Philips UCB1300BE Datasheet

INTEGRATED CIRCUITS

DATA SH EET

UCB1300

Advanced modem/audio analog front-end

Preliminary speciﬁcation File under Integrated Circuits, <Handbook>

1999 Jul 20

Philips Semiconductors Preliminary speciﬁcation

Advanced modem/audio analog front-end

FEATURES

• 48 pin LQFP (SOT313) small body SMD package and low external component count results in minimal PCB space requirement

• 12-bit sigma delta audio codec with programmable sample rate, input and outputvoltagelevels,capableofconnecting directly to speaker and microphone, including digitally controlled mute, loopback and clip detection functions

• 14-bit sigma delta telecom codec with programmable sample rate, including digitally controlled input voltage level, mute, loopback and clip detection functions. The telecom codec can be directly connected to a Data Access Arrangement (DAA) and includes a built in sidetone suppression circuit

• Complete 4 wire resistive touch screen interface circuit supporting position, pressure and plate resistance measurements

• 10-bit successive approximation ADC with internal track and hold circuit and analog multiplexer for touch screen read-out and monitoring of four external high voltage (7.5V) analog voltages

• High speed, 4 wire serial interface data bus (SIB) for communication to the system controller

• 3.3V supply voltage and built in power saving modes make the UCB1300 optimal for portable and battery powered

applications

• Maximum operating current 25 mA

• 10 general purpose IO pins

APPLICATIONS

• Handheld Personal Computers, Personal Intelligent Communicators, Personal Digital Assistants

• Smart Mobile Phones

• Screen/Web Phones

• Internet Access Terminal

• Modems

UCB1300

GENERAL DESCRIPTION

The UCB1300 is a single chip, integrated mixed signal audio and telecom codec. The single channel audio codec is designed for direct connection of a microphone and a speaker. The built-in telecom codec can directly be connected to a DAA and supports high speed modem protocols. The incorporated analog to digital converter and the touch screen interface provides complete control and read-out of an 4 wire resistive touch screen. The 10 general purpose I/O pins provide programmable inputs and/or outputs to the system.

The UCB1300 has a serial interface bus (SIB) intended to communicate to the system controller. Both the codec input data and codec output data and the control register data are multiplexed on this SIB interface.

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ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

UCB1300BE LQFP48 plastic low proﬁle quad ﬂat package; 48 leads; body 7 × 7 × 1.4 mm SOT313-2

BLOCK DIAGRAM

PACKAGE

IO(n)

TINP

TINN

TOUTP

TOUTN

MICP

MICGND

SKRP

SKRN

1 bit ADC

4 bit DAC

1 bit ADC

4 bit DAC

down sample filter

up sample filter

down sample filter

up sample filter

Digital IO circuits

data / control registers

Voltage reference

10 bit ADC

Fig.1 Block diagram.

Clock buffers &

sample rate

multiplexer

AD(n)

Serial bus interface

dividers

touch screen interface

SIBDIN SIBDOUT SIBSYNC IRQOUT

SIBCLK

TSPX,TSMX TSPY,TSMY

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PINNING

SYMBOL PIN DESCRIPTION

RESET STATE

IO7 1 general purpose I/O pins input I/O IO8 2 general purpose I/O pins input I/O IO9 3 general purpose I/O pins input I/O ADCSYNC 4 ADC synchronization pulse input - I V

SSD

5 digital ground - S n.c 6 not connected - V

SSA2

7 analog speaker driver ground - S SPKRN 8 negative speaker output hi Z O SPKRP 9 positive speaker output hi Z O V

DDA2

10 analog speaker driver supply - S TOUTP 11 positive telecom codec output hi Z O TOUTN 12 negative telecom codec output hi Z O TEST 13 test mode protection ‘0’ I TINN 14 negative telecom codec input hi Z I TINP 15 positive telecom codec input hi Z I VREFBYP 16 external reference voltage input hi Z I/O V V

DDA1 SSA1

17 analog supply - S

18 analog ground - S n.c 19 not connected - MICGND 20 microphone ground switch input hi Z I MICP 21 microphone signal input hi Z I AD3 22 analog voltage inputs hi Z I AD2 23 analog voltage inputs hi Z I AD1 24 analog voltage inputs hi Z I AD0 25 analog voltage inputs hi Z I V

SSA3

26 analog touch screen ground - S TSPY 27 positive Y-plate touch screen hi Z I/O TSMX 28 negative X-plate touch screen hi Z I/O TSMY 29 negative Y-plate touch screen hi Z I/O TSPX 30 positive X-plate touch screen hi Z I/O n.c 31 not connected - V

DDD

32 digital supply - S IO0 33 general purpose I/O pins input I/O IO1 34 general purpose I/O pins input I/O IO2 35 general purpose I/O pins input I/O IO3 36 general purpose I/O pins input I/O V

SSD

37 digital ground - S RESET 38 asynchronous reset input - I SIBSYNC 39 SIB synchronization input - I

TYPE

C C C

(2)

A A

A C A A

A A A A A A

A A A A

C C C C

C C

(1)

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SYMBOL PIN DESCRIPTION

SIBDOUT 40 SIB data output ‘1’

RESET STATE

(6)

SIBCLK 41 SIB serial interface clock − I SIBDIN 42 SIB data input − I IRQOUT 43 interrupt output ‘0’ O

TYPE

C C C

(1)

n.c 44 not connected −− IO4 45 general purpose I/O pins input I/O IO5 46 general purpose I/O pins input I/O IO6 47 general purpose I/O pins input I/O V

DDD

48 digital supply − S

C C C

Notes

1. I/OC= CMOS bidirectional; ID= digital input; S = supply; OA= analog output; IC= CMOS input; IA= analog input; I/OA= analog bidirectional; OC= CMOS output.

2. V

(pins 5 and 37) and V

SSD

(pin 18) are connected internally within the UCB1300.

SSA1

3. SKPRN/SPKRP (pins 8 and 9), TINN/TINP (pins 14 and 15) and TOUTP/TOUTN are differential pairs

4. TEST (pin 13) is connected to an internal pull-down resistor. This pin should be held LOW during normal operation of the circuit.

5. The not connected pins (pins 6, 19, 31 and 44) are reserved for future applications and should be left floating.

6. SIBDOUT reset state is 1 until the SIB bus is running. SIBDOUT will be active once the SIB bus has started.

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book, full pagewidth

IO7 IO8 IO9

ADCSYNC

SSD

n.c.

SSA2

SPKRN SPRKP

DDA2

TOUTP TOUTN

DDD

1 2 3 4 5 6 7 8

9 10 11 12

TEST

IO5

IO6

TINP

TINN

n.c.

IO4

UCB1300

DDA1VSSA1

IRQOUT

XXX

VREFBYP

SIBCLK

SIBDIN

n.c.

MICGND

SIBDOUT

MICP

RESET

SIBSYNC

AD3

AD2

SSD

AD1

36 35 34 33 32 31 30 29 28 27 26 25

MXXxxx

IO3 IO2 IO1

IO0 V

DDD

n.c.

TSPX

TSMY TSMX TSPY

SSA3

AD0

Fig.2 Pin configuration.

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Advanced modem/audio analog front-end UCB1300

FUNCTIONAL DESCRIPTION

The UCB1300 consists of several analog and digital sub circuits which can be programmed via the Serial Interface Bus (SIB). This enables the user to set the UCB1300 functionality according to actual application requirements.

AUDIO CODEC

Theaudiocodeccontainsaninputchannel,built up with an 64 timesoversampling sigma delta analog to digitalconverter (ADC) with digital decimation filters and a programmable gain microphone preamplifier. The programmable gain microphone amplifier features a built-in offset cancellation stage, which reduces the distortion of this stage at high gain settings, caused by the offset voltages of the internal amplifiers or leakage on the board. It can be deactivated (reg13, bit 13) for improved performance at low gain settings. A general rule is that below a gain setting of 16 (24dB gain) the offset cancellation circuit will reduce THD and signal bandwidth and should then be deactivated.

The output path consists of a digital up sample filter, a 64 time oversampling 4 bit digital to analog converter (DAC) circuit followed by a BTL speaker driver, capable of driving a 16 Ω speaker. The output path features a digital programmable attenuation and a mute function.

The audio codec also incorporates a loopback mode, in which codec output path and the input path are connected in series.

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Advanced modem/audio analog front-end UCB1300

AUD_GAIN[4,3] AUD_OFF_CAN AUD_LOOP AUD_GAIN[2..0]

MICP

MICGND

VCCSPKR

SPKRP

SPKRN

VSSSPKR

AUD_MUTE AUD_ATT[2..0]

Fig.3 Audio codec block diagram.

4bit DAC

1bit ADC

DIGITAL ATTENUATOR

AUD_ATT[4,3]

DIGITAL DECIMATION FILTER

AUD_IN_ENA

AUD_OUT_ENA

DIGITAL NOISE SHAPER

The audio sample rate (fsa) is derived from the SIB interface clock pin (SIBCLK) and is programmable through the SIB interface using AUD_DIV[n]. The audio sample rate is given by the following equation:

×()

SIBCLK

-------------------------------------------------64 AUD_DIV[n]×()

(7< AUD_DIV[n] < 128)

For example, a serial clock of 9.216 MHz, with a divisor of 12, results in an audio sample rate of 24.0 kHz. Both the rising and the falling edges of SIBCLK are used in case AUD_DIV[n] is set to an odd number, which demands a 50% duty cycle of SIBCLK to obtain time equidistant sampling.

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DDA1

MICP

MICGND

SSA1

PASSIVE

UCB1300 UCB1300

DDA1

MICGND

MICP

SSA1

ACTIVE

Fig.4 Possible microphone connections.

The UCB1300 audio codec input path accepts microphone signals directly, only a DC blocking capacitor is needed since the MICP input is biased around 1.4V. The ‘ground’ side of the microphone is either connected to the analog ground (V

)or to the MICGND pin. The latter will decrease the current consumption ofactive microphones, since the MICGND

ssa1

pin is made Hi-Z when the audio codec input path is disabled. The full scale input voltage of the audio input path is programmable in 1.5 dB steps by setting the appropriate number in

AUDIO_GAIN[n] in the audio control register A. Using very high gains may require the use of the internal offset cancellation circuit programmable in reg 13 to avoid clipping in the ADC.

A clip detection circuit will inform the user whenever the input voltage exceeds the maximum input voltage, since this will lead to a high distortion. In that case AUD_CLIP_STAT in the audio control register B is set. When ACLIP_RIS_INT is set, an interrupt is generated on the IRQOUT pin on the rising edge of the clip detect signal. When ACLIP_FAL_INT is set, an interrupt is generated on the falling edge of the clip detect signal.

The frequency response of the audio codec depends mainly on the selected sample rate, since the bandwidth is limited in the down and up sampling filters. These digital filters both contain several FIR and IIR low pass filters and a DC removal filter (high pass filter). A 3rd order smoothing filter is implemented in the DAC path, between DAC and speaker driver stage to reduce the spurious frequencies at the speaker outputs.

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48dB

24dB

0dB

21dB

0dB

24dB

programmed attenuation

48dB 69dB

Fig.5 Analog and digital attenuation settings audio output path.

The output level can be attenuated in 3 dB steps down to -69 dB. The first 8 attenuation steps (0 to 21 dB) are implemented in the analog domain. The digital up sample filter contains a 24 dB and a 48 dB attenuation setting. This arrangement preserves the resolution, thus the ‘audio quality’ of the audio output signal for attenuation settings till 21 dB.

The speaker driver is muted when AUDIO_MUTE in the audio control register B is set. The speaker driver will remain activated in that case, however no signal is produced by the speaker driver circuit.

The speaker driver is designed to directly drive a bridge tied load (BTL). This yields the highest output power and this arrangementdoes not require external DC blocking capacitors. Thespeaker driver also accepts single ended connection of a speaker, in which case the maximum output power is reduced to a quarter of the BTL situation. Consequently this way of connecting the speaker to the speaker driver reduces the power consumption of the speaker driver in the UCB1300 by a factor of 2. Fig.6 shows possible ways to connect a speaker to the driver. Loading the amplifiers with a capacitive load may cause high frequency oscillations and should be done cautiously.

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BRIDGE TIED SPEAKER LOAD

UCB1300 UCB1300 UCB1300

SPKRP 9

8 SPKRN

SINGLE ENDED SPEAKER CONNECTIONS

SPKRP 9

8 SPKRN

SPKRP 9

8 SPKRN

Fig.6 Possible speaker connections.

The audio input and output path are activated independently; the input path is enabled when AUDIO_IN_ENA is set, the output path is enabled when AUD_OUT_ENA is set in the audio control register B. This provides the user the means to reduce the current consumption of the UCB1300 if one part of the audio codec is not used in the application.

The audio codec has a loopback mode for system test purposes, which is activated when the AUDIO_LOOP bit in the audio control register B is set. This is an analog loopback which internally connects the output of the audio output path to the input of the audio input path, (see Fig.3). In this mode the normal microphone input is ignored, but the speaker driver can be operated normally.

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Advanced modem/audio analog front-end UCB1300

TELECOM CODEC

The telecom codec contains an input channel, built up from a 64 times oversampling sigma delta analog to digital converter (ADC) with digital decimation filters, programmable attenuationgain and built-in sidetone suppression circuit.

The output path consist of a digital up sample filter, a 64 time oversampling 4 bit digital to analog converter (DAC) circuit followed by a differential output driver, capable of directly driving a 600 Ω isolation transformer. The output path includes a mute function. The telecom codec also incorporates a loopback mode, in which codec output path and the input path are connected in series.

TOUTP

TOUTN

TINP

TINN

TEL_SIDE_ENA

SIDETONE

SUPPRESSION

CIRCUIT

TEL_MUTE

TEL_ATTATT TEL_GAIN

1bit ADC

4bit DAC

DIGITAL DECIMATION FILTER

TEL_IN_ENA

TEL_OUT_ENA

DIGITAL NOISE SHAPER

Fig.7 Telecom codec block diagram.

The telecom sample rate (fst) is derived from the SIB interface clock pin (SIBCLK) and is programmable through the SIB interface. The telecom sample rate is given by the following formula:

×()

------------------------------------------------- -

SIBCLK

64 TEL_DIV[n]×()

(15 < TEL_DIV[n] <128)

For example, a SIBCLK of 9.216 MHz, with a divisor of 40, results in a telecom sample rate of 7.2 kHz. Both the rising and the falling edges of the SIBCLK are used in case TEL_DIV[n] is set to an odd number. In that case a 50% duty cycle of the SIBCLK signal is mandatory to obtain time equidistant sampling.

The input path of the telecom codec has a programmable attenuationgain. It also implements a voice band filter, which consists of an digital low pass filter, which is a part of the decimation filter. Therefore the pass band of the voice band

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Advanced modem/audio analog front-end UCB1300

filter is determined by the selected telecom codec sample rate. This voice band filter is activated by setting TEL_VOICE_ENA in the telecom control register B. The resulting telecom input filter curves are given in Fig.37 and Fig.38.

The output section of the telecom codec is designed to interface with a 600 Ω line through an isolation transformer. The built in mute function is activated by TEL_MUTE in the telecom control register B. The output driver remains active in the mute mode, however no output signal is produced. Loading the drivers with a capacitive load may cause high frequency oscillations and should be done cautiously.

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Advanced modem/audio analog front-end UCB1300

TOUCH SCREEN MEASUREMENT MODES The UCB1300 contains an on chip interface for a 4 wire resistive touch screen. This interface supports three modes of

touch screen measurements: position, pressure and plate resistance.

POSITION MEASUREMENT Twoposition measurements are needed to determine the location ofthe pressed spot. First an X measurement, secondly

a Y measurement. The X plate is biased during the X position measurement of the X plate and the voltage on one or both Y terminals (TSPY, TSMY) measured. The circuit can then be represented by a potentiometer, with the TSPY and/or TSMY electrode being the ‘wiper’. The measured voltage on the TSPY/TSMY terminal is proportional to the X position of the pressed spot of the touch screen.

Vposition

Vtscbias

tspx

tsmy

tspy

tsmx

Fig.8 Touch screen setup for position measurement.

In the Y position mode the X plate and Y plate terminals are interchanged, thus the Y plate is biased while the voltage on the TSPX and/or TSMX terminal is measured.

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Advanced modem/audio analog front-end UCB1300

PRESSURE MEASUREMENT

Thepressure used to press the touch screen canbe determined. In fact the contact resistance between the X and Y plate is measured, which is a good indication of the size of the pressed spot and the applied pressure. A soft stylus, e.g. a finger, leads to a rather large contact area between the two plates when a large pressure is applied. A hard stylus, e.g. a pen, leads to less variation in measured contact resistance since the contact area is rather small.

Vtscbias

ipressure

tspx

tsmy

tspy

tsmx

Fig.9 Touch screen setup for pressure measurement.

One plate is biased at one or both terminals during this pressure measurement, whereas the other plate is grounded, again on one or both terminals. The current flowing through the touch screen is a direct indication for the resistance between both plates. A compensation for the series resistance, formed by the touch screen plates itself will improve the accuracy of this measurement. The measurement is done with a resistive voltage divider. The internal resistor should be taken into account to evaluate the settling time of the pressure measurement given the board capacitors connected to the ADC tap point in pressure mode.

Vtscbias

Switch matrix

Fig.9 Pressure measurement scheme.

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Measured resistor

To ADC

Internal resistor (about 1kΩ)

Philips Semiconductors Preliminary speciﬁcation

Advanced modem/audio analog front-end UCB1300

PLATE RESISTANCE MEASUREMENT

Theplate resistance of a touchscreen varies typically a lotdue to processing spread. Knowingthe actual plate resistance makes it possible to compensate for the plate resistance effects in pressure resistance measurements. The plate resistance decreases when two or more spots on the touch screen are pressed. In that case a part of one plate, e.g. the X plate is shorted by the other plate, which decreases the actual plate resistance

Vtscbias

iplate

tspx

tsmy

tspy

tsmx

Fig.10 Touch screen setup for plate resistance.

The plate resistance measurement is executed in the same way as the pressure resistance measurement. In this case only one of the two plates is biased and the other plate is kept floating. The current through the connected plate is again a direct indication of the connected resistance.

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Advanced modem/audio analog front-end UCB1300

TOUCH SCREEN INTERFACE

The UCB1300 contains a universal resistive touch screen interface for 4-wire resistive touch screen, capable of performing position, pressure and plate resistance measurements. In addition the touch screen can be programmed to generate interrupts when the touch screen is pressed. The last mode is also active when the UCB1300 is set in the stand-by mode.

ts..power

ts..ground

tsc_mode

(pressure)

vssa3

adc_input[2:0]

tspx

tsmx

tspy

tsmy

1kΩ

analog mux

Fig.11 Block diagram of the touch screen interface.

tsc_mode (interrupt)

vdda1

touch screen bias voltage

vssa1

tsc_bias_ena

Current sense input

tsc_mode_sel

to adc input

The touch screen interface connects to the touch screen by four wires: TSPX, TSMX, TSPY and TSMY. Each of these pinscan be programmed to be floating, powered or grounded in the touch screenswitch matrix. The setting of eachtouch screen pin is programmable through the touch screen control register. Possible conflicting settings (grounding and powering of a touch screen pin at the same time) are detected by the UCB1300. In that case the touch screen pin will be grounded.

In position mode, opening the TS..gnd switch can take a long time. To avoid unpredictable delays after changing the plates configuration, the touch screen interface should be programmed to pressure mode for the duration 1 SIB frame before resuming a position measurement.

TheUCB1300’s internal voltage reference(V the touch screen biasing independent of supply voltage and temperature variations. Four low pass filters, one on each touch screen terminal, are built in to minimize the noise coupled from the LCD into the touch screen signals. An LCD typically generates large noise glitches on the touch screen, since they are closely coupled. The influence of the glitches

1999 Jul 20 17

)is used as referencevoltage for the touch screen bias circuit. This makes

ref

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