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| PRELIMINARY ML2713 Radio IF Transceiver GENERAL DESCRIPTION The ML2713 combined with the ML2712 forms an FSK (Frequency Shift Keying) 2.4 GHz radio chipset for systems based on IEEE802.11 and other wireless communication protocols using the 2.4HGz ISM band. The ML2713 is the complete IF section of Micro Linear's 2.4GHz frequency hopping, half duplex radio transceiver chipset. The chip's down conversion super-heterodyne receiver circuit contains an image reject down-convert mixer, a limiter, a discriminator, a receive data filter and a tracking A/D converter. The chips transmit circuit contain a 6 bit D/A converter to digitally modulate the IF, an anti alias filter and an image reject up-convert mixer. FEATURES n Highly integrated IF transceiver n Data rates up to 4Mbps n Integrated discriminator and filter alignment circuits n High signal to noise ratio at the discriminator output n Received signal strength indicator (RSSI) n D/A Converter for digitally generated IF n Low sleep mode current - typically less than 1mA n 3.0V to 5.5V operation n Fast 10msec switch time between transmit and receive modes n 48 Pin TQFP, 7mm body APPLICATIONS n 2.4GHz FSK radios n PC Card and FlashCard Wireless Transceivers n Systems based on IEEE802.11 1Mbps and 2Mbps Standard n TDMA Radio IF circuits SIMPLIFIED BLOCK DIAGRAM R. C. Loop Filter ML2731 Bias Controller Transmit Power Amplifier 2LO Loop Filter & Tank Circuit 3 ML2712 1LO Loop Filter & Tank Circuit Baseband Controller (e.g., MSM7730B) 6 Reference Frequency Input 32MHz Clock 2LO Input Image Reject Rx IF Downconverter RSSI Limiter Discriminator Data Filter ML2713 Quad & Filter Auto Align DC Restore Tx Regulator Output DC Reg Image Reject Tx IF Upconverter + Control Circuits DAC - Rx Out Control Interface D/A Input PRELIMINARY DATASHEET January, 2000 PRELIMINARY TABLE OF CONTENTS ML2713 General Description ................................................................................................................................................... 1 Applications ............................................................................................................................................................... 1 Features ...................................................................................................................................................................... 1 Simplified Block Diagram .......................................................................................................................................... 1 Block Diagram ........................................................................................................................................................... 3 Pin Configuration ....................................................................................................................................................... 4 Pin Descriptions ......................................................................................................................................................... 4 Functional Description ............................................................................................................................................... 7 Introduction .............................................................................................................................................................. 7 Operational Modes .................................................................................................................................................. 8 Mode Control ........................................................................................................................................................... 8 Filter Align Mode ..................................................................................................................................................... 8 Receive Mode ......................................................................................................................................................... 12 Sleep Mode .............................................................................................................................................................. 14 Test Mode Control .................................................................................................................................................... 14 Absolute Maximum Ratings ........................................................................................................................................ 15 Electrical Characteristics ............................................................................................................................................ 15 Operating Conditions ................................................................................................................................................. 15 Physical Dimensions .................................................................................................................................................. 20 Ordering Information .................................................................................................................................................. 20 WARRANTY Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness of the contents of this publication and reserves the right to make changes to specifications and product descriptions at any time without notice. No license, express or implied, by estoppel or otherwise, to any patents or other intellectual property rights is granted by this document. The circuits contained in this document are offered as possible applications only. Particular uses or applications may invalidate some of the specifications and/or product descriptions contained herein. The customer is urged to perform its own engineering review before deciding on a particular application. Micro Linear assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear products including liability or warranties relating to merchantability, fitness for a particular purpose, or infringement of any intellectual property right. Micro Linear products are not designed for use in medical, life saving, or life sustaining applications. (c) Micro Linear 2000. is a registered trademark of Micro Linear Corporation. All other trademarks are the property of their respective owners. Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376; 5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174; 5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165; 5,825,223; 5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending. 2 PRELIMINARY DATASHEET January, 2000 BLOCK DIAGRAM RSSI 17 19 20 30 29 34 35 38 42 40 41 BPI BPIB BPO BPOB DPSB DPS DISCO DFI1 DFO1 DFI2 RSSI Limiter Receive Image Reject Down-Convert Mixer 0/90 0/90 Limiter LOWPASS FILTER Limiter Unity Gain Op Amp Discriminator Unity Gain Op Amp 43 DFO2 1IF 26 1IFB Rx I/P Amplifier 27 44 VDC January, 2000 VARIABLE CAPACITOR ARRAY Comparator Tx O/P Amplifier VARIABLE CAPACITOR ARRAY VARIABLE CAPACITOR ARRAY 0/90 7 Transmit Image Reject Up-Convert Mixer 7-Bit Up/Down COUNTER 6 BIT DAC 0/90 FREQUENCY DIVIDER 22 2LO 2LOB 23 9 16 18 28 39 5 4 3 2 1 47 DD0 DD1 DD2 DD3 DD4 DD5 GND GND GND GND GND DC REC 46 SLICE VCC1 6 VCC1 7 Comparator 8 CMO VCC2 21 VCC2 24 PRELIMINARY VCC2 25 VCC3 10 14 TS VCC4 33 CONTROL 15 13 LOE RS REG 32 TX VCO REGULATOR 45 MS1 31 MS2 37 MS3 PRELIMINARY DATASHEET ML2713 3 PRELIMINARY PIN CONFIGURATION ML2713 48-Pin TQFP (H48-7) DISCO DFO2 DFO1 SLICE GND DFI2 DFI1 VDC DD5 MS1 MS3 NC ML2713 48 47 46 45 44 43 42 41 40 39 38 37 DD4 DD3 DD2 DD1 DD0 VCC1 VCC2 CMO GND VCC3 NC NC 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 36 35 34 33 32 31 30 29 28 27 26 25 NC DPS DPSB VCC4 REG MS2 BPO BPOB GND 1IF 1IF VCC2 RS TS BPI GND GND BPIB RSSI 2LO LOE LON2 VCC2 TOP VIEW PIN DESCRIPTIONS Pin # Signal Name POWER AND GROUND 6, 7 21, 24, 25 10 33 9 18, 28 16 39 CONTROL 13 14 15 RS TS LOE I (CMOS) I (CMOS) I (CMOS) Receive mode enable. This CMOS input is referenced to VCC1 and has an on-chip pull-up. See Table 1 for operation Transmit mode enable. This CMOS input is referenced to VCC1 and has an on-chip pull-up. See Table 1 for operation. Chip enable and filter align control. This CMOS input is referenced to VCC1 and has an on-chip pull up. The pin must be low for the IC to operate in either transmit, receive or align modes. See Table 1 for operation VCC1 VCC2 VCC3 VCC4 GND GND GND GND I/O Type POWER POWER POWER POWER GND GND GND GND Description Voltage supply for digital I/O circuits. VCC1 should be greater than or equal to VCC2, VCC3, and VCC4 in normal operation Voltage supply for receive image reject down-converter and transmit image reject up-converter Voltage supply for D/A converter, comparator, mode control, and alignment circuits Voltage supply for limiters, discriminator, data filter, and transmit regulator Ground for VCC1 Ground for VCC2 Ground for VCC3 Ground for VCC4 4 PRELIMINARY DATASHEET January, 2000 VCC2 PRELIMINARY PIN DESCRIPTIONS (CONTINUED) Pin # 45 31 Signal Name MS1 MS2 I/O Type MODE SELECT MODE SELECT Description CONTROL (continued) ML2713 37 RECEIVE 8 17 MS3 CMO RSSI MODE SELECT O (CMOS) O(ANLG) Auto filter alignment disable. Tie to VCC4 to disable the on-chip filter alignment. Tie to ground for normal operation Receive A/D converter disable. Tie MS2 to VCC2 to disable the on-chip comparator and D/A converter in the receive mode. The D/A will still be enabled in the transmit mode. Tie to ground for normal operation Test mode control pin. Tie this pin to ground at all times Comparator output. Active in receive mode, this CMOS output that is referenced to VCC1 and has a nominal drive capability of 10mA Receive Signal Strength Indicator. This output has a nominal 1Volt range. The RSSI voltage decreases with increasing received signal level. The RSSI output has a 10k source impedance. It is referred to VCC2 DC time constant restore control. This input controls whether VDC is in the hold or acquire mode. A high on this pin puts VDC in the acquire mode, low puts VDC in the hold mode. This CMOS input is referred to VCC1 Six data inputs to Digital to Analog Converter. Inputs are not latched. DD5 is the most significant bit (MSB). DD4 DD3 DD2 DD1 DD0 is the least significant bit (LSB) 2LO input. These pins are connected to a differential input stage that is connected in a common base configuration. A pull-down resistor with a nominal value of 4k is required on each pin to bias this input. The pull down resistors are included on the ML2712 and do not need to be added if that chip is used. The nominal differential input impedance is 200W Receive 1IF input and transmit 2IF output. These pins are bi-directional I/O are connected to the receive input amplifier and transmit output amplifier. These pins have a nominal differential impedance of 340W set by on-chip resistances Transmit regulator output. This output of the on-chip regulator is enabled in transmit mode. The nominal output voltage of the regulator is 2.8V and drives current up to 25mA. The pin requires a de-coupling capacitor with a nominal value 100nF 46 SLICE I(CMOS) RECEIVE AND TRANSMIT 47 DD5 I (CMOS) 1 2 3 4 5 22 23 DD4 DD3 DD2 DD1 DD0 2LO 2LOB I I I I I (CMOS) (CMOS) (CMOS) (CMOS) (CMOS) I(ANLG) 26 27 1IF 1IFB I/O(ANLG) TRANSMIT 32 REG O (ANLG) FILTERS - RECEIVE 35 34 DPS DPSB ANLG Discriminator phase shift. These pins connect to the external discriminator phase shift filter. These pins have a nominal differential impedance of 600W set by on-chip resistors January, 2000 PRELIMINARY DATASHEET 5 PRELIMINARY PIN DESCRIPTIONS (CONTINUED) Pin # 38 40 Signal Name DISCO DFI1 I/O Type O (ANLG) I (ANLG) Description FILTERS - RECEIVE (continued) ML2713 41 42 43 44 DFO1 DFI2 DFO2 VDC O(ANLG) I (ANLG) O (ANLG) I/O (ANLG) Discriminator voltage output. This emitter follower provides a nominal drive capability of 100mA and a 200W source impedance Stage 1 data filter input. Two on-chip operational amplifiers, Stage 1 and Stage 2, can be configured to make a 5th order filter with the use of external resistors and capacitors Stage 1 data filter output. The nominal output drive capability is 100mA Stage 2 data filter input Stage 2 data filter output. The nominal output drive capability is 100mA DC time constant restore. An external capacitor sets the acquisition time constant of the DC receiver restoration circuits that feed the onchip receive comparator. In the acquisition mode the nominal impedance is 15kW. In hold mode the impedance is much higher, with a nominal leakage current less than 2nA. The SLICE input determines if VDC is in hold mode or in acquisition mode. This circuit ensures that the received signal is centered on the on-chip D/A converter by removing DC drift and transmitter and receiver frequency errors FILTERS - TRANSMIT AND RECEIVE 19 20 BPI BPIB I(FLTR) 2IF filter input. These pins connect to the receive image reject downconvert mixer in the receive mode, to the 6-bit D/A converter in the transmit mode, and to the 2LO input in the filter align mode. These pins have a nominal differential impedance of 450 ohms set by on-chip resistances 2IF filter output. These pins connect to the discriminator 0/90 phase shift circuit in the receive mode and alignment modes, and the transmit image reject up-convert mixer in the transmit mode 29 BPOB O(FLTR) 30 BPO NON-CONNNECTED PINS 11, 12, 36, 48 NC No connect These pins should be left open 6 PRELIMINARY DATASHEET January, 2000 PRELIMINARY FUNCTIONAL DESCRIPTION INTRODUCTION The ML2713 is the complete IF section of Micro Linear's 2.4GHz frequency hopping, half duplex transceiver chipset. The down conversion super-heterodyne receiver circuits contain an image reject down-convert mixer, a limiter, a discriminator, a receive data filter and a tracking A/D converter. The transmit circuits contain a 6bit D/A converter to digitally generate the IF, an anti alias filter and an image reject up-convert mixer. When combined with the ML2712 it enables design of high performance 2.4GHz half duplex radios with a fast switching time between receive and transmit modes. This is ideal for applications such as frequency hopping radios based on the IEEE 802.11 FH standard. The ML2713 has four modes of operation; 1) Filter Align, 2) Transmit, 3) Receive, and 4) Sleep. The operating modes of the ML2713 can be programmed through a 3 pin parallel interface. The ML2713 has three filters; the 2IF, discriminator, and data. Part of each filter is off chip, made up of external components, and part is on chip. The 2IF and discriminator filters have external inductors and capacitors configured to give a bandpass characteristic. In the Filter Align mode the ML2713 will adjust an on chip capacitor array that is in parallel with the external capacitance to correct for any tolerances in the external components values, thereby centering the bandpass filters to the correct frequency. In this way any production trimming of the filters is eliminated. The data filter is made up of on chip op-amps and off chip resistors and capacitors and does not need to be aligned or trimmed. In the Filter Align mode the ML2713 will adjust an on chip capacitor array that is in parallel with the external capacitance to correct for any tolerances in the external components values, thereby centering the bandpass filters to the correct frequency. In this way any production trimming of the filters is eliminated. The data filter is made up of on chip op-amps and off chip resistors and capacitors and does not need to be aligned or trimmed. In the Filter Align mode the ML2712 provides an 8MHz signal to the 2LO port of the ML2713. The 2IF filter will remove the fundamental of this signal, and pass the third harmonic at 24Mhz to the limiter and discriminator. This 24MHz should result in a zero signal at the discriminator output. If it does not, the alignment circuit will adjust the on chip capacitor array until a zero signal is achieved. In the Transmit mode, the ML2712 drives the 2LO port at 236MHz, and the 6-bit D/A converter is driven by a digitally generated FSK modulated signal from the baseband chip. Digital generation ensures that the ML2713 transmit modulation can be maximized without concern for variations over temperature and process that result from varying a VCO frequency directly. The D/A is typically driven at 32 MHz, and the fundamental component is 8MHz. The output of the D/A is connected to the 2IF filter (which is acting as an anti alias filter) where the 1st alias, which is 32MHz minus 8MHz or 24MHz, is passed. In this way the frequency of the digitally generated transmit IF is normally designed to equal the received 2IF, as will be described below. (This radio architecture allows for a fast receive-to-transmit switching speed, as no PLLs require re-tuning.) The output of the 2IF filter is connected to the transmit image reject up-convert mixer. This output mixes with the 2LO port 236MHz signal, and produces a 260MHz IF signal, which is sent to the ML2712. In addition, the transmit signal is passed through the SAW filter, which acts to select the wanted alias, remove the unwanted up conversion products, and perform part or all of the modulation filter functions. In the Receive mode, the ML2712 (in typical applications) drives a 1IF signal of 260MHz through the SAW filter and into the ML2713's 1IF port, and provides the same 236MHz signal to the 2LO input as above. The 1IF port gains up the signal to improve the noise figure, and sends the 1IF signal to the image reject down-convert mixer. The mixer produces a 260MHz minus 236MHz or 24MHz 2IF signal which is then filtered by the 2IF filter. This signal is gained up by the limiter stage, and sent to the discriminator. The discriminator will convert changes in the 2IF signal into a time varying signal which is then filtered by the data filter. Increases in the 2IF result in increasing voltage at the data filter output. The data filter in turn drives one input of the output comparator. The other input of the comparator is driven by the 6-bit D/A converter. If the output of the D/A converter is lower than the output of the data filter, the comparator output will drive high. If the output of the D/A converter is higher than the output of the data filter, the comparator output will drive low. In this way a tracking A/D whose outputs are the inputs to the D/A, and which follows the data filter output, is implemented. The offset errors of a transmitting source may be removed by a receiving ML2713 during preamble. During preamble, the Vdc capacitor can be put in the acquire mode, and the average level of the data filter output will appear across it. Once Vdc is put in the hold mode, and data begins, all levels out of the data filtered are referenced to the Vdc voltage, thereby removing any offsets in the data. In the Sleep mode, all circuits are powered off and the chip typically draws less than 1mA. January, 2000 PRELIMINARY DATASHEET 7 PRELIMINARY OPERATIONAL MODES MODE CONTROL The ML2713 has four modes of operation; 1) Filer Align, 2) Transmit, 3) Receive, and 4) Sleep. The operating modes of the ML2713 are programmed through the parallel interface made up of pins RS, TS, and LOE. These pins dynamically control the mode, and will enable the appropriate circuitry within 1msec of transitioning low. These control pins have on chip pull ups to VCC1, and are CMOS compatible. The relationship between the operating modes and control pins is shown in Table 1. ML2713 RS High TS High LOE High Mode of Operation Sleep Mode Filter Align Some Receiver Circuits Enabled, Auto Filter Alignment On Receive Mode Transmit Mode High High Low Low High High Low Low Low Table 1. Mode Control Logic FILTER ALIGN MODE The ML2713 has three filters; the 2IF, discriminator, and data. Part of each filter is off chip, made up of external components, and part is on chip. The 2IF and discriminator filters have external inductors and capacitors configured to give a bandpass characteristic. In the Filter Align mode the ML2713 will adjust an on chip capacitor array that is in parallel with the external capacitance to correct for any tolerances in the external components values, thereby centering the bandpass filters to the correct frequency. In this way any production trimming of the filters is eliminated. The data filter is made up of on chip op-amps and off chip resistors and capacitors and does not need to be aligned or trimmed. The Filter Align mode can be disabled by tying MS1 to VCC4. In the Filter Align mode the ML2712 provides an 8MHz signal to the 2LO port, pins 2LO and 2LOB, of the ML2713. The 2LO port is a low impedance common base stage such that the 2LO signal is not attenuated by the parasitic capacitance of the ML2712, ML2713, the interconnect between them, and their packages. The 2LO port then drives the 2IF filter, and a frequency divider. The frequency divider divides the 8MHz signal down to a 500kHz which then clocks a 7-bit up/down counter. The 2IF filter will remove the fundamental of this signal, and pass the third harmonic at 24Mhz through a 0/90 degree phase splitter to the limiters which in turn drive the discriminator. The output of the discriminator connects to a low pass filter, which then drives a comparator. This comparator looks to see if the discriminator output is greater than or less than zero volts differential. If the discriminator filter bandpass characteristic is centered properly on 24MHz, then the 24MHz input to the discriminator should result in a zero signal at the discriminator output. If the center frequency is too high, the discriminator output will go high. If the center frequency is too low, the discriminator output will go low. A high or a low here will signal the up/down counter to increment or decrement respectively. The up/down counter then drives three identical variable capacitor arrays, leading to changes in on chip capacitors. Two of these on chip capacitors are in parallel with off chip capacitors in the 2IF filter, and one is in parallel with the off chip capacitor in the discriminator filter. These will cancel any tolerance associated with the off chip components such that the center frequencies of both filters are properly centered. The 7 bit up/down counter begins at mid code of 128 levels, so there will be a maximum of 64 counts in either direction. Since the up/ down counter is clocked at the 500kHz frequency, the filters will align within 128msec. Therefore, in a WLAN system, the filters can be re-aligned every time the radio hops to a new frequency because it can do so in less time than it takes for the PLLs to settle. When switching from Filter Align mode, the up/down counter freezes, keeping the 7-bit result of the alignment fixed. Whenever the ML2713 is put in the Sleep mode, the up/down counter resets to the mid point. Therefore, if the Filter Align is being used, the filters must be realigned prior to receiving or transmitting. Active circuits in Filter Align Mode are shown in Figure 1. 8 PRELIMINARY DATASHEET January, 2000 PRELIMINARY OPERATIONAL MODES (CONTINUED) ML2713 RSSI 17 BPI BPIB BPO BPOB 19 20 30 29 DPSB DPS 34 35 DISCO DFI1 38 40 DFO1 41 DFI2 42 RSSI Limiter Receive Image Reject Down-Convert Mixer 1IF 1IFB 26 27 Rx I/P Amplifier Limiter VARIABLE CAPACITOR ARRAY 0/90 Discriminator Unity Gain Op Amp Unity Gain Op Amp 43 DFO2 0/90 Limiter LOWPASS FILTER 44 VDC Comparator DC REC 46 SLICE VCC1 VCC1 VCC2 VCC2 VCC2 VCC3 VCC4 REG 6 7 21 24 25 10 33 32 Tx O/P Amplifier Transmit Image Reject Up-Convert Mixer VARIABLE CAPACITOR ARRAY VARIABLE CAPACITOR ARRAY 7 -Bit Up/Down COUNTER 7 Comparator 8 CMO 0/90 6 BIT DAC 14 TS CONTROL TX VCO REGULATOR 0/90 FREQUENCY DIVIDER 15 LOE 13 RS 22 23 2LO 2LOB 9 16 18 28 39 5 4 3 2 1 47 45 31 37 GND GND GND GND GND DD0 DD1 DD2 DD3 DD4 DD5 MS1 MS2 MS3 Figure 1: Circuits Active in Filter Align Mode January, 2000 PRELIMINARY DATASHEET 9 PRELIMINARY OPERATIONAL MODES (CONTINUED) TRANSMIT MODE The transmitter is a Frequency Shift Key (FSK) transmitter in which the modulating signal is a digitally generated signal from the baseband chip. This signal in turn is passed through an anti alias filter, and mixed with an LO signal to produce a 260MHz 2IF signal which is then passed to the ML2712. The digitally generated 1st If is designed to be equal to the received 2IF. Such a radio architecture allows for rapid switching between receive and transmit modes because the PLLs and filters don't need to be re-tuned or aligned with each mode switch. In the Transmit mode, the ML2712 drives the 2LO port at 236MHz, and the 6-bit D/A converter pins DD5-DD0 are driven by a digitally generated FSK modulated signal from the baseband chip. Digital generation ensures that the transmit modulation can be maximized without concern for variations over temperature and process that result from varying a VCO frequency directly. The D/A is typically driven at 32 MHz, and the fundamental component is 8MHz. The output of the D/A is connected to the 2IF filter (which is acting as an anti alias filter) where the 1st alias, which is 32MHz minus 8MHz or 24MHz, is passed. The 2IF filter connects to a 0/90 degree phase splitter, which in turn connects to the transmit image reject up-convert mixer. The 2LO port connects to a 0/90 degree phase splitter, which in turn drives the other input of up-convert mixer. This phase splitter output mixes with the 2LO port 236MHz signal, and produces a 260MHz IF signal, which is sent to the ML2712. In addition, the transmit signal is passed through the SAW filter, which acts to select the wanted alias, remove the unwanted up conversion products, and perform part or all of the modulation filter functions. Transmitter Circuits The main circuits active during the transmit mode are: 6-bit D/A Converter The D/A converter on the ML2713 is a parallel interface, binary weighted D/A converter, with non-latched CMOS compatible inputs. The D/A can be driven at frequencies up to 40MHz. 2IF Filter The 2IF filter is an off chip inductor and capacitor filter which is shared between the receive and transmit circuits. IF Up-Converter The image reject transmit mixer consists of a 2IF input 0/ 90 degree splitter, 2LO input buffer a 2LO 0/90 degree splitter, two mixers and an output combiner. The 0/90 degree networks are passive and internal to the IC. The mixer performs optimally with a 1IF of 260MHz, and a ML2713 2IF of 24MHz. Under these conditions, the image rejection is typically better than 25dB. This is shown in Figure 2. The fundamental, at 260MHz, is at least 25dB greater than the image. The products at 8MHz intervals are unwanted aliases from the D/A converter. The differential 2LO input port has a nominal 200-Ohm impedance. The 2LO port is a low impedance common base stage such that the 2LO signal is not attenuated by the parasitic capacitance of the ML2712, ML2713, the interconnect between them, and their packages. Each input requires external pull down resistors of 4k to properly bias them. These resistors are internal to the ML2712, and do not need to be included if that device is used. 0 -10 Data Marker 1 Marker 2 -20 Power into 50W (dBm) -30 -40 -50 -60 -70 160 180 200 220 240 260 Frequency (MHz) 280 300 320 340 360 Figure 2. Typical Transmit Output Spectrum 10 PRELIMINARY DATASHEET January, 2000 PRELIMINARY OPERATIONAL MODES (CONTINUED) Transmit Output Buffer The transmit output buffer is a limiting amplifier. Its nominal output power at 260MHz is -12dBm, driving a 340W differential load. PSD (nVrms/rtHz) ML2713 100000 On IC Transmit Regulator which is enabled and disabled with the transmit circuits. The regulator powers external circuits such as a transmit VCO. The noise floor of the ML2713 is shown in the Figure 3. The regulator minimizes noise output above 5KHz to avoid introducing phase noise into the VCO. The transmitter circuits in the ML2713 are shown in Figure 4. 10000 1000 100 10 100 1000 10000 100000 1000000 10000000 Frequency (Hz) Figure 3. Transmit Regulator Noise Floor RSSI 17 BPI BPIB BPO BPOB 19 20 30 29 DPSB DPS 34 35 DISCO DFI1 38 40 DFO1 41 DFI2 42 RSSI Limiter Receive Image Reject Down-Convert Mixer 1IF 1IFB 26 27 Rx I/P Amplifier Limiter VARIABLE CAPACITOR ARRAY 0/90 Discriminator Unity Gain Op Amp Unity Gain Op Amp 43 DFO2 0/90 Limiter LOWPASS FILTER 44 VDC Comparator DC REC 46 SLICE VCC1 VCC1 VCC2 VCC2 VCC2 VCC3 VCC4 REG 6 7 21 24 25 10 33 32 Tx O/P Amplifier Transmit Image Reject Up-Convert Mixer VARIABLE CAPACITOR ARRAY VARIABLE CAPACITOR ARRAY 7 -Bit Up/Down COUNTER 7 Comparator 8 CMO 0/90 6 BIT DAC 14 TS CONTROL TX VCO REGULATOR 0/90 FREQUENCY DIVIDER 15 LOE 13 RS 22 23 2LO 2LOB 9 16 18 28 39 5 4 3 2 1 47 45 MS1 31 MS2 37 MS3 GND GND GND GND GND DD0 DD1 DD2 DD3 DD4 DD5 Figure 4. Circuits Active in Transmit Mode January, 2000 PRELIMINARY DATASHEET 11 PRELIMINARY OPERATIONAL MODES (CONTINUED) RECEIVE MODE The receiver on the ML2713 is a single conversion, superheterodyne receiver with on chip A/D conversion. Input signals from the ML2712 are down converted from 260MHz to 24MHz, filtered, limited, and then converted to DC voltages by the discriminator. A tracking A/D then converts the filtered discriminator output into a 6-bit digital word. In the Receive mode, the ML2712 (in typical applications) drives a 1IF signal of 260MHz through the SAW filter and into the ML2713's 1IF port, and provides the same 236MHz signal to the 2LO input as above. The 1IF port gains up the signal to improve the noise figure, and sends the 1IF signal to the image reject down-convert mixer. The 2LO port drives a 0/90 degree phase splitter whose output is connected the down-convert mixer. The mixer produces a 260MHz minus 236MHz or 24MHz 2IF signal which is then filtered by the 2IF filter. The output of the 2IF filter passes through another 0/90-degree phase splitter, and is gained up by the limiter stages, and sent to the discriminator. The discriminator will convert changes in the 2IF signal into a time varying signal, which is then filtered by the data filter. Increases in the 2IF result in RSSI 17 BPI BPIB BPO BPOB 19 20 30 29 ML2713 increasing voltage at the data filter output. The data filter in turn drives one input of the output comparator. The other input of the comparator is driven by the 6-bit D/A converter. If the output of the D/A converter is lower than the output of the data filter, the comparator output will drive high. If the output of the D/A converter is higher than the output of the data filter, the comparator output will drive low. The comparator output then drives an external up/down counter, counting up when the comparator output is high, and counting down when it is low. The outputs of the up/down counter can then drive the input of the 6-bit D/A converter. In this way a tracking A/D whose outputs are the inputs to the D/A, and which follows the data filter output, is implemented. This circuit samples at a rate of up to 20MHz, and yields a 5bit digitization of the signal. The offset errors of a transmitting source may be removed by a receiving ML2713 during preamble. During preamble, the Vdc capacitor can be put in the acquire mode, and the average level of the data filter output will appear across it. Once Vdc is put in the hold mode, and data begins, all levels out of the data filtered are referenced to the Vdc voltage, thereby removing any offsets in the data. An external capacitor connected to VDC sets the acquire time constant. DPSB DPS 34 35 DISCO DFI1 38 40 DFO1 41 DFI2 42 RSSI Limiter Receive Image Reject Down-Convert Mixer 1IF 1IFB 26 27 Rx I/P Amplifier Limiter VARIABLE CAPACITOR ARRAY 0/90 Discriminator Unity Gain Op Amp Unity Gain Op Amp 43 DFO2 0/90 Limiter LOWPASS FILTER 44 VDC Comparator DC REC 46 SLICE VCC1 VCC1 VCC2 VCC2 VCC2 VCC3 VCC4 REG 6 7 21 24 25 10 33 32 Tx O/P Amplifier Transmit Image Reject Up-Convert Mixer VARIABLE CAPACITOR ARRAY VARIABLE CAPACITOR ARRAY 7-Bit Up/Down COUNTER 7 Comparator 8 CMO 0/90 6 BIT DAC 14 TS LOE RS CONTROL TX VCO REGULATOR 0/90 FREQUENCY DIVIDER 15 13 22 23 2LO 2LOB 9 16 18 28 39 5 4 3 2 1 47 45 MS1 31 MS2 37 MS3 GND GND GND GND GND DD0 DD1 DD2 DD3 DD4 DD5 Figure 5. Circuits Active in Receive Mode 12 PRELIMINARY DATASHEET January, 2000 PRELIMINARY OPERATIONAL MODES (CONTINUED) RECEIVER CIRCUITS The main circuits active in the receive mode are: Image Reject Receive Mixer The image reject receive mixer consists of an input splitter, a 2LO input buffer, a 0/90 degree splitter, two mixers and a 0/90 degree IF combiner. The 0/90 degree networks are passive and internal to the IC. The design of the mixer is centered to give optimum performance with a 260MHz 1IF, 24MHz 2IF. Under these conditions the image rejection is typically better than 25dB. The differential 2LO input port has a nominal 200W impedance. The 2LO port is a low impedance common base stage such that the 2LO signal is not attenuated by the parasitic capacitance of the ML2712, ML2713, the interconnect between them, and their packages. Each input requires external pull down resistors of 4k to properly bias them. These resistors are internal to the ML2712, and do not need to be included if that device is used. 2IF FILTER The 2IF filter requires two external inductors and four external capacitors. This circuit is differential to minimize noise pick up in the 2IF circuit. This filter is auto aligned and is slaved to the discriminator. The ML2713 has been designed so that the same inductors and nearly the same capacitors can be used in both the discriminator and filter. It is recommended that the same inductors be used for the two circuits and that they be co-located on a reel of components. This will ensure minimal difference between the inductor values so that the filter and discriminator center frequencies are very similar, if not identical. Discriminator Phase Shift The discriminator performs the frequency to voltage conversion. The 0/90 degree phase shift is internal, but external components (one inductor and one capacitor) are required for the differential phase shift versus frequency (d/df). The center frequency of the d/df circuit is tuned by a capacitor array during Align Mode. This capacitor array has a nominal variation of 10pF, which for a 24MHz IF is sufficient to cope with a 10% total component tolerance (including temperature) in the external L and C (e.g., 5% capacitor & 5% inductor tolerance). Receiver Data Filter The receiver data filter is made up of two on chip unity gain op-amps, and off chip inductors and resistors configured as a 5th order filter. This filter does not need to be tuned or aligned. DC Restoration ML2713 The receiver is intended for use in TDMA radios. This requires rapid turn on of circuits, then the ability to remove the effect of DC offsets and the frequency offset of any received signal. DC restoration circuits on the ML2713 let the acquisition time be controlled by the value of an external capacitor. The DC restoration, during acquisition, forces the mean input voltage of the comparator to equal the mid-range voltage of the D/A. This is important as it minimizes the number of bits required in the tracking A/D. This DC restoration is achieved by estimating the mean level of the receive data filter output voltage and subtracting the difference between this and the D/A mid point. For small errors a single pole internal resistor and external capacitor is used to calculate the mean. When the error is large (e.g., when first enabling the receiver or at the start of a TDMA packet) a fast charge circuit speeds acquisition. Receive A/D External digital circuits can be used to make a tracking A/D converter by using the D/A and comparator. The digital circuits try to force the A/D output to be the same as the received signal input to the comparator. The digital circuits require an up/down counter, which will drive the D/A. This is shown in Figure 6. + - CMO 6 BIT D/A DD0 - DD5 COUNT UP/DOWN TO DEMODULATOR Figure 6. Tracking ADC Block Diagram When the receive signal at the comparator input voltage is greater than the D/A output voltage (inverting input to comparator), the comparator output (CMO) goes high, which increments the digital counter, which in turn increases the D/A output voltage. The circuit is clocked to keep the D/A output tracking the received signal. If the comparator output is low, then the counter decrements and reduces the D/A output voltage. This means the output of the D/A, or the counter output, is a digitized version of the received signal. This is shown in Figure 7. V RECEIVED SIGNAL D/A OUTPUT CMO SAMPLE CLOCK IN COUNTER TIME Figure 7. Receive Tracking A/D Signals Illustrated January, 2000 PRELIMINARY DATASHEET 13 PRELIMINARY OPERATIONAL MODES (CONTINUED) The D/A voltage (overlaid on the received signal) and the CMO output are relative to the sample clock of the external counter circuit. For some applications the counts and D/A output can be incremented and decremented in one LSB. However, if the rate of change of voltage is too high, then two or more counts/LSB may needed to keep track of the received signal. A typical application is where the update rate of the tracking A/D is 16MHz. RSSI The Received Signal Strength Indicator (RSSI) is generated by summing the signal measured in the 2IF limiter and the 1IF amplifier. Inclusion of the 1IF amplifier in the RSSI equation enables the maximum input level to be higher than with normal IF superheterodyne receiver ICs. The RSSI output is referenced to VCC2 and decreases with increasing signal level. See Figure 8. The RSSI output is compatible with the ML2712's RSSI A/D converter. The rise and fall times are typically 4msec which is ideal for performing clear channel assessment or preamble antenna diversity in a WLAN system. 3.1 3.0 2.9 2.8 VOLTS (V) ML2713 SLEEP MODE When going into sleep mode all circuits are powered off and the chip typically draws less than 1mA. Sleep mode also resets the alignment up/down counter to its midpoint. Test Mode Control MS1, MS2, and MS3 are CMOS logic inputs that activate on chip test modes. For normal operation, ground all of these pins. Each of these pins has a large value pull down resistor to ground. Tying MS1 to VCC4 will disable the Filter Align circuitry. Tying MS2 to VCC2 will disable the Receive A/D converter by shutting off both the 6-bit D/A converter and comparator in the receive mode. MS3 should remain tied to ground at all times. 2.7 2.6 2.5 2.4 2.3 2.2 2.1 -100 -80 -60 -40 -20 0 20 POWER (dBm) Figure 8. Typical RSSI Response with a 260MHz 1IF 14 PRELIMINARY DATASHEET January, 2000 PRELIMINARY ABSOLUTE MAXIMUM RATINGS Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. VCC1, VCC2 ............................................................ 6.0V VCC3, VCC4, VCC5, VCC6, VCC7 . -0.3 TO VCC1 + 0.3V GND .......................................................... -0.3V to 0.3V Junction Temperature .............................................. 150C Storage Temperature Range ...................... -65C to 150C Lead Temperature (Soldering, 10s) .......................... 260C ML2713 OPERATING CONDITIONS Commercial Temperature Range .................... 0C to 70C Extended Temperature Range ..................... -20C to 70C VCC Range .................................................. 3.3V to 5.5V Thermal Resistance (qJA) (Note 1) ...................... 100C/W ELECTRICAL CHARACTERISTICS Unless otherwise specified, VCC3, VCC4, VCC5, VCC6, VCC7 = 3.3V, VCC1, VCC = 5V, TA = Operating Temperature Range (Note 1) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS POWER CONSUMPTION TX RF AND RX RF All Circuits, Sleep Mode Supply Current DC Connected Filter Align Mode Receive Mode Transmit Mode INTERFACE LOGIC LEVELS Input High Output Low Input capacitance MODE CONTROL PINS Input High Output Low Input bias current Filter Alignment Time Connect to VCC1 Connect to GND All states From LOE asserted to aligned, 2IF 24MHz, 8MHz square wave cal tone on 2LO input Time from TR asserted to valid TX IF signal at output From RS asserted to the ADC input signal DC adjusted to the mid point of the ADC. CW 260MHz signal at -80dBm -1 120 VCC1 - 0.3 VCC1 GND GND +0.3 1 V V mA s (not tested) (The ML2713 has internal pullup resistors to VCC1) VCC1 0.7 -0.4 4 5.5 VCC1 0.3 V V pF 1 30 30 23 A mA mA mA Transmit Turn On Time Receive Turn On Time 2 10 s s January, 2000 PRELIMINARY DATASHEET 15 PRELIMINARY ELECTRICAL CHARACTERISTICS (CONTINUED) SYMBOL PARAMETER CONDITIONS MIN TYP RECEIVE COMPARATOR OUTPUT Output High Output Low Output Sink/Source RECEIVER AC ELECTRICAL SPECIFICATION (Note 3) F2IF F1IF 2LO 2IF Frequency 1IF Frequency 2LO Input Frequency 2LO Input Signal Level 1IF Input Impedance 2IF Input Impedance, IF Band Pass Filter Discriminator Phase Shift Circuit Input Noise Figure Irreducible Error Rate (Note 4) Preamble Settling Time 2Mb/s measured -60dBm -80dBm Signal, with IEEE 802.11 FH preamble, to within 10% of mid point 260MHz IF input at -50dBm, modulation rate (2FSK h = 0.32) for 3dB reduction in eye opening, compared to 100kHz modulation. 10 -5 10 Differential 200W, with 2kW pull down to GND on each pin Differential, 260MHz Differential, 24MHz Differential, 24MHz Nominal, modulated Nominal modulated 240 216 24 260 236 -23 340 450 600 7 10 VCC1 - 0.5 ML2713 MAX UNITS V 0.4 V mA MHz 280 256 MHz MHz dBm W W W dB BER s 3dB Modulation Bandwidth, from Input to ADC Output (Note 5) 500 700 kHz RSSI PERFORMANCE RSSI Rise Time. Noise to -10dBm into the IF Mixer. RSSI Fall Time, -10dBm to Noise into the IF Mixer. RSSI Linearity RSSI Maximum Voltage RSSI Minimum Voltage RSSI Sensitivity, Mid Range RSSI Maximum Signal into IC The highest signal at which the RSSI sensitivity is >50% nominal for the IC The lowest signal at which the RSSI sensitivity is >50% nominal No signal applied 7 20pF loading the RSSI output 20pF loading the RSSI output Differential gradient from -84dBm to -15dBm 4 4 1.0 VCC1 VCC1 - 1 10 -6 13 10 10 s s V V V mV/dB dBm RSSI Minimum Signal into IC -100 -85 dBm 16 PRELIMINARY DATASHEET January, 2000 PRELIMINARY ELECTRICAL CHARACTERISTICS (CONTINUED) SYMBOL PARAMETER CONDITIONS MIN TYP TRANSMITTER AC ELECTRICAL SPECIFICATION (Continued) Level of Image Frequency (2LO - F2IF) Product Spurious Output Level (DC to 600MHz) 2LO Breakthrough SNR of Transmit IF (Note 6) Relative to Transmit IF output Relative to Transmit IF output Relative to Transmit IF output Measured over 1MHz bandwidth, centered on 260MHz. CW 24MHz tone generated by DAC. -25 -25 -25 36 ML2713 MAX UNITS dBc dBc dBc dB Relative Accuracy Output Settling Time Signal to Noise and Distortion TXVCO REGULATOR (Note 7) Output voltage Current RMS Output Noise, >6000Hz. PSRR Turn On Time Turn Off Time To 90% of final voltage from transmit enable To 90% of final voltage from transmit enable 100 22 1 2 2.6 2.8 To within 1LSB At 24MHz alias, 1MHz bandwidth 10 36 0.5 LSB ns dB 3.1 25 V mA nV/OHz dB s s Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions. Note 2: qJA is measured with the component mounted on the Evaluation PCB in free air. Note 3: IF center frequency is 260MHz, 2IF center frequency is 24MHz, 2LO frequency is 236MHz. Note 4: Irreducible error rate derived from eye opening using a 4FSK input signal and measuring SNR > 32dB post digitization. Note 5: With recommended data filter component values. Note 6: SNR measured over a 1MHz bandwidth using a CW 24MHz tone. Note 7: 100nF decoupling capacitor required to ground. January, 2000 PRELIMINARY DATASHEET 17 PRELIMINARY PHYSICAL DIMENSIONS ML2713 Package: H48-7 48-Pin (7 x 7 x 1mm) TQFP 0.354 BSC (9.00 BSC) 0.276 BSC (7.00 BSC) 0 - 8 37 0.003 - 0.008 (0.09 - 0.20) 1 PIN 1 ID 0.276 BSC (7.00 BSC) 0.354 BSC (9.00 BSC) 25 0.018 - 0.030 (0.45 - 0.75) 13 0.020 BSC (0.50 BSC) 0.007 - 0.011 (0.17 - 0.27) 0.048 MAX (1.20 MAX) 0.037 - 0.041 (0.95 - 1.05) SEATING PLANE ORDERING INFORMATION PART NUMBER ML2713CH ML2713EH TEMPERATURE RANGE 0C to 70C -20C to 70C PACKAGE 48 Pin TQFP 48 Pin TQFP Micro Linear Corporation 2092 Concourse Drive San Jose, CA 95131 Tel: (408) 433-5200 Fax: (408) 432-0295 www.microlinear.com DS2713-01 18 PRELIMINARY DATASHEET January, 2000 |
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