19-2141; Rev 0; 8/01 75Ω/100Ω/120Ω Switchable Termination Networks The MAX3406/MAX3407/MAX3408 are general-purpose line-terminating networks designed to change the termination value of a line, depending on the state of a digital control line, allowing the connection to a coaxial cable or a twisted pair wire. These devices are switchable between 75Ω, 100Ω, and 120Ω. The MAX3406 can switch from 75Ω to 100Ω, the MAX3407 can switch from 75Ω to 120Ω, and the MAX3408 can switch from 100Ω to 120Ω termination. Termination resistance values are guaranteed to ±2.5% through -40°C to +85°C and for signal levels of ±3.6V. The MAX3406/MAX3407/MAX3408 consume only 50µA supply current and are fully specified for operation from a +4.5V to +5.5V power supply. These devices are available in a tiny 5-pin SOT23 package. All specifications are guaranteed over the extended temperature range of -40°C to +85°C. Features ♦ Available in 5-Pin SOT Package ♦ ±2.5% Resistance Accuracy Over Extended Temperature Range ♦ -3.6V to +3.6V Input Voltage Range ♦ 50µA Supply Current (max) ♦ Bipolar Input Range Off a Single Supply ♦ Switchable Termination 75Ω or 100Ω (MAX3406) 75Ω or 120Ω (MAX3407) 100Ω or 120Ω (MAX3408) Applications Ordering Information Telecom E1/T1/J1 Coax/Twisted Pair Termination Data Routers Telecom Racks PART TEMP. RANGE PINPACKAGE TOP MARK MAX3406EUK -40°C to +85°C 5 SOT23-5 ADSV Video Security MAX3407EUK -40°C to +85°C 5 SOT23-5 ADSW Industrial Networks MAX3408EUK -40°C to +85°C 5 SOT23-5 ADSX Ethernet Networks Selector Guide Pin Configuration TOP VIEW TERMINATION PART VCC 1 GND 2 5 A MAX3406 MAX3407 MAX3408 ENABLE 3 4 ENABLE = 1 ENABLE = 0 MAX3406EUK 75Ω 100Ω MAX3407EUK 75Ω 120Ω MAX3408EUK 100Ω 120Ω B SOT23-5 ________________________________________________________________ Maxim Integrated Products 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. 1 MAX3406/MAX3407/MAX3408 General Description 75Ω/100Ω/120Ω Switchable Termination Networks MAX3406/MAX3407/MAX3408 ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND unless otherwise noted.) VCC ...........................................................................-0.3V to +6V ENABLE......................................................-0.3V to (VCC + 0.3V) A, B (applied individually) ...........................................-4V to +4V Differential Voltage Across A-B ...................................-4V to +4V Continuous Power Dissipation (TA = +70°C) 5-Pin SOT23 (derate 7.1mW/°C above +70°C)..........571mW Operating Temperature Range ...........................-40°C to +85°C Maximum Junction Temperature .....................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+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 (VCC = +4.5V to +5.5V, TA =TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 5.5 V 30 50 µA DC CHARACTERISTICS Supply Range VCC Supply Current ICC 4.5 VCC = +5.5V, ENABLE = 0 or VCC TERMINATOR NETWORK -3.6V < VAB < ,+3.6V, ENABLE = 0 -3.6V < VAB < +3.6V, ENABLE = 0, frequency up to 36MHz On-Resistance RON -3.6V < VAB < +3.6V, ENABLE = 1 -3.6V < VAB < +3.6V, ENABLE = 1, frequency up to 36MHz MAX3406 97.5 100 102.5 MAX3407/ MAX3408 117 120 123 MAX3406 100 MAX3407/ MAX3408 120 Ω MAX3406/ MAX3407 73.1 75 76.9 MAX3408 97.5 100 102.5 MAX3406/ MAX3407 75 MAX3408 100 Turn-On Time tON 50 µs Turn-Off Time tOFF 50 µs Input Low Voltage VIL Input High Voltage VIH Input Current IIL, IIH Input Hysteresis VHYST ENABLE = 0 or VCC V 1 µA V -1 200 Note 1: All parameters tested at +25°C. Limits through temperature are guaranteed by design. 2 0.8 2.0 _______________________________________________________________________________________ mV 75Ω/100Ω/120Ω Switchable Termination Networks MAX3406/MAX3407/MAX3408 Typical Operating Characteristics (VCC = +5V, TA = +25°C, unless otherwise noted.) 120 90 ENABLE = VCC 80 120 ENABLE = 0 110 100 90 ENABLE = VCC 80 70 -25 0 25 50 75 100 0 25 50 75 100 -50 25 50 75 RESISTANCE vs. INPUT VOLTAGE (MAX3408) 120 VB = 0 125 120 ENABLE = 0 110 100 90 ENABLE = VCC 80 70 -1.2 0 1.2 2.4 3.6 ENABLE = VCC 105 95 90 60 -2.4 ENABLE = 0 110 100 70 60 115 -3.6 -2.4 -1.2 0 1.2 2.4 -3.6 3.6 -2.4 -1.2 0 1.2 2.4 VAB (V) VAB (V) VAB (V) IMPEDANCE vs. FREQUENCY 75Ω MODE—MAX3406/MAX3407 IMPEDANCE vs. FREQUENCY 100Ω MODE—MAX3406/MAX3408 IMPEDANCE vs. FREQUENCY 120Ω MODE—MAX3407/MAX3408 MAGNITUDE 120 60 100 30 45 0 PHASE 30 -30 15 0 0.1 1 FREQUENCY (MHz) 10 100 MAX3406/7/8 toc08 MAGNITUDE 80 -90 0 60 120 0 PHASE 40 20 140 30 60 -60 90 0.01 0.1 1 FREQUENCY (MHz) -30 10 100 PHASE (DEGREES) MAGNITUDE (Ω) 75 90 PHASE (DEGREES) MAGNITUDE (Ω) MAX3406/7/8 toc07 90 100 MAX3406/7/8 toc06 VB = 0 RESISTANCE (Ω) ENABLE = VCC 80 130 MAX3406/7/8 toc05 130 MAX3406/7/8 toc04 ENABLE = 0 0.01 0 RESISTANCE vs. INPUT VOLTAGE (MAX3407) 100 60 -25 RESISTANCE vs. INPUT VOLTAGE (MAX3406) RESISTANCE (Ω) RESISTANCE (Ω) -25 TEMPERATURE (°C) 110 MAGNITUDE (Ω) 90 -50 TEMPERATURE (°C) VB = 0 -3.6 ENABLE = VCC 105 TEMPERATURE (°C) 120 90 110 95 60 -50 ENABLE = 0 100 70 60 115 3.6 MAX3406/7/8 toc09 60 MAGNITUDE 100 30 80 0 PHASE 60 -60 40 -90 20 90 -30 -60 -90 0.01 0.1 1 10 100 FREQUENCY (MHz) _______________________________________________________________________________________ 3 PHASE (DEGREES) ENABLE = 0 125 RESISTANCE (Ω) RESISTANCE (Ω) 100 130 MAX3406/7/8 toc02 130 MAX3406/7/8 toc01 110 RESISTANCE (Ω) RESISTANCE vs. TEMPERATURE (MAX3408) RESISTANCE vs. TEMPERATURE (MAX3407) MAX3406/7/8 toc03 RESISTANCE vs. TEMPERATURE (MAX3406) Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) ACCURACY DISTRIBUTION 100Ω MODE 60% 50% 40% 30% 20% 10% 90% 80% 70% 80% PERCENTAGE OF PRODUCTION 70% 90% MAX3406/7/8 toc11 80% PERCENTAGE OF PRODUCTION MAX3406/7/8 toc10 90% ACCURACY DISTRIBUTION 120Ω MODE 60% 50% 40% 30% 20% 10% 0% 74.40 74.80 75.00 75.20 75.40 75.60 70% 60% 50% 40% 30% 20% 10% 0% 74.60 MAX3406/7/8 toc12 ACCURACY DISTRIBUTION 75Ω MODE PERCENTAGE OF PRODUCTION MAX3406/MAX3407/MAX3408 75Ω/100Ω/120Ω Switchable Termination Networks 98.8 99.2 99.6 RESISTANCE (Ω) 100.0 100.4 100.8 0% 118.5 101.2 119.0 RESISTANCE (Ω) 119.5 120.0 120.5 121.0 121.5 RESISTANCE (Ω) Pin Description PIN NAME FUNCTION 1 VCC Supply Voltage +4.5V to +5.5V. Bypass to GND with a 0.1µF capacitor. 2 GND Ground 3 ENABLE 4 B Cable Terminator Terminal B 5 A Cable Terminator Terminal A Digital Control Input. Drive ENABLE high to turn on the internal switch, pull ENABLE low to disable the internal switch. Detailed Description Applications Information The MAX3406/MAX3407/MAX3408 are line-terminating networks. They provide 75Ω, 100Ω, and 120Ω termination to be compatible with twisted pair or coaxial cable. The MAX3406/MAX3407/MAX3408 consume only 50µA supply current and operate from a +4.5V to +5.5V power supply. They are available in a space-saving 5pin SOT23 package. All specifications are guaranteed over the extended temperature range of -40°C to +85°C. The ENABLE pin allows switching from one termination value to another: 75Ω to 100Ω for the MAX3406, 75Ω to 120Ω for the MAX3407, and 100Ω to 120Ω for the MAX3408 (Figure 1 and Table 1). In order for the MAX3406/MAX3407/MAX3408 to terminate transmission lines correctly, they should look like a precision resistance. These devices look this way under all operating conditions as can be seen from the Typical Operating Characteristics. The very small variations in resistance with temperature, input voltage, and frequency should not be of any concern in most applications, though the users should be aware of them. The next three sections describe these variations and explain what end application effect they could have. 4 The function of a termination is to minimize line reflections by terminating a transmission line in its characteristic impedance. The reflection coefficient for a line of Z0 characteristic impedance terminated with a given ZL is: Voltage Reflection Coefficient = (ZL - Z0)/(ZL + Z0) _______________________________________________________________________________________ 75Ω/100Ω/120Ω Switchable Termination Networks mance over discrete 5% resistors with a 100ppm tempco, which are typically used for termination, ±5.6% worst case. The reflections from such a mistermination are minimal and correspond to a worst-case reflection coefficient for the MAX3406/MAX3407/MAX3408 of ±0.015 or a -36dB return loss. PART RAB (Ω) ENABLE = 1 RAB (Ω) ENABLE = 0 MAX3406EUK 75 100 MAX3407EUK 75 120 Resistance vs. Input Voltage Range MAX3408EUK 100 120 The MAX3406/MAX3407/MAX3408 accept input voltages (VAB) from -3.6V to +3.6V. There is virtually no resistance variation over this range (0.02% typically). The initial accuracy specifications in the data sheet already account for resistance variations of the signal voltage range. ENABLE Impedance vs. Frequency MAX3406 MAX3407 MAX3408 A VCC R1 R2 B GND Figure 1. Simplified Block Diagram This is the voltage that would be reflected from any line termination. As ZL becomes equal to Z0, this quantity becomes zero. Often this is expressed in dB and is called return loss. Reflection coefficient values less than 0.1 corresponding to a return loss of -20dB are generally seen as adequate. The MAX3406/MAX3407/ MAX3408 will typically provide reflection coefficients below 0.01 or -40dB return loss. As seen in the Typical Operating Characteristics, there is a slight impedance variation in the MAX3406/ MAX3407/MAX3408 with frequency. The reactive components are parasitic inductance and capacitance associated with packaging, lead frame, and bond wires. These impedance components are very small up to frequencies above 20MHz. These parasitics are also similar to those that would be present with a discrete resistor terminator, and they can generally be ignored. These effects should be evaluated for applications with significant frequency content above 20MHz. This applies to sine wave sources above 20MHz and square and video sources above 8MHz. For all intended applications, E1/T1, Standard Video, etc. they can be ignored. Decoupling VCC The VCC pin for the MAX3406/MAX3407/MAX3408 must be decoupled with a 0.1µF ceramic capacitor to GND placed as close to the device as possible. This is required for proper operation of the part. Chip Information TRANSISTOR COUNT: 102 PROCESS: BiCMOS In most cases, Z0 and ZL are considered real resistive quantities and the result is a dimensionless scalar quantity, but the equation is valid in the complex case as well. Resistance vs. Temperature The MAX3406/MAX3407/MAX3408 resistance is constant over temperature. The typical temperature coefficient of resistance is 150ppm/°C. Over a -40°C to +85°C range centered at +25°C, this would be a ±1% change in resistance. The initial accuracy at room temperature is ±1.5%. This provides improved perfor_______________________________________________________________________________________ 5 MAX3406/MAX3407/MAX3408 Table 1. Termination Mode Selection 75Ω/100Ω/120Ω Switchable Termination Networks SOT5L.EPS MAX3406/MAX3407/MAX3408 Package Information 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. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.