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Ordering number : EN5736
Monolithic Linear Integrated Circuit
LA7775M
Wideband FSK Receiver
Overview
The LA7775M is an FM receiver for CATV or FM communications equipment. In addition to functions for FM demodulation (oscillator, mixer, limiting IF amplifier, and quadrature detection circuits) it also includes on chip an FSK data shaper circuit, an RF amplifier, and a local oscillator frequency switching circuit.
Package Dimensions
unit: mm 3045B-MFP24
[LA7775M]
Functions
* * * * * * * RF amplifier Mixer Oscillator Oscillator switching Limiting IF amplifier Quadrature detection Data shaper
SANYO: MFP24
Features
* Wideband RF input * On-chip RF amplifier * On-chip oscillator frequency switching circuit
Specifications
Maximum Ratings at Ta = 25C
Parameter Maximum supply voltage Allowable power dissipation Operating temperature Storage temperature Symbol VCC max Pd max Topr Tstg Conditions Ratings 7 350 -20 to +75 -55 to +125 Unit V mW C C
Operating Conditions at Ta = 25C
Parameter Recommended supply voltage Operating supply voltage range Input frequency Symbol VCC VCCop fin21, fin24 Conditions Ratings 5 4.5 to 5.5 40 to 350 Unit V V MHz
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
63097HA(OT) No. 5736-1/5
LA7775M Operating Characteristics at Ta = 25C (VCC = 5 V, fo = 106.5 MHz, fIF = 10.7 MHz)
Parameter Current drain Preamplifier input capacitance Preamplifier input resistance Preamplifier voltage gain Mixer input capacitance Mixer input resistance Mixer conversion gain -3 dB limiting sensitivity Demodulation output SAW switching threshold level Data output high level Data output low level Oscillator output Symbol ICCO Ci21 Ri21 Gp Ci24 Ri24 Gc Vi Vo V19TH V18H V18L V2 117.2 MHz 0.35 100 MHz 100 MHz 350 MHz 100 MHz 100 MHz 350 MHz F = 75 kHz dev, at 1 kHz F = 75 kHz dev, at 1 kHz 180 1.35 4.5 0.5 Conditions Ratings min typ 20 7 1 15 7 1 25 10 250 1.50 1.65 16 max 26 Unit mA pF k dB pF k dB dB mVrms V V V Vp-p
Equivalent Circuit Block Diagram and Test Circuit
VCC 100 nH 13 pF
RF INPUT
0.1 F LO SELECT DATA OUTPUT 2 k 10 k 470 pF 220 pF 10 k 20 GND 19 VCC 18 17 16 15 470 pF 14
2200 pF
5 pF 24 23
22
21
2200 pF
390
13
PRE AMP DATA SHAPER MIXER FM DET OSC 330 LIM.AMP 1 k RFGND 1 2 3 4 5 6 7 8 9 10 0.033 F 510 SFE10.7MS2 117.2 MHz 0.01 F 119.2 MHz 0.01 F 1k 20 pF 20 pF 1 H 0.01 F 47 F VCC 11 0.033 F 12 6 pF 0.01F 3.9 H 43 pF
T00078
390
1000 pF 20 pF
OSC OUTPUT
No. 5736-2/5
LA7775M Pin Functions
Pin No. 1 Pin RFGND Pin voltage(V) Notes Equivalent circuit
2
LOOUT
3.3
Oscillator output after the limiting amplifier. This pin is used when constructing a PLL synthesizer or related circuit. A 1k external resistor is required when using this pin.
2
100 mA
3
T00079
3
LOCOM
1.2
4
4 LORES1 1.9 When pin 19 is low, pin 4 is selected, when high, pin 5 is selected.
5
Switching circuit
3
19
5
LORES2
0.8
T00080
6
RFVCC
4 pF 1 k 1 k 330
7 IFOUT 4.1 A matching resistor for the SAW filter is built in.
7
8 pF
0.5 mA
T00081
8
VCC
9
LIMITER INPUT1
1.5
9
10 LIMITER INPUT2 1.5 Insert a 510- resistor between pins 9 and 11 when using this circuit.
10
1k 330 50k 50k
11
11
LMITER BIAS
1.5
T00082
VCC 390
12
12 LIMITER OUTPUT 4.2
LIMITER AMP
T00083
Continued on next page.
No. 5736-3/5
LA7775M
Continued from preceding page.
Pin No. Pin Pin voltage(V) Notes Equivalent circuit
13
13
QUAD INPUT
4.3
4 k
T00084
14
FILTER INPUT
2.5
14
15 DET. OUTPUT 1.8
15
0.7 mA
T00085
16
DATASHAPER INPUT1 DATASHAPER INPUT2 DATA OUTPUT
10 k
18 16 17
17
18
T00086
19
LOSELECT
When pin 19 is low, pin 4 is selected, when high, pin 5 is selected.
19
40 k 1.5 V
T00087
20
GND
VCC
21 RF AMP INPUT 1.6
6.7 k 3.3 k
23
22
RF AMP BIAS
0.6
The optimal collector current is between 1.5 and 2 mA.
1 k 5 k
22 21
23
RF AMP OUTPUT
T00088
2.5 V 3 k
24 MIX INPUT 1.9
MIXER 1.5 k 24
2 k
T00089
No. 5736-4/5
LA7775M Design Notes
C1
1. RF amplifier This circuit is formed as a two-transistor cascode amplifier and takes an LC tank circuit as its load. The operating current is set by the external resistor connected to pin 22. The optimal operating current is between 1.5 and 2 mA. The capacitor (C2) connected between pins 23 and 24 is related to the tank circuit Q, and must not be too large.
21
C2 23 24
22
2. Oscillator circuit This is a grounded collector oscillator circuit, and supports using either an LC, a crystal, or a SAW resonator. Care is required when constructing this circuit, since the input sensitivity may be suppressed if the oscillator circuit output leaks into the IF limiting amplifier. It is extremely important to use a capacitor (e.g. a ceramic capacitor) with excellent high-frequency characteristics for the 1000 pF bypass capacitor inserted between the oscillator circuit power supply pin (pin 6) and the ground pin (pin 1). In addition, this capacitor must be located as close as possible to pins 1 and 6. When forming an oscillator circuit using a SAW resonator, the optimal values for C1 through C3 will vary with the oscillator frequency. Thus this circuit must be adjusted for optimal 3 4 5 C1 performance. Since the capacitor C3 between pin 3 and ground will be shared if a C2 circuit that switches between two SAW resonators is used, the difference between C3 the frequencies must be held to under 10 MHz. If a large frequency difference is required, design a circuit that also switches the capacitance between pin 3 and ground.
T00090 T00091
3. IF limiting amplifier This circuit consists of a six-stage direct coupled differential amplifier to which DC feedback is applied. Since an internal 1-k resistor is built in between the IF input pin (pin 9) and pin 11, the input and output impedance of the 330- IF filter can be matched with an external 510- resistor. No external matching resistor is required for the IF output (pin 7), since a 330- resistor is built in. 4. Quadrature detection circuit An external phase shifting circuit is formed from an LC tuning circuit and a ceramic discriminator.
12 390 W 13 4 kW 12 13
T00092 T00093
s No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. s Anyone purchasing any products described or contained herein for an above-mentioned use shall: Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. s Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provides information as of June, 1997. Specifications and information herein are subject to change without notice. No. 5736-5/5

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