Datasheet

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
10
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
t
ACQ
Aa Ab Ab Ac Ad
XDaDb DbDc
CS
CSTART
DATA IN
EOC
DATA OUT
Async Flag
Read Out
Cycle
Read Out
Cycle
Read Out
Cycle
FS
(DSP Mode)
Complete Extended
Sample Cycle
t
ACQ
NOTES: A. Aa = Address for input channel a.
B. Da = Conversion result from channel a.
Hi–Z Hi–Z Hi–Z Hi–Z Hi–Z Hi–Z
Normal
Cycle
Normal
Cycle
Extended
Sample
Cycle
Extended
Sample
Cycle
Figure 2. Extended Sampling Operation
reference voltage inputs
There are two reference inputs used with the TLV1544/TLV1548, REF+ and REF–. These voltage values
establish the upper and lower limits of the analog inputs to produce a full-scale and zero-scale reading
respectively. The values of REF+, REF–, and the analog input should not exceed the positive supply or be lower
than GND consistent with the specified absolute maximum ratings. The digital output is at full scale when the
input signal is equal to or higher than REF+ and is at zero when the input signal is equal to or lower than REF–.
programmable conversion rate
The TLV1544/TLV1548 offers two conversion rates to maximize battery life when high-speed operation is not
necessary. The conversion rate is programmable. Once the conversion rate has been selected, it takes effect
immediately in the same cycle and stays at the same rate until the other rate is chosen. The conversion rate
should be set at power up. Activation and deactivation of the power-down state (digital logic active) has no effect
on the preset conversion rate.