MT6631 BT/WiFi/GPS/FM Design Notice [1.1 ed.]

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CONFIDENTIAL B

MT6631 BT/WiFi/GPS/FM Design Notice V1.1 2018.04.16

Document Change List Version

Date of change

Description of change

V0.1

20150630

Initial updated from MT6631 design notice V0.1

V0.2

20151117

Update bypass cap value sync with reference schematic

8,9

V0.3

20160126

Correct some wording about different platform supported

26

Update the rule that avoid the audio noise de-sense to FM

Add 24

LTE B39 to GPS system level de-sense

Add 34~37

WiFi 2.4G BAW/FBAR matching Design Guide

Add 34~35

Change power domain description, add Vcore, AVDD12_WBG

8

New chip GPS use single-ended design

15,27

FM circuit add MT6355 design

25

Correct VSWR define

18

Correct FM control block diagram

4

Remove co-rx feature

5

Update GPS description

6, 12, 15

Update GPS application design

21

Update LTE B34/B39 and GPS co-existence

39

Update WiFi 2.4G BAW/FBAR matching Design Guide

36

V1.0

V1.1

201601024

20180416

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Agenda  MT6631 Block Diagram  MT6631 Performance & Feature Overview  MT6631 sub-system application circuit guide    

Control and IQ interface Application Design WiFi/BT Application Design GPS Application Design FM Receiver Application Design

 MT6631 sub-system Layout Guide  MT6631 system level de-sense design guide  Primary MT6631 documents

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FM Antenna XO in

FM Rx

Always-On LDO FM DSP

FM Rx Modem

IPD

FM RX RF+AFE

Pin 38

FM ant in

FM 2-wire

1.6G Antenna

GPS RF

MN

LNA

GPS Rx IQ

LNA

GPS RF Pin 39

GPS RF in GPS 2-wire GPS dig

5G PTA Control

AUX_5G Pin 35

5G TRSW

LNA

5G RF TRx

PA

5G 3-wire Ctrl

LNA

5G WiFi RF

5G WiFi RF IO

Pin 34

5G / 2.4G Antenna

External Filter / Diplexer

Mux

2.4G WiFi/BT RF

2-wire 2.4/ 5G WiFi & BT RF dedicated control

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TOP & 2-wire Ctrl

WBT 2-wire Ctrl PTA / WBT Control

TRSW

WiFi / BT Shared RF TRx

LNA LNA

BT Tx/Rx IQ

NC Balun + MN

2.4G

Pin 32 Pin 31

2.4G RF I/O

Co-RX LNA

WiFi Tx/Rx IQ

PA

k diagram

MT6631 Block Diagram

Pin 30

AUX_2G

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▪ General • •

MT6631 Feature

MT6631 is a 4-in-1 connectivity RF chip which contains front-ends of a 2.4GHz Wi-Fi and Bluetooth transceiver, a 5GHz Wi-Fi transceiver, a GPS receiver and an FM receiver. MT6631 supports integrated passive device to save footprint on PCB and cost due to Wi-Fi/Bluetooth/GPS external BoM (bill of materials) in a 40-pin QFN package.

▪ Wi-Fi / BT •

Simultaneous operation (FDD) of WiFi-5GHz and Bluetooth.

▪ Wi-Fi •

• • •

• •

Dual-band (2.4GHz and 5GHz) single stream 802.11 a/ b/g/n/ac RF, 20/40/80MHz bandwidth Supports worldwide Wi-Fi 5G channel including new band in US and China (5925MHz), and Bluetooth FDD operation Integrated 2.4GHz PA with max. 20dBm CCK output power, 5GHz PA OFDM 54Mbps output power 17dBm and VHT80 MCS9 output power 15dBm. Typical Rx sensitivity with companion chip modem: -76.5dBm at both 11g 54Mbps mode and 11a 54Mbps mode, -62dBm at 11ac VHT80 MCS9 mode Integrated power detector to support per packet Tx power control Supports external PA and LNA for WiFi-2.4GHz and WiFi-5GHz.

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MT6631 Feature ▪

Bluetooth • • •

▪

ANT/ANT+ • •

▪

The wireless protocol standard for sport and fitness monitors Supports different profiles for various applications: sport & fitness, health & wellness, recreational activity, transportation, and information management, etc.

FM • • • •

▪

Bluetooth specification v2.1+EDR, 3.0+HS and v4.1+HS compliant Integrated PA with 8dBm (class 1) transmit power Typical Rx sensitivity with companion chip modem: GFSK -94dBm, DQPSK -93dBm, 8-DPSK -87.5dBm

65 -108MHz with 50kHz step Supports RDS/RBDS Digital stereo modulator/demodulator Digital audio interface

GPS • • • •

RF supports GPS, Galileo, GLONASS, and Beidou. Simultaneous reception of GPS + Galileo + GLONASS + Beidou for more accurate positioning. (note: MT6765 series platform) Typical RX tracking sensitivity of -165dBm. Support external LNA CONFIDENTIAL B

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MT6631 Pin-out Pin39: GPS RF

Pin 36: FM 2V8 Pin 37: FM RF_N Pin 38:FM_RF_P Pin 33: WiFi/BT 3V3 Pin30,31,34,35 WiFi / BT RF pin

Pin40: GPS 1V8 & 6631 Top logic power

Pin 28~29: WiFi ePA Feedback voltage detect

Host reset Package type: QFN 40-lead Package size: 5 x 5mm2

Top digital control

Pin 26~Pin27: WiFi/BT 1V8

WiFi/BT control line

System clock input NOT Support Xtal !!

Pin 9~12: GPS I/Q

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Pin 13~16: BT IQ Pin17~20: WiFi IQ 7

MT6631 Power Scheme For PMIC LDO stability Requirement: MT6797 10uF, others 4.7uF

WBT_3V3

VCN33 4.7uF

1uF

100pF

VCN28 10nF

VCN18

FM_2V8

MT6631

Star Connection 1uF

100nF

(Connectivity RF)

100pF

WBT_1V8

PMIC PMIC side bypass cap please refer to PMIC design notice

GPS_1V8 4.7nF

Other IP VCore

VCCK Large cap

BB Chip (Connectivity digital)

Other IP VIO18

AVDD18_WBG Large cap

100nF

Other IP

AVDD12_WBG

VA12 Large cap

AVDD18_GPS AVDD18_WB AVDD28_FM AVDD33_WB CONFIDENTIAL B

AVDD18_WBG

100nF

MT6797 doesn’t have AVDD12_WBG 20mA :10mil power domain 50mA:10mil 20mA:6~8mil Max 500mA : ≧ 12mil is better(more than 2 VIAs when change layer) As wide as possible L/W ≦ 2800/12 35mA:10mil(MT6797), 25mA:8~10mil (others)

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MT6631 Power Scheme-2 PMIC

MT6631 FM_2V8

VCN28 1uF

10nF

TCXO 10nF

GPS LNA 10nF

1. VCN28 total bypass cap must bigger than 1uF and smaller than 2.1uF for LDO stability.

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MT6631 Host Interface CONN 2-wire Pin #3, #4 WB PTA Pin #5 Reset from Host Pin #2 GPS I/Q

Host BB chip (Connectivity digital)

Pin #9~ #12 BT T/Rx I/Q Pin #13~ #16 WiFi T/Rx I/Q

Connectivity RF chip MT6631

Pin #17~ #20 WiFi 3-wire hi-speed command line Pin #21~ #23 BT 2-wire command line

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Pin #24~ #25

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MT6631 IPD ▪ ▪

MT6631’s IPD (Integrated Passive Devices) integrate matching Network and Balun for WiFi/BT. The co-existence filter and 2.4G/5G diplexer (or Triplexer) will be connected externally on PCB.

IPD block diagram for MT6631 CONFIDENTIAL B

w/o any filter block, so need external filter.

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MT6631 RF Front-end Architectures ▪ Dual-antenna configuration (for better GPS performance)

Filter dual-band antenna

DPX M

Filter DPX: 2.4G/5G Diplexer

▪ Single-antenna configuration

Filter TPX M

1.5G/2.4G/5G Triple-band antenna Filter TPX: Triplexer

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Control and IQ interface Application Design

Control Application Circuit  MT6631 Control interface – – – –

Top 2-wire control lines. BT 2-wire control lines. Wi-Fi 3-wire dedicated high speed control bus. WB_PTA control line.

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IQ Interface Circuit ▪

IQ signals Connected to companion modem.

▪

WF_IP/IN/QN/QP is WiFi dedicated T/Rx IF IQ signals. BT_IP/IN/QN/QP is Bluetooth dedicated T/Rx IF IQ signals. GPS_IP/IN/QN/QP is GNSS receiver IF IQ signals. MT6797 use differential pairs, and other chips use single-ended design (only need to connect GPS IP/QP that use same layout rule which can reduce chip size and PCB layout area and no performance degradation)

▪ ▪

Others:

MT6797:

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WiFi/BT and control interface Application Design

WiFi/BT Application Circuit 

Make star connection for VCN_1V8_PMU, route VCN_1V8_PMU to MT6631 and add 1μF bypass pass, than start connection to AVDD18_WB(MT6631), AVDD18_GPS(MT6631)  Keep WBG_ANT trace away from noisy traces e.g. WLFDO 3.3V / WB_CTRL, switching power supply, clock, and antenna control signals.  Shielding cover is must for MT6631.  Route WBG RF traces on top layer with well-controlled 50ohm line, avoid transition between layers

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MT6631 WB RF matching (Critical) ▪ MT6631 WBT RF output (pin-31) matching is required for WiFi Tx performance (such as Tx EVM) • • • •

Making PCB trace 50Ω and as short as possible. Matching target 50Ohm (VSWR0.75 ( VSWR > 7) and Phase +50~-25degs

M95 PCB L2

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All rights reserved.

2.495GHz S11 S22 antenna portarea Suggested

M95 PCB S11 chip out port L1

2.495GHz S11 located in 2018/4/18 Forbidden area

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System Level De-sense Design Guide

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LTE B34/B39 and GPS Co-existence

LTE B34/B39 to GPS De-sense Solution  B34/39 not TXM reuse case: – Antenna isolation between GPS and B34/39 + Band-Pass Filter after B34/39 PA > 35dB for 3dB de-sense or 40dB for 1dB de-sense • Use B39 SAW filter (ex: SAFEA1G90MA0F0A) for B39 only SKU • B34+B39 dual SAW filter (ex: SAWEN1G90PA0F0A) for both B34 and B39 SKU • Use BPF (ex: LFB181G95CT9E362) + antenna isolation 14dB TXM Main Ant

GSM LB GSM HB B34/B39

3G/4G MMPA

1. Originally use a LPF and need ANT isolation >35dB to avoid GPS desense

Antenna isolation 2. Replace to use B39 SAW filter for B39 only SKU

GPS Ant GPS SAW LNA MT6625L

3. Use B34+B39 dual SAW filter for both B34 and B39 SKU

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Primary MT6631 documents

Primary MT6631 documents ▪ MT6631 Design Notice ▪ MT6631 External Data Sheet ▪ GPS Crystal Layout Guidelines

•these documents can be downloaded from MTK on-line CONFIDENTIAL B

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