SL2009KG

SL2009 Dual stage IF amplifier for cable tuners DS5507 ISSUE 1.4 March 2002 Features • • • • • Single chip solution for tuner IF gain and AGC Contains 34 dB of AGC shared between two AGC stages Design optimised for high signal handling with low inter-modulation spurious generation I/O ports optimised to interface with standard SAW filters ESD protection (Normal ESD handling procedures should be observed) O rdering Information S L2009/KG/NP1T (Tape and Reel) SL2009/KG/NP1S (Tubes) The devices includes two stages of IF gain which are both optimised to interface with inter-stage filters. Both stages contain independent AGC facility, and the first stage contains a level detect for control of the tuner AGC. Applications • • Cable Network interface modules and tuners Data communications systems IFIP IFIPB VCCIF AGC2 IFOP 1 16 VCCSAW SDRIVEOP SDRIVEOPB AGCOUT AGC1 SDRIVEIP SDRIVEIPB Description The SL2009 is a dual IF amplifier intended for application in cable tuners, and integrates all of the IF gain and AGC required to deliver 1Vp-p in a standard tuner configuration. VEE IFOPB VEE 8 9 AGCBIAS NP16 F igure 1 - Pin allocation (12) AGC1 AGC SENDER AGC SENDER AGCBIAS (9) AGCOUT (13) (11) SDRIVEIP (10) SDRIVEIPB (15) SDRIVEOP SAW Driver VccSAW (16) Vee (6,8) VccIF (3) (14) SDRIVEOPB (1) IFIP (2) IFIPB AGC IFOP (5) IFOPB (7) (4) AGC2 SENDER F igure 2 - Block diagram 1 SL2009 Characteristics SAWF driver stage Input operating range Input NF, referred to 2kΩ OPIP3 Gain IF Amplifier stage Input operating range Input NF, referred to 2 kΩ OPIP3 Gain Table 1 - Quick reference data 30 - 50 6 8 20 - 40 MHz dB dBV dB 30 - 50 4 4 14 - 28 MHz dB dBV dB Units Functional Description The SL2009 is an IF amplifier intended primarily for application in cable tuners, and requiring a minimum external component count to integrate the IF gain, AGC facility and level detect. The pin allocation is contained in figure (1) and the block diagram in figure (2) different AGCBIAS conditions is contained in figure (4). See figures (5) and (6) for SAW amplifier input and output impedances respectively. I F amplifier section In normal application the output of the SAW filter is coupled differentially to the input preamplifier of the IF amplifier, which presents a differential 2 kΩ 3 pF load to the SAW filter and is optimised for both signal handling and NF. See figure (8) for IF amplifier input impedance. The input preamplifier, then interfaces with the variable gain stage which is under control of the second AGC sender and this provides for 20 dB of gain control. The typical AGC characteristic is contained in figure (7) The AGC output is then connected to the output driver stage, which presents a low differential output impedance, see figure (9) and is optimised for output signal handling. The typical key performance data at 5V Vcc and 25 deg C ambient are shown in the table entitled 'QUICK REFERENCE DATA'. SAWF driver stage In normal application the IF output of the tuner, which is typically in the region of 30-50 MHz, is interfaced to input preamplifier of the SAWF driver stage, which is optimised for both signal handling and NF referred to 2 kΩ. The input preamplifier interfaces with the variable gain stage, which is under control of the first AGC sender and provides for 14 dB of gain control. The typical gain characteristic is contained in figure (3). The AGC stage then interfaces with the output buffer amplifier, which presents a balanced 50 Ω drive to the IF SAW filter and offers high signal handling to minimise intermodulation distortions. The SAWF amplifier also incorporates a level detect block whose output AGCOUT, can be used to control the gain of the SAWF amplifier or other gain stages in front of the SL2009. This AGC characteristic can be set up by a "current set" resistor connected between the AGCBIAS input and Vee. The typical characteristic curve for AGC set, output level under 2 SL2009 SAWF Driver AGC Slope, (Vcc = 5v, 25'C) 35 30 25 Gain (dB) 20 15 10 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 AGC Voltage (V) Figure 3 - Typical SAWF driver stage AGC characteristic Closed Loop SAWF Driver OP vs RAGC (Vcc = 5v, 25'C) 114 112 110 O/P Level (dBuV) 108 106 104 102 100 0 1 2 3 4 5 RAGC (Kohm) Figure 4 - AGCOUT characteristic versus AGCBIAS resistor 3 SL2009 CH1 S11 1 U FS Ω 8 Feb 2001 16:27:29 Ω PRm Cor Avg 16 Normalised to 2 K 1 1: 2.3 K - 56 2.3 K = 2.8 nF @ 1MHz 4 2 3 2: 1.2 K - 1.0 K = 1.2 K 4.4 pF @ 36 MHz 3: 932 - 1.1 K 932 = 2.9 pF @ 50 MHz = 2.0 pF @100MHz START 1.000 000 MHz STOP 100.000 000 MHz 4: 448 - 760 448 F igure 5 - Typical SAWF driver input impedance, single-ended CH1 S11 1 U FS 1_: 132.01 Ω 9 Feb 2001 12:27:19 -1.5938 Ω 99.862 nF 1.000 000 MHz PRm Cor Avg 16 1 Normalised to 50 Ω 43 2 2_: 121.2 -12.078 36MHZ 3_: 117.25 50MHz 4_: 110.06 -7.5742W 100MHz Ω Ω Ω Ω START 1.000 000 MHz STOP 100.000 000 MHz Figure 6 - Typical SAWF driver output impedance, single-ended 4 SL2009 IFAmp AGC Slope ( Vcc = 5v, 25'C) 50 40 30 Gain (dB) 20 10 0 -10 -20 0 1 2 3 4 5 AGC Voltage (V) Figure 7 - Typical IF amplifier stage AGC characteristic 5 SL2009 8 Feb 2001 16:19:58 CH1 S11 1 U FS Ω Ω PRm Cor Avg 16 1 Normalised to 2 K 1: 2.3 K - 60 2.38 K 2 4 3 = 2.6 nF @ 1MHz 2: 1.1 K - 1.2 K = 1.1 K 3.7 pF @ 36 MHz 3: 736 - 1.08 K = 733 2.9 pF @ 50 MHz 4: 340 - 728 344 = 2.2 pF START 1.000 000 MHz STOP 100.000 000 MH z Figure 8 - Typical IF amplifier input impedance, single-ended CH1 S11 1 U FS 1_: 9.8564 9 Feb 2001 16:17:56 Ω114.26 m Ω17.66 nH 1.029 700 MHz PR m Cor 3 21 4 Normalised to 50 Ω 2_: 7.8931 6.0146 36MHZ 3_: 11.521 9.3154 50MHz 4_: 26.014 2.7539 100MHz START 1.000 000 MHz STOP 100.000 000 MHz Ω Ω Ω Ω Ω Ω Figure 9 - Typical IF amplifier output impedance, single-ended 6 SL2009 Electrical Characteristics Test conditions (unless otherwise stated) Tamb = -40˚ to 85˚C, Vee= 0V, VccIF = 5V+-5%, VccSAW =5V+-5% These characteristics are guaranteed by either production test or design. They apply within the specified ambient temperature and supply voltage unless otherwise stated. Characteristics Supply current pin 3,16 min typ 50 max 70 units mA Conditions Pin (3) VccIF and pin (16) VccSAW are isolated on chip. Operating frequency Gain Flatness 30 50 1dB MHz Over specified output range. Excluding SAW filter contributions. 8MHz B/W. See note (4) kΩ pF SAWF driver Input impedance 10,11 2 3 Noise Figure 4 6 Differential, see figure (5) dB Tamb=27˚C, referred to source impedance of 2 kΩ conversion gain set at 28 dB Variation in NF with gain adjust Output referred IP3 Gain 3 -1 dB/dB dBV Over specified gain range, see note (1) and (4) Voltage conversion gain from 2 kΩ differential source to 1 kΩ//10 pF single-ended load, see note (4) Vagc1=1.5V Vagc1=3.5V AGC monotonic from Vee to Vcc. See Figure (3) Single-ended, see figure (6) Single-ended into 1 kΩ // 10 pF load 3rd Harmonic of wanted output signal better than 10dBC. Vee