Texas Instruments TS3A227E, Руководство пользователя, Страница: 7 / 30

4
1
3
2
Key1
4
1
3
2
Key2
4
1
3
2
Key3
4
1
3
2
Key4
SLEEVE
R9
DNP
RING2
1
2
MK1
2.2kohm
1.0
R10
143
R11
270
R12
590
R13
1 2
J15
1 2
J20
1
2
J16
GND
2.8 V: R1 = 1.07M
2.5 V: R1 = 866k
2.2 V: R1 = 673k
Feeback Loop Resistors
Vout = (Vref) * (1 + (R1/R2))
Vref = 1.20 V R2= 1M
FB
1
NC
3
IN
4
OUT
5
2
GND
U2
TPS71401DCKT
GND
R20
DNP
806k
R24
1.07M
R21
866k
R22
GND
GND GND
33µF
C10
2.2µF
C9
VCC
1µF
C7
0.1µF
C8
2.20k
R14
MICP
680k
R23
1
2
3
4
5
6
7
8
J22
1 2
J24
www.ti.com
TS3A227E-EVM Connections Overview
4.5 On-Board MICBIAS Output
U2 provides the following MICBIAS outputs by moving the jumper position on J22 and shorting different
sets of pins. The EVM also has a spare 0603 resistor and jumper position if a different MICBIAS voltage is
desired.
• Pins 7–8
→
2.2 V
• Pins 5–6
→
2.5 V
• Pins 3–4 → 2.8 V
• Pins 1–2 → user-populated resistor
Figure 6. On-Board MICBIAS Output
4.6 Key-Press Matrix
The TS3A227E EVM features on-board keys for quick evaluation of the key press functionality. Setting up
the EVM for key press is discussed in
Section 7.3.1 . By placing a jumper on both headers J15 and J20,
the matrix is attached to the TS3A227E SLEEVE and RING2 pins allowing the keys to be used.
The on-board microphone is used to simulate a headset microphone in parallel with the keys and can be
disconnected by removing the jumper on J16. R9 is not populated to allow for headset manufacturers to
develop key resistances that fall accurately into the buckets.
Figure 7. Key Press Schematic
7 SLVUAD9 – December 2014 TS3A227E EVM User's Guide
Submit Documentation Feedback
Copyright © 2014, Texas Instruments Incorporated