CA3306 CMOS Parallel Analog-to-Digital Converter Technical Summary

CA3306 CMOS Parallel (FLASH) Analog-to-Digital Converter

Overview

The CA3306 is a high-performance CMOS parallel (FLASH) analog-to-digital converter (ADC) designed for applications requiring both low power consumption and high-speed digitization. This 6-bit resolution ADC operates at a remarkable 15MHz sampling rate while maintaining low power consumption, making it ideal for video processing, transient signal analysis, and other high-speed applications. The device features a parallel conversion technique that enables rapid digitization of analog signals with minimal latency.

With its wide operating voltage range of 3V to 7.5V and typical power consumption of just 70mW, the CA3306 offers excellent flexibility for both portable and high-performance systems. The inclusion of latched three-state outputs with an overflow bit further enhances its usability in complex digital systems.

Key Features

CMOS technology for low power consumption with video-speed performance (70mW typical)
Parallel (FLASH) conversion architecture for high-speed operation
Wide operating voltage range: 3V to 7.5V
15MHz sampling rate with single 5V supply
6-bit resolution with digital output
Latched three-state outputs with overflow bit
Pin-for-pin compatible with CA3300 series for easy upgrades
Operating temperature range: -40°C to +85°C
Fast conversion time: 66ns typical

Applications

The CA3306's combination of high speed and low power makes it suitable for a wide range of demanding applications:

Video Processing
- TV video digitizing
- Video capture and processing systems
- Digital video effects processing
Medical and Scientific Instrumentation
- Ultrasound signature analysis
- High energy physics research equipment
- Medical imaging systems
Test and Measurement
- Transient signal analysis
- High-speed oscilloscope storage/display
- Radar pulse analysis
Industrial and Automation
- Robot vision systems
- Motion signature analysis
- Optical character recognition
General Purpose
- Hybrid ADC systems
- High-speed data acquisition
- Digital signal processing front-ends

Electrical Characteristics

Absolute Maximum Ratings

Supply Voltage (VDD): -0.5V to +8V
Input Voltage Range: -0.5V to VDD +0.5V
Operating Temperature Range: -40°C to +85°C
Storage Temperature Range: -65°C to +150°C

Recommended Operating Conditions

Supply Voltage (VDD): 3V to 7.5V
Analog Input Voltage Range: 0V to VDD
Clock Frequency: 0Hz to 15MHz
Operating Temperature Range: -40°C to +85°C

DC Characteristics (VDD = 5V, TA = 25°C)

Power Supply Current: 14mA typical (15MHz operation)
Power Dissipation: 70mW typical
Input Leakage Current: ±1μA maximum
Output Leakage Current: ±1μA maximum
Output High Voltage: 4.9V minimum (IOH = -360μA)
Output Low Voltage: 0.1V maximum (IOL = 1.6mA)

AC Characteristics (VDD = 5V, TA = 25°C)

Conversion Rate: 15MHz maximum
Conversion Time: 66ns typical
Aperture Delay: 5ns typical
Output Enable Time: 25ns maximum
Output Disable Time: 25ns maximum
Clock Pulse Width: 20ns minimum

Package Information

The CA3306 is available in multiple package options to suit different application requirements:

20-Pin Plastic Dual In-Line Package (PDIP)
- Package Code: D
- Dimensions: 25.4mm x 6.35mm body
- Lead Pitch: 2.54mm
- Operating Temperature: -40°C to +85°C
20-Pin Small Outline Package (SOIC)
- Package Code: DW
- Dimensions: 12.8mm x 7.5mm body
- Lead Pitch: 1.27mm
- Operating Temperature: -40°C to +85°C
20-Pin Ceramic Dual In-Line Package (CDIP)
- Package Code: E
- Dimensions: 25.4mm x 6.35mm body
- Lead Pitch: 2.54mm
- Operating Temperature: -55°C to +125°C

Functional Description

The CA3306 employs a parallel (FLASH) conversion technique where all possible quantization levels are compared simultaneously. This architecture enables the extremely fast conversion speeds that make this device suitable for video and other high-speed applications.

The analog input is applied to a resistor ladder network that establishes reference voltages for 63 comparators (for 6-bit resolution). The comparator outputs are processed by a priority encoder that generates the corresponding digital output code. The digital outputs are latched and provided with three-state capability for easy interface with microprocessors or digital signal processors.

An overflow output is provided to indicate when the input signal exceeds the converter's full-scale range. The device includes an internal sample-and-hold function, with the sampling instant controlled by an external clock signal.

Design Considerations

Power Supply Decoupling

Proper power supply decoupling is essential for optimal performance. A 0.1μF ceramic capacitor should be placed as close as possible to the VDD pin, with a larger (10μF) electrolytic capacitor nearby for bulk decoupling.

Clock Requirements

The conversion process is initiated by the rising edge of the clock signal. The clock should have fast rise and fall times (typically <10ns) to ensure accurate timing. Jitter on the clock signal will directly affect conversion accuracy.

Analog Input Considerations

The analog input should be driven by a low-impedance source to maintain accuracy at high conversion rates. For best performance, use an operational amplifier configured as a voltage follower between the signal source and the ADC input.