LM733CN Wide-Band Video Amplifier

Overview

The LM733CN is a high-performance, two-stage differential input and differential output wide-band video amplifier designed for applications requiring high bandwidth and low phase distortion. Its architecture utilizes internal series-shunt feedback to achieve excellent gain stability and wide bandwidth without the need for external frequency compensation. The device features emitter-follower outputs, providing high current drive capability and low output impedance, making it suitable for driving various memory elements and video signal processing applications.

With a bandwidth of 120 MHz and selectable gains of 10, 100, and 400, the LM733CN offers flexibility in system design while maintaining signal integrity. The amplifier is particularly well-suited for high-frequency applications where common-mode rejection and phase linearity are critical.

Features

• 120 MHz bandwidth for high-frequency signal processing
• Differential input and differential output configuration
• Selectable voltage gains: 10, 100, and 400
• No external frequency compensation required
• High input resistance: 250 kΩ
• Excellent common-mode rejection ratio (CMRR) at high frequencies
• High output current drive capability
• Low output impedance for driving capacitive loads
• Internal series-shunt feedback for gain stability
• Available in dual-in-line package (DIP) and metal can package options

Applications

• Magnetic tape recording and playback systems
• Disk file memory systems
• Thin and thick film memory applications
• Woven and plated wire memory systems
• Wide-band video amplifiers and processing circuits
• Pulse amplification systems
• High-speed data acquisition systems
• Test and measurement equipment
• Radar and communication systems
• Medical imaging equipment

Electrical Characteristics

(TA = 25°C, VCC = ±15V, unless otherwise specified)

DC Characteristics

• Input Offset Voltage: 5 mV (max)
• Input Offset Current: 200 nA (max)
• Input Bias Current: 1 μA (max)
• Input Resistance: 250 kΩ (typ)
• Large Signal Voltage Gain (G=10): 90 V/mV (min)
• Power Supply Rejection Ratio: 80 dB (typ)

AC Characteristics

• Bandwidth (-3dB): 120 MHz (typ) at G=10
• Slew Rate: 900 V/μs (typ)
• Rise Time: 3 ns (typ) for 10V step
• Overshoot: 10% (max) for 10V step
• Common Mode Rejection Ratio (at 10 MHz): 60 dB (typ)

Gain Selection Characteristics

• Gain of 10: Bandwidth 120 MHz
• Gain of 100: Bandwidth 30 MHz
• Gain of 400: Bandwidth 10 MHz

Absolute Maximum Ratings

• Supply Voltage (VCC to VEE): ±18V
• Differential Input Voltage: ±5V
• Output Short-Circuit Duration: Continuous
• Operating Temperature Range (LM733CN): 0°C to +70°C
• Storage Temperature Range: -65°C to +150°C
• Junction Temperature: 150°C
• Lead Temperature (Soldering, 10 sec): 300°C

Package Information

Dual-In-Line Package (N14A)

• Package Type: 14-pin PDIP
• Package Dimensions: 19.3mm x 6.35mm x 4.57mm
• Pin Spacing: 2.54mm
• Lead Material: Copper Alloy
• Finish: Matte Tin

Metal Can Package (H10D)

• Package Type: 10-pin TO-100
• Package Dimensions: 9.4mm diameter x 5.2mm height
• Pin Spacing: 36° radial
• Case Material: Metal
• Note: Pin 5 is connected to the case

Thermal Characteristics

• Thermal Resistance, θJA (DIP): 80°C/W
• Thermal Resistance, θJA (Metal Can): 150°C/W
• Maximum Power Dissipation (at 25°C): 800 mW

Detailed Description

The LM733CN is a sophisticated video amplifier that combines two amplifier stages with internal feedback networks to achieve its high performance characteristics. The first stage provides the majority of the voltage gain while the second stage serves as a buffer with current gain to drive low impedance loads. The internal feedback network ensures stability across all gain settings without requiring external compensation components.

The differential architecture of the LM733CN provides excellent common-mode rejection, particularly important in video applications where noise immunity is critical. The emitter-follower output stage can deliver up to ±50mA of output current, enabling the device to drive transmission lines or capacitive loads with minimal signal degradation.

The gain selection is accomplished through simple external resistor connections, allowing the same device to be used in multiple applications with different signal level requirements. The bandwidth remains relatively constant for a given gain setting, with the highest bandwidth available at the lowest gain setting.

Typical Performance Characteristics

(Graphs and plots would typically be included here showing):

• Frequency response at various gain settings
• Step response characteristics
• Common-mode rejection versus frequency
• Output voltage swing versus frequency
• Power supply rejection versus frequency
• Distortion characteristics

Application Notes

When implementing the LM733CN in circuit designs, several considerations should be made:

• Proper power supply decoupling is essential for optimal performance. Use 0.1μF ceramic capacitors close to the power pins.
• For high-frequency applications, maintain short lead lengths and proper PCB layout techniques to minimize parasitic effects.
• The metal can package version provides better thermal performance but requires attention to grounding as pin 5 is connected to the case.
• When driving capacitive loads, a small series resistor (10-50Ω) at the output can help maintain stability.
• For best common-mode rejection, maintain balanced impedance in the input circuit.