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
s
s
s
s
High Controlled Gain
Low Noise
Wide bandwidth
Low Supply Current
: 60dB
±1dB
typical
: 40Ω Equivalent Noise
Resistance, or 800pV/√Hz
: 15MHz typical
: <3mA from 5V
CM6
ZN459CP
ABSOLUTE MAXIMUM RATINGS
Supply voltage
Operating Temperature Range:
for ZN459
for ZN459CP
Storage Temperature Range
6 Volts
DP8
-55 to +125°C
0 to +70°C
-55 to +125°C
Fig.1 ZN459 Outline circuit
ZN459
ELECTRICAL CHARACTERISTICS
Test condltions (unless otherwise stated):
(V
CC
= 5V, T
amb
= 25°C)
Parameter
Supply Current
Voltage Gain
TC of Voltage Gain
V
CC
Coefficient of Voltage Gain
Cut-off Frequency
Input Resistance
Input Capacitance
Noise Resistance
White Noise Voltage
L.F. Spot Noise
White Noise Current
Output Level
Supply Voltage Coefficient
of Output Level
Output Current Limit
Total Harmonic Distortion
Output Resistance
Supply Rejection Ratio
Delay Time
Delay Time
Positive Input Overdrive
Negative Input Overdrive
Note 1:
Min.
2.0
59
Typ.
2.5
60
-0.2
25
15
7
80
40
800
3
1
2.0
0.34
0.8
0.15
75
42.5
20
40
10
-5
Max.
3.0
61
Units
mA
dB
%/°C
%/V
MHz
kΩ
pF
Ω
pV/√HZ
nV/√HZ
pA/√HZ
V
V/V
mA
%
Ω
dB
ns
ns
mA
V
Conditions
10KHz
3dB down
10KHz
Note 1
R
S
= 0
R
S
= 0
R
S
= 0, f = 25Hz
3.5
1100
1.5
2.5
0.6
1.1
Sink current
1 Vpp at 10KHz
10KHz
Small signal
100mV rms input
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 R
1
to vary the gain (R
1
= 0, gain = 10
3
; R
1
=
470Ω, gain = 10
2
).
C
d
is required to decouple the internal feedback loop and in
order to obtain a flat frequency response make C
d
> C
c
.
The earth lead of the supply decoupling capacitor should be as
close as possible to that of R
1
.
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 V
S
Frequency
Fig.9 Gain and noise resistance V
S
emitter resistance
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