
Table 3. Transmitting
INPUT DI 1 0 OUTPUTS Z 0 1 Y 1 0
Table 4. Receiving
INPUTS A, B +0.2V -0.2V Inputs Open OUTPUT RO 1 0 1
10dB/div
10dB/div
0Hz
500kHz/div
5MHz
0Hz
500kHz/div
5MHz
Figure 13. Driver Output Waveform and FFT Plot of MAX3485/ MAX3490/MAX3491 Transmitting a 125kHz Signal
Figure 14. Driver Output Waveform and FFT Plot of MAX3483/ MAX3488 Transmitting a 125kHz Signal
11
______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
B 1V/div DI 2V/div Z 1V/div A 1V/div
Y 1V/div 20ns/div
RO 2V/div 20ns/div
Figure 15. MAX3485/MAX3490/MAX3491 Driver Propagation Delay
Figure 16. MAX3485/MAX3490/MAX3491 Receiver Propagation Delay Driven by External RS-485 Device
B 1V/div DI 2V/div Z 1V/div Y 1V/div 1s/div A 1V/div
RO 2V/div 1s/div
Figure 17. MAX3483/MAX3488 Driver Propagation Delay
Figure 18. MAX3483/MAX3488 Receiver Propagation Delay
DI 5V/div VY - VZ 2V/div
DI 5V/div VY - VZ 2V/div
RO 5V/div
RO 5V/div
2s/div
2s/div
Figure 19. MAX3483/MAX3488 System Differential Voltage at 125kHz Driving 4000 ft of Cable
Figure 20. MAX3485/MAX3490/MAX3491 System Differential Voltage at 125kHz Driving 4000 ft of Cable
12
______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
120 DI B 120 B DE
D
DE RO RE A B A B A A
D
DI
R R R D
R
RO RE
MAX3483 MAX3485 MAX3486
DI
D
DE
RO RE
DI
DE
RO RE
Figure 21. MAX3483/MAX3485/MAX3486 Typical RS-485 Network
Driver Output Protection
Excessive output current and power dissipation caused by faults or by bus contention are prevented by two mechanisms. A foldback current limit on the output stage provides immediate protection against short circuits over the whole common-mode voltage range (see Typical Operating Characteristics). In addition, a thermal shutdown circuit forces the driver outputs into a high-impedance state if the die temperature rises excessively.
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, see Figure 23. Figures 19 and 20 show the system differential voltage for parts driving 4000 feet of 26AWG twisted-pair wire at 125kHz into 120 loads.
Typical Applications
The MAX3483, MAX3485, MAX3486, MAX3488, MAX3490, and MAX3491 transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figures 21 and 22 show typical network applications circuits. These parts can also be used as line repeaters, with cable lengths longer than 4000 feet, as shown in Figure 23. To minimize reflections, the line should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possible. The slew-rate-limited MAX3483/MAX3488 and the partially slew-rate-limited MAX3486 are more tolerant of imperfect termination.
Propagation Delay
Figures 15-18 show the typical propagation delays. Skew time is simply the difference between the low-to-high and high-to-low propagation delay. Small driver/receiver skew times help maintain a symmetrical mark-space ratio (50% duty cycle). The receiver skew time, |tPRLH - tPRHL|, is under 10ns (20ns for the MAX3483/MAX3488). The driver skew times are 8ns for the MAX3485/MAX3490/MAX3491, 11ns for the MAX3486, and typically under 100ns for the MAX3483/MAX3488.
______________________________________________________________________________________
13
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
A RO RE DE Z DI B 120 Y Y Z B A Y Z B A 120 A Y 120 B 120 Z DE RE RO
R
D
DI
D
R
R D D
R
MAX3488 MAX3490 MAX3491
DE RE RO
DI
DE RE RO
DI
NOTE: RE AND DE ON MAX3491 ONLY.
Figure 22. MAX3488/MAX3490/MAX3491 Full-Duplex RS-485 Network
A RO RE DE Z DI 120 Y
MAX3488 MAX3490 MAX3491
120 DATA IN
R
B
D
DATA OUT
NOTE: RE AND DE ON MAX3491 ONLY.
Figure 23. Line Repeater for MAX3488/MAX3490/MAX3491
14
______________________________________________________________________________________
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
_Ordering Information (continued)
PART MAX3486CPA MAX3486CSA MAX3486C/D MAX3486EPA MAX3486ESA MAX3488CPA MAX3488CSA MAX3488C/D MAX3488EPA MAX3488ESA MAX3490CPA MAX3490CSA MAX3490C/D MAX3490EPA MAX3490ESA MAX3491CPD MAX3491CSD MAX3491C/D MAX3491EPD MAX3491ESD TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 14 Plastic DIP 14 SO Dice* 14 Plastic DIP 14 SO
__________________ Chip Topography
V CC
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
RO A RE B Z/B
0.146" (3.71mm)
DE DI Y/A GND GND 0.086" (2.18mm)
* Contact factory for for dice specifications.
TRANSISTOR COUNT: 810 SUBSTRATE CONNECTED TO GROUND
______________________________________________________________________________________
15
3.3V-Powered, 10Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers
MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/MAX3491
________________________________________________________Package Information
DIM INCHES MAX MIN 0.069 0.053 0.010 0.004 0.019 0.014 0.010 0.007 0.157 0.150 0.050 0.244 0.228 0.050 0.016 MILLIMETERS MIN MAX 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 3.80 4.00 1.27 5.80 6.20 0.40 1.27
D A e B
0.101mm 0.004in.
0-8
A1
C
L
A A1 B C E e H L
E
H
SO SMALL OUTLINE PACKAGE (0.150 in.)
DIM PINS D D D 8 14 16
INCHES MILLIMETERS MIN MAX MIN MAX 0.189 0.197 4.80 5.00 0.337 0.344 8.55 8.75 0.386 0.394 9.80 10.00
21-0041A
E D A3 A A2 E1
DIM A A1 A2 A3 B B1 C D1 E E1 e eA eB L
L A1 e B D1
0 - 15 C B1 eA eB
INCHES MAX MIN 0.200 - - 0.015 0.175 0.125 0.080 0.055 0.022 0.016 0.065 0.045 0.012 0.008 0.080 0.005 0.325 0.300 0.310 0.240 - 0.100 - 0.300 0.400 - 0.150 0.115 INCHES MIN MAX 0.348 0.390 0.735 0.765 0.745 0.765 0.885 0.915 1.015 1.045 1.14 1.265
MILLIMETERS MIN MAX - 5.08 0.38 - 3.18 4.45 1.40 2.03 0.41 0.56 1.14 1.65 0.20 0.30 0.13 2.03 7.62 8.26 6.10 7.87 2.54 - 7.62 - - 10.16 2.92 3.81 MILLIMETERS MIN MAX 8.84 9.91 18.67 19.43 18.92 19.43 22.48 23.24 25.78 26.54 28.96 32.13
Plastic DIP PLASTIC DUAL-IN-LINE PACKAGE (0.300 in.)
DIM PINS D D D D D D 8 14 16 18 20 24
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 (c) 1994 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

▲Up To Search▲

Price & Availability of MAX3483

	To Download MAX3483 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .