آر اف (فرکانس رادیویی) و بی‌سیم سایر آی سی‌ و ماژول‌های آر اف

Product Attributes

Introduction

TL851 is a low-cost digital I²L ranging control IC designed to interface with the Texas Instruments TL852 sonar ranging receiver IC. The TL851 is designed to measure distances from 6 inches to 35 feet. The device features an internal oscillator that uses a low-cost external ceramic resonator. With a simple interface and a 420 kHz ceramic resonator, the device can drive a 50 kHz electrostatic transducer. A device cycle begins when the initiate signal (INIT) goes to a high logic level. A minimum of 5 ms must elapse between initial power-up (VCC) and the first INIT signal to allow all internal latches to reset and the ceramic-resonator-controlled oscillator to stabilize. Each time INIT goes high, the device transmits a burst of 16 pulses. The oscillator output (OSC) is enabled by INIT. During the first 16 cycles (transmit period), the oscillator frequency is the ceramic resonator frequency divided by 8.5; for the remainder of the device cycle, the oscillator frequency becomes the ceramic resonator frequency divided by 4.5. When used with an external 420 kHz ceramic resonator, the internal blanking function disables the receive input (REC) for 3.8 ms after initiation to reject spurious receive inputs that may be caused by transducer ringing. The internal blanking function also eliminates echoes from objects closer than 1.3 feet from the transducer. If detection of objects closer than 1.3 feet is required, the internal blanking time can be shortened by driving the blanking inhibit signal (BINH) high, thereby enabling the receive input. The blanking input (BLNK) can be used to disable the receive input at any point during the device cycle and reset the echo signal (ECHO) to a low logic level, allowing selective echo rejection or multi-echo operating modes. The device provides a synchronous 4-bit gain control output (12 levels) for controlling the gain of the TL852 sonar ranging receiver IC. The digital gain control waveform is shown in Figure 2, and the nominal transition times from INIT are listed in the gain control output table. The internal receive level detector threshold is 1.2 V. The TL851 operates over a supply voltage range of 4.5 V to 6.8 V and a temperature range of 0°C to 40°C.

Features

• Designed specifically for use with TL852 in sonar ranging modules (e.g., SN28827)
• Single-supply operation
• Precise clock output for external use
• Synchronous 4-bit gain control output
• Internal 1.2V receive level detector
• TTL compatible
• Compatible with electrostatic or piezoelectric transducers