TLC2543-EP Datasheet, PDF (3/25 Pages) Texas Instruments – 12-BIT ANALOG-TO-DIGITAL CONVERTER WITH SERIAL CONTROL AND 11 ANALOG INPUTS

www.ti.com
TERMINAL
NAME
NO.
AIN0
1
AIN1
2
AIN2
3
AIN3
4
AIN4
5
AIN5
6
AIN6
7
AIN7
8
AIN8
9
AIN9
11
AIN10
12
CS
15
DATA INPUT
17
DATA OUT
16
EOC
19
GND
10
I/O CLOCK
18
REF+
14
REF–
13
V_CC
20
TLC2543-EP
12-BIT ANALOG-TO-DIGITAL CONVERTER
WITH SERIAL CONTROL AND 11 ANALOG INPUTS
SGLS125A – JULY 2002 – REVISED NOVEMBER 2006
TERMINAL FUNCTIONS
I/O
DESCRIPTION
Analog input. These 11 analog-signal inputs are internally multiplexed. The driving source
I impedance should be less than or equal to 50 Ω for 4.1-MHz I/O CLOCK operation, and be capable
of slewing the analog input voltage into a capacitance of 60 pF.
Chip select. A high-to-low transition on CS resets the internal counters and controls and enables
I DATA OUT, DATA INPUT, and I/O CLOCK. A low-to-high transition disables DATA INPUT and I/O
CLOCK within a setup time.
Serial-data input. A 4-bit serial address selects the desired analog input or test voltage to be
I
converted next. The serial data is presented with the most significant bit (MSB) first and is shifted in
on the first four rising edges of I/O CLOCK. After the four address bits are read into the address
register, I/O CLOCK clocks the remaining bits in order.
The 3-state serial output for the A/D conversion result. DATA OUT is in the high-impedance state
when CS is high and active when CS is low. With a valid CS, DATA OUT is removed from the
O
high-impedance state and is driven to the logic level corresponding to the most significant bit/least
significant bit (MSB/LSB) value of the previous conversion result. The next falling edge of I/O
CLOCK drives DATA OUT to the logic level corresponding to the next MSB/LSB, and the remaining
bits are shifted out in order.
O
End of conversion. EOC goes from a high to a low logic level after the falling edge of the last I/O
CLOCK and remains low until the conversion is complete and the data is ready for transfer.
Ground. GND is the ground return terminal for the internal circuitry. Unless otherwise noted, all
voltage measurements are with respect to GND.
Input/output clock. I/O CLOCK receives the serial input and performs the following four functions:
• It clocks the eight input data bits into the input data register on the first eight rising edges of I/O
CLOCK with the multiplexer address available after the fourth rising edge.
• On the fourth falling edge of I/O CLOCK, the analog input voltage on the selected multiplexer input
I
begins charging the capacitor array and continues to do so until the last falling edge of the I/O
CLOCK.
• It shifts the 11 remaining bits of the previous conversion data out on DATA OUT. Data changes on
the falling edge of I/O CLOCK.
• It transfers control of the conversion to the internal state controller on the falling edge of the last
I/O CLOCK.
Positive reference voltage. The upper reference voltage value (nominally V_CC) is applied to REF+.
I The maximum input voltage range is determined by the difference between the voltage applied to
this terminal and the voltage applied to the REF– terminal.
I
Negative reference voltage. The lower reference voltage value (nominally ground) is applied to
REF–.
Positive supply voltage
Submit Documentation Feedback
3