LTC1403AIMSE Linear Technology, LTC1403AIMSE Datasheet - Page 12

• Manufacturer Part Number: LTC1403AIMSE
• Description: IC ADC 14BIT 2.8MSPS DIFF 10MSOP
• Manufacturer: Linear Technology

Specifications of LTC1403AIMSE

• Number Of Bits: 14
• Sampling Rate (per Second): 2.8M
• Data Interface: Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 12mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LTC1403/LTC1403A
APPLICATIONS INFORMATION
Board Layout and Bypassing
Wire wrap boards are not recommended for high resolu-
tion and/or high speed A/D converters. To obtain the best
performance from the LTC1403/LTC1403A, a printed circuit
board with ground plane is required. Layout for the printed
circuit board should ensure that digital and analog signal
lines are separated as much as possible. In particular, care
should be taken not to run any digital track alongside an
analog signal track. If optimum phase match between the
inputs is desired, the length of the two input wires should
be kept matched.
High quality tantalum and ceramic bypass capacitors
should be used at the V
the Block Diagram on the fi rst page of this data sheet.
12
Figure 5. Recommended Layout
DD
and V
REF
pins as shown in
For optimum performance, a 10μF surface mount AVX
capacitor with a 0.1μF ceramic is recommended for
the V
capacitors such as Murata GRM235Y5V106Z016 may
be used. The capacitors must be located as close to the
pins as possible. The traces connecting the pins and the
bypass capacitors must be kept short and should be made
as wide as possible.
Figure 5 shows the recommended system ground connec-
tions. All analog circuitry grounds should be terminated
at the LTC1403/LTC1403A GND (Pins 4, 5, 6 and exposed
pad). The ground return from the LTC1403/LTC1403A (Pins
4, 5, 6 and exposed pad) to the power supply should be
low impedance for noise free operation. Digital circuitry
grounds must be connected to the digital supply com-
mon. In applications where the ADC data outputs and
control signals are connected to a continuously active
microprocessor bus, it is possible to get errors in the
conversion results. These errors are due to feedthrough
from the microprocessor to the successive approximation
comparator. The problem can be eliminated by forcing the
microprocessor into a Wait state during conversion or by
using three-state buffers to isolate the ADC data bus.
POWER-DOWN MODES
Upon power-up, the LTC1403/LTC1403A is initialized to
the active state and is ready for conversion. The Nap and
Sleep mode waveforms show the power-down modes for
the LTC1403/LTC1403A. The SCK and CONV inputs control
the power-down modes (see Timing Diagrams). Two rising
edges at CONV, without any intervening rising edges at SCK,
put the LTC1403/LTC1403A in Nap mode and the power
drain drops from 14mW to 6mW. The internal reference
remains powered in Nap mode. One or more rising edges
at SCK wake up the LTC1403/LTC1403A for service very
quickly, and CONV can start an accurate conversion within
a clock cycle. Four rising edges at CONV, without any
DD
and V
REF
pins. Alternatively, 10μF ceramic chip
1403fb