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19-2143; Rev 1; 12/01
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters
General Description
The MAX3040-MAX3045 is a family of 5V quad RS485/RS-422 transmitters designed for digital data transmission over twisted-pair balanced lines. All transmitter outputs are protected to 10kV using the Human Body Model. In addition the MAX3040-MAX3045 withstand 4kV per IEC 1000-4-4 Electrical Fast Transient/Burst Stressing. The MAX3040/MAX3043 (250kbps) and the MAX3041/MAX3044 (2.5Mbps) are slew-rate limited transmitters that minimize EMI and reduce reflections caused by improperly terminated cables, thus allowing error-free transmission. The MAX3040-MAX3045 feature a hot-swap capability* that eliminates false transitions on the data cable during power-up or hot insertion. The MAX3042B/MAX3045B are optimized for data transfer rates up to 20Mbps, the MAX3041/MAX3044 for data rates up to 2.5Mbps, and the MAX3040/MAX3043 for data rates up to 250kbps. The MAX3040-MAX3045 offer optimum performance when used with the MAX3093E or MAX3095 5V quad differential line receivers or MAX3094E/MAX3096 3V quad differential line receivers. The MAX3040-MAX3045 are ESD-protected pin-compatible, low-power upgrades to the industry-standard `SN75174 and `DS26LS31C. They are available in spacesaving TSSOP, narrow SO, and wide SO packages.
*Patent pending
Features
o ESD Protection: 10kV--Human Body Model o Single +5V Operation o Guaranteed Device-to-Device Skew (MAX3040/MAX3041/MAX3043/MAX3044) o Pin-Compatible with `SN75174, `26LS31C and LTC487 o Hot-Swappable for Telecom Applications o Up to 20Mbps Data Rate (MAX3042B/MAX3045B) o Slew-Rate Limited (Data Rates at 2.5Mbps and 250kbps) o 2nA Low-Power Shutdown Mode o 1mA Operating Supply Current o 4kV EFT Fast Transient Burst Immunity per IEC 1000-4-4 o Level 2 Surge Immunity per IEC 1000-4-5, Unshielded Cable Model o Ultra-Small 16-Pin TSSOP, 16-Pin Narrow SO, and Wide 16-Pin SO
MAX3040-MAX3045
Ordering Information
PART MAX3040CUE MAX3040CSE MAX3040CWE MAX3040EUE MAX3040ESE TEMP RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO DATA RATE 250kbps 250kbps 250kbps 250kbps 250kbps 250kbps
Applications
Telecommunications Equipment Industrial Motor Control Transmitter for ESD-Sensitive Applications Hand-Held Equipment Industrial PLCs Networking
PART MAX3040 MAX3041 MAX3042B MAX3043 MAX3044 MAX3045B DATA RATE (bps) 250k 2.5M 20M 250k 2.5M 20M
MAX3040EWE -40C to +85C
Ordering Information continued at end of data sheet.
Selector Guide
INDUSTRY STANDARD PINOUT 75174, 34C87, LTC487 75174, 34C87, LTC487 75174, 34C87, LTC487 26LS31 26LS31 26LS31
TOP VIEW
T1IN 1 Y1 2 Z1 3 EN12 4 Z2 5 Y2 6 T2IN 7 GND 8
Pin Configurations
16 VCC 15 T4IN 14 Y4
MAX3040 MAX3041 MAX3042B
13 Z4 12 EN34 11 Z3 10 Y3 9 T3IN
16 TSSOP/SO
Pin Configurations continued at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
ABSOLUTE MAXIMUM RATINGS
All voltages referenced to ground (GND). Supply Voltage (VCC).............................................................+7V Control Input Voltage (EN, EN, EN_) .........-0.3V to (VCC + 0.3V) Driver Input Voltage (T_IN).........................-0.3V to (VCC + 0.3V) Driver Output Voltage (Y_, Z_) (Driver Disabled) .............................................-7.5V to +12.5V Driver Output Voltage (Y_, Z_) (Driver Enabled) .................................................-7.5V to +10V Continuous Power Dissipation (TA = +70C) 16-Pin TSSOP (derate 9.4mW/C above +70C) ..........755mW 16-Pin Narrow SO (derate 8.70mW/C above +70C) ..696mW 16-Pin Wide SO (derate 9.52mW/C above +70C) .....762mW Operating Temperature Range MAX304_C_E .......................................................0C to +70C MAX304_E_E ....................................................-40C to +85C Maximum Junction Temperature .....................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+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.
ELECTRICAL CHARACTERISTICS
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Note 1)
PARAMETER DRIVER Driver Differential Output Change in Magnitude of Differential Output Voltage Driver Common-Mode Output Voltage Change In Magnitude of Common-Mode Voltage Input High Voltage Input Low Voltage Hot-Swap Driver Input Current Driver Input Current Driver Short-Circuit Output Current VOD VOD VOC VOC VIH VIL IHOT
SWAP
SYMBOL
CONDITIONS Figure 1, R = 50 Figure 1, R = 27 Figure 1, R = 50 or 27 (Note 2) Figure 1, R = 50 or 27 Figure 1, R = 50 or 27 (Note 2) T_IN, EN_, EN, EN T_IN, EN_, EN, EN EN_, EN, EN (Note 3) T_IN, EN_, EN, EN -7V < VOUT < +10V (Note 4) MAX3040/MAX3041/MAX3042B EN_ = GND MAX3043/MAX3044/MAX3045B EN = GND, EN = VCC Human Body Model IEC 1000-4-4
MIN 2.0 1.5
TYP
MAX
UNITS
V 0.2 VCC / 2 3 0.2 V V V V 0.8 200 1 V A A mA
2.0
IIN ISC
25
250
Output Leakage (Y_, Z_) when Disabled
1
A
ESD Protection (Y_, Z_) Electrical Fast Transient/Burst Immunity SUPPLY CURRENT Supply Current ICC
10 4
kV kV
No load MAX3040/MAX3041/MAX3042B EN_ = GND, TA = +25C
1
2
mA
Supply Current in Shutdown Mode
ISHDN
MAX3043/MAX3044/MAX3045B EN = GND, EN = VCC, TA = +25C
0.002
10
A
2
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10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters
SWITCHING CHARACTERISTICS--MAX3040/MAX3043
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.)
PARAMETER Maximum Data Rate Driver Propagation Delay SYMBOL fMAX tPLH tPHL Driver Differential Output Rise-Time/Fall-Time tF tR tDSKEW Skew Driver to Driver tSSKEW Driver Differential Output Skew | tPLH - t PHL | Driver Enable to Output High Driver Enable from Shutdown to Output High Driver Enable to Output Low Driver Enable from Shutdown to Output Low Driver Disable Time from Low Driver Disable Time from High tSKEW tZH tZH(SHDN) tZL tZL(SHDN) tLZ tHZ Same chip Figures 2 and 3, R DIFF = 54, C DIFF = 50pF Figures 2 and 3, R DIFF = 54, C DIFF = 50pF Different chips Figures 2 and 3, RDIFF = 54, CDIFF = 50pF 0.48 0.48 CONDITIONS MIN 250 0.7 0.7 0.75 0.75 1.5 s 1.5 1.33 s 1.33 350 ns 100 100 2.0 2.0 2.0 2.0 500 500 ns s s s s ns ns TYP MAX UNITS kbps
MAX3040-MAX3045
Figures 2 and 3, R DIFF = 54, C DIFF = 50pF MAX3040, Figures 4 and 5, S2 closed, R L = 500, C L = 100pF Figures 4 and 5, S2 closed, R L = 500, C L = 100pF MAX3040, Figures 4 and 5, S1 closed, R L = 500, C L = 100pF Figures 4 and 5, S1 closed, R L = 500, C L = 100pF Figures 4 and 5, S1 closed, R L = 500, C L = 15pF Figures 4 and 5, S2 closed, R L = 500, C L = 15pF
SWITCHING CHARACTERISTICS--MAX3041/MAX3044
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.)
PARAMETER Maximum Data Rate Driver Propagation Delay Driver Differential Output Rise-Time/Fall-Time SYMBOL fMAX tPLH tPHL tF tR tDSKEW Skew Driver to Driver tSSKEW Driver Differential Output Skew | tPLH - t PHL | Driver Enable to Output High tSKEW tZH Same chip Figures 2 and 3, RDIFF = 54, C DIFF = 50pF Figures 2 and 3, RDIFF = 54, C DIFF = 50pF Different chips Figures 2 and 3, RDIFF = 54, CDIFF = 50pF 33 33 CONDITIONS MIN 2.5 70 70 70 70 150 150 133 133 52 15 15 400 ns TYP MAX UNITS Mbps ns ns
Figures 2 and 3, RDIFF = 54, C DIFF = 50pF MAX3041, Figures 4 and 5, S2 closed, RL = 500, C L = 100pF
ns ns
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3
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
SWITCHING CHARACTERISTICS--MAX3041/MAX3044 (continued)
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.)
PARAMETER Driver Enable from Shutdown to Output High Driver Enable to Output Low Driver Enable from Shutdown to Output Low Driver Disable Time from Low Driver Disable Time from High SYMBOL tZH(SHDN) tZL tZL(SHDN) tLZ tHZ CONDITIONS Figures 4 and 5, S2 closed, RL = 500, C L = 100pF MAX3041, Figures 4 and 5, S1 closed, RL = 500, C L = 100pF Figures 4 and 5, S1 closed, RL = 500, C L = 100pF Figures 4 and 5, S1 closed, RL = 500, C L = 15pF Figures 4 and 5, S2 closed, RL = 500, C L = 15pF MIN TYP MAX 400 400 400 500 500 UNITS ns ns ns ns ns
SWITCHING CHARACTERISTICS--MAX3042B/MAX3045B
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.)
PARAMETER Maximum Data Rate Driver Propagation Delay Driver Differential Output Rise-Time/Fall-Time Skew Driver to Driver tSSKEW Differential Driver Output Skew | t PLH - t PHL | Driver Enable to Output High Driver Enable from Shutdown to Output High Driver Enable to Output Low Driver Enable from Shutdown to Output Low Driver Disable Time from Low Driver Disable Time from High tSKEW tZH tZH(SHDN) tZL tZL(SHDN) tLZ tHZ Same chip Figures 2 and 3, RDIFF = 54, C DIFF = 50pF MAX3042B, Figures 4 and 5, S2 closed, RL = 500, C L = 100pF Figures 4 and 5, S2 closed, RL = 500, C L = 100pF MAX3042B, Figures 4 and 5, S1 closed, RL = 500, C L = 100pF Figures 4 and 5, S1 closed, RL = 500, C L = 100pF Figures 4 and 5, S1 closed, RL = 500, C L = 15pF Figures 4 and 5, S2 closed, RL = 500, C L = 15pF SYMBOL fMAX tPLH tPHL tF tR tDSKEW Figures 2 and 3, RDIFF = 54, C DIFF = 50pF Figures 2 and 3, RDIFF = 54, C DIFF = 50pF Different chips Figures 2 and 3, R DIFF = 54, CDIFF = 50pF 8 8 8 300 300 300 300 400 400 ns CONDITIONS MIN 20 23 23 40 40 17 17 TYP MAX UNITS Mbps ns ns
ns ns ns ns ns ns ns
Note 1: All currents into the device are positive; all currents out of the device are negative. All voltages are referenced to device ground unless otherwise noted. Note 2: VOD and VOC are the changes in VOD and VOC, respectively, when the transmitter input changes state. Note 3: This input current level is for the hot-swap enable (EN_, EN, EN) inputs and is present until the first transition only. After the first transition the input reverts to a standard high-impedance CMOS input with input current IIN. For the first 20s the input current may be as high as 1mA. During this period the input is disabled. Note 4: Maximum current level applies to peak current just prior to foldback-current limiting. Minimum current level applies during current limiting. 4 _______________________________________________________________________________________
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
Typical Operating Characteristics
(VCC = +5V, TA = +25C, unless otherwise noted.)
MAX3040/MAX3043 SUPPLY CURRENT vs. DATA RATE
MAX3040 toc01
MAX3041/MAX3044 SUPPLY CURRENT vs. DATA RATE
35 SUPPLY CURRENT (mA) 30 25 20 15 10 5 0 NO LOAD ALL FOUR TRANSMITTERS SWITCHING
MAX3040 toc02
MAX3042B/MAX3045B SUPPLY CURRENT vs. DATA RATE
NO LOAD ALL FOUR TRANSMITTERS SWITCHING
MAX3040 toc03
45 40 SUPPLY CURRENT (mA) 35 30 25 20 15 10 5 0 0.1 1 10 DATA RATE (kbps) 100 NO LOAD ALL FOUR TRANSMITTERS SWITCHING
40
60 50 SUPPLY CURRENT (mA) 40 30 20 10 0
1000
0.1
1
10
100
1000
10,000
0.1
1
10
100
1000 10,000 100,000
DATA RATE (kbps)
DATA RATE (kbps)
SUPPLY CURRENT vs. TEMPERATURE
MAX3040 toc04
OUTPUT CURRENT vs. TRANSMITTER OUTPUT HIGH VOLTAGE
MAX3040 toc06
OUTPUT CURRENT vs. TRANSMITTER OUTPUT LOW VOLTAGE
MAX3040 toc06
1.2 VCC = 5.25V VCC = 5V 1.0 VCC = 4.75V
80 70 OUTPUT CURRENT (mA) 60 50 40 30 20 10 0
70 60 OUTPUT CURRENT (mA) 50 40 30 20 10 0
1.1 SUPPLY CURRENT (mA)
0.9
0.8 NO LOAD NO SWITCHING 0.7 0 10 20 30 40 50 60 70 TEMPERATURE (C)
-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 OUTPUT LOW VOLTAGE (V)
0
2
4
6
8
10
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX3040 toc07
TRANSMITTER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE
DIFFERENTIAL OUTPUT VOLTAGE (V) 2.50 2.45 2.40 2.35 2.30 2.25 2.20 2.15 2.10
MAX3040 toc08
70 60 OUTPUT CURRENT (mA) 50 40 30 20 10 0 0 1 2 3 4 5 DIFFERENTIAL OUTPUT VOLTAGE (V)
2.55 RDIFF = 54
0
10
20
30
40
50
60
70
TEMPERATURE (C)
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5
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
Pin Description
PIN MAX3040/MAX3041/ MAX3042B 1 2 3 MAX3043/MAX3044/ MAX3045B 1 2 3 NAME T1IN Y1 Z1 Transmitter 1 Input Noninverting Transmitter 1 Output Inverting Transmitter 1 Output Transmitter Enable High Input. Drive EN high to enable all four transmitters. When EN is low and EN is high, all transmitters are disabled and the part enters a low-power shutdown state. The transmitter outputs are high impedance when disabled. Transmitter Enable Input to Control Transmitters 1 and 2. Drive EN12 high to enable transmitters 1 and 2. Drive EN12 low to disable transmitters 1 and 2. The transmitter outputs are high impedance when disabled. The part enters a low-power shutdown state when both EN12 and EN34 are low. Inverting Transmitter 2 Output Noninverting Transmitter 2 Output Transmitter 2 Input Ground Transmitter 3 Input Noninverting Transmitter 3 Output Inverting Transmitter 3 Output Transmitter Enable Low Input. Drive EN low to enable all four transmitters. When EN is low and EN is high, all transmitters are disabled and the part enters a low-power shutdown state. The transmitter outputs are high impedance when disabled. Transmitter Enable Input to Control Transmitters 3 and 4. Drive EN34 high to enable transmitters 3 and 4. Drive EN34 low to disable transmitters 3 and 4. The transmitter outputs are high impedance when disabled. The part enters a low-power shutdown state when both EN12 and EN34 are low. Inverting Transmitter 4 Output Noninverting Transmitter 4 Output Transmitter 4 Input Positive Supply. Bypass with a 0.1F capacitor to GND. FUNCTION
--
4
EN
4
--
EN12
5 6 7 8 9 10 11
5 6 7 8 9 10 11
Z2 Y2 T2IN GND T3IN Y3 Z3
--
12
EN
12
--
EN34
13 14 15 16
13 14 15 16
Z4 Y4 T4IN VCC
6
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10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters
Detailed Description
The MAX3040-MAX3045 are quad RS-485/RS-422 transmitters. They operate from a single +5V power supply and are designed to give optimum performance when used with the MAX3093E/MAX3095 5V quad RS-485/ RS-422 receivers or MAX3094E/MAX3096 3V quad RS-485/RS-422 receivers. The MAX3040-MAX3045 only need 1mA of operating supply current and consume 2nA when they enter a low-power shutdown mode. The MAX3040-MAX3045 also feature a hot-swap capability allowing line insertion without erroneous data transfer. The MAX3042B/MAX3045B are capable of transferring data up to 20Mbps, the MAX3041/MAX3044 for data rates up to 2.5Mbps, and the MAX3040/MAX3043 for data rates up to 250kbps. All transmitter outputs are protected to 10kV using the Human Body Model. ESD Test Conditions ESD performance depends on a number of conditions. Contact Maxim for a reliability report that documents test setup, methodology, and results. Human Body Model Figure 6a shows the Human Body Model, and Figure 6b shows the current waveform it generates when discharged into low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5k resistor.
MAX3040-MAX3045
3V DI 0 1.5V tPLH tPHL 1.5V 1/2 VO
10kV ESD Protection
As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against electrostatic discharges (ESD) encountered during handling and assembly. The MAX3040-MAX3045 transmitter outputs have extra protection against electrostatic discharges found in normal operation. Maxim's engineers have developed state-of-the-art structures to protect these pins against the application of 10kV ESD (Human Body Model), without damage.
Y Z VO Y 1/2 VO VO VDIFF 0 -VO 10% tR tSKEW = | tPLH - tPHL | VDIFF = V (Y) - V (Z) 90% 90% tF
10%
Figure 3. Driver Propagation Delays
R VOD VOC R
RL OUTPUT UNDER TEST CL
S1
VCC
S2
Z
Figure 4. Driver Enable/Disable Timing Test Load
3V DE 1.5V 0 tZL(SHDN), tZL Y, Z tLZ VOL +0.5V 1.5V
Figure 1. Driver DC Test Circuit
5V DE DI Y VOD Z RDIFF CDIFF
VOL Y, Z
2.5V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH 2.5V
0 tZH(SHDN), tZH tHZ
VOH -0.5V
Figure 2. Driver Timing Test Circuit
Figure 5. Driver Enable and Disable Times 7
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10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
Machine Model The Machine Model for ESD testing uses a 200pF storage capacitor and zero-discharge resistance. It mimics the stress caused by handling during manufacturing and assembly. Of course, all pins (not just RS-485 inputs) require this protection during manufacturing. Therefore, the Machine Model is less relevant to the I/O ports than are the Human Body Model. 4kV Electrical Fast Transient/Burst Testing (IEC 1000-4-4) IEC 1000-4-4 Electrical Fast Transient/Burst (EFT/B) is an immunity test for the evaluation of electrical and electronic systems during operating conditions. The test was adapted for evaluation of integrated circuits with power applied. Repetitive fast transients with severe pulsed EMI were applied to signal and control ports. Over 15,000 distinct discharges per minute are sent to each interface port of the IC or equipment under test (EUT) simultaneously with a minimum test duration time of one minute. This simulates stress due to displacement current from electrical transients on AC mains, or other telecommunication lines in close proximity. Short rise times and very specific repetition rates are essential to the validity of the test. Stress placed on the EUT is severe. In addition to the controlled individual discharges placed on the EUT, extraneous noise and ringing on the transmission line can multiply the number of discharges as well as increase the magnitude of each discharge. All cabling was left unterminated to simulate worst-case reflections. The MAX3040-MAX3045 were setup as specified in IEC 1000-4-4 and the Typical Operating Circuit of this data sheet. The amplitude, pulse rise time, pulse duration, pulse repetition period, burst duration, and burst period (Figure 8) of the burst generator were all verified with a digital oscilloscope according to the specifications in IEC 1000-4-4 sections 6.1.1 and 6.1.2. A simplified diagram of the EFT/B generator is shown in Figure 7. The burst stresses were applied to Y1-Y4 and Z1-Z4 simultaneously. IEC 1000-4-4 provides several levels of test severity (see Table 1). The MAX3040-MAX3045 pass the 4000V stress, a special category "X" beyond the highest level for severe (transient) industrial environments for telecommunication lines.
RC 1M CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 1.5k DISCHARGE RESISTANCE DEVICE UNDER TEST
Cs 100pF
STORAGE CAPACITOR
Figure 6a. Human Body ESD Test Model
IP 100% 90% AMPERES 36.8% 10% 0 0 tRL TIME
Ir
PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE)
tDL CURRENT WAVEFORM
Figure 6b. Human Body Model Current Waveform
Table 1. Test Severity Levels for Communication Lines
ON I/O, SIGNAL, DATA AND CONTROL LEVEL PORTS PEAK VOLTAGE 1 2 3 4 X 250 500 1000 2000 4000 EFT INDUSTRIAL ELECTROMAGNETIC ENVIROMENT
REPETITION RATE (kHz) 5 5 5 5 5
Well protected Protected Typical Severe MAX3040-MAX3045
8
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10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters
IEC 1000-4-4 Burst/Electrical Fast Transient Test Levels (For Communication Lines)
RC
MAX3040-MAX3045
SPARK GAP RM CD
The stresses are applied while the MAX3040-MAX3045 are powered up. Test results are reported as: 1) Normal performance within the specification limits. 2) Temporary degradation or loss of function or performance which is self-recoverable. 3) Temporary degradation, loss of function or performance requiring operator intervention, such as system reset. 4) Degradation or loss of function not recoverable due to damage. The MAX3040-MAX3045 meets classification 2 listed above. Additionally, the MAX3040-MAX3045 will not latchup during the IEC burst stress events.
COAXIAL OUTPUT 50
U
CE
RS
U = HIGH-VOLTAGE SOURCE RC = CHARGING RESISTOR CE = ENERGY STORAGE CAPACITOR RS = PULSE DURATION SHAPING RESISTOR RM = IMPEDANCE MATCHING RESISTOR CD = DC BLOCKING CAPACITOR
Figure 7. Simplified Circuit Diagram of a Fast Transient/Burst Generator
Hot-Swap Capability
Hot-Swap Inputs When circuit boards are plugged into a "hot" backplane, there can be disturbances to the differential signal levels that could be detected by receivers connected to the transmission line. This erroneous data could cause data errors to an RS-485/RS-422 system. To avoid this, the MAX3040-MAX3045 have hot-swap capable inputs. When a circuit board is plugged into a "hot" backplane there is an interval during which the processor is going through its power-up sequence. During this time, the processor's output drivers are high impedance and will be unable to drive the enable inputs of the MAX3040-MAX3045 (EN, EN, EN_) to defined logic levels. Leakage currents from these high impedance drivers, of as much as 10A, could cause the enable inputs of the MAX3040-MAX3045 to drift high or low. Additionally, parasitic capacitance of the circuit board could cause capacitive coupling of the enable inputs to either GND or V CC . These factors could cause the enable inputs of the MAX3040-MAX3045 to drift to levels that may enable the transmitter outputs (Y_ and Z_). To avoid this problem, the hot-swap input provides a method of holding the enable inputs of the MAX3040-MAX3045 in the disabled state as V CC ramps up. This hot-swap input is able to overcome the leakage currents and parasitic capacitances that may pull the enable inputs to the enabled state. Hot-Swap Input Circuitry In the MAX3040-MAX3045 the enable inputs feature hot-swap capability. At the input there are two NMOS
PULSE
REPETITION PERIOD (DEPENDS ON THE TEST VOLTAGE LEVER, IN CONFORMITY WITH THE VALUES INDICATED IN 6.1.2). BURST
15ms BURST DURATION BURST PERIOD 300ms
Figure 8. General Graph of a Fast Transient Burst
devices, Q1 and Q2 (Figure 9). When VCC is ramping up from 0, an internal 10s timer turns on Q2 and sets the SR latch, which also turns on Q1. Transistors Q2, a 700A current sink, and Q1, an 85A current sink, pull EN to GND through a 5.6k resistor. Q2 is designed to pull the EN input to the disabled state against an external parasitic capacitance of up to 100pF that is trying to enable the EN input. After 10s, the timer turns Q2 off and Q1 remains on, holding the EN input low against three-state output leakages that might enable EN. Q1 remains on until an external source overcomes the
9
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10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
VCC 10s TIMER TIMER
5.6k EN 85A Q1 700A Q2
EN (HOT SWAP)
Figure 9. Simplified Structure of the Driver Enable Pin (EN)
required input current. At this time the SR latch resets and Q1 turns off. When Q1 turns off, EN reverts to a standard, high-impedance CMOS input. Whenever VCC drops below 1V, the hot-swap input is reset. The EN12 and EN34 input structures are identical to the EN input. For the EN input, there is a complimentary circuit employing two PMOS devices pulling the EN input to VCC. Hot-Swap Line Transient The circuit of Figure 10 shows a typical offset termination used to guarantee a greater than 200mV offset when a line is not driven. The 50pF represents the minimum parasitic capacitance which would exist in a typical application. In most cases, more capacitance exists in the system and will reduce the magnitude of the glitch. During a "hot-swap" event when the driver is connected to the line and is powered up, the driver must not cause the differential signal to drop below 200mV. Figures 11 and 12 show the results of the MAX3040-MAX3045 during power-up for two different VCC ramp rates (0.1V/s and 1V/s). The photos show the VCC ramp, the single-ended signal on each side of the 100 termination, the differential signal across the termination, and shows the hot-swap line transient stays above the 200mV RS-485 specification.
Operation of Enable Pins
The MAX3040-MAX3045 family has two enable-functional versions: The MAX3040/MAX3041/MAX3042B have two transmitter enable inputs EN12 and EN34. EN12 controls the transmitters 1 and 2, and EN34 controls transmitters 3 and 4. EN12 and EN34 are active-high and the part will enter the low-power shutdown mode when both are pulled low. The transmitter outputs are high impedance when disabled (Table 2). The MAX3043/MAX3044/MAX3045B have two transmitter enable inputs EN and EN, which are active-high and active-low, respectively. When EN is logic high or EN is logic low all transmitters are active. When EN is pulled low and EN is driven high, all transmitters are disabled and the part enters the low-power shutdown mode. The transmitter outputs are high impedance when disabled (Table 3).
Applications Information
Typical Applications
The MAX3040-MAX3045 offer optimum performance when used with the MAX3093E/MAX3095 5V quad receivers or MAX3094E/MAX3096 3V quad differential line receivers. Figure 13 shows a typical RS-485 connection for transmitting and receiving data and Figure 14 shows a typical multi-point connection.
10
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10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
Table 2. Function Table for MAX3040/ MAX3041/MAX3042B (Each Pair of Transmitters)
OUTPUTS INPUT H L X H = Logic High L = Logic Low EN_ Y_ H H L H L High-Z Z_ H L H High-Z L H L X X = Don't Care High-Z = High Impedance H = Logic High L = Logic Low H H X X L X X L L H X = Don't Care High-Z = High Impedance INPUT EN
Table 3. Function Table for MAX3043/ MAX3044/MAX3045B (All Transmitters)
EN OUTPUTS Y H L H L High-Z Z L H L H High-Z
VCC
5V
1k Y TIN (VCC OR GND) Z 1k VCC 2V/div Y 200mV/div Z 200mV/div Y-Z (20mV/div) 238mV
0.1k
50pF
Figure 10. Differential Power-Up Glitch (Hot Swap)
Figure 11. Differential Power-Up Glitch (0.1V/s)
VCC 2V/div Y 50mV/div Z 50mV/div
Y-Z (5mV/div) 238mV 1s/div
Figure 12. Differential Power-Up Glitch (1V/s)
______________________________________________________________________________________
11
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
MAX3043-MAX3045 MAX3095
T1IN
D1
RT
R1
R1OUT
T2IN
D2
RT
R2
R2OUT
T3IN
D3
RT
R3
R3OUT
T4IN
D4
RT
R4
R4OUT
EN EN G G
VCC
GND
VCC
GND
Figure 13. Typical Connection of a Quad Transmitter and a Quad Receiver as a Pair
Typical Multiple-Point Connection
Figure 14 shows a typical multiple-point connection for the MAX3040-MAX3045 with the MAX3095. Because of the high frequencies and the distances involved, high attention must be paid to transmission-line effects while using termination resistors. A terminating resistor (RT) is simply a resistor that should be placed at the extreme ends of the cable to match the characteristic impedance of the cable. When the termination resistance is not the same value as the characteristic
impedance of the cable, reflections will occur as the signal is traveling down the cable. Although some reflections are inevitable due to the cable and resistor tolerances, large mismatches can cause significant reflections resulting in errors in the data. With this in mind, it is very important to match the terminating resistance and the characteristic impedance as closely as possible. As a general rule in a multi-drop system, termination resistors should always be placed at both ends of the cable.
12
______________________________________________________________________________________
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters MAX3040-MAX3045
1/4 MAX3040-MAX3045 1/4 MAX3040-MAX3045 RT RT
1/4 MAX3095 UP TO 32 RS-485 UNIT LOADS
1/4 MAX3095
1/4 MAX3040-MAX3045 1/4 MAX3095
1/4 MAX3040-MAX3045 1/4 MAX3095
Figure 12. Typical Connection for Multiple-Point RS-485 Bus
Ordering Information (continued)
PART MAX3041CUE MAX3041CSE MAX3041CWE MAX3041EUE MAX3041ESE MAX3041EWE MAX3042BCUE MAX3042BCSE MAX3042BCWE TEMP RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C PIN-PACKAGE 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO DATA RATE 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps 250kbps 250kbps 250kbps 250kbps 250kbps 250kbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps
16 TSSOP/SO TOP VIEW
T1IN 1 Y1 2 Z1 3 EN 4 Z2 5 Y2 6 T2IN 7 GND 8 16 VCC 15 T4IN 14 Y4
PART MAX3045BCUE MAX3045BCSE MAX3045BCWE
TEMP RANGE 0C to +70C 0C to +70C 0C to +70C
PIN-PACKAGE 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO
DATA RATE 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps
MAX3045BEUE -40C to +85C MAX3045BESE -40C to +85C MAX3045BEWE -40C to +85C
Pin Configurations (continued)
MAX3042BEUE -40C to +85C MAX3042BESE -40C to +85C MAX3042BEWE -40C to +85C MAX3043CUE MAX3043CSE MAX3043EWE MAX3043EUE MAX3043ESE MAX3043EWE MAX3044CUE MAX3044CSE MAX3044CWE MAX3044EUE MAX3044ESE MAX3044EWE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C
MAX3043 MAX3044 MAX3045B
13 Z4 12 EN 11 Z3 10 Y3 9 T3IN
Chip Information
TRANSISTOR COUNT: 545 PROCESS: CMOS
13
______________________________________________________________________________________
10kV ESD-Protected, Quad 5V RS-485/422 Transmitters MAX3040-MAX3045
Ordering Information (continued)
PART MAX3041CUE MAX3041CSE MAX3041CWE MAX3041EUE MAX3041ESE MAX3041EWE MAX3042BCUE MAX3042BCSE MAX3042BCWE TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C PIN-PACKAGE 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO DATA RATE 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps 250kbps 250kbps 250kbps 250kbps 250kbps 250kbps PART MAX3044CUE MAX3044CSE MAX3044CWE MAX3044EUE MAX3044ESE MAX3044EWE MAX3045BCUE MAX3045BCSE MAX3045BCWE TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C PIN-PACKAGE 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO 16 TSSOP 16 Narrow SO 16 Wide SO DATA RATE 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 2.5Mbps 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps 20Mbps
MAX3042BEUE -40C to +85C MAX3042BESE -40C to +85C MAX3042BEWE -40C to +85C MAX3043CUE MAX3043CSE MAX3043EWE MAX3043EUE MAX3043ESE MAX3043EWE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C -40C to +85C
MAX3045BEUE -40C to +85C MAX3045BESE -40C to +85C MAX3045BEWE -40C to +85C
Pin Configurations (continued)
TOP VIEW
T1IN 1 Y1 2 Z1 3 EN 4 Z2 5 Y2 6 T2IN 7 GND 8 16 VCC 15 T4IN 14 Y4
MAX3043 MAX3044 MAX3045B
13 Z4 12 EN 11 Z3 10 Y3 9 T3IN
16 TSSOP/SO
14
______________________________________________________________________________________
10kV ESD-Protected, Quad 5V RS-485/RS-422 Transmitters
Package Information (continued)
SOICW.EPS
MAX3040-MAX3045
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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