TLV1544C, TLV1544I, TLV1548C, TLV1548I, TLV1548M
LOW-VOLTAGE 10-BIT ANALOG-TO-DIGITAL CONVERTERS
WITH SERIAL CONTROL AND 4/8 ANALOG INPUTS
SLAS139C – DECEMBER 1996 – REVISED JANUARY 1999
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Terminal Functions
TERMINAL
I/O
DESCRIPTION
NAME
NO.
I/O
DESCRIPTION
A0–A3
A4–A7
6–9
–
1–4
5–8
I
Analog inputs. The analog inputs are internally multiplexed. (For a source impedance greater than
1 k
, the asynchronous start should be used to increase the sampling time.)
CS
16
15
I
Chip select. A high-to-low transition on CS resets the internal counters and controls and enables DATA IN,
DATA OUT, and I/O CLK within the maximum setup time. A low-to-high transition disables DATA IN, DATA
OUT, and I/O CLK within the setup time.
CSTART
10
9
I
Sampling/conversion start control. CSTART controls the start of the sampling of an analog input from a
selected multiplex channel. A high-to-low transition starts the sampling of the analog input signal. A
low-to-high transition puts the sample-and-hold function in hold mode and starts the conversion. CSTART
is independent from I/O CLK and works when CS is high. The low CSTART duration controls the duration
of the sampling cycle for the switched capacitor array. CSTART is tied to VCC if not used.
DATA IN
2
17
I
Serial data input. The 4-bit serial data selects the desired analog input and test voltage to be converted next
in a normal cycle. These bits can also set the conversion rate and enable the power-down mode.
When operating in the microprocessor mode, the input data is presented MSB first and is shifted in on the
first four rising (INV CLK = VCC) or falling (INV CLK = GND) edges of I/O CLK (after CS↓).
g(
CC)g (
)
g
(
)
When operating in the DSP mode, the input data is presented MSB first and is shifted in on the first four
falling (INV CLK = VCC) or rising (INV CLK = GND) edges of I/O CLK (after FS↓).
After the four input data bits have been read into the input data register, DATA IN is ignored for the remainder
of the current conversion period.
DATA OUT
1
16
O
Three-state serial output of the A/D conversion result. DATA OUT is in the high-impedance state when CS
is high and active when CS is low or after FS
↓ (in DSP mode). With a valid CS signal, DATA OUT is removed
from the high-impedance state and is driven to the logic level corresponding to the MSB or LSB value of
the previous conversion result. DATA OUT changes on the falling (microprocessor mode) or rising (DSP
mode) edge of I/O CLK.
EOC
4
19
O
End of conversion. EOC goes from a high to a low logic level on the tenth rising (microprocessor mode)
or tenth falling (DSP mode) edge of I/O CLK and remains low until the conversion is complete and data is
ready for transfer. EOC can also indicate that the converter is busy.
FS
13
12
I
DSP frame synchronization input. FS indicates the start of a serial data frame into or out of the device. FS
is tied to VCC when interfacing the device with a microprocessor.
GND
11
10
Ground return for internal circuitry. All voltage measurements are with respect to GND, unless otherwise
noted.
INV CLK
12
11
I
Inverted clock input. INV CLK is tied to GND when an inverted I/O CLK is used as the source of the input
clock. This affects both microprocessor and DSP interfaces. INV CLK is tied to VCC if I/O CLK is not
inverted. INV CLK can also invoke a built-in test mode.
Terminal numbers are for the D package.
Terminal numbers are for the DB, J, and FK packages.