REFERENCE CLOCK: application on Sysol ME and Dragon Fly VYn_ps12660 CS - Philips Semiconductors Le Mans

Philips Semiconductors, Costumer Support, 04/12/20032 Introduction: Importance of the reference clock Reference clock: Motor of the mobile All mobile functions depend on it Bad reference clock’s performances means bad mobile’s performances

Philips Semiconductors, Costumer Support, 04/12/20033 Training Content: Reference clock presentation Reference clock contents Reference clock on Sysol ME Reference clock working on Sysol ME Reference clock performances to check Problems linked to reference clock Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/20034 Training Content:  Reference clock presentation Reference clock contents Reference clock on Sysol ME Reference clock working on Sysol ME Reference clock performances to check Problems linked to reference clock Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/20035 REFERENCE CLOCK PRESENTATION

Philips Semiconductors, Costumer Support, 04/12/20036  Heart of the mobile:

Philips Semiconductors, Costumer Support, 04/12/20037 For Base-Band: - Clock for processor - Generation of all clocks

Philips Semiconductors, Costumer Support, 04/12/20038 For the Radio part: Reference clock for the synthetisers (PLL) With Fout= N x Fref

Philips Semiconductors, Costumer Support, 04/12/20039 In Sysol 2

Philips Semiconductors, Costumer Support, 04/12/  Frequency of the reference clock Fref = N x 13 MHz For ALL GSM mobiles kHz/48 = kbits/s 48 clock cycle = 1 time bit 12 clock cycle = 1 quarter bit (time unity in mobiles) System clock must allow to have complete quarter bits. It is this with 3.25, 6.5, 13, 26 MHz

Philips Semiconductors, Costumer Support, 04/12/ Training Content: Reference clock presentation  Reference clock contents Discrete or integrated Reference clock on Sysol ME Reference clock working on Sysol ME Reference clock performances to check Problems linked to reference clock Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/ REFERENCE CLOCK CONTENTS

Philips Semiconductors, Costumer Support, 04/12/ Reference clock purpose:  Provide a sinusoidal signal with a stable frequency of Nx13 MHz:  No square waves generator  32 kHz of BB is not enough - Not enough stable - Can’t provide easily Nx13 MHz

Philips Semiconductors, Costumer Support, 04/12/ Use of a Crystal-based oscillator

Philips Semiconductors, Costumer Support, 04/12/ Description of a quartz The piezo electrical quartz crystal is deformed by the application of an electrical voltage. The crystal behaves like an electrical resonance circuit.  Z: Quartz impedance with no load

Philips Semiconductors, Costumer Support, 04/12/ Oscillation conditions The quartz is not perfect. It has losses  Oscillations can not appear  Losses must be compensated  « Negative resistor » (amplifier) needed

Philips Semiconductors, Costumer Support, 04/12/ Let’s see electrical characteristics of a crystal

Philips Semiconductors, Costumer Support, 04/12/ Crystal has others defaults:  Tolerance on components value  Frequency initial adjustment: RefCal Done on the production line  Frequency shift vs. temperature  Temperature compensation  Frequency shift with age  Frequency adjustment: AFC

Philips Semiconductors, Costumer Support, 04/12/ Crystal temperature deviation 416 Hz deviation 520 Hz deviation 156 Hz deviation

Philips Semiconductors, Costumer Support, 04/12/  Influence of V supply (Pushing)  Regulated supply  Influence of load (Pulling)  Load adjustment + Buffers + Frequency drift with time  Frequency enslavement: AFC

Philips Semiconductors, Costumer Support, 04/12/ Final overview of the clock AFC RefCal Output BB Output RF

Philips Semiconductors, Costumer Support, 04/12/ Discrete vs integrated clock Two ways to implement the clock:  Discrete. Each function is done with discrete components  Module. Reference clock is generated by a component containing all functions

Philips Semiconductors, Costumer Support, 04/12/ Module clock Advantages Nber of components Reduced bulkiness Nber of supply Nber of signals Easy to implement Disadvantages Cost (twice discrete’s) No possible adaptation

Philips Semiconductors, Costumer Support, 04/12/ Discrete clock Disadvantages Nber of components Bulkiness Nber of supply Nber of signals difficult to implement Technical limits Advantages Cost (half module) Possible adaptation

Philips Semiconductors, Costumer Support, 04/12/ Discrete clock is limited to GPRS class 10, 2 Tx slots (due to PA heat) Synchronisation algorithm is common Temperature compensation:  hardware way for discrete  Integrated in the module Temperature and load compensation are made internally for the module: RefCal not needed. Consumption is a little bit important for module (~ 1 mA).

Philips Semiconductors, Costumer Support, 04/12/ Overview of a module clock No RefCal

Philips Semiconductors, Costumer Support, 04/12/ Training Content: Reference clock presentation Reference clock contents  Reference clock on Sysol ME Reference clock working on Sysol ME Reference clock performances to check Problems linked to reference clock Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/ REFERENCE CLOCK ON SYSOL ME

Philips Semiconductors, Costumer Support, 04/12/ Topology of the 26MHz The topology of the 26MHz oscillator is from Pierce principle as follows. 3537

Philips Semiconductors, Costumer Support, 04/12/ Characteristics of the ref. clock on SSME Frequency: 26 MHz  Radio: UAA3537. Need 26 MHz  BBand: OM ( ): 26 MHz Quartz: NDK NX4025DA 26 MHz Semi-integrated clock: Three blocks are in 3537: - RF buffer - BB buffer - Negative resistance

Philips Semiconductors, Costumer Support, 04/12/ Supply for the clock: not needed. Negative resistance and buffers supplies are provided by 3537 with an internal regulator. Signals: 2 signals are needed:  AFC: provided by BB  Clkfdbx: provided by 3537 RefCal signal is generated by a register of (CAFC register)

Philips Semiconductors, Costumer Support, 04/12/ Crystal NX4025DA specifications

Philips Semiconductors, Costumer Support, 04/12/ VariableL oading Quartz Temperature compensation RF Buffer BB Buffer Negative resistance Clkfdbk from 3537 AFC: from BB Internal regulator

Philips Semiconductors, Costumer Support, 04/12/ Training Content: Reference clock presentation Reference clock contents Reference clock on Sysol ME  Reference clock working on Sysol ME Reference clock performances to check Problems linked to reference clock Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/ REFERENCE CLOCK WORKING ON SYSOL ME

Philips Semiconductors, Costumer Support, 04/12/ Some hard parameters Magnitude of the clock:  Input of 3537: 670 mVpp  Provided by 3537: 1.2 Vpp DC value: 1.2 V 3537 specifications.

Philips Semiconductors, Costumer Support, 04/12/ Input of 3537 F=26 MHz (Refin pin) Output of 3537 F=26MHz

Philips Semiconductors, Costumer Support, 04/12/ Synchronisation with network Step 1: wake up of the 26 MHz  26 MHz is not the real frequency.  Clock is not enslaved Step 2: Mobiles goes in Rx mode to receive the FCB DESPITE the clock is not at 26 MHz (FCB: Frequency Control Burst) Step 3: with FCB, mobile can correct its frequency error.

Philips Semiconductors, Costumer Support, 04/12/ After synchronisation with network Regularly, mobile measures the frequency error with FCB  Frequency Offset Information (FOI) Software value, given by tracer or a communication tester (CMD) Coded with 16 bits (2 bytes). Positive FOI value = negative frequency error. Negative FOI value = positive frequency error. Using FOI information, mobile adjusts AFC.

Philips Semiconductors, Costumer Support, 04/12/ Using FOI information, mobile increases or decreases AFC. Since AFC is provided by AuxDAC2 on 50732, it can change only step by step. Foi_step How mobile adjusts AFC: FOI_STEP

Philips Semiconductors, Costumer Support, 04/12/ FOI_STEP Calculation Take the specified minimum voltage range of the AFC DAC defined by ΔV ( unit in V). The correction per LSB is derived by: ΔV/(2 n ) for a n bits DAC (unit in V). Then, the TCXO slope needs to be measured on a statistical quantity of units (> 30). The slope is expressed by S (unit in ppm/V).

Philips Semiconductors, Costumer Support, 04/12/ FOI_STEP phy is equal to (ΔV x S x F)/ 2 n (unit in Hz/LSB) Where F is the middle Rx RF frequency corresponding to the band used for the calculation x 10 6 Hz for the GSM850 (channel 189) x 10 6 Hz for the GSM900 (channel 62) x 10 6 Hz for the GSM1800 (channel 699) x 10 6 Hz for the GSM1900 (channel 661). The correction is: (FOI/ FOI_STEP phy ) (unit in LSB)

Philips Semiconductors, Costumer Support, 04/12/ BUT: a division between an integer and a real number is an inconvenient operation for soft Parameter FOI_step FOI_STEP = 2 16 /(FOI_STEP phy ) (unit LSB/Hz) Thus, we have: [2 16 /(FOI_STEP phy )] x [FOI / 2 16 ]=[FOI_STEP] x [FOI / 2 16 ] Instead of: FOI / FOI_STEP phy One multiplication better than a division One division with an integer One division between one integer and one real number

Philips Semiconductors, Costumer Support, 04/12/ What will happen if initial frequency error is too important? Mobile can not synchronize Use of an Initial FOI (FOInit)

Philips Semiconductors, Costumer Support, 04/12/ DSP has a Rx frequency window (+/- 25 kHz). It comes from DSP firmware. Mobile can synchronize only if frequency error is in this window FOI_Init put frequency error in the synchronization range

Philips Semiconductors, Costumer Support, 04/12/ Settings of this parameters REF_Cal, FOI_Init, FOI_Step are stored in EEPROM It is possible to see and change their value with TAT software Ref_Cal and FOI_Init are tuned for each mobile. Ref_Cal is first tuned, then Foi_Init. FOI is a soft parameter. Value accessible only with TRACER or Communication TESTER

Philips Semiconductors, Costumer Support, 04/12/ FoiStep: One per band RefCal Foi-Init: Needs an HWL reset (init button)

Philips Semiconductors, Costumer Support, 04/12/ Values for Sysol ME (updated on W347) FOIinit: 2340 * RefCal: 78 ** FOIstep GSM850: 8082 FOIstep GSM900: 7759 FOIstep GSM1800: 3856 FOIstep GSM1900: 3634 * : Depends on layout, quartz, diode… ** : Statistical value * & **: Defaults values – Tuned in production

Philips Semiconductors, Costumer Support, 04/12/ GSM standard requirements: In all bands, in normal conditions, frequency error must not be greater than 0.1 ppm  For GSM 850: 85 Hz  For GSM 900: 90 Hz  For DCS 1800: 180 Hz  For PCS 1900: 190 Hz

Philips Semiconductors, Costumer Support, 04/12/ Training Content: Reference clock presentation Reference clock contents Reference clock on Sysol ME Reference clock working on Sysol ME  Reference clock performances to check Problems linked to reference clock Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/ REFERENCE CLOCK PERFORMANCES TO CHECK

Philips Semiconductors, Costumer Support, 04/12/ List of measurements to check 26 MHz Frequency drift vs output power  Current freq error when Pout goes from PCL high to low and low to high Waveform Wake-up time DAC frequency correction AFC linearity Frequency drift with temperature Spectrum

Philips Semiconductors, Costumer Support, 04/12/ Wake up time with temperature: Spec: 9 ms; meas: 1.09 ms Spectrum (Refin pin): spec: -20 dBc; meas: dBc (H2) Frequency drift with temperature (–30 to 70°): Spec: +/- 7 ppm; Measured: +/- 2 ppm Waveform: Vpp = 1.25 V; Duty Cycle = 42 – 57 % Some specs and measurements:

Philips Semiconductors, Costumer Support, 04/12/ Training Content: Reference clock presentation Reference clock contents Reference clock on Sysol ME Reference clock working on Sysol ME Reference clock performances to check  Problems linked to reference clock Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/ PROBLEMS LINKED TO 26 MHz

Philips Semiconductors, Costumer Support, 04/12/ Main problem: Frequency error 26 MHz: origin of all synthesized frequencies Frequency drift on 26 MHz means frequency drift on all synthesizers degradation of frequency error

Philips Semiconductors, Costumer Support, 04/12/ Degradation also of other performances  Phase error  Training sequence loss  Problem of synchronisation  Sensitivity DUE TO FREQUENCY ERROR

Philips Semiconductors, Costumer Support, 04/12/ Case of the sensitivity Sensitivity can be degraded by phase noise But also by the Ref Clock itself with the harmonics  GSM 850: H34 for channel 202  GSM 900: H36 for channel 5 Concern mainly GSM 850 and GSM 900

Philips Semiconductors, Costumer Support, 04/12/ Training Content: Reference clock presentation Reference clock contents Reference clock on Sysol ME Reference clock working on Sysol ME Reference clock performances to check Problems linked to reference clock  Reference clock on Dragon Fly

Philips Semiconductors, Costumer Support, 04/12/ REFERENCE CLOCK ON DRAGON FLY

Philips Semiconductors, Costumer Support, 04/12/ Characteristics of the ref. clock on Dragon Fly Frequency: 26 MHz  Radio: UAA3537. Need 26 MHz  BBand: PCF 5213 (SWIFT) 26 MHz Internal divider in 3537 not used Integrated clock: Module END 3512A (NDK) Buffers for radio and BB still in 3537

Philips Semiconductors, Costumer Support, 04/12/ Supply for the clock: 2.5 V, provided by an internal regulator in 3537 Signals: 1 signal is now needed: AFC: provided by BB  Clkfdbx: no more used RefCal: not used Synchronization algorithm is identical

Philips Semiconductors, Costumer Support, 04/12/ Temp. Comp: Unused Variable load: unused Supply: Internal regulator Buffers Module AFC

Philips Semiconductors, Costumer Support, 04/12/ Values for Dragon Fly (updated on W347) FOIinit: 2230 – Default value for Vafc=1.2V RefCal: Unused FOIstep GSM850: FOIstep GSM900: FOIstep GSM1800: 5601 FOIstep GSM1900: 5243

Philips Semiconductors, Costumer Support, 04/12/ Used module on Dragon Fly: END 3512A

Philips Semiconductors, Costumer Support, 04/12/200366

Philips Semiconductors, Costumer Support, 04/12/ Input of 3537 F=26 MHz (Refin pin) Output of 3537 F=26 MHz (Clockout pin)

Philips Semiconductors, Costumer Support, 04/12/ CONCLUSION: COMPARISON WITH SYSOL 2

Philips Semiconductors, Costumer Support, 04/12/ Since Sysol 2 clock is a module, it’s easier to compare with Dragon Fly. More integrated:  On sysol 2: external and discrete buffer  External supply by a regulator INTEGRATED IN SYSOL ME AND DRAGON FLY. Frequency change: 26 MHz instead of 13.

Philips Semiconductors, Costumer Support, 04/12/ QUESTIONS