LTC1407CMSE-1 Linear Technology, LTC1407CMSE-1 Datasheet - Page 14

• Manufacturer Part Number: LTC1407CMSE-1
• Description: IC ADC 12BIT 3MSPS SAMPLE 10MSOP
• Manufacturer: Linear Technology

Specifications of LTC1407CMSE-1

• Number Of Bits: 12
• Sampling Rate (per Second): 3M
• Data Interface: Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 14mW
• Voltage Supply Source: Single Supply
• Operating Temperature: 0°C ~ 70°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

APPLICATIONS INFORMATION
LTC1407-1/LTC1407A-1
LT1818/LT1819: 400MHz, 2500V/μs, 9mA, Single/Dual
Voltage Mode Operational Amplifi er.
LT6200: 165MHz GBWP , –85dBc distortion at 1MHz,
unity-gain stable, rail-to-rail in and out, 15mA/amplifi er,
0.95nV/√Hz.
LT6203: 100MHz GBWP , –80dBc distortion at 1MHz,
unity-gain stable, rail-to-rail in and out, 3mA/amplifi er,
1.9nV/√Hz.
LT6600: Amplifi er/Filter Differential In/Out with 10MHz
Cutoff.
INPUT FILTERING AND SOURCE IMPEDANCE
The noise and the distortion of the input amplifi er and
other circuitry must be considered since they will add
to the LTC1407-1/LTC1407A-1 noise and distortion. The
small-signal bandwidth of the sample-and-hold circuit is
50MHz. Any noise or distortion products that are pres-
ent at the analog inputs will be summed over this entire
bandwidth. Noisy input circuitry should be fi ltered prior
to the analog inputs to minimize noise. A simple 1-pole
RC fi lter is suffi cient for many applications. For example,
Figure 1 shows a 47pF capacitor from CHO
and a 51Ω source resistor to limit the net input bandwidth
to 30MHz. The 47pF capacitor also acts as a charge
reservoir for the input sample-and-hold and isolates the
ADC input from sampling-glitch sensitive circuitry. High
quality capacitors and resistors should be used since these
14
ANALOG
ANALOG
1.5V DC
1.5V DC
INPUT
INPUT
V
V
CM
CM
*TIGHT TOLERANCE REQUIRED TO AVOID
Figure 1. RC Input Filter
APERTURE SKEW DEGRADATION
51Ω*
51Ω*
10μF
47pF*
47pF*
11
1
2
3
4
5
CH0
CH0
V
GND
CH1
CH1
LTC1407A-1
REF
LTC1407-1/
+
–
+
–
14071 F01
+
to ground
components can add distortion. NPO and silvermica type
dielectric capacitors have excellent linearity. Carbon surface
mount resistors can generate distortion from self heating
and from damage that may occur during soldering. Metal
fi lm surface mount resistors are much less susceptible to
both problems. When high amplitude unwanted signals
are close in frequency to the desired signal frequency a
multiple pole fi lter is required.
High external source resistance, combined with 13pF
of input capacitance, will reduce the rated 50MHz input
bandwidth and increase acquisition time beyond 39ns.
INPUT RANGE
The analog inputs of the LTC1407-1/LTC1407A-1 may be
driven fully differentially with a single supply. Either input
may swing up to 3V, provided the differential swing is no
greater than 1.25V. In the valid input range, each input of
each channel is always up to ±1.25V away from the other
input of each channel. The –1.25V to 1.25V range is also
ideally suited for AC-coupled signals in single supply
applications. Figure 2 shows how to AC-couple signals
in a single supply system without needing a mid-supply
1.5V DC external reference. The DC common mode level
is supplied by the previous stage that is already bounded
by single supply voltage of the system. The common
mode range of the inputs extends from ground to the
supply voltage V
and CH0
1.25V, the output code will stay fi xed at zero and all ones,
and if this difference goes below –1.25V, the output code
will stay fi xed at one and all zeros.
Figure 2. AC Coupling of AC Signals with 1kHz Low Cut
V
IN
–
56pF
inputs or the CH1
51Ω
C3
R3
DD
C1, C2: FILM TYPE
C3: COG TYPE
C4: CERAMIC BYPASS
. If the difference between the CH0
1.6k
1.6k
1μF
R2
R1
C2
C1
1μF
+
and CH1
10μF
C4
4.09V
+
1
2
3
–
CHO
CHO
V
LTC1407A-1
LTC1407-1/
inputs exceeds
REF
+
–
14071 F02
14071fb
+