參數(shù)資料
型號: TDA8785H
廠商: NXP SEMICONDUCTORS
元件分類: ADC
英文描述: 8-bit high-speed analog-to-digital converter with gain and offset controls
中文描述: 1-CH 8-BIT PROPRIETARY METHOD ADC, PARALLEL ACCESS, PQFP44
封裝: 10 X 10 MM, 1.75 MM HEIGHT, PLASTIC, SOT-307-2, QFP-44
文件頁數(shù): 6/24頁
文件大?。?/td> 169K
代理商: TDA8785H
1997 Dec 18
6
Philips Semiconductors
Product specification
8-bit high-speed analog-to-digital converter
with gain and offset controls
TDA8785
FUNCTIONAL DESCRIPTION
The TDA8785 is composed of an 8-bit ADC (30 Msps),
a wide-band gain amplifier, an input offset amplifier and an
8-bit dynamic adjustment DAC.
Input signal
Two input pins are provided to apply a differential input
signal with a wide range (100 to 1000 mV differential).
It is also possible to apply a single signal by setting a DC
voltage on one of the differential pins and supplying the
signal to the other.
Controlled gain amplifier
The gain amplifier is used to adjust the wide input signal
range to the fixed ADC input range of 1 V (p-p).
A large gain of 20 dB can be achieved with low-noise
behaviour and a large bandwidth of 100 MHz to correctly
amplify square type signals with step edges. Using pin 6,
it is possible to reduce the internal bandwidth of the gain
amplifier via an external capacitor and thus improve its
noise behaviour. The gain amplifier is controlled via an
external differential voltage (single input can also be
applied).
Input offset amplifier and adjustment DAC
The Input offset amplifier contains two different control
inputs (which can also be single):
Slow offset control, for slow variation characteristics
(e.g. temperature, supply voltage, etc.)
Fast offset control, for correction related to the clock
rate.
Slow offset control is carried out by an external voltage
while fast offset control is digitally carried out via the
internal 8-bit DAC with external connections of the
respective pins V
DACO(n)
, V
DACO(p)
, V
FOFF(n)
and V
FOFF(p)
.
The internal 8-bit DAC operates at the ADC clock rate to
allow dynamic corrections on the input signal chain based
on the signal processing information carried out after the
digital conversion. The output voltage amplitude of the
DAC can be controlled via a different input voltage (which
can also be single) in a range of
±
25% with a 150
DAC
output load.
The DAC can also be used for the gain or the slow offset
control with some external DC voltage adaptations and
can be considered as a separate function of the ADC
chain. The DAC can be used independently, for example
as a video DAC.
8-bit ADC
The 8-bit ADC converts a signal of 1 V (p-p) from the
controlled gain amplifier into an 8-bit coded digital word at
a maximum rate of 30 Msps. Its reference voltage is
supplied by the general voltage regulator. The output data
format can either be binary, two’s complement or 3-state
by selecting pin OF.
When all the differential inputs on the offset amplifier
(V
SOFF(p)
, V
SOFF(n)
, V
FOFF(n)
, V
FOFF(p)
, V
i(p)
and V
i(n)
) are at
0 V (equivalent to both inputs short-circuited), the output
code of the ADC is code 8.
Internal voltage regulator
An internal voltage regulator provides all the references for
the different blocks. A stable 2.75 V voltage reference
output is provided for use in the application environment.
One application is to connect all the slow control inputs
(V
FSDAC(p)
, V
FSDAC(n)
, V
SOFF(p)
, V
SOFF(n)
, V
FSAD(p)
and
V
FSAD(n)
) to this reference, either to their two differential
inputs to get the nominal settings or to one of the
differential inputs to have easy single-input control.
All these control inputs have the same control range.
相關PDF資料
PDF描述
TDA8787A 10-bit, 3.0 V, up to 25 Msps analog-to-digital interface for CCD cameras
TDA8787 10-bit, 3.0 V analog-to-digital interface for CCD cameras
TDA8790 8-bit, 40 Msps 2.7 to 5.5 V universal analog-to-digital converter
TDA8792 3.3 V, 25 MHz 8-bit analog-to-digital converter ADC
TDA8793HL 8-bit, low-power, 3 V, 100 Msps Analog-to-Digital Converter ADC
相關代理商/技術參數(shù)
參數(shù)描述
TDA8786 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:10-bit analog-to-digital interface for CCD cameras
TDA8786A 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:10-bit analog-to-digital interface for CCD cameras
TDA8786AG 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:10-bit analog-to-digital interface for CCD cameras
TDA8786G 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:10-bit analog-to-digital interface for CCD cameras
TDA8787 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:10-bit, 3.0 V analog-to-digital interface for CCD cameras