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BTM8605
Bluetooth Module Data Sheet

Document Type: Bluetooth Module Datasheet

Document Version: V1.0

Release Date: December 04, 2012

Copyright 2012 by Buddies Technology Limited. All Rights Reserved.

Reproduction of this document, in part of in whole, by any means is prohibited without written permission
from Buddies Technology Limited. The information contained herein is believed to be accurate as of
the date of publication. However, Buddies is not liable for any damages, including indirect or
consequential from the use of software this document represents, or any reliance of the accuracy of
this document. Buddies reserves the right to change the contents of this document at any time
without notice.
This document contains proprietary confidential trade secrets and may be subject to additional
restrictions contained in the licensing agreement under which this document was obtained.

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Revision History

Date Version Description Author

2012-12-04 V1.0
First Release

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CONTENT
1. INTRODUCTION................................................................................................................................. 4

1.1 BLOCK DIAGRAM ................................................................................................................................. 4

1.2 FEATURES ............................................................................................................................................ 5
1.3 APPLICATIONS ..................................................................................................................................... 6

2. GENERAL SPECIFICATION ............................................................................................................ 7

3. PHYSICAL CHARACTERISTIC....................................................................................................... 8

3.1 Pin Description.................................................................................................................................... 9

4. REFERENCE SCHEMATIC ............................................................................................................ 11

5. PHYSICAL
INTERFACE………………….……………………………………………….…………………………..13

5.1 POWER SUPPLY ................................................................................................................................... .13

5.2 AUDIO
INTERFACES.......................................................................................................................................................13
5.2.1 ADC ............................................................................................................................................
13
5.2.2 ADC Pre-amplifier and ADC Analogue Gain ........................................................................... 14
5.2.3 ADC Gain................................................................................................................................... 14
5.2.4 DAC ........................................................................................................................................... 14
5.2.5 DAC Gain................................................................................................................................... 14
5.2.6 Line Input .................................................................................................................................. 14
5.2.7 Audio Output Stage .................................................................................................................... 14
5.3 RF INTERFACE .................................................................................................................................... 15
5.4 GENERAL PURPOSE ANALOG IO ......................................................................................................... 15
5.5 GENERAL PURPOSE DIGITAL IO .......................................................................................................... 15
5.6 SERIAL INTERFACES ............................................................................................................................ 15
5.6.1 UART ......................................................................................................................................... 15
5.6.2 SPI .............................................................................................................................................. 16

6. ELECTRICAL CHARACTERISTIC ............................................................................................... 17

6.1 ABSOLUTE MAXIMUM RATING ........................................................................................................... 17

6.2 RECOMMENDED OPERATING CONDITIONS .......................................................................................... 18
6.3 INPUT/OUTPUT TERMINAL CHARACTERISTICS .................................................................................... 19
6.3.1 Codec: Analogue to Digital Converter....................................................................................... 19
6.3.1 Codec: Digital to Analogue Converter....................................................................................... 20

7. RECOMMENDED TEMPERATURE REFLOW PROFILE......................................................... 21

8. PACKAGING INFORMATION ....................................................................................................... 22

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1. INTRODUCTION

The BTM8605 Bluetooth® module is a perfect solution for enhanced audio applications,
such as headphones. It can be connected with any Bluetooth® devices in an operating
range. It is slim and light so the designers can have better flexibilities for the product
shapes.

The BTM8605 Bluetooth® module complies with Bluetooth® specification version 4.0. It
supports A2DP(mono),AVRCP profiles. It integrates RF Baseband controller, antenna,…
etc. and programmable I/O, speaker output… etc.

The detail information of BTM8605 Bluetooth® module is presented in this document

below.

1.1 Block Diagram

CSR8605

EEPROM
+3V3

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1.2 Features

 Small overall dimension(14mm x 16mm x 2mm)

 Bluetooth Specification V4.0

 Class 2 support

 Physical connection as SMD type

 Built-in RF combo filter, Integrated 26M Crystal.

 Support A2DP(mono),AVRCP profile.

 No radio signal interference, support for 802.11 co-existence

※ Some features are optional for customization on demand.

1.3 Application

 High Quality Mono Bluetooth Headphone

 Bluetooth Speakers(mono)

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2. GENERAL SPECIFICATION

Bluetooth Specification
Chip Set CSR 8605 (ROM)
Module ID BTM8605
BT Standard Bluetooth® V4.0
RF TX Output Power 4dBm (Class II)
Sensitivity -86dBm@0.1%BER

Frequency Band 2.402GHz~2.480GHz ISM Band

Baseband Crystal OSC 26MHz

Hopping 1600hops/sec, 1MHz channel space
RF Input Impedance 50 ohms

 Microphone : Input (Differential)

 Speaker : Output (Differential)
 PCM : Output
Major Interface
 UART : Tx/Rx (for test)
 PIOs
 Antenna

Profile A2DP,AVRCP

Voice Processor 80MIPS Kalimba with cVc support

Power
Supply Voltage 3.3V ~ 4.2V DC
Working Current 30mA typical,Depends on profiles
Standby Current <1mA
Operating Environment
Temperature -40C to +85

Humidity 10%~90% Non-Condensing

Environmental RoHS Compliant

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3. PHYSICAL CHARACTERISTIC
Dimension:

Figure 2

Pin Definition:

Figure 3

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3.1 Pin Description

Pin# Pin Name Pad Type Description

CMOS output, tri-state, with weak

1 SPI_MISO SPI data output
internal pull-down
Chip select for Serial Peripheral Interface
2 Input with weak internal pull-up
SPI_CSB (SPI),active low

3 SPI_CLK Input with weak internal pull-down SPI clock

CMOS input, with weak internal
4 SPI_MOSI SPI data input
pull-down
5 SPI_EN Input with weak pull-down SPI select input

Bi-directional with programmable

6 PIO_1 Programmable input/output line
strength internal pull-up/down
Bi-directional with programmable
7 PIO_0 Programmable input/output line
strength internal pull-up/down

8 VBAT_SENSE Battery charger sense input Connect directly to the battery positive pin

Exernal battery charger External battery charger transistor

9 CHG_EXT
control base control
Alternative supply via bypass regulator for 1.8V
and 1.35V

10 VBUS Power supply switchmode power supply regulator inputs.

Must be connected to the same potential as

VOUT_3V3.

Reset if low.Pull low for minimum 5ms

11 BT_Reset Input with strong pull-up
to cause a reset
12 LED_1 Open drain output LED driver

13 LED_0 Open drain output LED driver

14 GND Ground Digital Ground

15 1V8 Open drain output LED driver

16 GND Ground Digital Ground

Regulator enable input.

Can also be sensed as an input.

17 PWR Input enable Regulator enable and multifunction button. A high

input (tolerant to VBAT) enables the on-chip

regulators, which can then be latched on

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internally and the button used as a multifunction
input.

18 VBAT Power supply Battery positive terminal

Regulator enable input.

Can also be sensed as an input.

Regulator enable and multifunction button. A high
19 3V3_USB Power supply input (tolerant to VBAT) enables the on-chip

regulators, which can then be latched on

internally and the button used as a multifunction
input.

20 USB_N Bidirectional USB data minus

USB data plus with selectable internal
21 USB_P Bidirectional
1.5kohm pull-up resistor
Bi-directional with programmable
22 PIO_21 Programmable input/output line
strength internal pull-up/down
Bi-directional with programmable
23 PIO_18 Programmable input/output line
strength internal pull-up/down
Bi-directional with programmable
24 PIO_19 Programmable input/output line
strength internal pull-up/down
Bi-directional with programmable
25 PIO_20 Programmable input/output line
strength internal pull-up/down

26 LED_2 Open drain output LED driver

27 SPKR_LP Analogue out Speaker output positive

28 SPKR_LN Analogue out Speaker output negative

29 AGND Ground Analogue Ground

30 LINE_AP Analogue in Line input positive

31 LINE_AN Analogue in Line input negative

32 GND Ground Digital Ground

33 RF
Bluetooth 50ohm transmitter
RF_IO output/receiver input
34 GND Ground Digital Ground

35 AIO_0 Bidirectional Analogue programmable input/output line 0

Bidirectional with strong

36 UART_TX UART Data Output
pull-up
37 Bidirectional with strong UART Data Input
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UART_RX pull-up
38 GND Ground Digital Ground

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4. REFERENCE SCHEMATIC

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5. PHYSICAL INTERFACE

Figure 4

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5.1 Power Supply

The transient response of the regulator is important. If the power rails of the module are
supplied from an external voltage source, the transient response of any regulator used
should be 20µs or less.

5.2 Audio Interfaces

Audio interface as following features:
■ Mono analogue line input for audio band
■ Mono analogue output for audio band
■ Support for digital audio bus standards such as I²S
■ Support for PCM interfaces including PCM master codecs that require an external
system clock

Figure 5

The CSR8605 QFN audio codec uses a fully differential architecture in the analogue signal
path, which results in low noise sensitivity and good power supply rejection while
effectively doubling the signal amplitude. It operates from a dual power supply,
VDD_AUDIO for the audio circuits and VDD_AUDIO_DRV for the audio driver circuits.

5.2.1 ADC
■ The ADC has a second-order Sigma-Delta converter.
■ There are 2 gain stages for the ADC, 1 of which is an analogue gain stage
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and the other is a digital gain stage.

5.2.2 ADC Pre-amplifier and ADC Analogue Gain

CSR8605 QFN has an analogue gain stage based on an ADC pre-amplifier and ADC
analogue amplifier:
■ The ADC pre-amplifier has 4 gain settings: 0dB, 9dB, 21dB and 30dB
■ The ADC analogue amplifier gain is -3dB to 12dB in 3dB steps
■ The overall analogue gain for the pre-amplifier and analogue amplifier is -3dB to 42dB
in 3dB steps.
■ Us a low gain levels for an audio line level amplifier

5.2.3 ADC Gain

A digital gain stage inside the ADC varies from -24dB to 21.5dB, see Table 9.2. There is
also a fine gain interface

with a 9-bit gain setting allowing gain changes in 1/32 steps, for more information contact

CSR. The firmware controls the audio input gain.

5.2.4 DAC
The DAC consists of:

■ 1 fourth-order Sigma-Delta converter, see Figure 9.2

■ 2 gain stages, 1 of which is an analogue gain stage and the other is a digital gain stage

5.2.5 DAC Gain

A digital gain stage inside the DAC varies from -24dB to 21.5dB, see Table 9.3. There is
also a fine gain interface
with a 9-bit gain setting enabling gain changes in 1/32 steps, for more information contact
CSR.

The overall gain control of the DAC is controlled by the firmware. Its setting is
a combined function of the digital and analogue amplifier settings.

5.2.6 Line Input

In the line input mode the input impedance varies from 6kΩ to 30kΩ,
depending on the volume setting. Figure 9.4 and Figure 9.5 show 2 circuits
for line input operation and show connections for either differential or
single-ended inputs.

5.2.7 Audio Output Stage

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The output stage digital circuitry converts the signal from 16-bit per
sample, linear PCM of variable sampling frequency to bit stream, which
is fed into the analogue output circuitry.

The analogue output circuit comprises a DAC, a buffer with gain-setting, a

low-pass filter and a class AB output stage amplifier. Figure 9.6 shows that
the output is available as a differential signal between SPKR_AN and
SPKR_AP.

5.3 RF Interface
The module integrates a balun filter. The user can connect a 50ohms antenna directly to the
RF port.

5.4 General Purpose Analog IO

The general purpose analog IOs can be configured as ADC inputs by software. Do not
connect them if not use.

5.5 General Purpose Digital IO

There are nine general purpose digital IOs defined in the module. All these GPIOs can be
configured by software to realize various functions, such as button controls, LED displays
or interrupt signals to host controller, etc. Do not connect them if not use.

5.6 Serial Interfaces

5.6.1 UART
This is a standard UART interface for communicating with other serial devices. The UART
interface provides a simple mechanism for communicating with other serial devices using
the RS232 protocol.

When the module is connected to another digital device, UART_RX and UART_TX
transfer data between the two devices. The remaining two signals, UART_CTS and
UART_RTS, can be used to implement RS232 hardware flow control where both are
active low indicators.
Note: The serial port interface(UART)can be used for system debugging. Don’t
support to use command set for profile function application by UART, such as
HFP/A2DP/AVRCP and so on. These profiles function application can be controlled
only by PIO ,such as pairing/connect/answer/play/pause/next/previous function
application and so on.

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5.6.2 SPI
The synchronous serial port interface (SPI) can be used for system debugging. It can also be
used for in-system programming for the flash memory within the module. SPI interface
uses the SPI_MOSI, SPI_MISO, SPI_CSB and SPI_CLK pins. Testing points for the SPI
interface are reserved on board in case that the firmware shall be updated during
manufacture.

The module operates as a slave and thus SPI_MISO is an output of the module.
SPI_MISO is not in high-impedance state when SPI_CSB is pulled high. Instead, the
module outputs 0 if the processor is running and 1 if it is stopped. Thus the module
should NOT be connected in a multi-slave arrangement by simple parallel connection
of slave SPI_MISO lines.

Figure 7

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6. ELECTRICAL CHARACTERISTIC

Note:

For all I/O terminal characteristics:

■ Current drawn into a pin is defined as positive; current supplied out of a pin is defined as negative.

6.1 Absolute Maximum Rating

Rating Mi Max Uni

Storage temperature -40 105 °C

Supply Voltage

Charger VCHG -0.4 5.75 / 6.50(a) V

LEDs LED[2:0] -0.4 4.40 V

VBAT -0.4 4.40 V

Battery
VREGENABLE -0.4 4.40 V

USB VDD_USB -0.4 3.6 V

VDD_AUDIO_DRV -0.4 1.95 V

VDD_AUX_1V8 -0.4 1.95 V

1.8V VDD_PADS_1 -0.4 3.60 V

VDD_PADS_2 -0.4 3.60 V

VDD_AUX_1V8 -0.4 1.95 V

SMPS_1V35_SENSE -0.4 1.45 V

1.35V VDD_AUDIO -0.4 1.45 V

VREGIN_DIG -0.4 1.95 V

Other terminal voltages VSS - 0.4 VDD + 0.4 V

Table 1

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6.2 Recommended Operating Conditions

Rating Mi Typ Max Uni

Operating temperature range -40 20 85 °C

Supply Voltage

Charger VCHG 4.75 / 3.10(a) 5.00 5.75 / 6.50(b) V

LEDs LED[2:0] 1.10 3.70 4.30 V

VBAT 0 3.70 4.25 V

Battery
VREGENABLE 0 3.70 4.25 V

USB VDD_USB 3.1 3.3 3.6 V

VDD_AUDIO_DRV 1.70 1.80 1.95 V

VDD_AUX_1V8 1.70 1.80 1.95 V

1.8V VDD_PADS_1 1.70 1.80 3.60 V

VDD_PADS_2 1.70 1.80 3.60 V

VDD_AUX_1V8 1.25 Table 2 1.80 1.95 V

SMPS_1V35_SENSE 1.30 1.35 1.45 V

1.35V VDD_AUDIO Table 2

1.30 1.35 1.45 V

VREGIN_DIG 1.30 1.35 or 1.80(c) 1.95 V

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6.3 Input/output Terminal Characteristics

6.3.1 Codec: Analogue to Digital Converter

Analogue to Digital Converter

Parameter Conditions Mi Typ Max Uni

Resolution - - - 16 Bits

Input Sample Rate,

- 8 - 48 kHz
Fsample
Maximum ADC 0dB = 1600mVpk-pk mVpk-pk
13 - 2260
Input
Fsample

fin = 1kHz 8kHz - 93.5 - dB

B/W = 20Hz→Fsample/2 16kHz - 92.5 - dB

SNR
(20kHz 32kHz - 91.4 - dB

max) 44.1kHz - 90.4 - dB

A-Weighted 48kHz - 89.6 - dB

fin = 1kHz Fsample

THD+N B/W = 20Hz→Fsample/2 8kHz - 0.0041 - %

(20kHz max) 48kHz - 0.0072 - %

Digital gain Digital gain resolution = 1/32 -24 - 21.5 dB

Pre-amplifier setting = 0dB, 9dB, 21dB or

Analogue gain 30dB -3 - 42 dB

Analogue setting = -3dB to 12dB in 3dB

Table 3

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6.3.2 Codec: Digital to Analogue Converter

Digital to Analogue Converter

Parameter Conditions Mi Typ Max Uni

Resolution - - - 16 Bits

Output Sample
- 8 - 96 kHz
Rate, Fsample
Fsample Load
fin = 1kHz
48kHz 100kΩ - 95.6 - dB
SNR B/W = 20Hz→20kHz
48kHz 32Ω - 95.8 - dB
A-Weighted
48kHz 16Ω - 95.6 - dB
THD+N < 0.1%
Fsample Load

8kHz 100kΩ - 0.0025 - %

8kHz 32Ω - 0.0056 - %

fin = 1kHz
THD+N 8kHz 16Ω - 0.0108 - %
B/W = 20Hz→20kHz
48kHz 100kΩ - 0.0027 - %
0dBFS input
48kHz 32Ω - 0.0067 - %

48kHz 16Ω - 0.0122 - %

Digital Gain Digital Gain Resolution = 1/32 -24 - 21.5 dB

Analogue Gain Analogue Gain Resolution = 3dB -21 - 0 dB

Output voltage
- - - 778 mV rms
full- scale swing

Table 4

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7. RECOMMENDED TEMPERATURE REFLOW PROFILE

The soldering profile depends on various parameters necessitating a set up for each
application. The data here is given only for guidance on solder reflow.

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8. PACKAGING INFORMATION

1. BLUETOOTH® Module: BTM8605

2. Assembly

3. Dimension

All rights are strictly reserved. Any portion of this paper shall not be reproduced, copied, or
translated to any other forms without permission from Buddies Technology Limited.
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