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TDA1311A/N2 View Datasheet(PDF) - Philips Electronics

Part Name
Description
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TDA1311A/N2
Philips
Philips Electronics Philips
TDA1311A/N2 Datasheet PDF : 20 Pages
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Philips Semiconductors
Stereo Continuous Calibration DAC
(CC-DAC)
Preliminary speciļ¬cation
TDA1311A
FUNCTIONAL DESCRIPTION
The basic operation of the continuous calibration DAC is
illustrated in Fig.3. The figure shows the calibration and
operation cycle. During calibration of the MOS current
source (see Fig.3a) transistor M1 is connected as a diode
by applying a reference current. The voltage Vgs on the
intrinsic gate-source capacitance Cgs of M1 is then
determined by the transistor characteristics. After
calibration of the drain current to the reference value IREF,
the switch S1 is opened and S2 is switched to the other
position (see Fig.3b). The gate-to-source voltage Vgs of
M1 is not changed because the charge on Cgs is
preserved. Therefore, the drain current of M1 will still be
equal to IREF and this exact duplicate of IREF is now
available at the OUT terminal.
The 32 current sources and the spare current source of the
TDA1311A; AT are continuously calibrated (see Fig.1).
The spare current source is included to allow continuous
converter operation. The output of one calibrated source is
connected to an 11-bit binary current divider consisting of
2048 transistors.
A symmetrical offset decoding principle is incorporated
that arranges the bit switching in such a way that the
zero-crossing is performed only by switching the LSB
currents.
The TDA1311A; AT (CC-DAC) accepts serial input data
formats of 16-bit word length. Left and right data words are
time multiplexed. The most significant bit (bit 1) must
always be first. The input data format is shown in Figs 4
and 5.
With a HIGH level on the word select input (WS), data is
placed in the left input register and with a LOW level on the
WS input, data is placed in the right input register (see
Fig.1). The data in the input registers are simultaneously
latched in the output registers which control the bit
switches.
An internal offset voltage VOS is added to the full scale
output voltage VFS; VOS and VFS are proportional to VDD:
VDD1/VDD2 = VFS1/VFS2 = VOS1/VOS2.
handbook, full pagewidth
(a) = calibration.
(b) = operation.
out
Iref
S1
Cgs
S2
M1
Vgs
(a)
out
Iref
Iref
S2
S1
Cgs
Vgs
(b)
M1
MBG860
Fig.3 Calibration principle.
1995 Dec 18
5
 

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