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SL1925 Satellite Zero IF QPSK Tuner IC Preliminary Information DS4955 ISSUE 3.1 October 2001 Features q q q q q q q q q Single chip system for direct quadrature down conversion from L-band High signal handling capability for minimum external component count application, requires external RF AGC of 30dB Compatible with DSS and DVB system requirements Excellent gain and phase match up to 30MHz baseband High output referred linearity for low distortion and multi channel application Fully balanced low radiation design Integral RF AGC amplifier Two selectable varactor tuned local oscillators with buffered output for driving external synthesiser loop ESD protection (Normal ESD handling procedures should be observed) Ordering Information SL1925/KG/NP2S (Tubes) SL1925/KG/NP2T (Tape and Reel) Description The SL1925 is a wideband quadrature converter operating from 950 to 2150 MHz, intended primarily for application in satellite tuners. The device contains all elements necessary, with the exception of local oscillator sustaining network, to fabricate a high performance I(n-phase) & Q(uadrature) phase splitter and downconverter optimised for systems containing RF AGC gain control. The device allows for systems containing higher power analog interferers. For most applications RF tunable filtering is not essential. The SL1925 is optimised for use with a low phase noise synthesiser, a range of which are available from Zarlink Semiconductor. This will form a complete front end tuner function for digital satellite receiver systems utilising DSP derotation recovery. The device includes a very high signal handling front end with AGC, this provides for gain control, reference local oscillator with output buffer, phase splitter with I and Q mixers and baseband buffer amplifiers with external interstage filtering. Applications q q Satellite receiver systems Data communications systems SL1925 Preliminary Information OPFI Vcc PSout PSoutb Vee Tanks Tanksb Vee Tankv Tankvb Vee NC Vcc OPFQ 14 1 28 Vee IPFI Vee Iout LOsel Vcc RF RFB Vee AGC Qout Vee IPFQ Vee 15 NP28 Figure 1 Pin connections 25 AGC 19 AGC SENDER Iout 27 IPFI 1 OPFI RF RFB 22 21 0 DEG 14 OPFQ 90 DEG 16 IPFQ Tankv Tankvb 9 10 vcov 18 Qout Tanks Tanksb 6 7 vcos DIVIDE BY 2 FREQUENCY AGILE PHASE SPLITTER 3 4 PSout PSoutb Vcc Vee LOsel 24 2, 13, 23 5, 8, 11, 15, 17, 20, 26, 28 Figure 2 Block diagram 2 Preliminary Information Quick Reference Data Characteristic Operating range Input noise figure, DSB, maximum gain, 1500MHz Maximum conversion gain (assuming 6dB filter loss) Minimum conversion gain (assuming 6dB filter loss) IP32T input referred Converter input referred IM3, two tones at 97dBV IP22T input referred P1dB input referred Baseband amplifier Output limit voltage Gain match up to 22 MHz Phase match up to 22 MHz Gain flatness up to 22 MHz Local oscillator phase noise across entire 950MHz to 2150MHz band: SSB @ 10 kHz offset Table 1 SL1925 950-2150 19 >55 <20 113 30 140 103 2.0 0.2 0.7 0.5 -80 Units MHz dB dB dB dBuV dBc dBuV dBuV V dB deg dB dBc/Hz Functional Description The SL1925 is a wideband direct conversion quadrature downconverter optimised for application in satellite receiver systems. A block diagram is given in Figure 2 and shows the device to include a broadband RF preamplifier with AGC control, two oscillator sustaining amplifiers, a frequency agile 90 phase splitter, I Q channel mixers and I Q channel baseband amplifiers. The only additional elements required are an external tank circuit for each oscillator, and baseband interstage filters. To fabricate a complete tuner an RF AGC stage offering +20dB to -10 dB of gain range and a 2.2 GHz PLL frequency synthesiser are also required. An example application is shown in Figure 16. In normal application the first satellite IF frequency of typically 950 to 2150 MHz is fed via the tuner RF AGC stage to the RF preamplifier, which is optimised for impedance match and signal handling. The RF preamplifier is designed such that no tracking RF filter is required and also allows for analog interferers at up to 10 dB higher amplitude. The converter RF input impedance is shown in Figure 5. The amplifier signal is then fed to an AGC stage providing a minimum of 35dB AGC control, which together with the RF attenuator provides a possible overall tuner dynamic range of 65dB, to allow for normal operating dynamic range and MCPC systems. The signal is then split into two balanced channels to drive the I and Q mixers. The AGC characteristic, and gain variation of IIP3, IIP2, P1dB and NF are contained in Figs. 6, 7, 8, 9 and 10 respectively. The required 950MHz to 2150MHz I and Q reference LO frequencies for quadrature direct conversion are generated by the on board oscillators named `vcos' and `vcov', and the phase splitter. Oscillator `vcos' operates nominally from 1900MHz to 3000MHz and is then divided by two to provide 950MHz to 1500MHz. Oscillator `vcov' operates nominally from 1400MHz to 2150MHz. Only one oscillator is active at any time and selection is made within the phase splitter under the control of the LOsel input. Each oscillator uses an external varactor tuned resonant network optimised for low phase noise with a single varactor line control. A recommended application circuit for the oscillators is shown in Figure 4. The LO from the phase splitter drives a buffer whose outputs `PSout' and `PSoutb' can be used for driving an external PLL control loop for the VCO's. The typical LO phase noise is shown in Figure 11. The mixer outputs are coupled to baseband buffer outputs `OPFI' and `OPFQ' which drive external band limit filters. The output impedance of these buffers is contained in Figure 12. The outputs of the filters are then connected to the inputs `IPFI' and `IPFQ' of the baseband channel amplifiers. The outputs `Iout' and `Qout' provide for a low impedance drive and can be used with a maximum load as in Figure 3. The output impedance of this section is contained in Figure 13. An example filter for application with 30MS/s systems is contained in Figure 14. All port peripheral circuitry for the SL1925 is shown in Figure 15a and 15b. The typical key performance data at 5V Vcc and 25C ambient are shown in the `QUICK REFERENCE DATA' of Table 1. 3 SL1925 Preliminary Information 100 1k 15pF Figure 3 Baseband output load condition 1T379 6.15MM STRIPLINE 1k 1T379 6.15MM STRIPLINE 6 Tanks "vcos" 7 Tanksb Vcnt BB811 9MM STRIPLINE 9 Tankv "vcov" Tankvb BB811 1k 9MM STRIPLINE 10 Note: Stripline width =0.44mm,dimensions are approximate. Figure 4 Local oscillator application circuit +j1 +j0.5 +j2 Marker +j0.2 +j5 Freq (MHz) 950 1350 1750 2150 Zreal Zimag 90 76 63 46 -18 -15 -35 -29 1 2 0 0.2 0.5 1 1X X2 X3 2 5 X 3 4 X 4 -j0.2 -j5 -j0.5 -j2 -j1 START 700 MHz Normalised to 50 STOP 2 500 MHz Figure 5 Converter RF input impedance (typical) 4 Preliminary Information SL1925 50.0 40.0 Converter conversion gain (dB) 30.0 30dB minimum, AGC <1V 20.0 10.0 0.0 -5dB maximum, AGC >4V -10.0 -20.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 AGC control voltage (V) Figure 6 Converter gain variation with AGC voltage (typical) 120 115 Converter input referred IP3 (dBuV) 110 105 100 95 90 -6 -1 4 9 14 Converter gain setting (dB) 19 24 29 34 Figure 7 Converter input referred IP3 variation with gain setting (typical) 5 SL1925 Preliminary Information 140 135 130 Converter input referred IP2 (dBuV) 125 120 115 110 105 100 -6 -1 4 9 14 Converter gain setting (dB) 19 24 29 34 Figure 8 Converter input referred IP2 variation with gain setting (typical) 110 105 Converter RF input level at P1dB (dBuV) 100 95 90 85 80 -6 -1 4 9 14 Converter gain setting (dB) 19 24 29 34 Figure 9 Converter input referred 1dB gain compression, P1dB (typical) 6 Preliminary Information SL1925 60 50 Noise Figure (dB) 40 30 20 10 20 25 30 35 System gain (dB) 40 45 50 55 Figure 10 Noise figure variation with gain setting (typical) 7 SL1925 Preliminary Information LO Frequency (MHz) -70 950 -72 1150 1350 1550 1750 1950 2150 vcos enabled -74 Phase noise @10kHz offset (dBc/Hz) vcov enabled -76 -78 -80 -82 -84 -86 -88 -90 Figure 11 LO phase noise variation with frequency (typical) +j1 +j0.5 +j2 +j0.2 x 2 3 Marker +j5 Freq (MHz) 1 10 30 Zreal Zimag 24 25 30 0.5 11 29 1 x 1 2 5 0 0.2 0.5 2 3 1x -j0.2 -j5 -j0.5 -j2 -j1 START 10kHz 700 Normalised to 50 STOP 2 500 50MHz Figure 12 Converter output impedance, OPFI and OPFQ (typical) 8 Preliminary Information SL1925 +j1 +j0.5 +j2 Marker +j0.2 +j5 Freq (MHz) 1 10 30 Zreal Zimag 11.4 9.6 7.3 3.4 0.2 4.7 1 2 0 3X 2X 1X 0.5 1 2 5 X 3 -j0.2 -j5 -j0.5 -j2 -j1 START 10kHz Normalised to 50 STOP 50MHz Figure 13 Baseband output impedance, Iout and Qout (typical) 100nF OPFI / OPFQ 1k IPFI / IPFQ 1k 3.9pF Figure 14 Example baseband interstage filter for 30MS/s application 9 SL1925 Preliminary Information Vcc IF-OP-SEL LOsel RF INPUTS VREF 3 Converter RF inputs (pins 21, 22) Oscillator select input (pin 24) VREF 2 1K TANK 1K TANKB OPFI & OPFQ Oscillator inputs (pins 6, 7, and 9,10) Converter outputs (pins 1, 14) Vcc VREF4 PSout LO OUTPUT PSoutb LO OUTPUTB 2K AGC 12K CONTROL Prescaler buffer drive (Pins 3,4) AGC input (pin 19) Figure15a Input/Output interface circuits 10 Preliminary Information SL1925 BIAS IPFI and IPFQ Iout and Qout Baseband amplifier inputs (pins 16,27) Baseband outputs (pins 18, 25) Figure 15b Input/Output interface circuits (continued) 11 SL1925 Electrical Charqacterisitics Preliminary Information These characteristics are guaranteed by either production test or design. They apply within the specified ambient temperature and supply voltage unless otherwise stated. Tamb = -20C to + 70C, Vee= 0V, Vcc = 4.75V to 5.25V. Desired channel at fc MHz Value Min Supply current, Icc RF input operating frequency SYSTEM System noise figure, DSB Variation in system NF with gain adjust System input referred IP2 System input referred IP3 System conversion gain 21,22 21,22 135 110 19 -1 140 113 dB dB/dB dBV dBV 2,13,23 21,22 950 Characteristic Pin Typ 130 Max 175 2150 Units mA MHz Conditions All system specification items should be read in conjunction with Note 1. Maximum gain, AGC = 1V See Figure 10 See Note 2. See Note 3. Terminated voltage conversion gain into load as in Figure 3. AGC monotonic from Vee to Vcc, see Figure 6 AGC = 4.0V, 950MHz AGC = 1.0V, 950MHz 950MHz to 2150MHz Excluding interstage filter stage Excluding interstage filter stage Excluding interstage filter stage See Note 5 See Note 6 Within 0 100MHz band, under all gain settings, RF input set to deliver 108dBV at baseband outputs See Figure 5 Minimum AGC gain Maximum AGC gain Gain Roll off System I/Q gain match System I/Q phase balance System I & Q channel in band ripple LO 2nd harmonic interference level LNA 2nd harmonic interference level All other spurii on I & Q outputs 20 59 5 18,25 18,25 18,25 -1 -3 +1 3 1 -50 -35 18,25 78 dB dB dB dB deg dB dBc dBc dBV CONVERTER Converter input impedance Converter input return loss Converter input referred IP2 Converter input referred IP3 Converter input referred IM2 Converter input referred IM3 Converter input referred 1dB gain compression (P1dB) Converter conversion gain Minimum AGC gain Maximum AGC gain AGC gain control slope variation AGC control input current 21,22 21,22 21,22 21,22 21,22 21,22 21,22 10 121 110 75 12 130 112 -33 -30 dB dBV dBV dBc dBc -24 -26 See Note 4 See Note 4 See Note 4 See Note 4 See Figure 9 Terminated voltage conversion gain in load as in Figure 3. AGC = 4.0V AGC = 1.0V Monotonic from Vee to Vcc, see Figure 6 AGC bandwidth 100kHz -5 30 19 -250 250 dB dB A 12 Preliminary Information Electrical Characteristics (continued) SL1925 These characteristics are guaranteed by either production test or design. They apply within the specified ambient temperature and supply voltage unless otherwise stated. Tamb = -20C to + 70C, Vee= 0V, Vcc = 4.75V to 5.25V. Desired channel at fc MHz Value Min Converter output impedance Converter output limiting Converter bandwidth 1dB Converter output roll off Oscillator vcos operating range Tanks/Tanksb Oscillator vcov operating range, Tankv/Tankvb Local oscillator SSB phase noise 1,14 1,14 1,14 6,7 9,10 6,7 Characteristic Pin Typ 25 1.2 Max 50 Units Conditions 0.5 40 6 1900 1450 Vp-p MHz dB/oct MHz MHz dBc/Hz 0.1 to 30MHz. See Figure 12 No Load No Load 3000 2150 -80 -76 Giving LO = 950MHz to1500MHz Application as in Figure 4. Application as in Figure 4. @ 10kHz offset PLL loop BW < 1kHz, application as Figure 4. Measured at baseband outputs of 10MHz Oscillator vcos enabled Oscillator vcov enabled LO leakage to converter input LOsel low voltage LOsel high voltage LOsel low current LOsel high current Prescaler output drive Prescaler output impedance Prescaler output return loss BASEBAND AMPLIFIERS Baseband amplifier input impedance Resistance Capacitance Baseband amplifier input referred IP3 Baseband amplifier input referred IP2 Baseband amplifier input referred IM3 Baseband amplifier input referred IM2 Baseband amplifier input referred 1dB compression (P1dB) Baseband amplifier gain 21,22 24 24 Vcc-0.7 24 24 3,4 88 3,4 3,4 16,27 10 59 69 0.6 -50 200 dBV V V A A dBV dB Single ended into 50. Synthesiser should be driven differentially 50 8 0.1 -30MHz bandwidth k pF dBV dBV -34 -22 dBc dBc dBV dB 5 16,27 16,27 16,27 16,27 16,27 16,18 27,25 84 30 94 99 97 111 -40 -34 See Note 7 See Note 7 See Note 7 See Note 7 Terminated voltage gain into load as in Figure 3. Terminated voltage gain into load as in Figure 3 13 SL1925 Electrical Characteristics (continued) Preliminary Information These characteristics are guaranteed by either production test or design. They apply within the specified ambient temperature and supply voltage unless otherwise stated. Tamb = -20C to + 70C, Vee= 0V, Vcc = 4.75V to 5.25V. Desired channel at fc MHz Value Min Characteristic Baseband amplifier output impedance Baseband amplifier output limiting Baseband amplifier 1dB bandwidth Baseband output roll off Pin 18,25 18,25 18,25 18,25 2.0 40 6 Typ Max 20 Units Vp-p MHz dB/oct Conditions pk-pk level at hard clipping. Load as in Figure 3. Load as in Figure 3. Above 3dB point, no load Notes : 1. Systems specifications refer to total cascaded system of front end converter/AGC stage and baseband amplifier stage with nominal 6dB pad as interstage filter and load impedance as in Figure 3. 2. AGC set to deliver output amplitude of 108dBV on desired channel, input frequency fc and amplitude of 79dBV, with two interferers of frequencies fc+146 and fc+155MHz at 97dBV generating output intermodulation spur at 9MHz. 40MHz 3dB bandwidth interstage filter included. 3. AGC set to deliver output amplitude of 108dBV on desired channel, input frequency fc and amplitude 79 dBV, with two interferers of frequencies fc+110 and fc+211MHz at 97 dBV generating output intermodulation spur at 9MHz. 40MHz 3dB bandwidth interstage filter included. 4. Two tones within RF operating frequency range at 97dBV, conversion gain set at 4dB. 5. The level of 2.01GHz downconverted to baseband relative to 1.01 GHz with the oscillator tuned to 1 GHz, measured with no input filtering. 6. The level of second harmonic of 1.01 GHz input at -25 dBm downconverted to baseband relative to 2.01 GHz at -40 dBm with the oscillator tuned to 2 GHz, measured with no input filtering. 7. Two tones within operating frequency range at 77dBV. Absolute Maximum Ratings All voltages are referred to Vee at 0V (pins 5,8,11,15,17,20,26,28) Characteristic Supply Voltage, Vcc PSout &PSoutb DC offset RF & RFB input voltage All other I/O ports DC offset Pin Min 2,13,23 3,4 21,22 1,6,7,9 10,12 14,16 18,19 24,25,27 Value Max 7 Vcc+0.3 2.5 Vcc+0.3 Units V Vp-p Vp-p V Conditions Transient condition only AC coupled, transient conditions only -0.3 Vcc-3.0 -0.3 Storage Temperature Junction Temperature NP28 package Thermal resistance Chip to ambient Chip to case Power consumption at 5.25V ESD protection -55 +150 +150 C C 85 20 893 All 4 C/W C/W mW kV Mil Std-883 latest revision method 3015 class 1 14 Preliminary Information SL1925 Demo Board The demo board contains an SL1925 direct conversion IC and SP5769 synthesiser. Reference to the specifications for each device may be required in conjunction with these notes. The board contains all components necessary to demonstrate operation of the SL1925. The schematic and PCB layout of the board are shown in figures 16, 17 and 18. The SP5769 synthesiser is provided to control each of the oscillators of the SL1925. Supplies The board must be provided with the following supplies: 5V for the synthesiser, 30V for the varactor line and 5V for the SL1925. The supply connector is a 5 pin 0.1" pitch pin header. The order of connections is 5V - GND - 30V - GND - 5V I2C Bus Connections The board is provided with a RJ11 I2C bus connector which feeds directly to the SP5769 synthesiser. This connects to a standard 4 way cable which is supplied with the interface box. Operating Instructions 4. Free running the VCO's 1. Software Use the Zarlink Semiconductor synthesiser software. Pull down the I2C bus section menu then select the SP5769. It is suggested that the charge pump setting 130uA is used, and the reference divider is set to 32. These settings give a small loop bandwidth (i.e. 100's Hz), which allows detailed phase noise measurements of the oscillators to be taken, if desired. 2. VCO control SL1925 The two VCO's are selected by toggling port P1 on the synthesiser which in turn toggles the LOsel input of the SL1925. VCOS is switched on (and hence VCOV off) by clicking P1 on - a tick will appear. VCOS oscillates at twice the LO frequency (lower band) and is then divided by two to provide the required LO frequency in the range 950MHz to 1500MHz approximately. VCOV is switched on (and hence VCOS off) by clicking P1 off - no tick. VCOV oscillates at the LO frequency (upper band) in the range 1450MHz to 2150MHz approximatley. 3. AGC control The AGC input of the SL1925 which determines the conversion gain should be controlled by application of an external voltage to the AGC pin, TP1. Caution: Care should be taken to ensure the chip is powered ON when +ve voltages are applied to the AGC input so as to avoid powering the chip up via the ESD protection diode of the AGC input. It is recommended that a low current limit is set on the external source used. Select the required VCO using port P1 and then using the software choose an LO frequency which is above the maximum frequency capability of the oscillator. 3GHz is suggested for both oscillators. Under this condition the varactor control voltage is pumped to its maximum value, i.e. to the top of the band. The oscillator frequency may be manually tuned by varying the 30V supply. 15 C42 100pF C47 100pF C43 100nF C49 100nF C33 100nF C44 100pF C41 4u7 3 30V C4 3p9 R3 1K C25 100nF R4 1K R100 0R +5V GND +30V GND +5V 1 2 3 4 5 C26 100nF 5V Synth R8 22K IC1 SL1925 J1 DC Power C51 100pF R9 15K 100nF C34 + C52 4u7 1 5V 2 Vcc IP FI Vee I OUT LO Sel Vcc RF inA RF inB Vee AGC Q OUT NC 13 11 14 10 9 5V Synth C23 100nF R1 1K R101 0R OP FI Vee 27 26 25 24 5V 23 22 21 20 19 18 Vee Vee Vcc OP FQ IP FQ Vee R2 1K C2 C1 C16 C6 220nF 28 SMA3 I OUT R5 100R C80 15pF R18 1K C50 100nF PSCb PSout PSoutb Vee Tanks Tanksb Vee Tankv Tankvb C39 2n2 C14 1nF 3 PSCa C13 1nF R10 1K VD1 1T379 4 5 6 7 8 L3 C31 15nF T1 BCW31 L1 L2 R19 1K VD2 1T379 R7 13K LO SELECT R102 120R 1nF 1nF 1nF TP1 Ext AGC Volts SMA2 Q OUT C32 68pF C30 82pF 1 CH PUMP DRIVE 9 10 11 12 5V Vee L4 16 15 14 PSCb PSCa VD4 BB811 1 1 APPROXIMATE STRIPLINE DIMENSIONS L1 & L2 6.0mm X 0.44mm L1 & L2 6.15mm X 0.44mm L3 & L49.0mm XX0.44mm L3 L4 8.0mm 0.44mm Title: SL1925 L BAND QUADRATURE DOWNCONVERTER 3 16 LINK INFORMATION SL1925 5V 2-3 FILTER INPUT 1-2 FILTER OUTPUT + J4 2 SMA5 IP/OP FI VD3 BB811 SMA1 RF IN 2 C60 150pF 3 XTAL CAP XTAL RF IP RF IP Vcc REF/COMP ADDRESS PORT P0 12 13 SDA SCL P3/LL P2 PORT P1 IC2 SP5769 J3 4 5 6 7 8 X1 4MHz 17 16 15 SDA5 5V0 GND SCL5 3 4 5 6 C5 220nF R6 100R C81 15pF R17 1K I2C BUS R16 10K C3 3p9 C37 100pF C38 100pF C24 100nF LINK INFORMATION 2-3 FILTER INPUT LO SELECT J2 1-2 FILTER OUTPUT 2 SMA6 IP/OP FQ MITEL Figure 16 Preliminary Information Preliminary Information SL1925 Figure 17 Top View 17 SL1925 Preliminary Information Figure 18 Bottom view 18 For more information about all Zarlink products visit our Web Site at www.zarlink.com Information relating to products and services furnished herein by Zarlink Semiconductor Inc. trading as Zarlink Semiconductor or its subsidiaries (collectively "Zarlink") is believed to be reliable. However, Zarlink assumes no liability for errors that may appear in this publication, or for liability otherwise arising from the application or use of any such information, product or service or for any infringement of patents or other intellectual property rights owned by third parties which may result from such application or use. Neither the supply of such information or purchase of product or service conveys any license, either express or implied, under patents or other intellectual property rights owned by Zarlink or licensed from third parties by Zarlink, whatsoever. Purchasers of products are also hereby notified that the use of product in certain ways or in combination with Zarlink, or non-Zarlink furnished goods or services may infringe patents or other intellectual property rights owned by Zarlink. This publication is issued to provide information only and (unless agreed by Zarlink in writing) may not be used, applied or reproduced for any purpose nor form part of any order or contract nor to be regarded as a representation relating to the products or services concerned. The products, their specifications, services and other information appearing in this publication are subject to change by Zarlink without notice. No warranty or guarantee express or implied is made regarding the capability, performance or suitability of any product or service. Information concerning possible methods of use is provided as a guide only and does not constitute any guarantee that such methods of use will be satisfactory in a specific piece of equipment. It is the user's responsibility to fully determine the performance and suitability of any equipment using such information and to ensure that any publication or data used is up to date and has not been superseded. Manufacturing does not necessarily include testing of all functions or parameters. These products are not suitable for use in any medical products whose failure to perform may result in significant injury or death to the user. All products and materials are sold and services provided subject to Zarlink's conditions of sale which are available on request. Purchase of Zarlink's I2C components conveys a licence under the Philips I2C Patent rights to use these components in an I2C System, provided that the system conforms to the I2C Standard Specification as defined by Philips. Zarlink and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc. Copyright 2002, Zarlink Semiconductor Inc. All Rights Reserved. TECHNICAL DOCUMENTATION - NOT FOR RESALE |
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