T H AT Corporation Balanced Line Driver ICs THAT 1606, 1646 FEATURES APPLICATIONS * Balanced, transformer-like floating output * Differential Line Drivers * OutSmarts(R) technology improves clipping into single-ended loads * * Audio Mixing Consoles Distribution Amplifiers * Stable driving long cables and capacitive loads * * Hi-Fi Equipment * Dynamic Range Processors Digital Effects Processors * High output: 18Vrms into 600 W * * Low noise: -101 dBu Low distortion: 0.0007% @ 1kHz * * * Industry-standard pinout * Audio Equalizers Telecommunications Systems Instrumentation Description The THAT 1606 and 1646 are a new generation of monolithic audio differential line drivers offering improved performance over conventional cross-coupled designs. Based on a high-performance, fully differential opamp and laser-trimmed thin-film resistors, both families exhibit low noise and distortion, high slew rate, and wide output swing. The parts are stable when driving difficult loads, and have short-circuit protected outputs. currents, making the designs inherently more stable and less sensitive to component tolerances than common CCOSes. As a result, THAT's topology prevents the loss of common-mode feedback that plagues common CCOS designs when clipping into single-ended loads. This avoids excessive ground currents that would otherwise upset power supplies and create additional distortion, even in adjacent channels. Designed from the ground up in THAT's complementary dielectric isolation process, both models incorporate THAT's patented OutSmarts1 technology. This is a dual feedback-loop design that prevents the excessive ground currents typical of cross-coupled output stages (CCOS) when clipping into single-ended loads. OutSmarts uses two individual negative-feedback loops to separately control the differential output voltage and common mode output The 1646 is pin-compatible with the TI DRV134 and DRV135, as well as the Analog Devices SSM2142. The 1606 offers an advanced common-mode offset voltage reduction scheme, which requires a small single capacitor instead of the two electrolytics required by the 1646 and its pin-compatible cousins. Additionally, the 1606 features differential inputs in a space-saving 16-pin QSOP package. Both parts offer +6 dB gain. THAT 1646 10k 25 Vcc OutCEXT Sns5k In+ 10k Din+ Dout- 10k Dout+ 10k Cin+ 10p 20k Cin- A D & A C 5k Gnd Din- 20k 10k Sns+ 10k Vee CEXT 25 Out+ Figure 1. THAT 1646 Equivalent Circuit Diagram Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1646 1606 DIP8 SO8 SO16W QSOP16 OutOutNC Gnd* SnsSnsNC NC Gnd Gnd OutOutIn In SnsCap1 Vee Vee Gnd Gnd Vcc Vcc In InSns+ Sns+ NC In+ Out+ Out+ NC Gnd* -- -- NC Gnd* -- -- NC NC -- -- Vee Vee -- -- Vcc Vcc -- -- Sns+ Cap2 -- -- Out+ Out+ -- -- NC NC -- -- NC Gnd* * See "Thermal Considerations" section on page 10 Table 1. THAT 1606/1646 pin assignments 1. For complete details of OutSmarts, see Hebert, Gary K., "An Improved Balanced, Floating Output Driver IC", presented at the 108th AES Convention, February 2000. Protected under US Patents numbers 4,979,218 and 6,316,970. Additional patents pending. THAT and OutSmarts are registered trademarks of THAT Corporation. THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; Document 600078 Rev. 05 Document 600078 Rev 05 Page 2 of 12 THAT1606/1646 Balanced Line Driver ICs SPECIFICATIONS 2 Absolute Maximum Ratings (T A = 25C) Positive Supply Voltage (Vcc) +20 V Storage Temperature (TST) -55 to +125C Negative Supply Voltage (Vee) -20 V Junction Temperature (TJ) 125C Output Short Circuit Duration Continuous Lead Temperature (TLEAD)(Soldering 60 sec) 300C Operating Temperature Range (TOP) -40 to +85C 1646 Electrical Characteristics 3 Parameter Symbol Input Impedance ZIN Gain G1 Gain G2 Gain Error DC Power Supply Rejection Ratio Output Common-Mode Rejection Ratio Output Signal Balance Ratio THD+N (Balanced) THD+N (Single Ended) Conditions Min. Typ. Max. Units 4.00 5.00 Balanced 5.80 6.00 6.20 dB Single Ended 5.76 5.96 6.16 dB Balanced 5.00 5.30 5.60 dB Single Ended 4.96 kW RL=100 kW per output RL= 600 W 5.26 5.56 dB 0.02 0.20 dB G1 RL=100 kW per output, Balanced PSRR 4V to 18V 85 107 dB CMRROUT f=1kHz, BBC Method 46 65 dB SBR f=1kHz, BBC Method 35 54 dB THD+N1 VO=10 VRMS, RL=600 W 20Hz-5kHz 20kHz 0.0007 0.002 0.005 % % VO=10 VRMS, RL=600 W 20Hz-5kHz 20kHz 0.0010 0.0030 0.0060 % % THD+N2 Output Noise Onoise Balanced, 22Hz -20kHz -101 dBu Maximum Output Level VoMAX 0.1% THD+N 27.5 dBu SR CL=50pF/output 15 V/S CL=50pF/output 10 MHz Slew Rate Small Signal Bandwidth Output Common Mode Voltage Offset Differential Output Offset VOCM1 w/o Sense capacitors -250 50 250 mV VOCM2 w/ Sense capacitors -15 3.5 15 mV -15 4 15 mV VOD Output Voltage Swing, Positive No Load Output Voltage Swing, Negative No Load Output Impedance VCC-2.9 VCC-2.2 ZO V VEE+2.25 VEE+2.9 40 50 2. All specifications are subject to change without notice. 3. Unless otherwise noted,.all measurements taken with VS=18V, T=25C, RL = 600 W Balanced, RSOURCE = 0 W THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. 60 V W THAT1606/1646 Balanced Line Driver ICs Page 3 of 12 Document 600078 Rev 05 1646 Electrical Characteristics (cont'd) Parameter Symbol Maximum Capacitive Load Conditions Min. Typ. Stable Operation Quiescent Supply Current IS Unloaded 4.9 Output Short Circuit Current ISC Both outputs to ground 70 Power Supply Voltage Range Max. Units Unlimited F 5.75 mA mA 4 18 V Max. Units 1606 Electrical Characteristics 3 Parameter Symbol Input Impedance ZIN Gain G1 Gain G2 Gain Error DC Power Supply Rejection Ratio Output Common-Mode Rejection Ratio Input Common-Mode Rejection Ratio Output Signal Balance Ratio THD+N (Balanced) THD+N (Single Ended) Conditions Min. Typ. 4.00 5.00 kW RL=100 kW / output Balanced 5.80 6.00 6.20 dB Single Ended 5.76 5.96 6.16 dB Balanced 5.00 5.30 5.60 dB Single Ended 4.96 5.26 5.56 dB 0.02 0.20 dB RL= 600 W G1 RL=100 kW / output, Balanced PSRR 4V to 18V 85 107 dB CMRROUT f=1kHz, BBC Method 46 65 dB CMRRIN f=1kHz 40 60 dB SBR f=1kHz, BBC Method 35 54 dB THD+N1 VO=10 VRMS, RL=600 W 20Hz-5kHz 20kHz 0.0007 0.002 0.005 % % VO=10 VRMS, RL=600 W 20Hz-5kHz 20kHz 0.0010 0.0060 0.0075 % % THD+N2 Output Noise Onoise Balanced, 22Hz -20kHz -101 dBu Maximum Output Level VoMAX 0.1% THD+N 27.5 dBu SR CL=50pF/output 15 V/S CL=50pF/output 10 MHz Slew Rate Small Signal Bandwidth Common Mode Output Voltage Offset Differential Output Offset VOCM1 w/o CM coupling capacitor -250 50 250 mV VOCM2 w/ CM coupling capacitor -20 -5 20 mV -15 4 15 mV VOD Output Voltage Swing, Positive No Load Output Voltage Swing, Negative Output Impedance No Load ZO Maximum Capacitive Load Quiescent Supply Current VCC-2.9 VCC-2.2 VEE+2.25 VEE+2.9 40 Unloaded V 60 W Unlimited F 5.75 mA 50 Stable Operation IS V 4.9 THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. Document 600078 Rev 05 Page 4 of 12 THAT1606/1646 Balanced Line Driver ICs 1606 Electrical Characteristics (cont'd) Parameter Symbol Conditions ISC Both outputs to ground Output Short Circuit Current Min. Typ. Max. 70 Power Supply Voltage Range mA 4 18 THAT 1646 10k 25 Vcc OutCEXT Sns10k 5k Din+ In+ Dout- 10k Dout+ 10k Cin+ 10p 20k Cin- A D & A C 5k Din- Gnd 20k 10k Sns+ CEXT 25 10k Vee Out+ Figure 2. THAT 1646 Equivalent Circuit Diagram CEXT Cap2 Cap1 REXT THAT 1606 25 Vcc Out10k 5k In+ Dout- 10k Cin+ Cin- In- 10k Din+ 5k 10p 7k AD & AC Din- Gnd Dout+ 10k 7k 10k 10k 25 Vee Units Out+ Figure 3. THAT 1606 Equivalent Circuit Diagram THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. V THAT1606/1646 Balanced Line Driver ICs Page 5 of 12 Document 600078 Rev 05 Theory of Operation OutSmarts(R) technology The THAT 1606 and 1646 family employs the OutSmarts topology, a variation of circuitry originally developed by Chris Strahm at Audio Teknology Inc., (and later acquired by Audio Toys, Inc.). THAT's OutSmarts topology employs two negative-feedback loops -- one to control the differential signal, and a separate loop to control the common mode output levels. Figures 2 and 3 show the gain core common to the 1606 and 1646. The gain core is a single amplifier that includes two differential input pairs, Cin+/and Din+/-, and complementary outputs, Vout+ and Vout-, related to each other by two gain expressions, AD(s) and AC(s). The first pair of differential inputs, Din+/-, is connected to the differential feedback network between the outputs and the input signal. The second differential input pair, Cin+/-, is connected to a bridge circuit which generates an error signal used to servo the common-mode behavior of the outputs. The loop equations are then: DOUT + - DOUT - = D DOUT = AD ( DIN + - DIN - ) , where AD is the differential open-loop gain, and DOUT + + DOUT - = S DOUT = AC( CIN + - CIN - ) , where AC is the common-mode open-loop gain. These equations can be solved much like standard op-amp loop equations. For the differential case, using superposition, we can see that this results in: DIN + = 1 3 DOUT - + 2 3 In+ , and DIN - = 1 3 DOUT + + 2 3 In - . Substituting and simplifying into the equation that defines differential operation yields: [ D DOUT = AD - DD OUT 3 + 2 (In + 3 ] - In- ) . Dividing through by AD (assuming that AD >> 3) and simplifying yields D DOUT = 2 ( In+ - In- ) . as one would expect for a +6 dB line driver. For the 1646, In- is hard-wired to ground (0v), so the differential equation above simplifies to: D DOUT = 2 ( In+ ) . The common mode equation is more complicated in that it is dependent on the attached load, and in any event doesn't yield much insight into the device's operation. For those who are interested, a more complete discussion is given in the reference mentioned in note 1. In op-amp analysis using negative feedback loops, the combination of negative feedback and high open-loop gain usually results in the open-loop gain "dropping out" of the equation, and the differential inputs being forced to the same potential. This is true for the core of the 1606 and 1646 ICs. If we start with that assumption, the operation of the common-mode feedback loop can be intuited as follows: Referring again to Figures 2 and 3, the commonmode input actually senses the sum of each IC's output currents by way of two 25 W resistors and the bridge network4. The resulting error signal is amplified and then summed into both outputs, with the net effect being to force the sum of the currents to be zero, and thus the common mode output current to zero. To see why this is important, consider what happens when the IC is loaded with a single-ended load, which shorts one or the other output to ground. Suppose Out- is grounded. In this case, the differential feedback loop increases the voltage at Dout+ to make up for most of the signal lost to the short at Out-. The common-mode feedback loop forces the current from Out- to be equal and opposite to that from Out+. But, during peak signals which drive Dout+ into clipping (exceeding its maximum output voltage capability), the differential loop is starved for feedback. Without the common-mode feedback, the result would be for the voltage at Dout- to decrease in an attempt to satisfy the differential loop's demand for feedback. This is one significant weakness of conventional cross-coupled output designs - common-mode feedback is lost when one output is clipped while the other is grounded. With OutSmarts, however, the common mode feedback loop senses this happening because of the increase in current at Out- (compared to that at Out+), and prevents the voltage at Out- from rising 4. The 10 pF capacitor can be ignored for the purposes of this analysis. It simply limits the maximum frequency at which the current-sensing action occurs THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. Document 600078 Rev 05 Page 6 of 12 out of control. This causes the OutSmarts design to more closely mimic the behavior of a true floating THAT1606/1646 Balanced Line Driver ICs balanced source (such as a transformer), compared to the behavior of a conventional CCOS design. Applications 1. Circuit implementations using the 1606 and 1646 are relatively straightforward. A quiet, solid ground reference, stiff voltage supplies, and adequate supply bypassing are all that are required to achieve excellent performance out of both ICs. 2. Both devices must be driven from a low-impedance source, preferably directly from opamp outputs, to maintain the specified performance. As an example, Belden 8451 is specified as having with 34 pF/ft of inter-conductor capacitance and 67 pF/ft of conductor to "other conductor + shield capacitance". Thus, we can assume a single conductor-to-shield capacitance of 33 pF/ft (the difference between 67 and 34) for each conductor. For balanced signals, the load capacitance across the 1646 outputs will be 34 pF/ft + 16.5 pF/ft = 50.5 pF/ft. The corner frequency of the THAT 1646 driving 500 ft of this cable (25.25 nF) will be 126 kHz. 3. Please refer to Figure 8 for a complete applications circuit. Stability and Load Capacitance The devices are stable into any capacitive load, and the maximum capacitance is limited only by slew rate and frequency response considerations. For the purposes of the frequency response calculation, the line driver's 25W sense resistors can be lumped into a single 50W resistor. The correct cable capacitance to use for the balanced-signal case is the sum of the inter-conductor capacitance and the two conductor-to-shield capacitances in series. Some manufacturers only specify the inter-conductor capacitance and the capacitance of one conductor to the other while connected to the shield, and some extraction may be required. fC = 1 2 x p x 50 W x 500 ( 34 pF ft +16.5 pF ft) = 126kHz One must also consider the slew rate limitations posed by excessive cable and other capacitances. We know that i = C dV dt and that dV dt = VPeak 2 x p x f Dennis Bohn of Rane Corporation has published work specifying some of the requirements for a balanced line driver, including a) stability into reactive loads, b) differential output voltage swing of at least 11 volts peak (+20dBu), and c) reliability5. This Vcc C4 100n 6 7 Vcc 4 Sns+ In In 3 8 Out+ Gnd Sns- Out1 Vee U1 2 5 THAT1646 Out+ Out- C5 100n Vee Figure 4. THAT 1646 without common-mode offset reduction 5. Dennis A. Bohn, "Practical Line-Driving Current Requirements"(Rane Note 126), Rane Corporation, 1991, revised 5/1996. Available at www.rane.com/note126.html. THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. THAT1606/1646 Balanced Line Driver ICs Page 7 of 12 supply rails without distortion, when driving into differential loads. work suggests a reasonable rule by which to calculate the output current requirements at 20kHz. The author concludes that the actual worst case peak level for various types of music and speech will be flat out to 5kHz, and roll off at 6dB/octave above this frequency. Thus the peak levels at 20kHz will be 12dB below those at 5kHz. Both devices, when driving single-ended loads, will clip at about half the output voltage as compared to a differential load. This is because only one of the two output signals will be available. Despite the output clipping, the input to the devices does not need to be constrained - they will work without undue problems being overdriven at their inputs when the outputs are clipping into single-ended loads. Using these, we can calculate the required slew rate and current drive. For the +26 dBu output levels that the 1646 is capable of, VPeak is 22V (below 5kHz), and at 20kHz, VPeak is 5.5V. Therefore, dV dt 1646 circuits = 2p x 5.5V x 20kHz = 0.69 mVs Figure 4 shows the most basic connection for a 1646. The only external components needed are the local 100nF bypass capacitors. These should be within 1 inch of the 1646 pins. As a consequence, i = 500 ft x (34 pF ft + 16.5 pF )x ft Document 600078 Rev 05 0.69 mVs = 17.5mA . Output DC offset Thus, driving this 25.25 nF cable requires 17.5 mAPeak, which is well within the capability of the 1606 and 1646. Because the 1646's outputs are connected directly to their respective sense inputs, this circuit may produce up to 250mV of common-mode dc offset at its outputs. As shown, the outputs are DC coupled to the output connector, so this dc will appear directly at the output of the system. Gain structure The 1606 and 1646 both provide +6 dB gain (factor of 2) between their inputs and differential outputs. This is appropriate, since with a balanced output, twice the voltage between the power supply rails is available at the output of the stage. The single-ended input of the 1646 can accept signals that swing to nearly the power supply rails without distortion, when driving into a differential (floating) load. The balanced input of the 1606 can accept signals at each input that swing to nearly one-half the power The output common-mode offset of a 1646 may be reduced by adding capacitors in the feedback loop, as shown in Figure 5. Capacitors C1 and C2 ac-couple the common-mode feedback loop. This changes the loop operation from servoing the common-mode output current at audio frequencies to servoing the common-mode output voltage to 0 at DC. This results in much lower common-mode out- Vcc C1 C4 100n In 6 4 3 In 7 Vcc Sns+ 10u NP Out+ 8 Out+ Gnd Sns- Out1 Vee U1 2 5 THAT1646 Out- C2 C5 100n Vee 10u NP Figure 5. THAT 1646 with common-mode offset reduction THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. Document 600078 Rev 05 Page 8 of 12 Vcc THAT1606/1646 Balanced Line Driver ICs C1 R1 1M0 100n C4 100n 12 4 Vcc 14 7 In+ Cap1 Out+ 6 InOut5 Gnd Cap2 3 Vee U1 13 11 THAT1606 In Out+ Out- C5 100n Vee Figure 6. THAT 1606 with output common-mode offset reduction and single-ended input drive Vcc R1 1M0 100n C4 100n In+ C1 12 7 4 Vcc In+ Cap1 Out+ 14 Out+ InOut5 Gnd Cap2 3 Vee U1 13 11 THAT1606 6 In- Out- C5 100n Vee Figure 7. THAT 1606 with output common-mode offset reduction and differential input drive put offset voltage, as indicated in the specifications section. C1 and C2 are typically high quality non-polarized electrolytic capacitors. 1606 circuits Figures 6 and 7 show the basic amplifier configurations for a 1606. The 1606 differs from the 1646 in two respects. First, the 1606 includes a negative-sense input pin (pin 6), so offers a differential input. This can be useful in connecting the output driver to the output of modern D/A converters, which usually present differential outputs. Second, instead of two 10uF capacitors, the 1606 uses an 0.1uf ca- pacitor (C1) and 1MW (R1) resistor to reduce common-mode dc offset. Generally, these components will cost less, and take up less space on the circuit board than the two large capacitors required for the 1646. C1 should be a high-quality film type capacitor to minimize low-frequency distortion when driving single-ended loads. RFI protection These line drivers can easily drive cables hundreds of feet in length without becoming unstable, but such long cables can act as antennae which can pick up RFI and direct it into the circuit. The circuit THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. THAT1606/1646 Balanced Line Driver ICs Page 9 of 12 Document 600078 Rev 05 Vcc D4 1N4004 Input Amplifier Block (from fig. 5, 6, or 7) Vcc Input Gnd Vee U1 D3 1N4004 XLR (M) L1 1 Out+ Out- D5 1N4004 D6 1N4004 Ferrite Bead C8 100p L2 Ferrite Bead 2 3 C3 100p Vee Figure 8. THAT 16x6 applications circuit with output common-mode offset protection, RFI protection, and surge protection of Figure 8 includes two 100 pF bypass capacitors C3 and C8 and two ferrite beads, whose purpose is to redirect this RF energy to the chassis before it can circulate inside the product's box and couple RF into other portions of the circuit. The capacitors should be located as close as possible to the output connector and connected via a low-inductance path to chassis ground, with the ferrite beads placed very nearby. These components ensure that RFI current is directed to the chassis and not through the relatively low-impedance output of the 1606/1646. The bypass capacitors and ferrite beads will have no effect on the gain error of these line drivers at audio frequencies. Output protection The 1606 and 1646 each incorporate a proprietary internal protection scheme, which will suffice for many situations seen in the field. However, one might foresee having the line driver's output mistakenly plugged directly into a microphone preamplifier input that has +48V phantom power applied. When this happens, the ac coupling capacitors on the preamp's input will discharge into the low-impedance output of the 1606/1646. This can result in surge currents of over 2 amperes6. The amount of energy stored in these capacitors is directly proportional to the capacitor value, which is, of course, not under the 1606/1646 designer's control. The 1606/1646's internal protection network will withstand this abuse for coupling capacitors up to about 33 uF. To protect against microphone preamplifiers that incorporate larger values of capacitance, a pair 1N4004 diodes from each output to the supply rails, as shown in Figure 8, is recommended. This shunts the discharge current to the power supply bypass and filter capacitors, thus protecting the output of the 1606 or 1646. Closing thoughts The integrated balanced line driver is one of those highly useful, cost-effective functional blocks that can provide significant improvement over discrete designs. The THAT 1646 goes a step or two further by improving over existing components. Both incorporate OutSmarts technology to tame the aberrant single-ended clipping behavior of conventional cross-coupled output stages. For more information on these or other THAT Corporation integrated circuits, please contact us directly, or through one of our international distributors. 6. Hebert, Gary K., Thomas, Frank W., "The 48V Phantom Menace", presented at the 110th Audio Engineering Society Convention, May, 2001 THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. Document 600078 Rev 05 Page 10 of 12 THAT1606/1646 Balanced Line Driver ICs Package Information Model SO8 Pkg 1646 1646S08-U 1606 --- DIP8 Pkg SO16W Pkg 1646P08-U 1646W16-U --- --- QSOP16 Pkg --1606Q16-U Table 2. Order Number Information The THAT1646 in available in 8-pin SO, 8-pin mini-DIP and 16-pin wide SOIC packages. The 1606 comes in a 16-pin QSOP package Package dimensions are shown in Figures 9, 10, 11, and 12, while pinouts are given in Table 1. Thermal Considerations As mentioned. the 1646 is available in an 8-pin DIP, and 16-pin wide SO, and an 8-pin SO, with junction-to-ambient thermal resistances of 100C/watt, 80C/watt, and 150C/watt, respectively, assuming a 2-sided PCB with no ground planes. Users of the SO-8 package should recognize driving 600 W loads or very long cables (several hundred feet) at high ambient temperatures (above 55C) continuously could lead to internal die temperatures that exceed the maximum rating and result in performance degradation. The 1606 is supplied in a 16-pin QSOP package in which pins 1, 8, 9, and 16 are fused to the die paddle to assist in conducting heat away from the die. These pins are connected to the die substrate, which is, in turn, connected to the ground pin of the device. When these pins are connected to a top-side ground plane of 1 square inch area, the junction-to-ambient thermal resistance is 125C/watt. Internal planes on multi-layer PCBs will reduce the thermal resistance further. THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. THAT1606/1646 Balanced Line Driver ICs Page 11 of 12 Document 600078 Rev 05 0-8 E F J C B 1 B H 1 G A C K hx45 D F H G A a1 ITEM A a1 B C D E F G H h D MILLIMETERS 4.78/5.00 0.10/0.20 3.81/3.99 5.84/6.20 0.36/0.46 1.27 1.52/1.73 0.18/0.25 0.41/0.89 0.31/0.71 ITEM A B C D E F G H J K INCHES 0.188/0.197 0.004/0.008 0.150/0.157 0.230/0.244 0.014/0.018 0.050 0.060/0.068 0.007/0.010 0.016/0.035 0.012/0.027 Figure 9. 8 pin SO package outline drawing E E MILLIMETERS 9.520.10 6.350.10 7.49/8.13 0.46 2.54 3.68/4.32 0.25 3.180.10 8.13/9.40 3.300.10 INCHES 0.3750.004 0.2500.004 0.295/0.320 0.018 0.100 0.145/0.170 0.010 0.1250.004 0.320/0.370 0.1300.004 Figure 10. 8 pin DIP package outline drawing F 1 D B A C H 1 E D G A B C G J H J I ITEM A B C D E F G H J MILLIMETERS 10.11/10.31 7.40/7.60 10.11/10.51 0.36/0.46 1.27 2.44/2.64 0.23/0.32 0.51/1.01 0.10/0.30 INCHES 0.398/O.406 0.291/0.299 0.398/0.414 0.014/0.018 0.050 0.096/0.104 0.009/0.013 0.020/0.040 0.004/0.012 Figure 11. 16 pin wide SO package outline drawing ITEM A B C D E G H I J 0-8 MILLIMETERS 4.80 - 4.98 3.81 - 3.99 5.79 - 6.20 0.20 - 0.30 0.635 BSC 1.35 - 1.75 0.10 - 0.25 0.40 - 1.27 0.19 - 0.25 INCHES 0.189 - 0.196 0.150 - 0.157 0.228 - 0.244 0.008 - 0.012 0.025 BSC 0.0532 - 0.0688 0.004 - 0.010 0.016 - 0.050 0.0075 - 0.0098 Figure 12. 16 pin QSOP package outline drawing THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. Document 600078 Rev 05 Page 12 of 12 THAT1606/1646 Balanced Line Driver ICs Revision History Revision ECO Date Changes Page 00 -- 9/26/2006 Released -- 01 -- 1/12/2007 - Changed 1606 THD+N specification. - Changed the XLR orientation in Figures 4 - 9. - Changed the recommendation for common-mode offset 3 6-9 8 capacitors to be high quality film type. 02 -- 8/6/2007 Reversed the SNS+ ans SNS- pins in Figures 1 and 2. 03 -- 9/24/2007 - Changed the Quiescent Supply Current specification. 2, 3 - Correction to the output pins in figures 4 through 9 6-9 04 2323 10/16/2009 Changed Table 1. toinclude all the pin numbers including unused 1, 4 1 and ground pins. 05 2526 5/11/2011 Revised Figures 4 - 9 and accompanying text to clarify the recommended application circuits. THAT Corporation; 45 Sumner Street; Milford, Massachusetts 01757-1656; USA Tel: +1 (508) 478-9200; Fax: +1 (508) 478-0990; Web: www.thatcorp.com Copyright (c) 2011, THAT Corporation; All rights reserved. 6 - 10