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19-2141; Rev 0; 8/01
75/100/120 Switchable Termination Networks
General Description
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 75, 100, and 120. The MAX3406 can switch from 75 to 100, the MAX3407 can switch from 75 to 120, and the MAX3408 can switch from 100 to 120 termination. Termination resistance values are guaranteed to 2.5% through -40C to +85C and for signal levels of 3.6V. The MAX3406/MAX3407/MAX3408 consume only 50A 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 -40C to +85C. o Available in 5-Pin SOT Package o 2.5% Resistance Accuracy Over Extended Temperature Range o -3.6V to +3.6V Input Voltage Range o 50A Supply Current (max) o Bipolar Input Range Off a Single Supply o Switchable Termination 75 or 100 (MAX3406) 75 or 120 (MAX3407) 100 or 120 (MAX3408)
Features
MAX3406/MAX3407/MAX3408
Applications
Telecom E1/T1/J1 Coax/Twisted Pair Termination Data Routers Telecom Racks Video Security Industrial Networks Ethernet Networks
PART MAX3406EUK MAX3407EUK MAX3408EUK
Ordering Information
TEMP. RANGE -40C to +85C -40C to +85C -40C to +85C PINPACKAGE 5 SOT23-5 5 SOT23-5 5 SOT23-5 TOP MARK ADSV ADSW ADSX
Pin Configuration
TOP VIEW
PART
VCC 1 5 A
Selector Guide
TERMINATION ENABLE = 1 MAX3406EUK MAX3407EUK MAX3408EUK 75 75 100 ENABLE = 0 100 120 120
GND 2
MAX3406 MAX3407 MAX3408
4 B
ENABLE 3
SOT23-5
________________________________________________________________ Maxim Integrated Products
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75/100/120 Switchable Termination Networks
ABSOLUTE MAXIMUM RATINGS
MAX3406/MAX3407/MAX3408
(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 = +70C) 5-Pin SOT23 (derate 7.1mW/C above +70C)..........571mW Operating Temperature Range ...........................-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 = +4.5V to +5.5V, TA =TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, TA = +25C.) (Note 1)
PARAMETER DC CHARACTERISTICS Supply Range Supply Current TERMINATOR NETWORK MAX3406 -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 Turn-On Time Turn-Off Time Input Low Voltage Input High Voltage Input Current Input Hysteresis tON tOFF VIL VIH IIL, IIH VHYST ENABLE = 0 or VCC 2.0 -1 200 1 MAX3407/ MAX3408 MAX3406 MAX3407/ MAX3408 MAX3406/ MAX3407 MAX3408 MAX3406/ MAX3407 MAX3408 73.1 97.5 97.5 117 100 120 100 120 75 100 75 100 50 50 0.8 s s V V A mV 76.9 102.5 102.5 123 VCC ICC VCC = +5.5V, ENABLE = 0 or VCC 4.5 30 5.5 50 V A SYMBOL CONDITIONS MIN TYP MAX UNITS
Note 1: All parameters tested at +25C. Limits through temperature are guaranteed by design.
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75/100/120 Switchable Termination Networks
Typical Operating Characteristics
(VCC = +5V, TA = +25C, unless otherwise noted.)
RESISTANCE vs. TEMPERATURE (MAX3406)
MAX3406/7/8 toc01
MAX3406/MAX3407/MAX3408
RESISTANCE vs. TEMPERATURE (MAX3407)
MAX3406/7/8 toc02
RESISTANCE vs. TEMPERATURE (MAX3408)
125 120 RESISTANCE () 115 110 105 100 95 90 ENABLE = VCC ENABLE = 0
MAX3406/7/8 toc03
110
130 120 110 100 90 80 ENABLE = 0
130
100 RESISTANCE () ENABLE = 0 90 ENABLE = VCC 80
RESISTANCE ()
ENABLE = VCC
70 70 60 -50 -25 0 25 50 75 100 TEMPERATURE (C) 60 -50 -25 0 25 50 75 100 TEMPERATURE (C)
-50
-25
0
25
50
75
100
TEMPERATURE (C)
RESISTANCE vs. INPUT VOLTAGE (MAX3406)
MAX3406/7/8 toc04
RESISTANCE vs. INPUT VOLTAGE (MAX3407)
VB = 0 120 RESISTANCE () 110 100 90 80 70 60 ENABLE = VCC ENABLE = 0
MAX3406/7/8 toc05
RESISTANCE vs. INPUT VOLTAGE (MAX3408)
VB = 0 125 120 RESISTANCE () 115 110 105 100 95 90 ENABLE = VCC ENABLE = 0
MAX3406/7/8 toc06
120 VB = 0 110 RESISTANCE () 100 90 80 70 60 -3.6 -2.4 -1.2 0 VAB (V) 1.2 2.4 ENABLE = 0 ENABLE = VCC
130
130
3.6
-3.6
-2.4
-1.2
0 VAB (V)
1.2
2.4
3.6
-3.6
-2.4
-1.2
0 VAB (V)
1.2
2.4
3.6
IMPEDANCE vs. FREQUENCY 75 MODE--MAX3406/MAX3407
90 75 MAGNITUDE () 60 45 30 15 0 0.01 0.1 1 FREQUENCY (MHz) 10 100 PHASE MAGNITUDE
MAX3406/7/8 toc07
IMPEDANCE vs. FREQUENCY 100 MODE--MAX3406/MAX3408
90 60 PHASE (DEGREES) MAGNITUDE () 30 0 -30 -60 -90 120 100 80 60 40 20 0 0.01 0.1 1 FREQUENCY (MHz) 10 100 PHASE MAGNITUDE
MAX3406/7/8 toc08
IMPEDANCE vs. FREQUENCY 120 MODE--MAX3407/MAX3408
90 60 PHASE (DEGREES) MAGNITUDE () 30 0 -30 -60 -90 140 120 100 80 60 40 20 0.01 0.1 1 FREQUENCY (MHz) 10 100 PHASE MAGNITUDE
MAX3406/7/8 toc09
90 60 30 0 -30 -60 -90 PHASE (DEGREES)
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75/100/120 Switchable Termination Networks MAX3406/MAX3407/MAX3408
Typical Operating Characteristics (continued)
(VCC = +5V, TA = +25C, unless otherwise noted.)
ACCURACY DISTRIBUTION 75 MODE
MAX3406/7/8 toc10
ACCURACY DISTRIBUTION 100 MODE
MAX3406/7/8 toc11
ACCURACY DISTRIBUTION 120 MODE
80% PERCENTAGE OF PRODUCTION 70% 60% 50% 40% 30% 20% 10%
MAX3406/7/8 toc12
90% 80% PERCENTAGE OF PRODUCTION 70% 60% 50% 40% 30% 20% 10% 0% 74.40 74.60 74.80 75.00 75.20 75.40
90% 80% PERCENTAGE OF PRODUCTION 70% 60% 50% 40% 30% 20% 10% 0%
90%
75.60
98.8
99.2
99.6
100.0
100.4
100.8
101.2
0% 118.5
119.0
119.5
120.0
120.5
121.0
121.5
RESISTANCE ()
RESISTANCE ()
RESISTANCE ()
Pin Description
PIN 1 2 3 4 5 NAME VCC GND ENABLE B A Ground Digital Control Input. Drive ENABLE high to turn on the internal switch, pull ENABLE low to disable the internal switch. Cable Terminator Terminal B Cable Terminator Terminal A FUNCTION Supply Voltage +4.5V to +5.5V. Bypass to GND with a 0.1F capacitor.
Detailed Description
The MAX3406/MAX3407/MAX3408 are line-terminating networks. They provide 75, 100, and 120 termination to be compatible with twisted pair or coaxial cable. The MAX3406/MAX3407/MAX3408 consume only 50A 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 -40C to +85C. The ENABLE pin allows switching from one termination value to another: 75 to 100 for the MAX3406, 75 to 120 for the MAX3407, and 100 to 120 for the MAX3408 (Figure 1 and Table 1).
Applications Information
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. 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)
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75/100/120 Switchable Termination Networks
Table 1. Termination Mode Selection
PART MAX3406EUK MAX3407EUK MAX3408EUK RAB () ENABLE = 1 75 75 100 RAB () ENABLE = 0 100 120 120
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.
MAX3406/MAX3407/MAX3408
Resistance vs. Input Voltage Range
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
A
MAX3406 MAX3407 MAX3408
VCC
R1
R2
B GND
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.
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. 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.
Decoupling VCC The VCC pin for the MAX3406/MAX3407/MAX3408 must be decoupled with a 0.1F 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
Resistance vs. Temperature
The MAX3406/MAX3407/MAX3408 resistance is constant over temperature. The typical temperature coefficient of resistance is 150ppm/C. Over a -40C to +85C range centered at +25C, this would be a 1% change in resistance. The initial accuracy at room temperature is 1.5%. This provides improved perfor_______________________________________________________________________________________ 5
75/100/120 Switchable Termination Networks MAX3406/MAX3407/MAX3408
Package Information
SOT5L.EPS
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 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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