TDA8780M Philips Semiconductors, TDA8780M Datasheet - Page 2

• Manufacturer Part Number: TDA8780M
• Description: True logarithmic amplifier
• Manufacturer: Philips Semiconductors

Philips Semiconductors
FEATURES
APPLICATIONS
GENERAL DESCRIPTION
The TDA8780M is a true logarithmic amplifier intended for
dynamic range reduction of IF signals at 10.7 MHz in
digital radio receivers. It offers true logarithmic
characteristics over a 72 dB input dynamic range, has a
small-signal gain-adjustment facility and a constant
limiting output voltage for large input levels.
QUICK REFERENCE DATA
ORDERING INFORMATION
1995 Jul 25
V
I
I
f
V
T
P
P(PD)
in
amb
72 dB true logarithmic dynamic range
Small-signal gain-adjustment facility
Constant limiting output voltage
Temperature and DC power supply voltage independent
Easy interfacing to analog-to-digital converters
Output DC level shift facility.
Dynamic range compression
IF signal dynamic range reduction in digital receivers
Compression receivers.
SYMBOL
P
in(M)
True logarithmic amplifier
TYPE NUMBER
TDA8780M
supply voltage
supply current
supply current in power-down mode
operating input frequency
dynamic logarithmic input voltage (peak value)
operating ambient temperature
SSOP20
NAME
PARAMETER
plastic shrink small outline package; 20 leads; body width 4.4 mm
2
A unique feature is the smooth “changeover” from linear
operation (inputs less than 60 V) to logarithmic mode.
The device is manufactured in an advanced BiCMOS
process which enables high performance being obtained
with low DC power supply consumption. The true
logarithmic amplifier can be driven by single-ended or
differential inputs. The DC operating point is set by overall
on-chip feedback decoupled by two off-chip capacitors,
which define the low-frequency cut-off point.
The performance of the amplifier is stabilized against
temperature and DC power supply variations. The
differential output is converted internally to a single-ended
output by an on-chip operational amplifier arrangement in
which the DC output level is set by an externally-supplied
reference voltage. A power-down facility allows the circuit
to be disabled from a control input.
DESCRIPTION
PACKAGE
4.5
0.06
20
MIN.
5.0
TYP.
5.5
6.7
250
15
300
+75
Product specification
MAX.
TDA8780M
V
mA
MHz
mV
SOT266-1
VERSION
C
A
UNIT