ML13155 Wideband FM IF

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1 Wideband FM IF SEMICONDUCTOR TECHNICAL DATA Legacy Device: Motorola MC355 The ML355 is a complete wideband FM detector designed for satellite TV and other wideband data and analog FM applications. This device may be cascaded for higher IF gain and extended Receive Signal Strength Indicator () range. 2 MHz Video/Baseband Demodulator Ideal for Wideband Data and Analog FM Systems Limiter for Cascade Operation Low Drain Current:.0 ma Low Supply Voltage: 3.0 to 6.0 V Operates to 300 Mhz Operating Temperature Range TA = 40 to +85 C MAXIMUM RATINGS Rating Pin Symbol Value Unit Power Supply Voltage, 4 VEE (max) 6.5 Vdc Input Voltage, 6 Vin.0 Vrms Junction Temperature TJ +50 C Storage Temperature Range Tstg 65 to +50 C 6 SO 6 = -5P PLASTIC PACKAGE CASE 5B (SO 6) CROSS REFERENCE/ORDERING INFORMATION PACKAGE MOTOROLA LANSDALE SO 6 MC355D ML355-5P Note: Lansdale lead free (Pb) product, as it becomes available, will be identified by a part number prefix change from ML to MLE. NOTE: Devices should not be operated at or outside these values. The Recommended Operating Conditions provide for actual device operation. PIN CONNECTIONS Figure. Representative Block Diagram Input 6 Input Decouple 2 5 Decouple Decouple 5 Buffered 3 2 Limiter 0 VCC VEE Buffer 5 2 Input Input 6 Three Stage Amplifier Detector 9 8 Quad Coil VCC2 Limiter Out Quad Coil VEE2 Limiter Out Quad Coil (Top View) 2 Decouple 4 Balanced s 5 Limiter NOTE: This device requires careful layout and decoupling to ensure stable operation. Page of 6

2 RECOMMENDED OPERATING CONDITIONS Rating Pin Symbol Value Unit Power Supply Voltage (TA= 25 C), 4 VEE 3.0 to 6.0 Vdc 40C TA 85 C 3, 6 VCC Grounded Maximum Input Frequency, 6 fin 300 MHz Ambient Temperature Range TJ 40 to + 85 C DC ELECTRICAL CHARACTERISTICS (TA = 25 C, no input signal.) Characteristic Pin Symbol Min Typ Max Unit Drain Current I ma (VEE = 5.0 Vdc) 4 I (VEE = 5.0 Vdc) 4 I Drain Current Total (see Figure 3), 4 ITotal ma (VEE = 5.0 Vdc) (VEE = 6.0 Vdc) (VEE = 3.0 Vdc) AC ELECTRICAL CHARACTERISTICS (TA = 25 C, fif = 0 MHz, VEE = 5.0 Vdc Figure 2, unless otherwise noted.) Characteristic Pin Min Typ Max Unit Input for 3 db Limiting Sensitivity, mvrms Differential Detector Voltage (Vin = 0 mvrms) 4, 5 mvp p (fdev = ± 3.0 MHz) (VEE = 6.0 Vdc) (VEE = 5.0 Vdc) (VEE = 3.0 Vdc) Detector DC Offset Voltage 4, mvdc Slope µa/db Dynamic Range db 2 µa (Vin = 00 µvrms) 2. (Vin =.0 mvrms) 2.4 (Vin = 0 mvrms) (Vin = 00 mvrms) 65 (Vin = 500 mvrms) 5 Buffer Maximum Current (Vin = 0 mvrms) madc Differential Limiter (Vin =.0 mvrms), (Vin = 0 mvrms) 80 Demodulator Video 3.0 db Bandwidth 4, 5 2 MHz Input Impedance (Figure 4), 0 MHz Rp (VEE = 5.0 Vdc) MHz Cp (C2=C5 = 00 p) 4.8 pf Differential IF Power Gain,, 0, 6 46 db mvrms NOTE: Positive currents are out of the pins of the device. Page 2 of 6

3 The ML355 consists of a wideband three stage limiting amplifier, a wideband quadrature detector which may be operated up to 200 MHz, and a received signal strength CIRCUIT DESCRIPTION indicator () circuit which provides a current output linearly proportional to the IF input signal level for approximately 35 db range of input level. Figure 2. Test Circuit Vin IN IN DEC DEC2 5 0n Video VCC DETO DETO2 VEE Buffer n.0k 0µ + VEE VEE Limiter VCC2 LIMO QUAD VEE2 LIMO2 QUAD n 330 Limiter 2 0µ + VEE p L L Coilcraft part number 46 09J08S 260n APPLICATIONS INFORMATION EVALUATION PC BOARD The evaluation PCB shown in Figures 9 and 20 is very versatile and is designed to cascade two ICs. The center section of the board provides an area for attaching all surface mount components to the circuit side and radial leaded components to the component ground side of the PCB (see Figures and 8). Additionally, the peripheral area surrounding the RF core provides pads to add supporting and interface circuitry as a particular application dictates. This evaluation board will be discussed and referenced in this section. LIMITING AMPLIFIER Differential input and output ports interfacing the three stage limiting amplifier provide a differential power gain of typically 46 db and useable frequency range of 300 MHz. The IF gain flatness may be controlled by decoupling of the internal feedback network at Pins 2 and 5. Scattering parameter (S parameter) characterization of the IF as a two port linear amplifier is useful to implement maximum stable power gain, input matching, and stability over a desired bandpass response and to ensure stable operation outside the bandpass as well. The ML355 is unconditionally stable over most of its useful operating frequency range; however, it can be made unconditionally stable over its entire operating range with the proper decoupling of Pins 2 and 5. Relatively small decoupling capacitors of about 00 pf have a significant effect on the wideband response and stability. This is shown in the scattering parameter tables where S parameters are shown for various values of C2 and C5 and at VEE of 3.0 and 5.0 V DC. Page 3 of 6

4 I and I 4, TOTAL DRAIN CURRENT (madc) I 4 and I Total, DRAIN CURRENT (madc) Figure 3. Drain Current versus Supply Voltage TA = 25 C ITotal = I4 + I 5.0 Vdc OUTPUT ( A) 2 µ I, 40 dbm VEE, SUPPLY VOLTAGE ( Vdc) Figure 5. Total Drain Current versus Ambient Temperature and Supply Voltage I4 VEE = 6.0 Vdc 3.0 Vdc TA, AMBIENT TEMPERATURE ( C) TYPICAL PERFORMANCE AT TEMPERATURE (See Figure 2. Test Circuit) DRAIN CURRENT (madc) I 4 and I, Figure 4. versus Frequency and Input Signal Level 0 dbm 0 dbm 20 dbm 30 dbm VEE = 5.0Vdc f, FREQUENCY (MHz) Figure 6. Detector Drain Current and Limiter Drain Current versus Ambient Temperature f = 0 MHz VEE = 5.0 Vdc I TA, AMBIENT TEMPERATURE ( C) I4 OUTPUT ( µ A) I, Figure. versus Ambient Temperature and Supply Voltage VEE = 6.0 Vdc VEE = 5.0 Vdc VEE = 3.0 Vdc OUTPUT ( µ A) I, Figure 8. versus Input Signal Voltage (Vin at Temperature) TA = + 85 C + 25 C 40 C TA, AMBIENT TEMPERATURE ( C) Vin, INPUT VOLTAGE (mvrms) Page 4 of 6

5 DIFFERENTIAL DETECTOR OUTPUT VOLTAGE (Pins 4, 5), (mv pp ) Figure 9. Differential Detector Voltage versus Ambient Temperature and Supply Voltage VEE = 6.0 Vdc Vdc Vdc TA, AMBIENT TEMPERATURE (C) DIFFERENTIAL LIMITER OUTPUT VOLTAGE (Pins, 0), (mvrms) Figure 0. Differential Limiter Voltage versus Ambient Temperature (Vin = and 0 mvrms) Vin = 0 mvrms f = 0 MHz VEE = 5.0 Vdc TA, AMBIENT TEMPERATURE (C) Vin =.0 mvrms DIFFERENTIAL DETECTOR OUTPUT (mv pp ) Figure A. Differential Detector Voltage versus Q of Quadrature LC Tank Vin = 30 dbm VEE = 5.0 Vdc fc = 0 MHz fmod =.0 MHz (Figure 6 no external capacitors between Pins, 8 and 9, 0) Q OF QUADRATURE LC TANK Figure. f dev = ± 6.0 MHz ± 5.0 MHz ±4.0 MHz ± 3.0 MHz ± 2.0 MHz ±.0 MHz ) DIFFERENTIAL DETECTOR OUTPUT (mv pp Figure B. Differential Detector Voltage versus Q of Quadrature LC Tank Vin = 30 dbm VEE = 5.0 Vdc fc = 0 MHz fmod =.0 MHz (Figure 6 no external capacitors between Pins, 8 and 9, 0) Q OF QUADRATURE LC TANK f dev = ± 6.0 MHz ± 5.0 MHz ± 4.0 MHz ± 3.0 MHz ± 2.0 MHz ±.0 MHz OUTPUT VOLTAGE, (Vdc) Figure 2. Voltage versus IF Input VEE = 5.0 Vdc fc = 0 MHz (See Figure 6) Capacitively coupled interstage: no attenuation IF INPUT, (dbm) 5 db Interstage Attenuator S+N, N (db) Figure 3. S+N, N versus IF Input S+N 50 fc = 0 MHz N fmod =.0 MHz 60 fdev = ± 5.0 MHz VEE = 5.0 Vdc IF INPUT (dbm) Page 5 of 6

6 In the S parameters measurements, the IF is treated as a two port linear class A amplifier. The IF amplifier is measured with a single ended input and output configuration in which the Pins 6 and are terminated in the series combination of a 4 resistor and a 0 nf capacitor to VCC ground (see Figure 4. S Parameter Test Circuit). The S parameters are in polar form a the magnitude (MAG) and angle (ANG). Also listed in the tables are the calculated values for the stability and factor (K) and the Maximum Available Gain (MAG). These terms are related in the following equations: K = ( IS I2 IS22I2 + I I2)/(2 I S2 S2 I) where: I I = I S S22 S2 S2 I. MAG = 0 log I S2 I/I S2 I + 0 log I K (K2 )/2 I where: K >. The necessary and sufficient conditions for unconditional stability are given as K>: B = + I S I2 I S22 I2 I I2 > 0 Figure 4. S Parameter Test Circuit IF Input SMA C2 2 IN DEC IN2 DEC2 6 5 C5 4 3 VCC VEE 4 VEE 4 DETO Buffer 3 00n 0µ + 5 DETO VCC2 LIMO QUAD VEE2 LIMO2 QUAD2 0 9 SMA IF Page 6 of 6

7 S Parameters (VEE = 5.0 Vdc, TA = 25 C, C2 and C5 = 0 pf) Frequency Input S Forward S2 Rev S2 S22 K MAG MHz MAG ANG MAG ANG MAG ANG MAG ANG MAG db S Parameters (VEE = 5.0 Vdc, TA = 25 C, C2 and C5 = 00 pf) Frequency Input S Forward S2 Rev S2 S22 K MAG MHz MAG ANG MAG ANG MAG ANG MAG ANG MAG db Page of 6

8 S Parameters (VEE = 5.0 Vdc, TA = 25 C, C2 and C5 = 680 pf) Frequency Input S Forward S2 Rev S2 S22 K MAG MHz MAG ANG MAG ANG MAG ANG MAG ANG MAG db S Parameters (VEE = 3.0 Vdc, TA = 25 C, C2 and C5 = 0 pf) Frequency Input S Forward S2 Rev S2 S22 K MAG MHz MAG ANG MAG ANG MAG ANG MAG ANG MAG db Page 8 of 6

9 S Parameters (VEE = 3.0 Vdc, TA = 25 C, C2 and C5 = 00 pf) Frequency Input S Forward S2 Rev S2 S22 K MAG MHz MAG ANG MAG ANG MAG ANG MAG ANG MAG db S Parameters (VEE = 3.0 Vdc, TA = 25 C, C2 and C5 = 680 pf) Frequency Input S Forward S2 Rev S2 S22 K MAG MHz MAG ANG MAG ANG MAG ANG MAG ANG MAG db Page 9 of 6

10 DC BIASING CONSIDERATIONS The DC biasing scheme utilizes two VCC connections (Pins 3 and 6) and two VEE connections (Pins 4 and ). VEE (Pin 4) is connected internally to the IF and circuits negative supply bus while the VEE2 (Pin ) is connected internally to the quadrature detector s negative bus. Under positive ground operation, this unique configuration offers the ability to bias the and IF separately from the quadrature detector. When two ICs are cascaded as shown in the 0 MHz application circuit and provided by the PCB (see Figures and 8), the first ML355 is used without biasing its quadrature detector, thereby saving approximately 3.0 ma. A total current of.0 ma is used to fully bias each IC, thus the total current in the application circuit is approximately ma. Both VCC pins are biased by the same supply. VCC (Pin 3) is connected internally to the positive bus of the first half of the IF limiting amplifier, while VCC2 is internally connected to the positive bus of the, the quadrature detector circuit, and the second half of the IF limiting amplifier (see Figure 5). This distribution of the VCC enhances the stability of the IC. CIRCUITRY The circuitry provides typically 35 db of linear dynamic range and its output voltage swing is adjusted by selection of the resistor from Pin 2 to VEE. The slope is typically 2. µa/db; thus, for a dynamic range of 35 db, the current output is approximately 4 µa. A 4 k resistor will yield an output voltage swing of 3.5 Vdc. The buffer output at Pin 3 is an emitter follower and needs an external emitter resistor of 0 k to VEE. In a cascaded configuration (see circuit application in Figure 6), only one of the Buffer outputs (Pin 3) is used; the outputs (Pin 2 of each IC) are tied together and the one closest to the VEE supply trace is decoupled to VCC ground. The two pins are connected to VEE through a 4 k resistor. This resistor sources a current which is proportional to the signal level at the IF input; typically.0 mvms ( 4 dbm) is required to place the ML355 into limiting. The measured output voltage response of the application circuit is shown in Figure 2. Since the current output is dependent upon the input signal level at the IF input, a careful accounting of filter losses, matching and other losses and gains must be made in the entire receiver system. In the block diagram of the application circuit shown below, an accounting of the signal levels at points throughout the system shows how the response in Figure 2 is justified. Block Diagram of 0 MHz Video Receiver Application Circuit Input 45 dbm 0 dbm 2 dbm 32 dbm 4 dbm Minimum Input to Acquire Level:.26 mvrms µvrms 5 µvrms 5 µvrms.0 mvrms Limiting in ML355 IF Input Saw Filter :4 Transformer 25 db 2.0 db (Insertion Loss) (Insertion Loss) 6 ML db Gain 0 5 db (Attenuator) 6 ML db Gain CASCADING STAGES The limiting IF output is pinned out differentially, cascading is easily achieved by AC coupling stage to stage. In the evaluation PCB, AC coupling is shown, however interstage filtering may be desirable in some application. In which case, the S parameters provide a means to implement a low loss interstage match and better receiver sensitivity. selecting the insertion loss. A network topology shown below may be used to provide a bandpass response with the desired insertion loss. Network Topology Where a linear response of the output is desired when cascading the ICs, it is necessary to provide at least 0 db of interstage loss. Figure 2 shows the response with and without interstage loss. A 5 db resistive attenuator is an inexpensive way to linearize the response. This has its drawbacks since it is a wideband noise source that is dependent upon the source and load impedance and the amount of attenuation that it provides. A better, although more costly, solution would be a bandpass filter designed to the desired center frequency and bandpass response while carefully µ 6 Page 0 of 6

11 QUADRATURE DETECTOR The quadrature detector is coupled to the IF with internal 2.0 pf. capacitors between Pins and 8 and Pins 9 and 0. For wideband data applications, such as FM video and satellite receivers, the drive to the the detector can be increased with additional external capacitors between these pins, thus, the recovered video signal level output is increased for a given bandwidth (see Figure A and Figure B). The wideband performance of the detector is controlled by the loaded Q of the LC tank circuit. The following equation defines the components which set the detector circuit's bandwidth: Q=RT/XL () where: RT is the equivalent shunt resistance across the LC Tank and XL is the reactance of the quadrature inductor at the IF frequency (XL = 2πfL). The inductor and capacitor are chosen to form a resonant LC Tank with the PCB and parasitic device capacitance at the desired IF center frequency as predicted by: fc = (2π (LCp)) (2) where: L is the parallel tank inductor and Cp is the equivalent parallel capacitance of the parallel resonant tank circuit. The following is a design example for a wideband detector at 0 MHz and a loaded Q of 5. The loaded Q of the quadrature detector is chosen somewhat less than the Q of the IF bandpass. For an IF frequency of 0 MHz and an IF bandpass of 0.9 MHz, the IF bandpass Q is approximately 6.4. Example: Let the external Cext = 20 pf. (The minimum value here should be greater than 5 pf making it greater than the internal device and PCB parasitic capacitance. Cint 3.0 pf). Cp = Cint + Cext = 23 pf Rewrite Equation 2 and solve for L: L = (0.59)2/(Cp fc2) L = 98 nh, thus, a standard value is chosen. L = 0.22 µh (tunable shielded inductor). The value of the total damping resistor to obtain the required loaded Q of 5 can be calculated by rearranging Equation : RT = Q(2πfl) RT = 5(2π)(0)(0.22) Ω The internal resistance, Rint between the quadrature tank Pins 8 and 9 is approximately 3200 Ω and is considered in determining the external resistance, Rext which is calculated from: Rext = ((RT)(Rint))/(Rint RT) Rext = 50, thus, choose the standard value Rext = 560 Ω SAW FILTER In wideband video data applications, the IF occupied bandwidth may be several MHz wide. A good rule of thumb is to choose the IF frequency about 0 or more times greater than the IF occupied bandwidth. The IF bandpass filter is a SAW filter in video data applications where a very selective response is needed (i.e., very sharp bandpass response). The evaluation PCB is laid out to accommodate two SAW filter package types: ) A five leaded plastic SIP package. Recommended part numbers are Siemens X6950M which operates at 0 MHz; 0.4 Mhz 3 db passband, X695M (X252.8) which operates at 0 Mhz; 9.2 MHz 3 db passband; and X6958M which operates at 0 MHz, 6.3 MHz 3 db passband, and 2) A four leaded TO 39 metal can package. Typical insertion loss in a wide bandpass SAW filter is 25 db. The above SAW filters require source and load impedances of 50 Ω to assure stable operation. On the PC board layout, space is provided to add a matching network, such as a :4 surface mount transformer between the SAW filter output and the input to the ML355. A :4 transformer, made by Coilcraft and Mini Circuits, provides a suitable interface (see Figures 6, and 8). In the circuit and layout, the SAW filter and the ML355 are differentially configured with interconnect traces which are equal in length and symmetrical. This balanced feed enhances RF stability, phase linearity, and noise performance. Page of 6

12 Det Out Figure 5. Figure 5. Simplified Internal Circuit Schematic Decouple Buffer VCC LIM Out Quad Coil LIM Out VCC k.6k 2.0p 2.0p 0p 8.0k.0k.0k 8.0k Bias Bias.0p 6 4 Input Input VEE VEE 2 Page 2 of 6

13 Figure 6. 0 MHz Video Receiver Application Circuit If Input :4 2 SAW Filter SAW Filter is Siemens Part Number X6950M ML355 IN IN2 6 00p 2 DEC DEC2 5 00p 0k 3 4 VCC DETO VEE Buffer 4 3 0n 4k 00n 5 DETO2 2 6 VCC2 LIMO VEE2 LIMO2 0 0n 8 QUAD QUAD µ VEE ML355 IN IN2 6 00p 2 DEC DEC2 5 00p Detector 00n 00n 33p 33p.0k.0k 2.0p VCC DETO DETO2 VCC2 LIMO QUAD VEE Buffer VEE2 LIMO2 QUAD n 0n 2.0p 0µ + VEE p L 0.22µ L Coilcraft part number 46 08J08S Page 3 of 6

14 Legacy Applications Information Figure. Component Placement (Circuit Side) Figure 8. Component Placement (Ground Side) Page 4 of 6

15 Legacy Applications Information Figure 9. Circuit Side View 4.0" 4.0" Figure 20. Ground Side View Page 5 of 6

16 OUTLINE DIMENSIONS SO 6 = -5P (ML355-5P) PLASTIC PACKAGE CASE 5B (SO 6) SEATING PLANE 6 G A 9 8 B P T D6 PL K 0.25 (0.00) M T B S A S C 8 PL 0.25 (0.00) M B M M R X 45 F J NOTES:. DIMENSIONING AND TOLERANCING PER ANSI Y4.5M, CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.5 (0.006) PER SIDE. 5. 5B 03 IS OBSOLETE, NEW STANDARD 5B 04. DIM A B C D F G J K M P R MILLIMETERS MIN MAX BSC BSC INCHES MIN MAX Lansdale Semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. Lansdale does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others. Typical parameters which may be provided in Lansdale data sheets and/or specifications can vary in different applications, and actual performance may vary over time. All operating parameters, including Typicals must be validated for each customer application by the customer s technical experts. Lansdale Semiconductor is a registered trademark of Lansdale Semiconductor, Inc. Page 6 of 6

NOT RECOMMENDED FOR NEW DESIGNS

NOT RECOMMENDED FOR NEW DESIGNS Order this document by MC355/D The MC355 is a complete wideband FM detector designed for satellite TV and other wideband data and analog FM applications. This device may be cascaded for higher IF gain