Maxim MAX218CWP, MAX218CPP, MAX218CAP, MAX218EAP, MAX218C-D Datasheet
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19-0246; Rev 1; 7/95
1.8V to 4.25V-Powered, True RS-232 Dual Transceiver
_______________General Description
The MAX218 RS-232 transceiver is intended for batterypowered EIA/TIA-232E and V.28/V.24 communications interfaces that need two drivers and two receivers with minimum power consumption. It provides a wide +1.8V to +4.25V operating voltage range while maintaining true RS-232 and EIA/TIA-562 voltage levels. The MAX218 runs from two alkaline, NiCd, or NiMH cells without any form of voltage regulator.
A shutdown mode reduces current consumption to 1µA, extending battery life in portable systems. While shut down, all receivers can remain active or can be disabled under logic control, permitting a system incorporating the CMOS MAX218 to monitor external devices while in low-power shutdown mode.
A guaranteed 120kbps data rate provides compatibility with popular software for communicating with personal computers. Three-state drivers are provided on all receiver outputs so that multiple receivers, generally of different interface standards, can be wire-ORed at the UART. The MAX218 is available in 20-pin DIP, SO, and SSOP packages.
________________________Applications
Battery-Powered Equipment
Computers
Printers
Peripherals
Instruments
Modems
____________________________Features
BETTER THAN BIPOLAR!
♦Operates Directly from Two Alkaline, NiCd, or NiMH Cells
♦+1.8V to +4.25V Supply Voltage Range
♦120kbps Data Rate
♦Low-Cost Surface-Mount Components
♦Meets EIA/TIA-232E Specifications
♦1µA Low-Power Shutdown Mode
♦Both Receivers Active During Low-Power Shutdown
♦Three-State Receiver Outputs
♦Flow-Through Pinout
♦On-Board DC-DC Converters
♦20-Pin SSOP, Wide SO, or DIP Packages
______________Ordering Information
PART |
TEMP. RANGE |
PIN-PACKAGE |
MAX218CPP |
0°C to +70°C |
20 Plastic DIP |
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MAX218CWP |
0°C to +70°C |
20 Wide SO |
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MAX218CAP |
0°C to +70°C |
20 SSOP |
MAX218C/D |
0°C to +70°C |
Dice* |
MAX218EPP |
-40°C to +85°C |
20 Plastic DIP |
MAX218EWP |
-40°C to +85°C |
20 Wide SO |
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MAX218EAP |
-40°C to +85°C |
20 SSOP |
*Contact factory for dice specifications.
__________Typical Operating Circuit |
__________________Pin Configuration |
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1 |
19 |
TOP VIEW |
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1.8V |
6 |
LX |
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V+ |
15 |
TO |
VCC |
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V- |
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4.25V |
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C1+ |
18 |
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MAX218 |
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3 |
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16 |
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ON/OFF |
SHDN |
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C1- |
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7 |
T1IN |
T1 |
T1OUT |
14 |
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8 |
T2IN |
T2 |
T2OUT |
13 |
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9 |
R1OUT |
R1 |
R1IN |
12 |
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10 |
R2OUT |
R2 |
R2IN |
11 |
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EN |
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GND |
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ENABLE |
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4 |
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5, 17, 20 |
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LX |
1 |
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20 |
GND |
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N.C. |
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V+ |
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2 |
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19 |
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SHDN |
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3 |
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18 |
C1+ |
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EN |
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GND |
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4 |
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17 |
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GND |
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MAX218 |
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C1- |
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5 |
16 |
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VCC |
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V- |
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6 |
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15 |
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T1IN |
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T1OUT |
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7 |
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14 |
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T2IN |
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T2OUT |
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8 |
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13 |
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R1OUT |
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R1IN |
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9 |
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12 |
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R2OUT |
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R2IN |
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10 |
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11 |
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DIP/SO/SSOP
________________________________________________________________ Maxim Integrated Products 1
MAX218
Call toll free 1-800-998-8800 for free samples or literature.
MAX218
1.8V to 4.25V-Powered,
True RS-232 Dual Transceiver
ABSOLUTE MAXIMUM RATINGS
Supply Voltages |
-0.3V to +4.6V |
VCC .................................................................... |
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V+ .......................................................... |
(VCC - 0.3V) to +7.5V |
V- ....................................................................... |
+0.3V to -7.4V |
VCC to V-.......................................................................... |
+12V |
LX ................................................................ |
-0.3V to (1V + V+) |
Input Voltages |
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———– |
-0.3V to +7V |
T_IN, EN, SHDN ................................................. |
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R_IN ................................................................................. |
±25V |
Output Voltages |
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T_OUT............................................................................. |
±15V) |
R_OUT.................................................... |
-0.3V to (VCC + 0.3V) |
Short-Circuit Duration, R_OUT, T_OUT to GND |
....... |
Continuous |
Continuous Power Dissipation (TA = +70°C) |
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Plastic DIP (derate 11.11mW/°C above +70°C) .......... |
889mW |
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Wide SO (derate 10.00mW/°C above +70°C).............. |
800mW |
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SSOP (derate 8.00mW/°C above +70°C) ................... |
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640mW |
Operating Temperature Ranges |
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MAX218C_ P..................................................... |
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0°C to +70°C |
MAX218E_ P ................................................... |
-40°C to +85°C |
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Storage Temperature Range ........................... |
-65°C to +150°C |
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Lead Temperature (soldering, 10sec) ........................... |
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+300°C |
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
(Circuit of Figure 1, VCC = 1.8V to 4.25V, C1 = 0.47µF, C2 = C3 = C4 = 1µF, L1 = 15µH, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 3.0V, TA = +25°C.)
PARAMETER |
CONDITIONS |
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MIN |
TYP |
MAX |
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UNITS |
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DC CHARACTERISTICS |
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Operating Voltage Range |
———– |
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1.8 |
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4.25 |
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V |
Supply Current (Note 1) |
= +25°C |
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1.9 |
3.0 |
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mA |
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No load, VCC = EN = SHDN = 3.0V, TA |
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———– |
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0.04 |
10 |
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Shutdown Supply Current |
SHDN = EN = 0V, all R_INs static |
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µA |
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———– |
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0.04 |
10 |
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SHDN = 0V, EN = VCC, all R_INs static |
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LOGIC |
———– |
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Input Logic Threshold Low |
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0.33 x VCC |
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V |
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T_IN, EN, SHDN |
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Input Logic Threshold High |
———– |
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0.67 x VCC |
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V |
T_IN, EN, SHDN |
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Input Hysteresis |
T_IN |
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0.1 |
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V |
Input Leakage Current |
———– |
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0.001 |
±1 |
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µA |
T_IN, EN, SHDN = 0V or VCC |
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Output Voltage Low |
R_OUT, IOUT = 1.0mA |
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0.4 |
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V |
Output Voltage High |
R_OUT, IOUT = -0.4mA |
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VCC - 0.25 VCC - 0.08 |
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V |
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Output Leakage Current |
R_OUT, 0V ≤ R_OUT ≤ VCC, EN = 0V |
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0.05 |
±10 |
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µA |
EIA/TIA-232E RECEIVER INPUTS |
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Input Voltage Range |
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-25 |
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+25 |
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V |
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Input Threshold Low |
VCC = 2.0V to 4.25V |
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0.4 |
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V |
VCC = 1.8V to 4.25V |
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0.3 |
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Input Threshold High |
VCC = 1.8V to 4.25V |
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3.0 |
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V |
VCC = 1.8V to 3.6V |
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2.8 |
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Input Hysteresis |
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0.7 |
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V |
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Input Resistance |
-15V < R_IN < +15V |
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3 |
5 |
7 |
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kΩ |
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EIA/TIA-232E TRANSMITTER OUTPUTS |
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Output Voltage Swing |
All transmitter outputs loaded with 3kΩ to ground |
±5 |
±6 |
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V |
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Output Resistance |
VCC = 0V, -2V < T_OUT < +2V |
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300 |
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Ω |
Output Short-Circuit Current |
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±24 |
±100 |
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mA |
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Note 1: Entire supply current for the circuit of Figure 1.
2 _______________________________________________________________________________________ 
1.8V to 4.25V-Powered, True RS-232 Dual Transceiver
TIMING CHARACTERISTICS
(Circuit of Figure 1, VCC = 1.8V to 4.25V, C1 = 0.47µF, C2 = C3 = C4 = 1µF, L1 = 15µH, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 3.0V, TA = +25°C.)
PARAMETER |
SYMBOL |
CONDITIONS |
MIN |
TYP |
MAX |
UNITS |
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Data Rate |
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1000pF || 3kΩ load each transmitter, |
120 |
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kbps |
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150pF load each receiver |
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Receiver Output Enable Time |
tER |
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90 |
300 |
ns |
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Receiver Output Disable Time |
tDR |
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200 |
500 |
ns |
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Transmitter Output Enable Time |
tET |
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140 |
450 |
µs |
Transmitter Output Disable Time |
tDT |
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500 |
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ns |
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Receiver Propagation Delay |
tPHLR |
150pF load |
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290 |
700 |
ns |
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tPLHR |
150pF load |
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260 |
700 |
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Transmitter Propagation Delay |
tPHLT |
2500pF || 3kΩ load |
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1.9 |
2.7 |
µs |
tPLHT |
2500pF || 3kΩ load |
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1.8 |
2.7 |
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TA = +25°C, VCC = 3.0V, RL = 3kΩ to 7kΩ , |
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Transition Region Slew Rate |
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CL = 50pF to 2500pF, measured from |
3.0 |
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30 |
V/µs |
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+3V to -3V or -3V to +3V |
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MAX218
______________________________________________________________Pin Description
PIN |
NAME |
FUNCTION |
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1 |
LX |
Inductor/Diode Connection Point |
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2 |
N.C. |
Not internally connected |
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3 |
———– |
Shutdown Control. Connect to VCC for normal operation. Connect to GND to shut down the |
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SHDN |
power supply and to disable the drivers. Receiver status is not changed by this control. |
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4 |
EN |
Receiver Output Enable Control. Connect to VCC for normal operation. Connect to GND to |
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force the receiver outputs into high-Z state. |
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5, 17, 20 |
GND |
Ground. Connect all GND pins to ground. |
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6 |
VCC |
Supply Voltage Input; 1.8V to 4.25V. Bypass to GND with at least 1µF. See Capacitor |
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Selection section. |
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7, 8 |
T1IN, T2IN |
Transmitter Inputs |
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9, 10 |
R1OUT, R2OUT |
Receiver Outputs; swing between GND and VCC. |
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11, 12 |
R2IN, R1IN |
Receiver Inputs |
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13, 14 |
T2OUT, T1OUT |
Transmitter Outputs; swing between V+ and V-. |
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15 |
V- |
Negative Supply generated on-board |
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16, 18 |
C1-, C1+ |
Terminals for Negative Charge-Pump Capacitor |
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19 |
V+ |
Positive Supply generated on-board |
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_______________________________________________________________________________________ 3
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