LTC2170IUKG-12#PBF Linear Technology, LTC2170IUKG-12#PBF Datasheet - Page 27

• Manufacturer Part Number: LTC2170IUKG-12#PBF
• Description: IC ADC 12BIT SER/PAR 25M 52-QFN
• Manufacturer: Linear Technology

Specifications of LTC2170IUKG-12#PBF

• Number Of Bits: 12
• Sampling Rate (per Second): 25M
• Data Interface: Serial, Parallel
• Number Of Converters: 4
• Power Dissipation (max): 238mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 52-WFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
GROUNDING AND BYPASSING
The LTC2172-12 requires a printed circuit board with a
clean unbroken ground plane. A multilayer board with an
internal ground plane in the fi rst layer beneath the ADC is
recommended. 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
or underneath the ADC.
High quality ceramic bypass capacitors should be used at
the V
capacitors must be located as close to the pins as possible.
Of particular importance is the 0.1μF capacitor between
REFH and REFL. This capacitor should be on the same
side of the circuit board as the A/D, and as close to the
device as possible (1.5mm or less). Size 0402 ceramic
capacitors are recommended. The larger 2.2μF capacitor
DD
, OV
DD
, V
CM
, V
REF
, REFH and REFL pins. Bypass
between REFH and REFL can be somewhat further away.
The traces connecting the pins and bypass capacitors must
be kept short and should be made as wide as possible.
The analog inputs, encode signals and digital outputs
should not be routed next to each other. Ground fi ll and
grounded vias should be used as barriers to isolate these
signals from each other.
HEAT TRANSFER
Most of the heat generated by the LTC2172-12 is transferred
from the die through the bottom-side exposed pad and
package leads onto the printed circuit board. For good
electrical and thermal performance, the exposed pad must
be soldered to a large grounded pad on the PC board. This
pad should be connected to the internal ground planes by
an array of vias.
LTC2171-12/LTC2170-12
LTC2172-12/
27
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