Document
FEATURES
y Ideal mate for THAT1570 preamplifier y Wide gain range:
– +13.6 to +68.6dB in 1dB steps, and – +5.6dB
y Wide supply range: ±5V to ±17V y Wide output swing:+27dBu (±17V sup.) y Wide input swing: +22dBu (±17V sup.) y Low THD+N: 0.0003% @ 22dB gain y Integrated differential servo minimizes
output offset y Zero-crossing detector minimizes
switching noise y Flexible, addressable SPI interface y Four general-purpose digital outputs y Small 7mm x 7mm QFN32 package
High-Performance Digital Preamplifier Controller IC
THAT 5171
APPLICATIONS
y Digitally controlled microphone preamplifiers
y Digitally-controlled instrumentation amplifiers
y Digitally-controlled differential amplifiers
y Audio mixing consoles y PC audio breakout boxes y Audio distribution systems y Digital audio snakes y Portable audio recorders
Description
The THAT5171 is a digital gain controller for low-noise, analog, differential, current-feedback audio preamplifiers such as the THAT 1570. When used in conjunction with an appropriate analog gain block, the 5171 can set gain to 5.6dB, or any gain from 13.6dB to 68.6dB in 1dB steps, while preserving low noise and distortion. It operates from ±5V to ±17V supplies, supporting input signal levels as high as +22 dBu (at 5.6dB gain, and ±17V supplies) in combination with the 1570 (without an external input pad). The 5171 includes a differential servo and zerocrossing detector to minimize dc offsets and glitches (zipper noise) during gain adjustments.
The 5171 is controlled via an addressable serial-peripheral interface (SPI) port. Four General Purpose Outputs (GPOs) can be controlled
via this interface. The GPOs may be connected to input pads, analog switches, mute circuits, LEDs, etc. The SPI bus supports read-back so that host software can verify proper operation.
The 5171 was designed to mate perfectly with the THAT 1570 Differential Audio Preamplifier IC. Together, these two ICs provide a best-ofclass solution for digitally-controllable audio preamplifier applications. However, for designers who prefer a more customized solution, the 5171 may also be used to control a discrete preamplifier.
Fabricated in a high-voltage CMOS process, the 5171 integrates an astonishing amount of circuitry within a very small package. It comes in a small (7x7 mm) 32-pin QFN package, making it suitable for small portable devices.
RST TRC BSY Vdd Vdd DGnd DGnd IN2 IN1
DOUT DIN
SCLK CS
GPO3 GPO2 GPO1 GPO0 SOUT2 SOUT1 SCAP1 SCAP2 AGnd AGnd
Rg2 Rg1
Figure 1. THAT 5171 Block Diagram THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com
Copyright © 2014, THAT Corporation Document 600133 Rev 08
Document 600133 Rev 08
Page 2 of 20
THAT5171 High-Performance Digital Preamplifier Controller IC
Pin Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 27 28 29 30 31 32
Thermal Pad
Pin Name
NC NC RG1 IN1 IN2 RG2 NC NC VCC AGND VEE DGND VDD TRC RST' CS' SCLK DIN DOUT DGND VDD BSY GPO0 GPO1 GPO2 GPO3 NC AGND SCAP1 SCAP2 SOUT1 SOUT2
PAD
Pin Description
No Connect No Connect Attenuator Network Output 1 [Connects to preamplifier feedback 1 (RG1)] Attenuator Network Input 1 [Connects to preamplifier output 1] Attenuator Network Input 2 [Connects to preamplifier Output 2] Attenuator Network Output 2 [Connects to preamplifier feedback Input 2 (RG2)] No Connect No Connect Positive Analog Supply Voltage Analog Ground Reference Negative Analog Supply Voltage Logic Ground Reference Logic Positive Supply Voltage R/C Timeout or External Clock Input Reset Input (Active Low) Chip Select Input (Active Low) Serial Clock Input Serial Data Input Serial Data Output Logic Ground Reference Logic Positive Power Supply Busy Output (Active High) During Reset: SPI address bit 0 input; During run time: General Purpose Output 0 During Reset: SPI address bit 1 input; During run time: General Purpose Output 1 During Reset: SPI address bit 2 input; During run time: General Purpose Output 2 General Purpose Output 3 No Connect Analog Ground Reference DC Servo Capacitor Input 1 DC Servo Capacitor Input 2 DC Servo Output 1 DC Servo Output 2
Connected internally to Vee. Solder to PCB (optionally connect to Vee) for optimal performance.
Table 1. Pin Assignments
THAT Corporation; 45 Sumner Street; Milford, MA 01757-1656; USA Tel: +1 508 478 9200; Fax: +1 508 478 0990; Web: www.thatcorp.com
Copyright © 2014, THAT Corporation; All rights reserved.
THAT5171 High-Performance Digital Preamplifier Controller IC
Page 3 of 20
Document 600133 Rev 08
SPECIFICATIONS1
Absolute Maximum Ratings2,3
Total Analog Supply Voltage (VCC-VEE)
36 V
Positive Analog Supply Voltage (VCC-AGND)
18 V
Negative Analog Supply Voltage (VEE-AGND)
-18 V
Digital Supply Voltage (VDD-DGND) Analog and Digital Ground Difference (DGND-AGND)
4.5 V ± 0.3 V
Maximum Analog Voltage at IN1, IN2 (VIAMax)
VCC
Maximum Current Through VDD, DGND
100 mA
Minimum Analog Voltage at IN1, IN2.