National LMV243 handbook
Contents
1. 20029012 Time Mask Plot vs Time 900MHz OUTPUT POWER PA dBc TIME 100 us div 20029014 Time Mask Plot vs Time 1900MHz OUTPUT POWER PA dBm TIME 100ps div 20029016 www national com Application Information 1 0 The LMV243 as an RF Power Amplifier PA Control ler The LMV243 is a member of the power loop controller family of National Semiconductor for a quad band TDMA GSM solution The typical application diagram demonstrates a basic approach for implementing the quad band solution around the RF Power Amplifier The LMV243 contains a 50 dB Logamp detector and interfaces directly with the direc tional coupler The LMV243 Base Band control interface consists of 2 signals TX EN to bring the device out of shutdown status within 5us and VgAwp for the transmit burst characteristic determining the desired Output Power level The LMV243 gives maximum flexibility to meet GSM frequency and time mask criteria for many different single supply Power Ampli fier types like HBT or MesFET in GaAs SiGe or Si technol ogy This is accomplished by the Programmable Ramp char acteristic from the Base Band and the TX EN signal along with the external compensation capacitor Power consumption requirements are supported by the TX EN function which puts the entire chip into a Power Saving Mode to enable maximum standby and talk time while ensuring the output does not glitch exc2. 0 LMV243 1 Noui Semiconductor LMV243 May 2002 Single Channel Quad Band GSM Power Controller in micro SMD General Description The device is intended for use within an RF transmit power control loop in GSM mobile phones and supports GaAs HBT and bipolar RF single supply power amplifiers The circuit operates with a single supply from 2 7V to 3 3V The LMV243 contains an RF detector error amplifier ramp V I converter and output driver The LMV243 input interface consists of the RF input Ramp voltage and a digital input to perform the function Shutdown Transmit Enable The de vice will be active in the case TX EN HI otherwise the device goes into a low power consumption shutdown mode During shutdown the output will be in high impedance tri state A single external RC combination is used to provide stable operations that accommodates individual PA characteristics The LMV243 is offered in a 8 bump micro SMD 1 5mm x 1 5mm package This space savings package supports flex ible product placement almost anywhere in the circuitboard Typical Application Features Typical Unless Otherwise Noted m 50dB RF detection range typical m micro SMD package 1 5mm x 1 5mm x 0 995mm m Support of GaAs HBT bipolar technology m Quad band operation m Shutdown mode for Power Save in Rx slot m GPRS compliant m External loop compensation option m Accurate temperature compensation m Frequency range is
3. CLOCKWISE 5 XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH X2 IS PACKAGE LENGTH AND X3 IS PACKAGE HEIGHT REFERENCE JEDEC REGISTRATION MO 211 VARIATION BC ex 0 21 0 29 10 9058 ICA 89 BLAO8XXX Rev B LIFE SUPPORT POLICY NATIONAL S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION As used herein 1 Life support devices or systems are devices or 2 A critical component is any component of a life Systems which a are intended for surgical implant into the body or b support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness labeling can be reasonably expected to result in a significant injury to the user N www national com National Semiconductor Corporation Americas Email support nsc com National Semiconductor Europe National Semiconductor Asia Pacific Customer Response Group Tel 65 2544466 Fax 65 2504466 Email ap support nsc com National Semiconductor Japan Ltd Tel 81 3 5639 7560 Fax 81 3 5639 7507 Fax 49 0 180 530 85 86
4. RAMP Amplifier Vramp Deadband 170 210 250 mV 150 270 1 Reamp Transconductance Note 8 pa V lout Ramp Amplifier Output Current Vramp 2V pA RF Input Pin RF Input Power Range Note 5 20kQ 27pF between 50 dBm and Vcomp 5 dBV Logarithmic Slope Note 9 9900 2 20kQ 27pF between Voyr and 1800MHz 20kQ 27pF between and 1900MHz 20kQ 27pF between and Vcomp Logarithmic Intercept Note 9 900MHz 20kQ 27pF between and Vcomp 1800MHz 20kQ 27pF dBm between and Vcomp 1900MHz 20kQ 27pF between Voyr and Vcomp Rin DC Resistance Note 8 50 Q Cin Input Capacitance Note 8 0 5 pF Error Amplifier GBW Gain Bandwidth Product Note 8 7 6 MHz www national com Electrical Characteristics Unless otherwise specified all limits are guaranteed to 25 C Vpp 2 8 Boldface limits apply at temperature extremes Continued Symbol Parameter Condition Typ Max Units Vo Output Swing from Rail Sourcing lo 5mA 55 85 105 mE mV Sinking lo 5mA 45 75 lo Output Short Circuit Current Sourcing Vo 0V 225 145 E Note 3 Sinking Vo 2 8V 180 Output Referred Noise RF input 1800 MHz 700 nV JHz 10dBm 20kQ 27pF between and Vcomp Vout 1 4 set by Vaamp Note 8 SR Slew Rate E 11 V us Note 1 Absolute Maximum Ratings indicate limits beyond which damage to
5. Email europe support nsc com Deutsch Tel 49 0 69 9508 6208 English Tel 44 0 870 24 0 2171 Fran ais Tel 33 0 1 41 91 8790 National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications GINS 19 0 3u07 459 pueg peno jJeuueu2 ejBurs
6. a typical LMV243 quad band application The key components are The LMV243 One power amplifier usually for the GSM and PCN DCS bands Asingle two channel RF coupler is used instead of the two RF couplers A dual or quad band antenna Figure 1 shows the LMV243 s internal architecture The LMV243 contains an RF detector error amplifier a ramp V I converter and an output driver The LMV243 input interface consists of an RF input Ramp voltage and a digital input to perform the function Shutdown Transmit Enable 5 0 Analog and Digital Input Signals of the LMV243 The LMV243 has the following inputs Veamp IS an analog signal Base band DAC ramp signal TX_EN is a digital signal performs the function Shutdown Transmit Enable 5 1 Vnawp in signal The actual Vaamp input value sets the RF output power applying a certain mask shape to the Ramp in pin the output voltage level of the LMV243 adjusts the PA control voltage to get a power level out of the PA which is proportional to the single ramp voltage steps The recom mended VgAye voltage range for RF power control is 0 2V to 2 0V The Vaamp input will tolerate voltages from OV to without malfunction or damage The VgAyp input does not change the output level until the level reaches about 200mV So offset voltages in the DAC or amplifier supplying the Ramp signal will not cause excess RF signal output and increased powe
7. will decrease to zero and the integrator output will be held steady thereby settling the loop If capacitor charge is lost over time the gain will decrease However this leakage will quickly be corrected by additional integrator current from the newly reduced detector current ANTENNA COUPLER DETECTOR 20029037 FIGURE 2 PA Control Loop The key usefulness of this circuit lies in its immunity to changes in the PA gain control function From a static per spective at least the relationship between gain and gain control voltage is of no consequence to the overall transfer function Based upon the value of the integrator will set the gain control voltage to whatever level is necessary to produce the desired output level Any temperature depen dency in the gain control function will be eliminated Also non linearity s in the gain transfer function of the PA do not appear in the overall transfer function VS Vaamp The only requirement is that the gain control function of the PA be monotonic It is crucial however that the detector is tem perature stable The circuit as described so far has been designed to pro duce a constant output level for varying input levels The only requirement is for it to be temperature stable for input levels that correspond to the setpoint voltage Vaamp If the detector used has a higher dynamic range the circuit to precisely set PA output levels over a wide dynamic range T
8. 0029007 Gain and Phase vs Frequency Error Amplifier PHASE 10k 100k 1M 10M 100M FREQUENCY Hz 20029026 www national com Typical Performance Characteristics Unless otherwise specified 2 8V 25 C Continued lcomp VS Vramp 200 150 100 lcomp HA 0 0 5 1 1 5 2 2 5 3 V 20029027 Sourcing Current vs Output Voltage 180 Isource MA 02 03 08 13 18 23 28 Vout V 20029032 Output Voltage vs Sourcing Current 20029029 Pin VS Vaamp RF INPUT POWER dBm 20029028 Sinking Current vs Output Voltage MA 2 8 Vout V 20029033 Output Voltage vs Sinking Current V 20029030 www national com LMV243 Typical Performance Characteristics unless otherwise specified 2 8V 25 C Continued Closed Loop Pour PA vs Vaamp 900 2 Po dBc Closed Loop Pour PA vs Vaamp 1900MHz dBc 30 40 30 20 0 1 0 2 0 3 0 4 0 5 0 6 07 08 0 9 1 Veamp V 04 06 08 Veamp V 20029011 20029013 Time Mask Plot vs Time 1800MHz OUTPUT POWER PA dBm TIME 100ps div 20029015 Closed Loop Pour PA vs Vaamp 1800MHz 40 30 20 dBc
9. 3 Vpp B3 RF IN GND 20029035 www national com LMV243 Pin Descriptions Pin Name Description Power Supply Vpp Supply Voltage A2 C3 GND Power Ground Operation requires both pins be grounded Digital Inputs 2 TX EN A Logic High to enable device Analog Inputs B3 RF IN RF Input connected to the Coupler output with optional attenuation to measure the Power Amplifier PA Antenna RF power levels C1 RAMP IN Sets the RF output power level The useful input voltage range is from 0 2V to 1 8V although voltages from OV to Vpp are allowed Compensation Connects an external RC network between the Comp pin and the Output pin for an overall loop compensation and to control the closed loop frequency response Conventional loop stability techniques can be used in selecting this network such as Bode plots A good starting value for the RC combination will be C 68pF and 00 Output A rail to rail output capable of sourcing 25mA and sinking 25mA with less than 200mV total voltage drop over the specified temperature The output is free from glitches when enabled by TX EN When TX EN is low the output voltage is near GND Note 1 All inputs and outputs are referenced to GND pin A2 C3 2 For the digital inputs a LOW is lt 0 8V and a HIGH is gt 1 8V 3 RF power detection is performed internally in the LMV243 and only an RF power coupler with optional extra at
10. 450MHz to 2GHz Applications m GSM mobile phone m AGC for digital audio m TDMA RF control m Wireless LAN ANTENNA COUPLER 20029034 2002 National Semiconductor Corporation DS200290 www national com GINS 59 pueg peno LMV243 Absolute Maximum Ratings note 1 If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage Mounting Temperature Infrared or convection 20 sec 235 C Operating Ratings Note 1 Vpp GND 4V Max Nominal Supply Voltage 2 7N to 3 3V ESD Tolerance Note 2 Temperature Range 40 C lt T lt 85 C Human Body Model 2000V Vramp Voltage Range OV to 2V Machine Model 200V Vuowe Voltage Range OV to 2V Storage Temperature Range 65 C to 150 C RF Frequency Range 450MHz to 2GHz Junction Temperature Note 6 150 C Max Electrical Characteristics uniess otherwise specified all limits are guaranteed to T 25 C 2 8V Boldface limits apply at temperature extremes Parameter Condition Units Supply Current Vout Vpp GND 2 mA In Shutdown TX EN 0 8V Vout Voo GND 2 Logic Level to Enable Power V Logic Level to Disable Power V Ton Turn on Time from Shutdown 3 7 6 5 us 7 5 len Current into TX_EN Pin 0 108 5
11. agram NO MINIMUM NO MINIMUM 6us 28 285 No MINIMUM NOMINAL NOMINAL MINIMUM gt gt i 1 8V lt TX EN HIGH lt Vpp OV lt TX EN LOW lt 0 8V lt RAMP LOW lt ABOUT 0 2V OUTPUT PROPORTIONAL TO RAMP SHAPE OUTPUT 20029039 11 www national com V cAWT1 LMV243 Typical Test Setup Diagram RF SIGNAL PULSE SPECTRUM GENERATOR GENERATOR ANALYZER EVALUATION BOARD POWER METER 20029022 Equipment List RF Signal Generator Rohde amp Schwarz SMIQ 03B Pulse Generator Tektronix AFG2020 Spectrum Analyzer Rohde amp Schwarz FSP Power Meter HP E4418B with Powersensor HP E4413A Coupler Pasternack PE 2208 10 www national com 12 Physical Dimensions unless otherwise noted inches millimeters SYMM 0 250 SYMM eL 20 215 0 5 0 5 DIMENSIONS ARE IN MILLIMETERS x3 B i r H UMP LAND PATTERN RECOMMENDATION TOP SIDE COATING BUMP A1 CORNER SILICON d 0 235 0 205 8 Bump micro SMD NS Package Number BLAO8AAC X1 1 514 0 03mm X2 1 514 0 03mm 0 995 0 1mm NOTES UNLESS OTHERWISE SPECIFIED 1 EPOXY COATING 2 8n 37Pb EUTECTIC BUMP 3 RECOMMEND NON SOLDER MASK DEFINED LANDING PAD 4 PIN A1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION REMAINING PINS ARE NUMBERED COUNTER
12. essively during Power up and Power down 2 0 A Typical GSM Power Amplifier Controlled Loop This section should give a general overview and understand ing of how a typical Power Amplifier control loop works and how to get rid of some of the most common problems confronted in the design Figure 2 shows the generic com ponents of such a loop Beginning at the output of the GSM Power Amplifier PA this signal is fed usually via a direc tional coupler to a detector The output current of the detec tor Idet drives the inverting input of an op amp configured as an integrator A reference voltage drives the non inverting input of the op amp Finally the output of the op amp inte grator drives the gain control input of the power amplifier Now to examine how this circuit works we will assume initially that the output of the PA is at some low level and that the VgAyp voltage is at 1V The V I converter converts the Voltage to a sinking current This current can only come from the integrator capacitor C Current flow in this direction increases the output voltage of the integrator This voltage which drives the PA increases the gain we assume that the PA s gain control input has a positive sense that is increasing voltage increases gain The gain will increase thereby increasing the amplifier s output level until the detector output current equals the ramp current lg Ap At that point the current through the capacitor
13. mance vs RF Input Power at 10 20 ERROR dB 20029001 ERROR dB 20029008 900MHz 3 20KQ BETWEEN COMP AND OUT 2 6 2 85 C 22 l 1 S 25 C a 5 iud r4 5 18 04009 gt i 1 4 1 Vour 40 E van ae 06 OUT 4 70 60 50 40 30 20 10 0 10 20 RF INPUT POWER dBm 20029003 www national com LMV243 Typical Performance Characteristics Unless otherwise specified 2 8V 25 C Continued Vou1 Log Conformance vs RF Input Power at 1800MHz 3 3 20kQ BETWEEN COMP AND OUT 2 6 2 2 2 LI S 5 18 05 tr e 14 N 1 1 Y d 2 1 0 6 70 60 50 40 30 20 10 0 10 20 RF INPUT POWER dBm 20029004 Logarithmic Slope vs Frequency 1 65 1 70 1 75 1 80 1 85 SLOPE uA dB 1 90 1 95 2 00 0 5 1 1 5 2 2 5 3 FREQUENCY GHz 20029006 RF Input Impedance vs Frequency Resistance and Reactance IMPEDANCE 05 07 09 11 13 15 17 19 21 FREQUENCY GHz 20029031 Vout V amp GAIN dB Vour Log Conformance vs RF Input Power at 1900MHz 20kQ BETWEEN COMP AND OUT ERROR dB 0 6 70 60 50 40 30 20 10 0 10 20 RF INPUT POWER dBm 20029005 Logarithmic Intercept vs Frequency INTERCEPT dBm 0 5 1 1 5 2 2 5 3 FREQUENCY GHz 2
14. o do this the integrator reference voltage is varied The voltage range on Vramp follows directly from the detec tor s transfer function For example if the detector delivers 0 5V for an input of 7dBm a reference voltage of 0 5V will cause the loop to settle when the detector input is 7dBm the PA output will be greater than this amount by whatever coupling factor exists between PA and detector The dy namic range for the variable RF Pour case will be deter mined by the device in the circuit with the least dynamic range i e the gain control range PA or linear dynamic of detector www national com LMV243 Application Information continued The response time of this loop can be controlled by varying the RC time constant of the integrator Setting this at a low level will result in fast output settling but can result in ringing in the output envelope Settling the RC time constant high will give the loop good stability but will increase settling time Figure 3 shows a typical RF power control loop realized by using the National s LMV243 with integrated RF detector The RF signal from the PA passes through a directional coupler on its way to the antenna Directional couplers are characterized by their coupling factor which is in the 10dB to 30dB range typical 20dB Because the coupled output must in its own right deliver some power in this case to the detector the coupling process take
15. r consumption 6 0 Analog Output The Output is driven by a rail to rail amplifier capable of both sourcing and sinking It is able to source and sink 25mA with less than 200mV voltage drop from either rail over recom mended operating conditions Please refer to the typical performance characteristics The output voltage vs Sourcing Sinking current show the typical voltage drop from the rail over temperature The Sourcing Sinking current vs output voltage characteristics show typical charging discharging current which the output is capable of delivering at a current voltage The output is free from glitches when enabled by TX_EN When TX_EN is low the selected output voltage is fixed or near GND 7 0 Bandwidth Compensation To compensate and prevent the closed loop arrangement from oscillations and overshoots at the output of the RF detector error amplifier LMV243 the system can be adjusted by means of external RC components connected between Comp and Out Exact values heavily depend on PA charac teristics A good starting point is R 0Q and C 68pF The vast combinations of PA s and couplers available preclude a generalized formula for choosing these component Please contact National Semiconductor for additional assistance 8 0 Evaluation Board An evaluation board in available for the LMV243 Please contact your local distributor or National Semiconductor sales office www national com Typical Timing Di
16. s some power from the main output This manifests itself as insertion loss the inser tion loss being higher for lower coupling factors 3 0 Attenuation between coupler and LMV243 detector It is very important to choose the right attenuation between PA output and detector input i e the total of coupling factor and extra attenuation in order to achieve power control over the full output power range of the PA A typical value for the output power of the PA is 35 5 dBm for GSM and 30 dBm for PCS DCS In order to accommodate these levels into the LMV243 detection range the minimum required total attenu ation is about 35 dBm please refer to typical performance characteristics in the datasheet A typical coupler factor is 20dB An extra attenuation of about 15 dB should be in serted Extra attenuation Z between the coupler and the RF input of the LMV243 can be achieved by 2 resistors and Ry according to Figure 3 where Z 20 log Rin Rin Ry e g Ry 3000 results in an attenuation of 16 9dB To prevent reflection back to the coupler the impedance seen by the coupler should be 50Q The impedance Ro consists of Ry Ry Ro Rin Rx can be calculated with the formula Rx Ro Ry Rin Ry Rx 50 1 50 Ry e g with Ry 3000 Rin 500 Ry 580 ANTENNA COUPLER 20029038 FIGURE 3 PA Control Loop With Extra Attenuation 4 0 Components of a Power Amplifier Loop Figure 3 shows the basics of
17. tenuation has to be used Ordering Information Package Part Number Package Marking Transport Media NSC Drawing LMV243BL 01 1k Units Tape and Reel LMV243BLX 01 3k Units tape and Reel 8 Bump micro SMD Block Diagram DETECTOR 10dB 10dB 10dB 0294 10dB a 20029036 FIGURE 1 www national com 4 Typical Performance Characteristics Supply Current vs Supply Voltage 11 o SUPPLY CURRENT mA 2 5 2 7 2 9 3 1 3 3 3 5 SUPPLY VOLTAGE V 20029024 Vout and Log Conformance vs RF Input Power at Corners of GSM Vout V ERROR dB 20kQ BETWEEN COMP AND OUT 70 60 50 40 30 20 10 0 10 20 RF INPUT POWER dBm 20029002 Vou and Log Conformance vs Pin Corners of PCS 3 2 1850MHz 1990MHz4 4 e 5 d 4 2 20 BETWEEN COMP AND OUT 70 60 50 40 30 20 10 0 10 20 RF INPUT POWER dBm 20029009 Unless otherwise specified 2 8V Ty 25 C Vour and Log Conformance vs RF Input Power Vout V Fy 4 CNI 20kQ BETWEEN COMP AND OUT 70 60 50 40 30 20 10 0 RF INPUT POWER dBm Vout and Log Conformance vs RF Input Power at Corners of DCS Vout 900 2 10 20 1880MHz 20kQ BETWEEN COMP AND OUT 70 60 50 40 30 20 10 0 RF INPUT POWER dBm Vout Log Confor
18. the device may occur Operating Ratings indicate conditions for which the device is intended to be functional but specific performance is not guaranteed For guaranteed specifications and the test conditions see the Electrical Characteristics Note 2 Human body model 1 5kQ in series with 100pF Machine model 00 in series with 100pF Note 3 Shorting circuit output to either V or V will adversely affect reliability Note 4 Electrical Table values apply only for factory testing conditions at the temperature indicated Factory testing conditions result in very limited self heating of the device such that Ty TA No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self heating where Ty gt Note 5 Power in dBV dBm 13 when the impedance is 500 Note 6 The maximum power dissipation is a function of Tymax and TA The maximum allowable power dissipation at any ambient temperature is Tumax All numbers apply for packages soldered directly into a PC board Note 7 All limits are guaranteed by design or statistical analysis Note 8 Typical values represent the most likely parametric norm Note 9 Slope and intercept are calculated from graphs vs RF input Power where the current is obtained by division of the voltage by 20kQ Connection Diagram 8 Bump micro SMD A2 GND A1 COMP B1 OUT C1 VRAMP C2 TX EN Top View A
Download Pdf Manuals
Related Search
National LMV243 handbook