MGCT03 Transmit Circuit for TDMA/AMPS Features • • • • • DS5418 The MGCT03 circuit is designed for use in dual band, dual mode cellular 900MHz/PCS1900MHz mobile phones. It can be used for TDMA/AMPS. The MGCT03 is compatible with baseband and mixed signal interface circuits from Zarlink Semiconductor and other manufacturers. Transmit Modulator and Up-converter in TDMA/ AMPS Mobile Phones Absolute Maximum Ratings Supply voltage (VCC) 4V Control input voltage -0.6V to VCC + 0.6V -55˚C to +125˚C Storage temperature, TSTG Operating temperature -40˚C to 100˚C 150˚C Max Junction Temperature (TJ) CP2 CP1 CP0 27 28 1 December 2000 Ordering Information MGCT03/KG/QP1S MGCT03/KG/QP1T Dual RF Ports for 900MHz and 1900MHz AGC Amplifier with 90dB of Variable Gain, Fully Compensated for Temperature On-chip Active Filter. Removes the Requirement for External IF SAW Filter High Power 900MHz and 1900MHz Output Stages Quadrature Modulator Applications • ISSUE 1.0 System costs have been kept to a minimum by removing the requirement for an additional SAW filter in the transmit IF path. The AGC has been split between RF and IF sections to reduce noise and a low pass filter has been included before the IF variable gain amplifier to remove spurious products produced in the modulator. For CDMA systems the MGCT04 is recommended. LO 2GHz LO 1GHz 23 25 UHF OSCILLATOR INPUT SELECT CONTROL LOGIC Q IN Q IN I IN I IN 17 POWER CONTROL 18 7 6 RF VGA ALL PASS PHASE SHIFT NETWORK IF VGA ÷2/4 AND 20 1900 MHz OUTPUT DRIVER PHASE SHIFT 3 4 9 19 8 SSB MIXER RF190 RF190 RFDEG1 RFDEG2 RF900 RF900 900 MHz OUTPUT DRIVER VGA CONTROL OSC BUFFER VREF BIAS BUFFER 12 VHF OSC IN 11 VHF OSC BIAS 2 AGC Figure 1 - MGCT03 Block Diagram 1 MGCT03 CP2 AGC RF DEG1 RF DEG2 RF GND RF 1900 RF 1900 RF 900 RF 900 VCO GND VHF OSC BIAS VHF OSC IN VCO VCC NC 1 28 2 27 3 26 4 25 5 24 6 23 7 8 MGCT03 22 21 9 20 10 19 11 18 12 17 13 16 14 15 CP0 CP1 RF VCC LO 1GHz UHF GND LO 2GHz UHF VCC VCC I IN I IN GND Q IN Q IN GND QSOP28 Figure 2 - Pin Connections - top view Pin Signal Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 CP2 AGC RF DEG1 RF DEG2 RF GND RF 1900 RF1900 RF 900 RF 900 VCO GND VHF OSC BIAS VHF OSC IN VCO VCC NC GND Q IN Q IN GND I IN I IN VCC UHF VCC LO 2GHZ GND UHF LO 1GHZ RF VCC CP1 CP0 Function Control pin 2. See Tables 4 and 5 for function Control voltage for IF and RF variable gain amplifiers Connection to external inductor to control gain of power amplifiers Connection to external inductor to control gain of power amplifiers Ground connection to RF circuits Inverse output from 1900MHz differential output driver Output from 1900MHz differential output driver Inverse output from 900MHz differential output driver Output from 900MHz differential output driver Ground connection for VHF oscillator Switched bias voltage for external VHF oscillator Input from external VHF oscillator Positive supply to VHF oscillator Not used Ground connection Q input Q input Ground connection I input I input Positive supply connection Positive supply to UHF oscillator input buffers 2GHz local oscillator input Ground connection to UHF oscillator input buffers 1GHz local oscillator input Positive supply connection to RF circuits Control pin 1. See Tables 4 and 5 for function Control pin 0. See Tables 4 and 5 for function Table 1 - Pin Assignments 2 MGCT03 Electrical Characteristics Test conditions (unless otherwise stated): Tamb = -30°C to +70°C, VCC = 2·7V to 3·6V. UHF LO level = -15dBm (both bands), I, Q input = 1.4 volts p.p, test frequency = 849MHz (900 output) and 1910MHz (1900 output).These characteristics are guaranteed by either production test or design. They apply within the specified ambient temperature and supply voltage ranges unless otherwise stated. Value Characteristics Units Min. Supply current Sleep current Standby mode supply current Total supply current Standby to operating mode switching time Logic inputs Logic high voltage Logic low voltage Typ. Max. 8 118 75 10 152 10 µA mA mA µs VCC 0·8 V V VCC -0.6 0 Conditions All circuits off See Tables 4 and 5 Maximum power PCS mode Table 2 - DC Characteristics Value Characteristics Units Min. Typ. Max. 1.0 1.4 2.0 Conditions I and Q modulator I and Q input voltage level I and Q common mode voltage 1.2 Vpp Differential V I and Q differential input resistance 13.5 kΩ I and Q input bandwidth 2.5 MHz IF Vector offset 30 dB SSB rejection 30 dB VHF oscillator input and divider Input drive level 22 VHF oscillator bias voltage 40 70 1.2 mVrms From external VHF osc. via matching network V Variable gain amplifiers IF amp. operating frequency range 50 200 MHz RF amp. operating frequency range 750 2000 MHz Gain control range 60 dB Control voltage for minimum gain 0.1 V Control voltage for maximum gain AGC control voltage slope 33 2.6 V 60 dB/V Table 3 - AC Characteristics 3 MGCT03 Value Characteristics Units Min. Typ. Conditions Max. SSB mixer and UHF oscillator inputs SSB rejection 18 dB Cellular band LO input level -15 -10 -5 dBm From external UHF osc. via matching network PCS band LO input level -15 -10 -5 dBm From external UHF osc. via matching network Cellular band local oscillator input frequency. (LO 1GHz) 850 1100 MHz PCS band local oscillator input frequency (LO 2GHz) 1500 2150 MHz 900MHz RF output stage Specifications assume 50 ohm load driven via a matching network (Fig. 6) RF amplifier operating frequency range 824 849 MHz Output power +8 +19 dBm Note 1 ACPR (TDMA) -45 -30 dBc Pout = +8dBm, Offset = 30kHz -90 -60 dBc Pout = +8dBm, Offset = 60kHz +14 +19 dBm Note 2 -123 -121 dBm/ Hz ftx = 849 MHz Pout = +8dBm LO Leakage -18 dBc Note 2, Pout = +8dBm LO Leakage -14 dBm VCC = 3V, T = 25˙C Pout = +8dBm Image Rejection -18 dBc Note 2, Pout = +8dBm Other Spurii -20 dBm Note 3 Output power AMPS +10 Receive band noise (869 - 894MHz) Spurious Outputs 1900MHz RF output stage (PCS) RF amplifier operating frequency range Specifications assume 50 ohm load driven via a matching network (Fig. 5) 1850 1910 MHz Output power +8 +18 dBm Note 1 ACPR (TDMA) -45 -30 dBc Pout = +8dBm, Offset = 30kHz -90 -60 dBc Pout = +8dBm, Offset = 60kHz Receive band noise (1930 - 1990 MHz) -123 -121 dBm/ Hz ftx = 1910MHz, Pout = +8dBm Receive band noise (1930 - 1990MHz) -128 -125 dBm/ Hz ftx = 1910MHz, Pout = +3dBm VCC = 3V, T =25˙C Table 3 - AC Characteristics (continued) 4 MGCT03 Value Characteristics Units Min. Typ. Conditions Max. Spurious Outputs LO Leakage -18 dBc Note 2, Pout = =8dBm LO Leakage -14 dBm VCC = 3V, T = 25˙C Pout = +8dBm Image Rejection -18 dBc Note 2, Pout = +8dBm Other Spurii -20 dBm Note 3 Table 3 - AC Characteristics (continued) Notes: 1. V (I/Q) = 1.4V differential, VHF LO = 22mV rms, UHF LO = -15dBm, VGA = 2.6volts 2. V (I/Q) = 1.4 V dc differential, VHF LO = 22mV rms, UHF LO = -15dBm 3. Frequency range 10MHz to 10*ftx except Rx and Tx bands Circuit Description General The MGCT03 circuit is designed to provide the transmit function in dual band dual mode IS136/ AMPS mobile phones. The circuit contains the following blocks: 1. 2. 3. 4. Quadrature modulator Active IF low pass filter IF variable gain amplifier Single sideband mixer with external UHF oscillator inputs 5. RF variable gain amplifier 6. 900MHz and 1900MHz high power output driver stages 7. Power and mode control logic VHF VCO and the quadrature modulator giving a choice of possible intermediate frequencies. VHF Oscillator Input Oscillator Bias and Divider An external VHF oscillator circuit is AC coupled to the VHF oscillator input to drive the quadrature modulator. An oscillator bias circuit is included on the chip so that the external VHF oscillator transistor can be switched off using the control inputs. The bias voltage is switched off in either of the sieep conditions shown in Tables 4 and 5. Active Low Pass Filter The output from the quadrature modulator is passed to the active low pass filter which attenuates wide band noise and spurious outputs. Quadrature Modulator I and Q data from a baseband circuit such as the Zarlink Semiconductor MGCM01 or MGCM02 circuit is applied to the I and Q inputs of the quadrature modulator to produce the intermediate frequency by mixing with the local oscillator frequency from the VHF VCO. The control inputs can select either a divide by two or divide by four function between the 5 MGCT03 IF Variable Gain Amplifier The filtered IF signal is passed to the IF variable gain amplifier which in turn drives the single sideband mixer. An externally applied AGC control voltage allows the total circuit gain to be varied. The AGC action is split between the IF and RF portions of the circuit and an internal AGC control circuit processes the external AGC control voltage to drive both IF and RF variable gain amplifiers and provides a near linear control characteristic over the entire AGC range. Single Sideband Mixer The modulated IF signal is fed to the single sideband mixer which up-converts the IF to the RF frequency to be transmitted by mixing with an RF signal from one of two external UHF oscillator input pins, seiected by an on chip multiplexer. When 1900MHz mode is programmed with the VHF oscillator in divide by four mode (Tables 4 and 5), the polarity of the quadrature oscillator drive signals to the single sideband mixer are reversed, thus selecting a low side LO for 1900MHz PCS and high side for 900MHz. This technique allows a common IF and filter to be used for both 900MHz and 1900MHz bands. transmit path is avoided by providing the gain variation after the mixer. The variable gain amplifier control circuit ensures that the attenuation from maximum power is initially controlled by the RF variable gain stage thus reducing the noise contribution from the RF mixer. Output Drivers Separate output drive stages are provided for 900MHz and 1900MHz operation. A differential design is used for both amplifiers to improve power efficiency and to ease power supply decoupling problems. The 900MHz output stage provides a linear output of 8dBm for TDMA operation, but is over-driven in AMPS mode to obtain a typical output of 11dBm. In both power driver stages the DC current is backed off as the RF and IF gain is reduced, improving efficiency when less than maximum output power is required. Control Inputs Three control inputs are provided to select different operating modes for the chip; the various modes selected by the control pins are shown in Tables 4 and 5. RF Variable Gain Amplifier The SSB mixer is followed by the RF variable gain amplifier stage which provides about 23dB of the total gain variation. An additional SAW filter in the CP2 CP1 CP0 Function 0 0 0 Sleep mode. All circuits powered down 0 0 1 Quadrature modulator on. 1900MHz mode. Low side UHF LO. IF = VHF VCO ÷ 4 0 1 0 Quadrature modulator on. 900MHz mode. high side UHF LO. IF = VHF VCO ÷ 4 0 1 1 Standby mode. VHF oscillator input buffer, oscillator bias on. All other circuits powered down Table 4 - Control pin functions; VHF LO in divide-by-four mode CP2 CP1 CP0 Function 1 0 0 Sleep mode. All circuits powered down 1 0 1 Quadrature modulator on. 1900MHz mode. Low side UHF LO. IF = VHF VCO ÷ 2 1 1 0 Quadrature modulator on. 900MHz mode. high side UHF LO. IF = VHF VCO ÷ 2 1 1 1 Standby mode. VHF oscillator input buffer, oscillator bias on. All other circuits powered down Table 5 - Control pin functions; VHF LO in divide-by-two mode 6 MGCT03 VCC VCC INPUT 400k 600 800k OSC BIAS VREF 1.2V Figure 3a - Control inputs CP0, CP1 and CP2 Figure 3b - Oscillator bias buffer VCC VCC 550 2.7k 550 2.7k VOUT− VOUT+ VBIAS VBIAS 10k 10k VHF OSC INPUT 4k5 4k5 LO2GHz LO1GHz 100 100 4p 540µA 1.6mA Figure 3c - VHF oscillator input buffer RF900 V CC RF900 VBIAS Figure 3d - LO2GHz and LO1GHz oscillator inputs RF1900 RF1900 VCC VBIAS RFDEG2 RFDEG1 Figure 3e - 900MHz and 1900MHz outputs 10k I IN/Q IN VCC 80k VCC TO QUAD MOD 27k VBIAS 1 AGC IN 27k 80k I IN/Q IN TO QUAD MOD 44k VBIAS 2 2.0p 10k Figure 3f - I and Q inputs Figure 3g - AGC input 7 MGCT03 1GHz LO 2GHz LO CONTROL MICROPROCESSOR AGC POWER SAW AMPS FILTERS 1900MHz MATCHING NETWORK 1900MHz DUPLEXER 900MHz MATCHING NETWORK 900MHz DUPLEXER OSC CONTROL 28 2 27 3 26 4 25 5 24 6 23 7 8 VCC OSC BIAS FROM PLL 1 OSC OUT EXTERNAL VHF OSCILLATOR MGCT03 VCC VCC 22 21 9 20 10 19 11 18 12 17 13 16 14 15 MIXED SIGNAL INTERFACE CIRCUIT Figure 4 - Typical application circuit VCC VCC 50Ω SAW FILTER C3 1.2p C1 1.2p L1 15n 50Ω SAW FILTER L2 15n C3 1.5p C1 100p L1 68n PIN 9 PIN 7 L5 5.6n L4 5.6n L3 3.9n L5 22n L4 22n 8 C2 1.2p L3 22n PIN 8 PIN 6 C4 1.2p L2 68n C4 1.5p C2 100p NOTE L1 and L2 are required to provide a DC feed to the output pins and do not form part of the matching network NOTE L1 and L2 are required to provide a DC feed to the output pins and do not form part of the matching network Figure 5 - Typical 1900MHz output matching network Figure 6 - Typical 900MHz output matching network MGCT03 VCC 1 28 2 27 3 26 4 25 5 24 6 23 7 8 VCO CONTROL VOLTAGE VCC VCC 22 MGCT03 21 9 20 10 19 11 18 12 17 13 16 14 15 Figure 7 - Typical circuit showing connection of external VHF oscillator 10n 68p 2n2 3n3 Pin 25 2p a) UHF LO 1GHz 5p6 Pin 23 b) UHF LO 2GHz 4n7 39n Pin 25 8P Note: Test signal generator impedance is 50 ohms in each case c) VHF LO Figure 8 - LO Input Test Circuits 9 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. 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 and I2C System, provided that the system conforms to the I2C Standard Specification as defined by Philips. Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc. Copyright Zarlink Semiconductor Inc. All Rights Reserved. TECHNICAL DOCUMENTATION - NOT FOR RESALE