OPA1632 SBOS286 − DECEMBER 2003 High-Perfomance, Fully-Differential AUDIO OP AMP FEATURES DESCRIPTION D D D D SUPERIOR SOUND QUALITY ULTRA LOW DISTORTION: 0.000022% LOW NOISE: 1.3nV/√Hz HIGH SPEED: D − Slew Rate: 50V/µs − Gain Bandwidth: 180MHz FULLY DIFFERENTIAL ARCHITECTURE: − Balanced Input and Output Converts Single-Ended Input to Balanced The OPA1632 is a fully-differential amplifier designed for driving high-performance audio analog-to-digital converters (ADCs). It provides the highest audio quality, with very low noise and output drive characteristics optimized for this application. The OPA1632’s excellent gain bandwidth of 180MHz and very fast slew rate of 50V/µs produce exceptionally low distortion. Very low input noise of 1.3nV/√Hz further ensures maximum signal-to-noise ratio and dynamic range. Differential Output D WIDE SUPPLY RANGE: ±2.5V to ±16V D SHUTDOWN TO CONSERVE POWER APPLICATIONS D D D D D AUDIO ADC DRIVER BALANCED LINE DRIVER BALANCED RECEIVER ACTIVE FILTER PREAMPLIFIER The flexibility of the fully differential architecture allows for easy implementation of a single-ended to fully-differential output conversion. Differential output reduces even-order harmonics and minimizes common-mode noise interference. The OPA1632 provides excellent performance when used to drive high-performance audio ADCs such as the PCM1804. A shutdown feature also enhances the flexibility of this amplifier. The OPA1632 is available in an SO-8 package and a thermally-enhanced MSOP-8 PowerPAD package. RELATED DEVICES OPAx134 High-Performance Audio Amplifiers OPA627/637 Precision High-Speed DiFET Amplifiers OPAx227/x228 Low-Noise Bipolar Amplifiers THD + NOISE vs FREQUENCY 0.001 Gain = +1 RF = 348Ω VO = 3Vrms Differential I/O VIN+ Digital Output VIN− VOCM VIN− VIN+ VCOM −15V THD + Noise (%) +15V 0.0001 RL = 600Ω RL = 2kΩ 0.00001 10 Typical ADC Circuit 100 1000 10k 100k Frequency (Hz) Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PowerPAD is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. Copyright 2003, Texas Instruments Incorporated ! ! www.ti.com "#$% www.ti.com SBOS286 − DECEMBER 2003 PACKAGE/ORDERING INFORMATION PRODUCT PACKAGE-LEAD(1) PACKAGE DRAWING SPECIFIED TEMPERATURE RANGE PACKAGE MARKING SO-8 D −40°C to +85°C OPA1632 MSOP-8 PowerPAD DGN −40°C to +85°C 1632 ORDERING NUMBER OPA1632 TRANSPORT MEDIA, QUANTITY OPA1632D Rails, 100 OPA1632DR Tape and Reel, 2500 OPA1632DGN Rails, 100 OPA1632DGNR Tape and Reel, 2500 (1) For the most current specification and package information, refer to our web site at www.ti.com. ABSOLUTE MAXIMUM RATINGS(1)(2) over operating free-air temperature range unless otherwise noted. Supply Voltage, ±VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±16.5V Input Voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±VS Output Current, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150mA Differential Input Voltage, VID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±3V Maximum Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C Operating Free-Air Temperature Range . . . . . . . . . . . . . . . −40°C to +85°C Storage Temperature Range, TSTG . . . . . . . . . . . . . . . . . −65°C to +150°C Lead Temperature 1,6mm (1/16th inch) from case for 10 seconds . . . . . . . . . . . . . . . . +300°C ESD Ratings: Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1kV Charge Device Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 500V Machine Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200V (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. (2) The OPA1632 MSOP-8 package version incorporates a PowerPAD on the underside of the chip. This acts as a heatsink and must be connected to a thermally dissipative plane for proper power dissipation. Failure to do so may result in exceeding the maximum junction temperature, which can permanently damage the device. See TI technical brief SLMA002 for more information about using the PowerPAD thermally enhanced package. 2 This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. PIN CONFIGURATION Top View MSOP, SO OPA1632 1 8 VIN+ VOCM 2 7 Enable V+ 3 6 V− VOUT+ 4 5 VOUT− VIN− "#$% www.ti.com SBOS286 − DECEMBER 2003 ELECTRICAL CHARACTERISTICS: VS = ±15V VS = ±15V: RF = 390Ω, RL = 800Ω, and G = +1, unless otherwise noted. PARAMETER OFFSET VOLTAGE Input Offset Voltage vs Temperature vs Power Supply, DC INPUT BIAS CURRENT Input Bias Current Input Offset Current CONDITIONS dVos/dT PSRR MIN 316 IB IOS NOISE Input Voltage Noise Input Current Noise f = 10 kHz f = 10 kHz INPUT VOLTAGE Common-Mode Input Range Common-Mode Rejection Ratio, DC INPUT IMPEDANCE Input Impedance (each input pin) 66 FREQUENCY RESPONSE Small-Signal Bandwidth (VO = 100mVPP, Peaking < 0.5 dB) G = +1, RF= 348Ω G = +2, RF = 602Ω G = +5, RF = 1.5kΩ G = +10, RF = 3.01kΩ G = +1, VO = 100mVPP VO = 100mVPP G = +2, VO = 20VPP G = +1 G = +1, VO = 5V Step G = +1, VO = 2V Step G = +1, VO = 2V Step G = +1, f = 1kHz, VO = 3Vrms RL = 600Ω RL = 2kΩ RL = 600Ω RL = 2kΩ G = +1, SMPTE/DIN, VO = 2VPP RL = 600Ω RL = 2kΩ RL = 600Ω RL = 2kΩ THD < 0.01%, RL = 2kΩ Bandwidth for 0.1dB Flatness Peaking at a Gain of 1 Large-Signal Bandwidth Slew Rate (25% to 75% ) Rise and Fall Time Settling Time to 0.1% 0.01% Total Harmonic Distortion + Noise Differential Input/Output Differential Input/Output Single-Ended In/Differential Out Single-Ended In/Differential Out Intermodulation Distortion Differential Input/Output Differential Input/Output Single-Ended In/Differential Out Single-Ended In/Differential Out Headroom OUTPUT Voltage Output Swing Short-Circuit Current Closed-Loop Output Impedance POWER-DOWN(1) ISC Enable Voltage Threshold Disable Voltage Threshold Shutdown Current Turn-On Delay Turn-Off Delay POWER SUPPLY Specified Operating Voltage Operating Voltage Quiescent Current TEMPERATURE RANGE Specified Range Operating Range Storage Range Thermal Resistance RL = 2kΩ RL = 800Ω Sourcing/Sinking G = +1, f = 100kHz MAX UNITS ±0.5 ±5 13 ±3 mV µV/_C µV/V 2 ±100 6 ±500 µA nA 1.3 0.4 (V−) + 1.5 74 OPEN-LOOP GAIN Open-Loop Gain , DC OPA1632 TYP (V+) − 1.9 (V+) − 4.5 +50/−60 VENABLE = −15V Time for IQ to Reach 50% Time for IQ to Reach 50% nV/√Hz pA/√Hz 90 (V+) − 1 V dB 34 || 4 MΩ || pF 78 dB 180 90 36 18 40 0.5 800 50 100 75 200 MHz MHz MHz MHz MHz dB kHz V/µs ns ns ns 0.0003 0.000022 0.000059 0.000043 % % % % 0.00008 0.00005 0.0001 0.0007 20.0 % % % % VPP (V−) + 1.9 (V−) + 4.5 85 0.3 V V mA Ω (V−) + 2 (V−) + 0.8 0.85 2 2 1.5 V V mA µs µs ±15 ±16 14 17.1 ±2.5 IQ Per Channel −40 −40 −65 qJA +85 +125 +150 200 V V mA _C _C _C _C/W (1) Amplifier has internal 50kΩ pull-up resistor to VCC+ pin. This enables the amplifier with no connection to shutdown pin. 3 "#$% www.ti.com SBOS286 − DECEMBER 2003 TYPICAL CHARACTERISTICS At TA = +25°C, VS = ±15V, and RL = 2kΩ, unless otherwise noted. THD + NOISE vs FREQUENCY THD + NOISE vs FREQUENCY 0.001 0.001 THD + Noise (%) THD + Noise (%) Gain = +1 RF = 348Ω VO = 3Vrms Differential I/O 0.0001 RL = 600Ω Gain = +1 RF = 348Ω VO = 3Vrms Single−Ended Input Differential Output 0.0001 RL = 600Ω RL = 2kΩ RL = 2kΩ 0.00001 0.00001 10 100 1k 10k 100k 10 100 Frequency (Hz) THD + NOISE vs OUTPUT VOLTAGE RL = 2kΩ IMD (%) 0.00001 0.01 0.1 1 10 0.001 RL = 600Ω 0.0001 Gain = +1 RF = 348Ω f = 1kHz Single−Ended Input Differential Output 0.00001 0.01 0.1 RL = 2kΩ 1 10 Differential Output Voltage (Vrms) Differential Output Voltage (Vrms) INTERMODULATION DISTORTION vs OUTPUT VOLTAGE INTERMODULATION DISTORTION vs OUTPUT VOLTAGE 0.1 0.1 0.01 0.01 RL = 600Ω 0.001 Gain = +1 RF = 348Ω Differential I/O SMPTE 4:1; 60Hz, 7kHz DIN 4:1; 250Hz, 8kHz 0.01 0.1 R L = 2kΩ 0.00001 1 10 100 100 RL = 600Ω 0.001 0.0001 Differential Output Voltage (VPP ) 4 100 THD + Noise (%) RL = 600Ω IMD (%) THD + Noise (%) Gain = +1 RF = 348Ω f = 1kHz Differential I/O 0.0001 0.00001 100k 0.01 0.001 0.0001 10k THD + NOISE vs OUTPUT VOLTAGE 0.1 0.01 1k Frequency (Hz) Gain = +1 RF = 348Ω Single−Ended Input Differential Output SMPTE 4:1; 60Hz, 7kHz DIN 4:1; 250Hz, 8kHz 0.01 0.1 RL = 2kΩ 1 10 Differential Output Voltage (VPP ) 100 "#$% www.ti.com SBOS286 − DECEMBER 2003 TYPICAL CHARACTERISTICS (Cont.) At TA = +25°C, VS = ±15V, and RL = 2kΩ, unless otherwise noted. CURRENT NOISE vs FREQUENCY VOLTAGE NOISE vs FREQUENCY 10 In (pA/√Hz) Vn (nV/√Hz) 10 1 1 0.1 10 100 1k 10k 10 100k 100 OUTPUT VOLTAGE vs DIFFERENTIAL LOAD RESISTANCE 100 VCC = ±15V VCC = ±5V 5 VO (V) Output Impedance (Ω) 10 0 VCC = ±5V −5 −10 100k 100M 1G VCC = ±5V 10 1 VCC = ±15V −15 100 10k OUTPUT IMPEDANCE vs FREQUENCY 15 RF = 1kΩ G = +2 1k Frequency (Hz) Frequency (Hz) 0.1 1k 10k RL (Ω) 100k 100k 1M 10M Frequency (Hz) 5 "#$% www.ti.com SBOS286 − DECEMBER 2003 APPLICATIONS INFORMATION changing the values of R1 and R2. The feedback resistor values (R3 and R4) should be kept relatively low, as indicated, for best noise performance. Figure 1 shows the OPA1632 used as a differential-output driver for the PCM1804 high-performance audio ADC. R5, R6, and C3 provide an input filter and charge glitch reservoir for the ADC. The values shown are generally satisfactory. Some adjustment of the values may help optimize performance with different ADCs. Supply voltages of ±15V are commonly used for the OPA1632. The relatively low input voltage swing required by the ADC allows use of lower power-supply voltage, if desired. Power supplies as low as ±8V can be used in this application with excellent performance. This reduces power dissipation and heat rise. Power supplies should be bypassed with 10µF tantalum capacitors in parallel with 0.1µF ceramic capacitors to avoid possible oscillations and instability. It is important to maintain accurate resistor matching on R1/R2 and R3/R4 to achieve good differential signal balance. Use 1% resistors for highest performance. When connected for single-ended inputs (inverting input grounded, as shown in Figure 1), the source impedance must be low. Differential input sources must have well-balanced or low source impedance. The VCOM reference voltage output on the PCM1804 ADC provides the proper input common-mode reference voltage (2.5V). This VCOM voltage is buffered with op amp A2 and drives the output common-mode voltage pin of the OPA1632. This biases the average output voltage of the OPA1632 to 2.5V. Capacitors C1, C2, and C3 should be chosen carefully for good distortion performance. Polystyrene, polypropylene, NPO ceramic, and mica types are generally excellent. Polyester and high-K ceramic types such as Z5U can create distortion. The signal gain of the circuit is generally set to approximately 0.25 to be compatible with commonly-used audio line levels. Gain can be adjusted, if necessary, by V+ +8V to +16V 10µF + 0.1µF R3 270Ω C1 1nF R1 1kΩ Balanced or + Single−Ended Input − R2 1kΩ 3 8 VOCM R5 40Ω 5 C3 2.7nF 2 OPA1632 1 6 7 4 R6 40Ω C2 1nF VCOM (2.5V) R4 270Ω Enable(1) OPA134 1kΩ 0.1µF NOTE: (1) Leave open to enable. Logic signals referenced to V− supply. See the Shutdown Function section. 0.1µF 10µF + −8V to −16V V− Figure 1. ADC Driver for Professional Audio 6 1/2 PCM1804 "#$% www.ti.com SBOS286 − DECEMBER 2003 FULLY-DIFFERENTIAL AMPLIFIERS Differential signal processing offers a number of performance advantages in high-speed analog signal processing systems, including immunity to external common-mode noise, suppression of even-order nonlinearities, and increased dynamic range. Fully-differential amplifiers not only serve as the primary means of providing gain to a differential signal chain, but also provide a monolithic solution for converting single-ended signals into differential signals allowing for easy, high-performance processing. A standard configuration for the device is shown in Figure 2. The functionality of a fully differential amplifier can be imagined as two inverting amplifiers that share a common noninverting terminal (though the voltage is not necessarily fixed). For more information on the basic theory of operation for fully differential amplifiers, refer to the Texas Instruments application note SLOA054, Fully Differential Amplifiers, available for download from the TI web site (www.ti.com). +15V VIN+ Digital Output AIN VOCM VIN− AIN VREF −15V Figure 2. Typical ADC Circuit SHUTDOWN FUNCTION The shutdown (enable) function of the OPA1632 is referenced to the negative supply of the operational amplifier. A valid logic low (< 0.8V above negative supply) applied to the enable pin (pin 7) disables the amplifier output. Voltages applied to pin 7 that are greater than 2V above the negative supply place the amplifier output in an active state, and the device is enabled. If pin 7 is left disconnected, an internal pull-up resistor enables the device. Turn-on and turn-off times are approximately 2µs each. Quiescent current is reduced to approximately 0.85mA when the amplifier is disabled. When disabled, the output stage is not in a high-impedance state. Thus, the shutdown function cannot be used to create a multiplexed switching function in series with multiple amplifiers. OUTPUT COMMON-MODE VOLTAGE The output common-mode voltage pin sets the DC output voltage of the OPA1632. A voltage applied to the VOCM pin from a low-impedance source can be used to directly set the output common-mode voltage. For a VOCM voltage at mid-supply, make no connection to the VOCM pin. Depending on the intended application, a decoupling capacitor is recommended on the VOCM node to filter any high-frequency noise that could couple into the signal path through the VOCM circuitry. A 0.1µF or 1µF capacitor is generally adequate. Output common-mode voltage causes additional current to flow in the feedback resistor network. Since this current is supplied by the output stage of the amplifier, this creates additional power dissipation. For commonly-used feedback resistance values, this current is easily supplied by the amplifier. The additional internal power dissipation created by this current may be significant in some applications and may dictate use of the MSOP PowerPAD package to effectively control self-heating. PowerPAD DESIGN CONSIDERATIONS The OPA1632 is available in a thermally-enhanced PowerPAD family of packages. These packages are constructed using a downset leadframe upon which the die is mounted (see Figure 3[a] and Figure 3[b]). This arrangement results in the lead frame being exposed as a thermal pad on the underside of the package (see Figure 3[c]). Because this thermal pad has direct thermal contact with the die, excellent thermal performance can be achieved by providing a good thermal path away from the thermal pad. DIE (a) Side View Thermal Pad DIE (b) End View (c) Bottom View Figure 3. Views of the Thermally-Enhanced Package. 7 "#$% www.ti.com SBOS286 − DECEMBER 2003 The PowerPAD package allows for both assembly and thermal management in one manufacturing operation. During the surface-mount solder operation (when the leads are being soldered), the thermal pad can also be soldered to a copper area underneath the package. Through the use of thermal paths within this copper area, heat can be conducted away from the package into either a ground plane or other heat-dissipating device. PowerPAD PCB LAYOUT CONSIDERATIONS 1. Prepare the printed circuit board (PCB) with a top-side etch pattern, as shown in Figure 4. There should be etch for the leads as well as etch for the thermal pad. ÓÓÓ ÓÓÓ ÓÓÓ ÓÓÓÓÓÓ ÓÓÓ ÓÓÓ ÓÓÓ ÓÓÓ ÓÓÓ ÓÓÓ Single or Dual 68mils x 70mils (via diameter = 13mils) Figure 4. PowerPAD PCB Etch and Via Pattern. 2. Place five holes in the area of the thermal pad. These holes should be 13mils in diameter. Keep them small so that solder wicking through the holes is not a problem during reflow. 3. Additional vias may be placed anywhere along the thermal plane outside of the thermal pad area. These vias help dissipate the heat generated by the 8 OPA1632 IC, and may be larger than the 13mil diameter vias directly under the thermal pad. They can be larger because they are not in the thermal pad area to be soldered so that wicking is not a problem. 4. Connect all holes to the internal ground plane. 5. When connecting these holes to the ground plane, do not use the typical web or spoke via connection methodology. Web connections have a high thermal resistance connection that is useful for slowing the heat transfer during soldering operations. This makes the soldering of vias that have plane connections easier. In this application, however, low thermal resistance is desired for the most efficient heat transfer. Therefore, the holes under the OPA1632 PowerPAD package should make their connection to the internal ground plane with a complete connection around the entire circumference of the plated-through hole. 6. The top-side solder mask should leave the terminals of the package and the thermal pad area with its five holes exposed. The bottom-side solder mask should cover the five holes of the thermal pad area. This prevents solder from being pulled away from the thermal pad area during the reflow process. 7. Apply solder paste to the exposed thermal-pad area and all of the IC terminals. 8. With these preparatory steps in place, the IC is simply placed in position and runs through the solder reflow operation as any standard surface-mount component. This results in a part that is properly installed. "#$% www.ti.com SBOS286 − DECEMBER 2003 The OPA1632 does not have thermal shutdown protection. Take care to assure that the maximum junction temperature is not exceeded. Excessive junction temperature can degrade performance or cause permanent damage. For best performance and reliability, assure that the junction temperature does not exceed 125°C. The thermal characteristics of the device are dictated by the package and the circuit board. Maximum power dissipation for a given package can be calculated using the following formula: P Dmax + T max * T A q JA (1) Where: PDmax is the maximum power dissipation in the amplifier (W). Tmax is the absolute temperature (_C). maximum junction TA is the ambient temperature (_C). qJA = qJC + qCA. qJC is the thermal coefficient from the silicon junctions to the case (_C/W). qCA is the thermal coefficient from the case to ambient air (_C/W). For systems where heat dissipation is more critical, the OPA1632 is offered in an MSOP-8 with PowerPAD. The thermal coefficient for the MSOP PowerPAD (DGN) package is substantially improved over the traditional SO package. Maximum power dissipation levels are depicted in Figure 5 for the two packages. The data for the DGN package assumes a board layout that follows the PowerPAD layout guidelines. MAXIMUM POWER DISSIPATION vs AMBIENT TEMPERATURE 3.5 Maximum Power Dissipation (W) POWER DISSIPATION AND THERMAL CONSIDERATIONS θ JA = 170 _ C/W for SO−8 (D) θ JA = 58.4 _ C/W for MSOP−8 (DGN) TJ = 150_ C No Airflow 3.0 2.5 MSOP−8 (DGN) Package 2.0 1.5 1.0 SO−8 (D) Package 0.5 0 −40 −15 10 35 Ambient Temperature (_ C) 60 85 Figure 5. Maximum Power Dissipation vs Ambient Temperature 9 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. 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