LTC2433-1IMS#TR Linear Technology, LTC2433-1IMS#TR Datasheet - Page 8

• Manufacturer Part Number: LTC2433-1IMS#TR
• Description: IC CONV A/D 16BIT DIFF 10-MSOP
• Manufacturer: Linear Technology

Specifications of LTC2433-1IMS#TR

• Number Of Bits: 16
• Sampling Rate (per Second): 6.8
• Data Interface: MICROWIRE™, Serial, SPI™
• Number Of Converters: 2
• Power Dissipation (max): 1mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LTC2433-1
APPLICATIO S I FOR ATIO
CONVERTER OPERATION
Converter Operation Cycle
The LTC2433-1 is a low power,
input/reference and an easy-to-use 3-wire serial interface
(see Figure 1). Its operation is made up of three states.
The converter operating cycle begins with the conversion,
followed by the low power sleep state and ends with the
data output (see Figure 2). The 3-wire interface consists
of serial data output (SDO), serial clock (SCK) and chip
select (CS).
Initially, the LTC2433-1 performs a conversion. Once the
conversion is complete, the device enters the sleep state.
The part remains in the sleep state as long as CS is HIGH.
While in this sleep state, power consumption is reduced by
nearly two orders of magnitude. The conversion result is
held indefinitely in a static shift register while the converter
is in the sleep state.
Once CS is pulled LOW, the device exits the low power
mode and enters the data output state. If CS is pulled HIGH
before the first rising edge of SCK, the device returns to the
low power sleep mode and the conversion result is still
held in the internal static shift register. If CS remains LOW
after the first rising edge of SCK, the device begins
outputting the conversion result. Taking CS high at this
point will terminate the data output state and start a new
8
Figure 2. LTC2433-1 State Transition Diagram
FALSE
U
DATA OUTPUT
CONVERT
CS = LOW
U
SCK
SLEEP
AND
TRUE
W
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ADC with differential
U
conversion. There is no latency in the conversion result.
The data output corresponds to the conversion just per-
formed. This result is shifted out on the serial data out pin
(SDO) under the control of the serial clock (SCK). Data is
updated on the falling edge of SCK allowing the user to
reliably latch data on the rising edge of SCK (see Figure 3).
The data output state is concluded once 19 bits are read
out of the ADC or when CS is brought HIGH. The device
automatically initiates a new conversion and the cycle
repeats. In order to maintain compatibility with 24-/32-bit
data transfers, it is possible to clock the LTC2433-1 with
additional serial clock pulses. This results in additional
data bits which are logic HIGH.
Through timing control of the CS and SCK pins, the
LTC2433-1 offers several flexible modes of operation
(internal or external SCK and free-running conversion
modes). These various modes do not require program-
ming configuration registers; moreover, they do not dis-
turb the cyclic operation described above. These modes of
operation are described in detail in the Serial Interface
Timing Modes section.
Conversion Clock
A major advantage the delta-sigma converter offers over
conventional type converters is an on-chip digital filter
(commonly implemented as a Sinc or Comb filter). For
high resolution, low frequency applications, this filter is
typically designed to reject line frequencies of 50Hz and
60Hz plus their harmonics. The filter rejection perfor-
mance is directly related to the accuracy of the converter
system clock. The LTC2433-1 incorporates a highly accu-
rate on-chip oscillator. This eliminates the need for exter-
nal frequency setting components such as crystals or
oscillators. Clocked by the on-chip oscillator, the
LTC2433-1 achieves a minimum of 87dB rejection over
the range 49Hz to 61.2Hz.
Ease of Use
The LTC2433-1 data output has no latency, filter settling
delay or redundant data associated with the conversion
cycle. There is a one-to-one correspondence between the
conversion and the output data. Therefore, multiplexing
multiple analog voltages is easy.
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