High Performance SoundWire Microphone
The CS7257B is a low profile digital microphone with SoundWire® interface optimized for use in high performance audio systems, as well as low power audio applications featuring “always-on” voice control. The CS7257B is manufactured using Cirrus Logic’s proprietary CMOS/MEMS membrane technology offering high reliability and excellent audio quality in a miniature, low profile package. The device incorporates a SoundWire interface compatible with the MIPI SoundWire bus interface and incorporates two operational modes that can be selected according to the applied clock frequency. High performance mode offers a low noise, wide dynamic range, plus class-leading THD even with very loud audio. Low power mode offers ultra low current consumption while maintaining excellent SNR. The CS7257B offers tight tolerance on the microphone sensitivity, giving reduced variation between parts and removing the need for in-line production calibration of part-to-part microphone variations.
Technology
Product Categories
Mobile Audio Devices, Smart Home, Speakers, Wearables, Headsets
Signal Chain Position
Features
- High SNR (66 dB)
- High AOP (131 dB SPL)
- Excellent THD (1% at 125 dB SPL)
- 35 Hz low frequency rolloff
- Low current consumption
- 5µA (Sleep)
- 260 µA (low power mode)
- 770 µA (high performance mode)
- PDM digital audio output
- Proprietary ADC technology
- Reduced clock-jitter sensitivity
- Low noise floor
- Stable in overload condition
- Bottom Port LGA Package
Parametric Specifications
| Port | Bottom |
| Voice Mode SNR (dB) | 62 |
| Record Mode SNR (dB) | 66 |
| AOP at 10% THD (dB SPL) | 131 |
| Sensitivity (dBV/Pa) | -36 |
| Sensitivity Tolerance +/- | 1 |
| Power Supply (V) | 1.62-1.98 |
| Low Power Mode Supply Current (µa) | 260 |
| High Performance Mode Supply Current (µa) | 770 |
| Package | 3.5 x 2.65 x 0.98 mm |
Technical Documents
CS7250B/57B Product Bulletin
May 17, 2017, n/a : 108 KbDesign Resources
WAN_0284 General Design Considerations for MEMS Microphones
Jan 6, 2016, WAN0284 rev 1.2 : 506 KbWAN_0287 Configuring the WM7216 and WM7236 Always-On Microphones
Jan 6, 2016, WAN0287 rev 1.2 : 635 KbWAN_0263 Interfacing WM72xx Digital Microphones
Nov 5, 2015, WAN0263 rev 1.2 : 326 KbWAN_0273 MEMS MIC Assembly and Handling Guidelines
Nov 5, 2015, WAN0273 rev 1.3 : 624 KbWAN_0285 Microphone Power Gating
Nov 5, 2015, WAN0285 rev 1.1 : 508 KbWAN_0290 An Introduction to MEMS Microphone Specifications
Jun 15, 2015, WAN0290 rev 1.0 : 538 KbPress Releases
2017
May 17
Cirrus Logic Packs Industry-Leading Combination of Performance and Power Consumption into Digital Microphones
CS7250B and CS7257B High-Performance Digital MEMS Microphones Set New Standard for Audio Performance and Drop Power Consumption to Half of Competitive Products
