Overview
The PGA2505IDBR, produced by Texas Instruments, is a digitally-controlled, analog microphone preamplifier. It is designed to serve as a front-end for high-performance audio analog-to-digital converters (ADCs). This device features a fully differential input-to-output architecture, which ensures low noise and a wide dynamic range. The PGA2505 is particularly suited for applications requiring precise gain control and high audio quality.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Gain Range | 9 | - | 60 | dB (3dB/step) |
| Gain Error | - | - | ±0.5 | dB |
| Equivalent Input Noise (ZS = 150Ω, Gain = 30dB) | -123 | - | - | dBu |
| Total Harmonic Distortion plus Noise (THD+N) at 1kHz, Gain = 30dB | -105 | -100 | -95 | dB |
| Input Resistance (Differential) | 9200 | - | - | Ω |
| Output Voltage Range (VCOMIN = 0V, RL = 600Ω) | VA– + 0.9 | - | VA+ – 0.9 | V |
| Output Offset Voltage (DC servo on, any gain) | ±0.08 | - | ±1 | mV |
| Supply Voltage (VA+, VA–, VD–) | ±4.75 | ±5 | ±5.25 | V |
| Operating Free-Air Temperature | -40 | - | 85 | °C |
| Package Type | - | - | SSOP-24 | - |
Key Features
- Digitally-Controlled Gain: Gain range of 9dB through 60dB in 3dB steps, with a unity gain setting via the serial port.
- Fully Differential Architecture: Ensures low noise and wide dynamic range.
- Dynamic Performance: Low equivalent input noise and total harmonic distortion plus noise (THD+N).
- DC Servo and Common-Mode Servo: Minimizes dc offset and enhances common-mode rejection ratio (CMRR).
- Serial Control Interface: Four-wire serial interface for programming gain settings and internal functions, supporting daisy-chaining of multiple devices.
- General-Purpose Digital Outputs: Four programmable digital outputs for controlling external switching of input pads, phantom power, and high-pass filters).
- Over-Range Indicator: Active high output pin indicating when the preamplifier output voltage exceeds preset thresholds).
- Zero Crossing Detection: Minimizes audible artifacts when gain switching).
Applications
- Digital Mixers and Recorders: Ideal for high-performance audio systems requiring precise gain control).
- Digital Audio Editing Systems: Suitable for professional audio editing environments).
- Broadcast Equipment: Used in broadcast applications where high audio quality is essential).
- Intercoms: Applicable in intercom systems requiring clear and reliable audio transmission).
Q & A
- What is the gain range of the PGA2505?
The PGA2505 has a gain range of 9dB through 60dB in 3dB steps, with a unity gain setting via the serial port).
- What type of architecture does the PGA2505 use?
The PGA2505 uses a fully differential input-to-output architecture).
- How is the gain controlled in the PGA2505?
The gain is controlled digitally using a four-wire serial interface).
- What is the purpose of the DC servo and common-mode servo in the PGA2505?
The DC servo minimizes dc offset, and the common-mode servo enhances common-mode rejection ratio (CMRR)).
- What is the function of the over-range indicator output in the PGA2505?
The over-range indicator output is an active high output pin that indicates when the preamplifier output voltage exceeds preset thresholds).
- What are the general-purpose digital outputs used for in the PGA2505?
The four general-purpose digital outputs are used to control external switching of input pads, phantom power, and high-pass filters).
- What is the significance of zero crossing detection in the PGA2505?
Zero crossing detection minimizes audible artifacts when gain switching).
- What is the operating voltage range for the PGA2505?
The PGA2505 operates with supply voltages of ±4.75V to ±5.25V).
- What is the package type of the PGA2505?
The PGA2505 is available in an SSOP-24 package).
- What are some typical applications of the PGA2505?
The PGA2505 is used in digital mixers and recorders, digital audio editing systems, broadcast equipment, and intercoms).
