TL852 Datasheet | Texas Instruments

TL852 SONAR RANGING RECEIVER D Designed for Use With the TL851 in Sonar Ranging Modules Like the SN28827 D Digitally Controlled Variable-Gain Variable-Bandwidth Amplifier D Operational Frequency Range of 20 k Hz to 90 k Hz D TTL-patible D Operates From Power Sources of 4.5 V to 6.8 V D Interfaces to Electrostatic or Piezoelectric Transducers D Overall Gain Adjustable With One External Resistor SLSS003 - SEPTEMBER 1983 - REVISED MARCH 1988 N PACKAGE (TOP VIEW) G1IN 1 XIN 2 GADJ 3 LC 4 VCC 5 G1OUT 6 G2IN 7 BIAS 8 16 GND 15 GCD 14 GCA 13 GCB 12 GCC 11 NC 10 NC 9 REC - No internal connection description The TL852 is an economical sonar ranging receiver integrated circuit for use with the TL851 control integrated circuit. A minimum of external ponents is required for operation, and this amplifier easily interfaces to Polaroid’s 50-k Hz electrostatic transducer. An external 68-kΩ ±5% resistor from BIAS to GND provides the internal biasing reference. Amplifier gain can be set with a resistor from G1IN to GADJ. Required amplifier gain will vary for different applications. Using the detect-level measurement circuit of Figure 1, a nominal peak-to-peak value of 230 m V input during gain step 2 is remended for most applications. For reliable operation, a level no lower than 50 m V should be used. The remended detect level of 230 m V can be obtained for most amplifiers with an R1 value between 5 kΩ and 20 kΩ Digital control of amplifier gain is provided with gain control inputs GCA, GCB, GCC, and GCD. These inputs must be driven synchronously (all inputs stable within 0.1 µs) to avoid false receive output signals due to invalid logic counts. This can be done easily with the TL851 control integrated circuit. A plot showing relative gain for the various gain steps versus time can be seen in Figure 2. To dampen ringing of the 50-k Hz electrostatic transducer, a 5-kΩ resistor from G1IN to XIN is remended. An external parallel bination of inductance and...