Description. 5k (10k) - + 5k (10k)

Transcription

1 THAT Corporation Low Noise, High Performance Microphone Preamplifier IC FEATURES Excellent noise performance through the entire gain range Exceptionally low THD+N over the full audio bandwidth Low power consumption: ma typ. Wide bandwidth: 3MHz G=1000 (THAT 110) High Slew Rate: G=10 and C L =0pF (THAT 110) Wide put Swing: ±13V typ. on ±1V supplies Gain adjustable from 1 to >1000 with a single external resistor Drop-in compatible with SSM-01 (THAT 110) THAT 110, 11 APPLICATIONS Mixing Consoles Public Address Systems Analog and Digital Snakes Breakout Boxes for Digital Systems Sonar Paging and Intercom systems Instrumentation The THAT 110 and 11 are high performance audio preamplifiers suitable for microphone preamp and bus summing applications. The ICs are pin compatible with the Analog Devices SSM01 in both the -pin DIP and 16-pin SOIC packages. The THAT11 follows a different gain equation than the 110, but exhibits significantly lower noise at lower gain settings and is recommended for new designs. Designed from the ground up in THAT's complementary bipolar, dielectric isolation Description process, the THAT 110 and 11 improve on existing integrated microphone preamps by offering lower noise at low gains, better distortion characteristics, lower power consumption, higher slew rate and bandwidth, and increased output voltage swing. The parts are fully protected against ESD on all critical pins, and reliability is further enhanced by their reduced power requirements. In short, the THAT 110 and 11 provide superior performance in a popular format at an affordable price (10k) (10k) - + Pin Name DIP SO V Table / 11 pin assignments 1 Gain Equation DIP- SO16 k G P 110S V- k G 0. 11P 11S Figure 1. THAT 110 / 11 Equivalent Circuit Diagram (THAT 11 values shown in parentheses) Table. Ordering Information

2 Page THAT 110 / 11 Microphone Preamplifier SPECIFICATIONS 1 Absolute Maximum Ratings (T A = C) Positive Supply Voltage (V CC ) +0 V Operating Temperature Range (T OP ) -40 to + C Negative Supply Voltage (V EE ) -0 V Storage Temperature Range (T ST ) -40 to +1 C put Short-Circuit Duration (t SH ) Continuous Junction Temperature (T J ) 10 C Lead Temp. (T LEAD ) (Soldering 10 sec) 60 C Recommended Operating Conditions Parameter Symbol Conditions Min Typ Max Units Positive Supply Voltage V CC + +0 V Negative Supply Voltage V EE - -0 V Electrical Characteristics Parameter Symbol Conditions Min Typ Max Min Typ Max Units Supply Current I CC, I EE No signal ma V CC = V EE = 0V.4.4 ma Input Bias Current I B No signal; Either input.6.6 A connected to GND Input Offset Current I B-OFF No signal ±. ±. A put erred Offset Voltage Vos OR No Signal, V CM =0 ± 0 ± mv Input erred Offset Voltage Vos IR 60 db gain ± 1. ± 1. mv Input Voltage Range Common Mode V IN-CM Common mode, all gains ± 13 ± 13 V Normal Mode V IN-UNBAL Unbalanced ± 13 ± 13 V One input to GND, 0dB gain Differential Gain G diff db Input Voltage Range ± ± V Input Impedance 10 1 k Input Gain to put 0 0 db Input Impedance Z IN-DIFF Differential 0dB gain M pf 0dB gain M pf 40dB gain M pf 60dB gain M pf Z IN-CM Common mode all gains. 9. M pf 1. All specifications are subject to change without notice.. Unless otherwise noted, V CC = +1V, V EE = V, T A = C,

3 Rev. /3/0 Page 3 Electrical Characteristics (Cont d) Parameter Symbol Conditions Min Typ Max Min Typ Max Units Common Mode Rejection CMR V CM =±10V;DCto60Hz 0 db gain 0 0 db 0 db gain db 40 db gain db 60 db gain db Power Supply Rejection PSR V CC = V EE ; ±V to ±0V; DC to 60 Hz 0 db gain db 0 db gain db 40 db gain db 60 db gain db Total Harmonic Distortion THD+N V OUT = Vrms; R L = f = Hz; BW = 0 khz 0 db gain % 0 db gain % 40 db gain % 60 db gain % f = 0kHz; BW = 0 khz 0 db gain % 60 db gain % Equivalent Input Noise e n(out) f = Hz, 0dB gain 34 nv/hz 0dB gain 4.6 nv/hz 40dB gain nv/hz 60dB gain 1 1 nv/hz Input Current Noise i n 60dB gain.3.3 pa/hz Noise Figure NF 60dB gain R S = db R S = db Slew Rate SR R L =k C L =0pF V/s Bandwidth -3dB BW -3dB R L =k C L =10pF 0dB gain 1 11 MHz 0dB gain 9 MHz 40dB gain MHz 60dB gain MHz put Gain Error G ER (OUT) f = Hz; R L =k 0dB gain ± 0. ± 1 ± 0. ± 1 db 0dB gain ± 0.0 ± 1 ± 0.0 ± 1 db 40dB gain ± 0.0 ± 1 ± 0.0 ± 1 db 60dB gain ± 0.0 ± 0. ± 0.0 ± 0. db put Voltage Swing V O R L =k all gains ±13 ±13.3 ±13 ±13.3 V put Short Circuit Current I SC R L =0 ±1 ± 1 ma Minimum Resistive Load R Lmin k Maximum Capacitive Load C Lmax pf Gain Equation k G 1 10 k G 0. Gain Resistor (ideal values) 0dB gain 10k 0dB gain 1, dB gain dB gain 10

4 Page 4 THAT 110 / 11 Microphone Preamplifier +1 C 4p R V- U1 3 4 THAT 110/11 Gain Setting A single external resistor between the 1 and pins is all that is needed to set the gain of the THAT 110 / 11, according to the formulae for the 110: G 1 10 k 10 k or G 1 for the 11: k G 0. or Figure. Basic 110 / 11 Circuit k G 0. Applications For unity gain operation on the 110, 1 and may be left open. should be set to 10k in the 11. To avoid excess noise and ensure temperature stability, non-inductive wirewound or metal-film resistors are recommended for. Total gain accuracy will depend on both the tolerance on, and on the gain equation accuracy of the THAT 110/11. Total gain drift will result from the mismatch between the tempco of and the +1 C V- 3 4 U1 THAT 110/11 C R3 4p R U k Figure / 11 Circuit with put Offset Correction

5 Rev. /3/0 Page +4V In- In+ R6 C R 4p C4 C R3 1R R4 1R R D3 D4 D1 1N D D6 D 1N V- U1 3 THAT Figure 4. Typical 110 / 11 Circuit with Phantom Power tempco of the internal resistors (±0 ppm/ C typical). Noise Performance Thoughtful design results in these devices having significantly lower noise at low gains than similar IC microphone preamps. At zero db gain, equivalent input noise of the THAT 110 is nv/hz, nearly 6 db better than competitive IC designs. The unusual topology of the THAT 11 results in an equivalent input noise of 34 nv/hz at zero db gain, which makes it comparable to some of the better discrete designs currently available. At 1 khz, the equivalent input noise for both devices is 1 nv/hz at 60 db gain. Inputs Protection diodes are employed at all pins except and V- of the THAT 110/11. These diodes reduce the likelihood of accidental ESD/EOS damage to the IC. Other diodes across the base-emitter junctions of the input transistors prevent reverse bias of these junctions and consequent degradation of their noise performance. The inputs of the THAT 110 and11's are floating, so a dc bias connection is required to maintain the inputs within the IC's input common-mode range. Four different schemes are shown in Figures, 3, 4, and. Note that the values of and R in these figures should be kept small to minimize pickup of unwanted noise and interference. A value of 1 k is often used, since some microphones require a differential input impedance of this magnitude. Unfortunately, one would usually desire a significantly higher common mode input impedance to minimize the common mode degradation caused by unbalanced source impedances. Figure shows a technique which allows higher common mode input impedance while maintaining a lower differential source impedance. erence Terminal The "" pin provides the reference for the output signal, and is normally connected to analog ground. If necessary, the "" pin can be used for offset correction or DC level shifting. A non-zero reference source resistance will reduce the IC's common-mode rejection (CMR) by the ratio of 10 k/r REF. Phantom Power Phantom power is required for condensor microphones. A phantom power circuit is shown in Figure 4. Diodes D1 through D6 are necessary to protect the THAT 110/11 from transient voltages

6 Page 6 THAT 110 / 11 Microphone Preamplifier +4V +1 R6 C 4p R9 k C4 R C R3 4R R4 4R D3 D4 D1 D +1 10k R 10k V- U1 THAT 110/11 4 Figure. Preferred 110 / 11 Circuit with Multiple Phantom Power that may occur when microphones are connected or disconnected. While figure 4 shows a protection scheme that reflects the current industry practice, a better solution is shown in figure. Like figure 4, this circuit uses a diode bridge (composed of very fast s), but in this case, the diodes are connected directly to the Package Information power supply rails. While this arrangement doesn't keep the inputs inside the common mode range, it has the advantage of working even when the power is off. For further insights in to this subject, see The 4 Volt Phantom Menace, by Gary K. Hebert and Frank W. Thomas, presented at the 110th AES Convention. The THAT 110 and 11 are available in -pin DIP and 16-pin SOIC packages. The package dimensions are shown in Figures 6 and while pinouts are given in Table 1. Figure 6. -P (-pin DIP) version package outline Figure. -S16 (16-pin SO) version package outline