19-3745; Rev 0; 7/05 47MHz to 870MHz Analog CATV Transimpedance Amplifier Features The MAX3654 analog transimpedance amplifier (TIA) is designed for CATV applications in fiber-to-the-home (FTTH) networks. This high-linearity amplifier is intended for 47MHz to 870MHz subcarrier multiplexed (SCM) signals in passive optical networks (PON). A gain-control input supports AGC operation with optical inputs having -6dBm to +2dBm average power. With 62dBΩ maximum gain at 47MHz and 18dB gain control range, the minimum RF output level is 14dBmV/channel at -6dBm optical input. A compact 4mm x 4mm package includes all of the active RF circuitry required to convert analog PIN photocurrent to a 75Ω CATV output. ♦ 47MHz to 870MHz Operation This 700mW SiGe RF IC provides a low-cost, low-power integrated analog CATV receiver solution for FTTH ONTs. ♦ 700mW Power Dissipation ♦ -6dBm to +2dBm Optical Input Range ♦ 21dBm OIP3, 47dBm OIP2 ♦ 5.5pA/√Hz EIN (Amplifier Alone) ♦ 62dB Gain at 47MHz ♦ 18dB Transimpedance (Gain) Control ♦ Integrated +4dB Gain Tilt (with Typical Photodiode) ♦ +5V Single-Supply Operation ♦ -40°C to +85°C Operating Temperature Range ♦ 4mm x 4mm TQFN Package Applications Ordering Information FTTH Optical Network Termination (ONT) PART TEMP RANGE MAX3654ETE+ PINPACKAGE -40°C to +85°C 16 TQFN-EP* PKG-CODE T1644F-4-A + Denotes lead-free package. *EP = Exposed pad. Pin Configuration appears at end of data sheet. Typical Application Circuit +5V TO +12V 10µH FERRITE BEAD +5V 1kΩ -6 TO +2dBm 0.001µF MAX3654 FTTH VIDEO TIA 0.001µF TIA IN- OUT- FERRITE BEAD HYST MUTE 100kΩ + OPAMP - 1:1 DRIVE VAGC 1kΩ 0.001µF OUT+ IN+ 75Ω 0.001µF +5V RHYST 10µH ________________________________________________________________ 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 MAX3654 General Description MAX3654 47MHz to 870MHz Analog CATV Transimpedance Amplifier ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC.............................................-0.3V to +6.0V IN+, IN-, VAGC, OUT+, OUT-, MUTE, HYST.........-0.3V to +5.5V TEST1, TEST2........................................................-0.3V to +5.5V Output Current (OUT+, OUT-) ............................................56mA Continuous Power Dissipation, 16-Lead TQFN-EP Package (TA = +70°C) (derate 16.9mW/°C above +70°C)....1349.1mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-55°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. DC ELECTRICAL CHARACTERISTICS (VCC = +4.75V to +5.25V, typical values at VCC = +5.0V, TA= +25°C, unless otherwise noted.) (Note 1) PARAMETER Supply Current SYMBOL CONDITIONS MIN ICC Gain Control Input Current VAGC = 1.4V TYP MAX UNITS 136 170 mA 50 200 µA Mute Input High VIH Mute Input Low VIL 0.8 V IIL, IIH 30 µA TYP MAX UNITS 870 MHz ±0.3 ±0.75 dB Mute Input Current 2.0 V AC ELECTRICAL CHARACTERISTICS (VCC = +4.75V to +5.25V, output ZL = 75Ω, typical values at VCC = +5.0V, TA = +25°C, unless otherwise noted.) PARAMETER Operating Frequency Range SYMBOL CONDITIONS f 47 Frequency Response Flatness 47MHz to 870MHz (Notes 2, 6) Transimpedance, Differential (ZT) 47MHz VAGC ≤ 0.175V 60.5 62 63.5 VAGC = 0.500V 51.5 53 54.5 VAGC = 1.400V 42 43.5 45 ±0.75 ±1.6 dB 4 5.5 dB Gain Control Stability VAGC = 0 to 1.4V, RHYST = open (Note 3) Gain Tilt Linear, 870MHz compared to 47MHz (Notes 4, 6) Output Second-Order Intercept OIP2 (Note 5) Output Third-Order Intercept OIP3 (Notes 4, 5) Equivalent Input Noise Including Photodiode EIN Gain Hysteresis, Optical Differential Output Level, Mute RF Output Return Loss -S22 MIN 3 18 dBΩ >47 dBm 21 dBm VAGC ≤ 0.175V (Notes 4, 6) 8 RHYST = open ±0.13 RHYST = GND ±0.65 MUTE ≤ 0.8V, 50MHz -58 47MHz to 870MHz 13 pA/√Hz dB -45 dBc dB Note 1: DC parameters are tested at +25°C, and guaranteed by design and characterization at -40°C and +85°C. Note 2: Maximum difference between frequency response at any point and a straight line connecting frequency response at end points. Note 3: Gain control stability is the maximum variation in transimpedance (over process, voltage, and temperature) for any VAGC control voltage. Note 4: AC parameters guaranteed by design and characterization. Note 5: OIP2 and OIP3 measured using two tones at f1 = 800MHz and f2 = 850MHz, POUT = -16dBm, VAGC = 1.4V. Note 6: Includes the effects of a packaged photodiode having the characteristics shown in Figure 2. 2 _______________________________________________________________________________________ 47MHz to 870MHz Analog CATV Transimpedance Amplifier MAX3654 +5V MINI-CIRCUITS ADTL 1-12* 0.001µF 12Ω* MINI-CIRCUITS ADTL 0.001µF 1-18-75 VCC IN+ OUT+ 0.001µF MAX3654 12Ω* 75Ω OUT- IN- 0.001µF VAGC GND *FOR 75Ω INPUT IMPEDANCE USE 25Ω RESISTORS AND ADTL 1-18-75 OIP2, OIP3 TEST CIRCUIT +5V ** * +5V 1kΩ 0.001µF VCC 0.001µF IN+ 75Ω OUT+ MAX3654 0.001µF SEE PHOTODIODE MODEL IN FIGURE 2 MINI-CIRCUITS ADTL 1-18-75 OUT- IN- 0.001µF VAGC GND 1kΩ ** * GAIN, GAIN vs. VAGC, GAIN TILT, S22, IRN TEST CIRCUIT *MURATA BLM15HD182SN **TDK MLF1608 E100K 10µH Figure 1. Test Circuits for Characterization _______________________________________________________________________________________ 3 MAX3654 47MHz to 870MHz Analog CATV Transimpedance Amplifier 5Ω 5nH 1nH 44dB TO 50dB 0.6pF 0.1pF 0.6pF 5Ω 0.6pF 50dB TO 56dB TIA IN+/- 5nH 1nH 0.1pF 56dB TO 62dB OUT+/- MAX3654 MUTE Figure 2. Photodiode and Header Model HYST VAGC Figure 3. Functional Diagram Typical Operating Characteristics (VCC = +5.0V, TA = +25°C, unless otherwise noted.) MAXIMUM GAIN vs. FREQUENCY (VAGC = 0V) 65 64 63 62 5.5 5.0 55 50 4.5 -40°C 4.0 +25°C 3.5 +85°C 3.0 45 61 2.5 60 0 4 MAX3654toc03 50MHz GAIN TILT (dB) 66 870MHz 60 6.0 MAX3654 toc02 TRANSIMPEDANCE GAIN (dBΩ) 67 65 TRANSIMPEDANCE GAIN (dBΩ) MAX3654 toc01 68 GAIN TILT vs. CONTROL VOLTAGE AND TEMPERATURE GAIN vs. CONTROL VOLTAGE 200 400 600 FREQUENCY (MHz) 800 1000 2.0 40 0.1 0.2 1.0 VAGC (V) 1.4 0 0.2 0.4 0.8 0.6 VAGC (V) _______________________________________________________________________________________ 1 1.2 1.4 1.6 47MHz to 870MHz Analog CATV Transimpedance Amplifier -4 -6 0.2 -8 S22 (dB) 0.4 0 -0.2 20 18 16 14 -10 -12 12 -0.6 -16 4 -0.8 -18 2 6 -20 +85°C NO PHOTODIODE 0 0 200 400 600 FREQUENCY (MHz) 800 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) 1000 OIP3 vs. CONTROL VOLTAGE OIP2 vs. CONTROL VOLTAGE 28 26 MAX3654toc08 80 MAX3654toc07 30 70 24 60 OIP2 (dBm) OIP3 (dBm) +25°C WITH PHOTODIODE 8 -14 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) +85°C WITH PHOTODIODE 10 -0.4 -1.0 MAX3654 toc06 0 -2 NOISE (pA/(Hz)1/2) 0.6 INPUT REFERRED NOISE vs. FREQUENCY (MAXIMUM GAIN, VGA = 0V) MAX3654 toc05 0.8 GAIN TILT DEVIATION (dB) DIFFERENTIAL S22 (NORMALIZED TO 75Ω) MAX3654 toc04 1.0 GAIN TILT DEVIATION vs. FREQUENCY (REFERRED TO A LINE FROM 50MHz TO 870MHz) 22 20 18 50 40 16 14 30 12 10 20 0 0.2 0.4 0.6 0.8 VAGC (V) 1.0 1.2 1.4 1.6 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 VAGC (V) _______________________________________________________________________________________ 5 MAX3654 Typical Operating Characteristics (continued) (VCC = +5.0V, TA = +25°C, unless otherwise noted.) 47MHz to 870MHz Analog CATV Transimpedance Amplifier MAX3654 Pin Description PIN NAME FUNCTION 1, 4, 9, 12 VCC 2 IN+ Positive Analog Photodiode Input Connection. Typically connected to photodiode cathode. 3 IN- Negative Analog Photodiode Input Connection. Typically connected to photodiode anode. 5 VAGC AGC Control Input. Range is 0 to 1.4V. See the Typical Operating Characteristics Gain vs. Control Voltage graph. 6 MUTE Mute Control Input, TTL. MUTE < 0.8V to mute output. +5.0V Power Supply 7 HYST AGC Hysteresis Control Input. A resistor from HYST to GND controls the hysteresis level. 8, 14, 16 GND Ground 10 OUT- Negative RF Output. The voltage on this pin decreases with increasing optical power when IN+ is connected to the photodiode cathode. 11 OUT+ Positive RF Output. The voltage on this pin increases with increasing optical power when IN- is connected to the photodiode anode. 13 TEST1 Reserved for Test. Connect to GND for normal operation. 15 TEST2 Reserved for Test. Connect to GND for normal operation. EP EP Exposed Pad. The exposed pad must be soldered to the circuit-board ground for proper thermal and electrical performance. Detailed Description The MAX3654 is a broadband, high-linearity, low-noise transimpedance amplifier. The transimpedance (gain) can be adjusted between 43.5dBΩ and 62dBΩ using the voltage at an external control input (VAGC). When connected as shown in the Typical Application Circuit, optical input levels from -6dBm to +2dBm will produce a minimum output of 14dBmV/channel, and 4dB tilt compensation. Gain deviation over frequency from 47MHz to 870MHz is less than ±0.75dB. Low-Noise Variable Gain Amplifier The input stage is a low-noise analog transimpedance amplifier (TIA) connected differentially to the analog photodiode. Desired performance can be achieved with a photodiode having capacitance (CPD) up to 1pF. VAGC input to select a gain stage. As the voltage at VAGC crosses the two locations in the gain vs. VAGC curve, where the gain stage changes (350mV and 700mV), there will be small deviations in the output which may lead to a brief interruption of CATV signals. See the Typical Operating Characteristics for Gain vs. Control Voltage. A hysteresis control input is provided to limit dithering when the optical level is close to a gain-switching point. The hysteresis level is controlled by the value of RHYST. Hysteresis is minimum (0.13dB) when this pin is open. RF Output and Cable Tilt Compensation With a typical photodiode, the gain at 870MHz is 4dB higher than at 47MHz. The overall frequency response of the TIA is within ±0.75dB of a straight line connecting the values at 47MHz and 870MHz. VAGC and Hysteresis Control The gain-control pin VAGC sets overall TIA gain implemented as three switchable gain stages, each with a continuously variable gain control, as shown in Figure 3. This produces a continuously variable gain ranging from 62dBΩ (at VAGC = 0.175V) to 43.5dBΩ at (VAGC=1.4V). A set of comparators examines the 6 Mute In normal operation, the TTL MUTE pin is held high. When MUTE is low, the output signal is attenuated by more than 45dB. _______________________________________________________________________________________ 47MHz to 870MHz Analog CATV Transimpedance Amplifier When connected as shown in the Typical Applications Circuit, the MAX3654 will maintain the electrical output constant (15dBmV/ch) for optical signals in the -6dBm to +2dBm range. TOP VIEW VCC 175mV ZT(dBΩ) = 62dBΩ + 20 × log VAGC(mV) (0.175V ≤ VAGC ≤ 1.4V). Pin Configuration OUT- AGC Operation For AGC operation, the optical average power can be measured from the voltage drop across the lower bias resistor, using high impedance to isolate the photodiode as shown in the EV kit schematic. TIA gain is inversely proportional to the voltage present at VAGC from 0.175V to 1.4V. From 0 to 0.175V, the gain is constant and maximum. The nominal gain is given by: OUT+ RF Output The differential TIA RF output should be connected (AC-coupled) to a balun transformer for normal singleended output. VCC Photodiode Parasitics The MAX3654 TIA is designed to operate with a lowcapacitance analog photodiode. Proper system design includes considerations of lead configuration, pad, and through-hole geometry, and PC board layer selection for connections to the IC. The TIA is designed to operate correctly when the total capacitance of the photodiode, package, leads and PC board is between 1.0pF and 2.5pF. ed with 5mm (nominal) leads into through-hole vias as in the EV kit configuration, a 4dB uptilt will normally be achieved. It is important to configure the layout with capacitance and inductance in the anode and cathode connection as symmetric as possible. The electrical input circuit is normally configured with a 50Ω input for use with conventional test and measurement equipment. If desired, the MAX3654 input can also be terminated with 75Ω as shown in the EV kit data sheet. The 75Ω EV kit outputs should be connected to 50Ω test and measurement equipment using a minimum loss pad. For more information, see the Maxim website: MAX3654 EV Kit data sheet— http://www.maxim-ic.com/Fiber.cfm Minimum Loss Pad— http://www.maxim-ic.com/appnotes.cfm/appnote_number/972 12 11 10 9 TEST1 13 GND 14 MAX3654 TEST2 15 EP* GND 16 8 GND 7 HYST 6 MUTE 5 VAGC IN+ 2 VCC The optical input circuit includes photodiode bias circuitry, an op amp to adjust VAGC according to the DC photodiode current (for AGC operation), an output balun, and a 75Ω output connector. Through-hole pads are provided to attach the triplexer analog photodiode leads. Since photodiode capacitance and package lead inductance affect the amount of uptilt, in configurations where lead inductance is significantly lower than the value shown in Figure 2, the uptilt may be increased by providing discrete inductance on the PC board. When a CPD = 0.5pF (typ) photodiode is mount- 1 *THE EXPOSED PAD MUST BE CONNECTED TO GROUND. 3 4 VCC The factory-assembled EV kit for the MAX3654 provides two versions: optical input and electrical input. IN- Evaluation Kit and PC Board Layout THIN QFN 4mm x 4mm Chip Information TRANSISTOR COUNT: 3376 PROCESS: SiGe Bipolar SUBSTRATE: SOI _______________________________________________________________________________________ 7 MAX3654 Applications Information Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) For the latest package outline information, go to www.maxim-ic.com/packages.) (TQFN 4mm x 4mm x 0.8mm, Package Code: T1644.) 24L QFN THIN.EPS MAX3654 47MHz to 870MHz Analog CATV Transimpedance Amplifier PACKAGE OUTLINE, 12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm 21-0139 D 1 2 PACKAGE OUTLINE, 12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm 21-0139 D 2 2 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.