ADVANCE INFORMATION DS3623 - 2.0 ZN459, ZN459CP ULTRA LOW NOISE WIDEBAND PREAMPLIFIER A versatile high grade a.c. pre-amplifier designed for applications requiring ultra low noise such as infra-red imaging and low noise wide band amplifiers e.g. microphone, acoustic emission, transducer bridge amplifier. The matching of open loop gain coupled with small physical size make the ZN459 series ideal for multichannel amplification. ZN459 FEATURES ■ ■ High Controlled Gain Low Noise : 60dB ±1dB typical : 40Ω Equivalent Noise Resistance, or 800pV/√Hz ■ ■ Wide bandwidth Low Supply Current : 15MHz typical : <3mA from 5V CM6 ZN459CP ABSOLUTE MAXIMUM RATINGS Supply voltage Operating Temperature Range: for ZN459 6 Volts -55 to +125°C for ZN459CP Storage Temperature Range 0 to +70°C -55 to +125°C DP8 Fig.1 ZN459 Outline circuit ZN459 ELECTRICAL CHARACTERISTICS Test condltions (unless otherwise stated): (VCC = 5V, Tamb = 25°C) Parameter Min. Supply Current 2.0 2.5 3.0 mA Voltage Gain TC of Voltage Gain VCC Coefficient of Voltage Gain Cut-off Frequency 59 60 -0.2 25 15 61 dB %/°C %/V MHz Input Resistance Input Capacitance Noise Resistance White Noise Voltage 3.5 L.F. Spot Noise White Noise Current Output Level Supply Voltage Coefficient of Output Level Output Current Limit Total Harmonic Distortion Output Resistance 1.5 0.6 Supply Rejection Ratio Delay Time Delay Time Positive Input Overdrive Negative Input Overdrive Note 1: Typ. 7 80 40 800 3 1 2.0 0.34 0.8 0.15 75 42.5 20 40 10 -5 Max. Units Conditions 10KHz 3dB down 1100 kΩ pF Ω pV/√HZ 10KHz Note 1 RS = 0 RS = 0 RS = 0, f = 25Hz 2.5 nV/√HZ pA/√HZ V 1.1 V/V mA % Ω dB ns ns mA Sink current 1 Vpp at 10KHz 10KHz Small signal 100mV rms input V In P.C.B. The input capacitance may be reduced to 25pF by screening between output and input. Fig.2 Pinning configuration - ZN459 Fig.3 Pinning configuration - ZN459CP ZN459 Fig.4 Gain Test Circuit (ZN459) The input impedance may be increased at the expense of noise by including R1 to vary the gain (R1 = 0, gain = 103; R1 = 470Ω, gain = 102). Cd is required to decouple the internal feedback loop and in order to obtain a flat frequency response make Cd > Cc. The earth lead of the supply decoupling capacitor should be as close as possible to that of R1. For optimum Common Mode Rejection connect a twisted pair between source and pins 4 and 5 of the device and complete the earth return from source ground. Fig.5 ZN459 Input and output circuit ZN459 Fig.6 PCB layout (ZN459) Fig.7 PCB layout (ZN459CP) ZN459 TYPICAL CHARACTERISTICS Fig.8 Gain VS Frequency Fig.9 Gain and noise resistance VS emitter resistance ZN459 Fig.10 Gain and Input Impedance Fig.11 Common Mode Rejection Vs Frequency (Measured between input earth and output earth) ZN459 Fig.12 Supply Current and Output Sink Current Fig.13 Noise Voltage ZN459 Fig.14 Quiescent Output Level