FAN3850T Microphone Pre-Amplifier with Temperature Compensation and Digital Output
March 2012
FAN3850T
Microphone Pre-Amplifier with Temperature
Compensation and Digital Output
Description
Features
The FAN3850T integrates a pre-amplifier, LDO, and
Optimized for Mobile Handset and Notebook PC
Analog-to-Digital Converter (ADC) to convert Electret
Microphone Applications
Condenser Microphone (ECM) outputs to digital Pulse
Density Modulation (PDM) data streams. The pre-
Accepts Input from Electret Condenser Microphones
amplifier accepts analog signals from the ECM and drives
Pulse Density Modulation (PDM) Output
an over-sampled sigma delta ADC and outputs PDM
data. The PDM digital audio has the advantage of noise
Standard 5-Wire Digital Interface
rejection and interface-to-mobile handset processors.
Amplifier Gain: 15.7dB or 13.7dB
The FAN3850T is powered from the system supply rails
Negative Temperature Coefficient to Compensate for
up to 3.63V, with a low power consumption of only
ECM Positive Temperature Coefficient
0.85mW, and less than 20W in Power-Down Mode.
The device compensates for the temperature variation
Low Input Capacitance, High PSR, 20kHz
of the microphone element to achieve a flat sensitivity
Pre-Amplifier
response over-temperature.
Low-Power, 1.5A Sleep Mode
Typical 420A Supply Current
Signal to Noise Ratio of 62.4dB(A)
Sleep
LDO
Total Harmonic Distortion: 0.01% Mode Ctrl
Input Clock Frequency Range of 1-4MHz
INPUT CLOCK
Integrated Low Drop-Out Regulator (LDO)
Pre-Amp
Small 1.26mm x 0.86mm 6-Ball WLCSP
ADC
DATA
SELECT
Applications
GND
Electret Condenser Microphones with Digital Output
Figure 1. Block Diagram
Mobile Handsets
Headset Accessories
Personal Computers (PC)
Ordering Information
Gain Operating Packing
Part Number Package
Option Temperature Range Method
FAN3850TUC15X35 15.7dB
6-Ball, Wafer-Level Chip-Scale 3000 Unit
-30C to +85C
Package (WLCSP) Tape & Reel
FAN3850TUC13X35 13.7dB
Note:
1. Alternate gain options and temperature coefficient slopes are possible. Please contact a Fairchild representative.
2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN3850T Rev. 3.0.2 FAN3850T Microphone Pre-Amplifier with Temperature Compensation and Digital Output
Pin Configuration
Figure 2. Pin Configuration (Top View)
Pin Definitions
Pin# Name Type Description
A1 CLOCK Input Clock Input
B1 GND Input Ground Pin
C1 DATA Output PDM Output 1-Bit ADC
A2 SELECT Input Rising or Falling Clock-Edge Select
B2 INPUT Input Microphone Input
C2 VDD Input Device Power Pin
2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN3850T Rev. 3.0.2 2