LTC2206IUK-14#PBF Linear Technology, LTC2206IUK-14#PBF Datasheet - Page 20

• Manufacturer Part Number: LTC2206IUK-14#PBF
• Description: IC ADC 14BIT 80MSPS 48-QFN
• Manufacturer: Linear Technology

Specifications of LTC2206IUK-14#PBF

• Number Of Bits: 14
• Sampling Rate (per Second): 80M
• Data Interface: Parallel
• Number Of Converters: 1
• Power Dissipation (max): 875mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-WFQFN, Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LTC2207-14/LTC2206-14
APPLICATIONS INFORMATION
Direct Coupled Circuits
Figure 5 demonstrates the use of a differential amplifi er to
convert a single ended input signal into a differential input
signal. The advantage of this method is that it provides
low frequency input response; however, the limited gain
bandwidth of any op amp or closed-loop amplifi er will de-
grade the ADC SFDR at high input frequencies. Additionally,
wideband op amps or differential amplifi ers tend to have
high noise. As a result, the SNR will be degraded unless
the noise bandwidth is limited prior to the ADC input.
Reference Operation
Figure 6 shows the LTC2207-14/LTC2206-14 refer-
ence circuitry consisting of a 2.5V bandgap reference,
a programmable gain amplifi er and control circuit. The
LTC2207-14/LTC2206-14 have three modes of reference
operation: Internal Reference, 1.25V external reference
or 2.5V external reference. To use the internal reference,
tie the SENSE pin to V
simply apply either a 1.25V or 2.5V reference voltage to the
SENSE input pin. Both 1.25V and 2.5V applied to SENSE
will result in a full scale range of 2.25V
1.25V output V
for input drive circuitry. An external bypass capacitor is
required for the V
low impedance path to ground for internal and external
20
ANALOG
Figure 5. DC Coupled Input with Differential Amplifi er
INPUT
AMPLIFIER = LTC6600-20,
LT1993, ETC.
DIFFERENTIAL
+
CM
–
CM
HIGH SPEED
AMPLIFIER
CM
is provided for a common mode bias
output. This provides a high frequency
+
–
DD
. To use an external reference,
25Ω
25Ω
2.2μF
12pF
12pF
V
A
A
CM
IN
IN
P-P
+
–
LTC2207-14/
LTC2206-14
(PGA = 0). A
2207614 F05
circuitry. This is also the compensation capacitor for the
reference; it will not be stable without this capacitor. The
minimum value required for stability is 2.2μF .
The internal programmable gain amplifi er provides the
internal reference voltage for the ADC. This amplifi er has
very stringent settling requirements and is not accessible
for external use.
The SENSE pin can be driven ±5% around the nominal 2.5V
or 1.25V external reference inputs. This adjustment range
can be used to trim the ADC gain error or other system
gain errors. When selecting the internal reference, the
SENSE pin should be tied to V
as possible. If the sense pin is driven externally it should
be bypassed to ground as close to the device as possible
with 1μF (or larger) ceramic capacitor.
PGA Pin
The PGA pin selects between two gain settings for
the ADC front-end. PGA = 0 selects an input range of
2.25V
2.25V input range has the best SNR; however, the distor-
tion will be higher for input frequencies above 100MHz.
For applications with high input frequencies, the low input
range will have improved distortion; however, the SNR
will be worse by up to approximately 2dB. See the Typical
Performance Characteristics section.
TIE TO V
EXTERNAL 1.25V
EXTERNAL 2.5V
INTERNAL 2.5V
OR INPUT FOR
OR INPUT FOR
REFERENCE
REFERENCE
REFERENCE
P-P
DD
TO USE
; PGA = 1 selects an input range of 1.5V
SENSE
2.2μF
V
Figure 6. Reference Circuit
CM
LTC2207-14/
LTC2206-14
BUFFER
DD
AND GAIN
CONTROL
SELECT
RANGE
as close to the converter
1.25V
PGA
REFERENCE
BANDGAP
REFERENCE
INTERNAL
220714614fc
P-P
2.5V
ADC
. The
2207614 F06