Demonstration board for low noise microphone preamplifier
Features
■ Low noise: 10 nV / √ Hz typ. equivalent input
noise @ F=1 kHz
■ Fully differential input/output
■ 2.2 V to 5.5 V single supply operation
■ Low power consumption @20 dB: 1.8 mA
■ Fast start up time @ 0dB: 5 ms typ.
■ Low distortion: 0.1% typ.
■ 40 kHz bandwidth @ -3 dB and adjustable gain
■ Active low standby mode function (1µA max)
■ Low noise 2.0 V microphone bias output
■ Available in flip-chip ECOPACK
QFN24 4x4 mm
■ ESD protection (2 kV)
■ RoHS compliant
®
package and
STEVAL-CCA023V1
with 2 V bias based on the TS472
Data brief
STEVAL-CCA023V1
Description
The STEVAL-CCA023V1 demonstration board is
designed as an evaluation platform for the TS472
low noise microphone preamplifier with 2.0 V bias
and active low standby mode.
The board supports customization of the testing
conditions, allowing the gain of the TS472 device
to be adjusted, or an electret microphone to be
biased either externally or using the TS472 builtin 2.0 V bias voltage.
August 2009 Doc ID 16138 Rev 1 1/4
For further information contact your local STMicroelectronics sales office.
www.st.com
4
Schematic circuit STEVAL-CCA023V1
1 Schematic circuit
Figure 1. Demonstration board schematic diagram
123
4
P2
R9
100nF
C9
1 2
OUTPUT
21
21
21
21
21
R5
Rgs
68
1k
Jumper J3
R4
R3
R2
R1
470k
NEG. OUTPUT
POS. OUTPUT
R8
100k
2 1
100k
2 1
Jumper J2
C8
100nF
1 2
13
12
Bias
123456
78
P8
5
Bias
Gain Select
Min
Max
Rgs
1uF
C3
12
10
4.7k
27k
1 2
3 4
5 6
7 8
470k
27k
4k71k68R
9 10
P9
100pF
C1
1 2
VCC
P5
Jumper J4
P11 Vbias
1
2
1
2
21
1uF
C7
12
C6
12
Vcc
R10
100nF
Bias
100pF
C2
1 2
R6
21
1uF
C10
12
OUT+
OUT-
SELECT
TS472_Adapter
1
C2
3
C1
14
Vcc
IN+
6
100nF
C4
1 2
GAIN
IN-
8
C5
1 2
POS. INPU T
NEG. INPUT
BYPASSBIAS
15
2 1
STDBY
GND
R11
C11
12
VCC
9
2 1
123
P6
StandBy
Jumper J1
Bias
Gain
4
Bias
100nF
R7
1
2
P10
Vx
2/4 Doc ID 16138 Rev 1
123
4
P1
INPUT