THAT Corporation 626x Low Noise Programmable Gain Preamplifiers
THAT Corporation 6261, 6263, and 6266 Low Noise Programmable Gain Preamplifiers are digitally controlled, 2-channel preamps with integrated ADC (Analog to Digital Converter) drivers. The gain for the 626x Preamplifiers is programmable from -8dB to +34 dB. These low-power (60mW) devices can be powered by unipolar (+10V and +5V) or bipolar (±5V) power supplies.
The 626x Preamplifier components include three variants distinguished primarily by the step size. The 6261 features a 1dB step, the 6263 features a 3dB step, and the 6266 offers a 6dB step. All three variants offer excellent noise performance. At maximum gain, the 6261 Equivalent Input Noise (EIN) is -127dBu, and the 6263 and 6266 are -126dBu. Dynamic range at minimum gain is up to 118.7dB.
To minimize audibility of gain changes with signal, all 626x devices can be programmed to synchronize gain changes with signal zero crossings. To enable seamless external gain changes, a BUSY pin for each channel allows external events to be synchronized with zero crossings.
The 626x Preamps are controlled via a 4-wire SPI interface running at up to 7.5MHz (+3.3V supply). Multiple devices may be daisy-chained using one chip select.
Four general-purpose logic outputs (GPOs) are available to control external circuitry, such as pad and phantom power. The GPOs may be synchronized with zero-crossings. Each channel may be set to low-power standby mode and can be muted by ~62dB.
The 6261, 6263, and 6266 Programmable Preamplifiers are offered in a 7mm X 7mm 48-pin QFN package.
Features
- Low -127dBu EIN (maximum gain)
- -8dB to +34dB gain
- Step size
- 1dB for 6261
- 3dB for 6263
- 6dB for 6266
- +16.5dBu maximum input (minimum gain)
- Integrated ADC driver with reference input
- High common-mode rejection of >65dB
- Very low 30mW power per channel
- Unipolar or Bipolar power supplies
- +10V, +5V, or ±5V analog
- +3.3V digital
- Zero crossing detectors minimize zipper noise
- Daisy-chainable SPI control interface
- Individually controlled Standby and Mute
- 7mm x 7mm QFN package
Applications
- Digitally controlled input stages
- Microphone preamplifiers
- Instrumentation amplifiers
- Differential amplifiers
- Audio mixing consoles
- PC audio interfaces
- Digital video cameras
- Digital audio snakes
- Portable audio recorders
- Programmable gain amplifiers
Block Diagram
Associated Development Board
THAT Corporation 626x Demonstration System
Digitally controlled mic preamp-ADC driver for the evaluation and comparison of 626x pre-amplifiers.
THAT Corporation 626x-DEMO Board allows developers to evaluate the performance of the 6261, 6263, and 6266 2-channel Programmable Preamplifiers. The 626x-DEMO Board provides a balanced audio input on a Neutrik combo connector with 48V phantom power and balanced audio output on XLR and 6.35mm (¼") TRS (Tip Ring Sleeve) Connectors. A Graphical User Interface (GUI) allows access to all functions of the 626x Preamp via USB. The 626x-DEMO Board also offers a prototyping area for adding or modifying circuitry.