Obsolescence Notice
This product is obsolete.
This information is available for your
convenience only.
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replacement product lists, please visit
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THIS DOCUMENT IS FOR MAINTENANCE
PURPOSES ONLY AND IS NOT
RECOMMENDED FOR NEW DESIGNS
ADVANCE INFORMATION
DS3612 - 1.0
SL1613
WIDEBAND LOG IF STRIP AMPLIFIER
The SL1613 is a bipolar monolithic integrated circuit
wideband amplifier intended for use in successive detection
logarithmic IF strips, operating at centre frequencies between
10MHz and 60MHz. The device provides amplification,
limiting and rectification, is suitable for direct coupling and
incorporates supply line decoupling. The mid-band voltage
gain of the SL1613 is typically 12dB.
DP8
MP8
FEATURES
s
s
s
s
s
s
s
Well Defined Gain
4.5dB Noise Figure
High I/P impedance
Low O/P impedance
150MHz Bandwidth
On-Chip Supply Decoupling
Low External Component Count
Fig.1 Pin connections (top)
ABSOLUTE MAXIMUM RATINGS
Storage temperature range
Operating temperature range
Thermal resistance
Chip-to-ambient
SL1613 DP
SL1613 MP
Chip-to-case
SL1613 DP
SL1613MP
Maximum instantaneous voltage
at video output
Supply voltage
-55°C to +150°C
-30°C to +85°C
111°C/W
163°C/W
71°C/W
57°C/W
+12V
9V
APPLICATIONS
s
s
s
Logarithmic IF Strips with Gains up to 108dB and
Linearity Better than 2dB
Low Cost Radar
Radio Telephone Filed Strength Meters
ORDERING INFORMATION
SL1613 C DP
SL1613 C MP
Fig.2 Circuit diagram
Fig.3 Voltage gain v. frequency
SL1613
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following condiotns (unless otherwise stated)
TA = +22°C
±2°C
Supply voltage = +6V
DC connection between input and bias pins
Characteristic
Voltage gain
Upper cut-off frequency (Fig. 3)
Lower cut-off frequency (Fig. 3)
Propagation delay
Max. rectified video output current
(Fig. 4 and 5)
Variation of gain supply voltage
Variation of maximum rectified output
current with supply voltage
Maximum input signal before overload
Noise figure (Fig. 6)
Maximum RF output voltage
Supply current
Value
Min.
10
Typ.
12
150
5
2
1
0.7
25
1.9
4.5
1.2
1.5
Max.
14
Units
dB
MHz
MHz
ns
mA
dB/V
%/V
V rms
dB
Vp-p
mA
Conditions
f = 30MHz, R
S
= 10Ω, C
L
= 8pF
R
S
= 10Ω, C
L
= 8pF
R
S
= 10Ω, C
L
= 8pF
f = 60MHz, V
IN
= 500mV rms
0.8
1.4
See Note 1
f = 60MHz, R
S
= 450Ω
20
Note 1. Overload occurs when the input signal reaches a level sufficent to forward bias the base-collector junction of TR1 on peaks
Fig.4 Rectified output current v. input signal
Fig.5 Maximum rectified output current v. temperature
Fig.6 Typical figure v. temperature
Fig.7 Input admittance with open circuit output
SL1613
Fig.9 Suitable interstage tuned circuit
Fig.8 Direct coupled amplifiers
OPERATING NOTES
The amplifiers are intended for use directly coupled, as
shown in Fig. 8.
The seventh stage in an untuned cascade will be giving
virtually full output on noise.
Noise may be reduced by inserting a single tuned circuit in
the chain. As there is a large mismatch between stages a
simple parallel or series circuit cannot be used. This choice of
network is also controlled by the need to avoid distorting the
logarithmic law: the network must give unity voltage transfer at
resonance. A suitable network is shown in Fig. 9. The value of
C1 must be chosen so that at resonance its admittance equals
the total loss conductance across the tuned circuit. Resistor
R1 may be introduced to improve the symmetry of filter
response, providing other values are adjusted for unity gain at
resonance.
A single capacitor may not be suitable for decoupling the
output line if many stages and fast rise times are required.
Values of supply line decoupling capacitor required for
untuned cascades are given below. Smaller values can be
used in high frequency tuned cascades.
The amplifiers have been provided with two ground leads to
avoid the introduction of common ground lead inductance
between input and output circuits. The equipment designer
should take care to avoid the subsequent introduction of such
inductance.
Number of stages
6 or more
5
4
3
Minimum capacitance
30nF
10nF
3nF lnF
The on-chip 500pF supply decoupling capacitor has a
resistance of, typically 10Ω. It is a junction type having a low
breakdown voltage and consequently the positive supply
current will increase rapidly if the supply voltage exceeds
7.5V. (See Absolute Maximum Ratings).
Centre frequency
60MHz
Dynamic Range
-75dBm to +15dBm
Video rise time
70nSec
Bandwidth
approx. 20MHz
Output voltage
0 - 1.5V
Typical log accuracy
±2dB
Fig.10 Circuit diagram of low strip