Philips ucb1200 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

UCB1200

Advanced modem/audio analog front-end

Product speciﬁcation File under Integrated Circuits, <Handbook>

1998 Jul 22

Philips Semiconductors Product 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 audiocodec with programmable sample rate,input andoutput voltage levels,capable ofconnecting 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 9397 750 04055 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

UCB1200

GENERAL DESCRIPTION

The UCB1200 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 UCB1200 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.

1998 Jul 22 2 853-205219059

Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

UCB1200BE 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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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

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 SKPRN 8 negative speaker output hi Z O SPRKP 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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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

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 UCB1200.

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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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

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

UCB1200

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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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

FUNCTIONAL DESCRIPTION

The UCB1200 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 UCB1200 functionality according to actual application requirements.

AUDIO CODEC

Theaudio codeccontains aninput channel,built upwith an64 timesoversampling sigmadelta analogto digitalconverter (ADC) with digital decimation filters and a programmable gain microphone preamplifier.

The output path consistsof adigital up sample filter, a64 timeoversampling 4 bit digital toanalog 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.

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

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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

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]×()

For example,a serialclock of 9.216 MHz,with a divisorof 12,results in anaudio sample rateof 24.0 kHz.Both the rising and the falling edgesof SIBCLKare used in case AUD_DIV[n]is setto an odd number, whichdemands a50% duty cycle of SIBCLK to obtain time equidistant sampling.

(8 < AUD_DIV[n] < 128)

DDA1

MICP

MICGND

SSA1

PASSIVE

UCB1200 UCB1200

DDA1

MICGND

MICP

SSA1

ACTIVE

Fig.4 Possible microphone connections.

The UCB1200audio codecinput path acceptsmicrophone signalsdirectly, only aDC blocking capacitor is neededsince the MICP input is biased around 1.4V. The ‘ground’ side of the microphone is either connected to the analog ground

)or tothe MICGNDpin. Thelatter willdecrease thecurrent consumptionof activemicrophones, sincethe 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 stepsby setting the appropriatenumber in

AUDIO_GAIN[n] in the audio control register A. A clipdetection circuit willinform the userwhenever the inputvoltage exceeds themaximum 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 responseof 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 passfilter). A 3rd order smoothing filter is implemented in the DAC path, between DAC andspeaker driver stage to reduce the spurious frequencies at the speaker outputs.

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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

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 preservesthe resolution, thusthe ‘audio quality’ of the audio output signalfor attenuation settingstill 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. The speakerdriver alsoaccepts singleended 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 UCB1200 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.

1998 Jul 22 9

Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

BRIDGE TIED SPEAKER LOAD

UCB1200 UCB1200 UCB1200

SPKRP 9

8 SPKRN

SINGLE ENDED SPEAKER CONNECTIONS

SPKRP 9

8 SPKRN

SPKRP 9

8 SPKRN

Fig.6 Possible speaker connections.

The audioinput and output pathare activated independently; the input path isenabled when AUDIO_IN_ENA isset, 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 UCB1200 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.

1998 Jul 22 10

Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

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 attenuation and built-in sidetone suppression circuit.

The outputpath consist of adigital up sample filter,a 64 time oversampling 4 bit digitalto analog converter (DAC)circuit followed bya differential outputdriver, capable ofdirectly driving a 600 Ω isolation transformer. The outputpath 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_LOOP

TEL_ATT

1bit ADC

4bit DAC

DIGITAL DECIMATION FILTER

TEL_IN_ENA

TEL_OUT_ENA

DIGITAL NOISE SHAPER

Fig.7 Telecom codec block diagram.

The telecomsample rate (fst) is derived from the SIB interface clock pin (SIBCLK) and is programmable through theSIB 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 thefalling edges of the SIBCLK are usedin case TEL_DIV[n] is set to anodd 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 attenuation. 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

1998 Jul 22 11

Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

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 sectionof the telecom codec is designedto interface with a 600 Ω line through an isolation transformer. The built inmute function isactivated by TEL_MUTEin the telecomcontrol register B.The output driverremains active inthe mute mode,however no output signalis produced. Loading thedrivers with a capacitive load may causehigh frequency oscillations and should be done cautiously.

1998 Jul 22 12

Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

TOUCH SCREEN MEASUREMENT MODES The UCB1200 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 measurementsare neededto determinethe locationof the pressedspot. Firstan Xmeasurement, secondly

a Y measurement. TheX plate is biased duringthe Xposition measurement ofthe Xplate and thevoltage onone 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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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

PRESSURE MEASUREMENT

Thepressure used to press the touch screen can bedetermined. Infact thecontact resistancebetween theX andY 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 screenplates itself will improve the accuracy of this measurement.

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Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

PLATE RESISTANCE MEASUREMENT

Theplate resistanceof atouch screenvaries typicallya lotdue toprocessing spread. Knowingthe actualplate resistance makes it possible to compensate for the plate resistance effects in pressure resistance measurements. The plate resistance decreases when two or more spotson the touch screen are pressed. In that casea 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 isbiased and the other plate is kept floating. Thecurrent through the connected plate is again a direct indication of the connected resistance.

1998 Jul 22 15

Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

TOUCH SCREEN INTERFACE

The UCB1200 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 UCB1200 is set in the stand-by mode.

ts..power

ts..ground

vssa3

adc_input[2:0]

tspx

tsmx

tspy

tsmy

analog mux

Fig.11 Block diagram of the touch screen interface.

tsc_mode

vdda1

touch screen bias voltage

touch screen current monitor

vssa1

tsc_bias_ena

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 beprogrammed tobe floating,powered orgrounded inthe touchscreen switchmatrix. Thesetting ofeach touch screen pin is programmable through the touch screen control register. Possible conflicting settings (grounding and powering ofa touch screen pinat the sametime) are detected bythe UCB1200. In that case the touchscreen pin will be grounded.

TheUCB1200’s internalvoltage 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 generateslarge noise glitcheson the touchscreen, since theyare closely coupled.The influence ofthe glitches can neverthelessbe minimized byperforming measurements whenthe LCD isquiet. This canbe done bysynchronizing the measurement and the video driver with the ADCSYNC pin.

1998 Jul 22 16

)is usedas referencevoltage forthe touch screenbias circuit.This makes

ref

Philips Semiconductors Product speciﬁcation

Advanced modem/audio analog front-end UCB1200

Vdda

tsmy

Rint

schmitt trigger

tspx

tspy

tsmx

schmitt trigger

Fig.12 Touch screen setup for interrupt detection.

In addition to the measurements mentioned above, the touch screen can also act as an interrupt source. In this mode the X plate of the touch screen has to be powered and the Y plate has to be grounded. In this case the touch screen is not biased by the active touch screen bias circuit, but by a resistor to V screen and the UCB1200 does not consume power unless the touch screen is touched. The voltage on the X plate terminals drops if the screen is pressed. This voltage drop is detected by Schmitt-trigger circuits, of which the outputs are connected to the interrupt control block. A touch screen interrupt is generated either when the touch screen is pressed (fallingedge enabled) orwhen the touch screenis released (risingedge enabled). It can be used toactivate the system around the UCB1200 to start a touch screen read-out sequence. The internal Schmitt-trigger circuits are connected to the TSPX and TSMX signals after the built in low pass filters. This reduces the number of spurious interrupts, due to the coupling between the LCD screen and the touch screen sensors.

Each of the four touch screen signalscan be selected as input for the built in10 bit ADC, which isused to determine the voltage on the selected touch screen pin. The flexible switch matrix and the multi- functional touch screen bias circuit enables the user of the UCB1200 to set each desired touch screen configuration.

The setting of the touch screen bias circuit and the ADC input multiplexer is determined by the setting of TSC_MOD[n] in the touch screen control register according the following table.

1998 Jul 22 17

. This configuration simply biases the touch

DDA1

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