LTC6252 Linear Technology, LTC6252 Datasheet - Page 16

• Manufacturer Part Number: LTC6252
• Description: 3.5mA Power Efficient Rail-to-Rail I/O Op Amps
• Manufacturer: Linear Technology

DataSheet.in
LTC6252/LTC6253/LTC6254
TYPICAL APPLICATIONS
5V Single-Supply 16-Bit ADC Driver
Figure 3 shows the LTC6253 driving an LTC2393-16 16-bit
A/D converter on a single 5V supply. The low wideband
noise of the LTC6253 helps to achieve better than 93dB
SNR. A gain of 1.17V/V is taken in the fi rst amplifi er, giv-
ing an input voltage range of 3.5V
to the ADC. By taking a small amount of gain, a –1dBFS
16
(3.5V + 27.4mV)
27.4mV TO
V
IN
845Ω
+
–
½ LTC6253
143Ω
5V
2.5k
~2.08V
P-P
2.5k
–
+
½ LTC6253
for a full-scale input
5V
Figure 3. 5V Single Supply 16-Bit ADC Driver
–100
–120
–140
–160
Figure 4. LTC6253 Driving LTC2393-16
16b ADC 5V Single-Supply Performance
–20
–40
–60
–80
0
0
3900pF
249Ω
249Ω
100
FREQUENCY (kHz)
200
100Ω
100Ω
output can be easily obtained without the amplifi er transi-
tioning between input regions, thus minimizing crossover
distortion. Furthermore, by driving VCM with 2.08V from
the ADC’s VCM pin, the LTC6253 is capable of driving the
LTC2393-16 to within 0.1dB of full scale. Figure 4 shows
an FFT obtained with a sampling rate of 1Msps and a
20kHz input waveform. Spurious free dynamic range is
an excellent 104.7dB.
300
10μF
f
F1 = 20.111kHz
F1 AMPLITUDE
SNR = 93.28dB
THD = –100.50dB
SINAD = 92.53dB
SFDR = 104.7dB
F2 = –106.39dBc
F3 = –104.70dBc
F4 = –114.13dBc
F5 = –105.48dBc
IN
IN
S
= 1Msps
+
–
= –1.032dBFS
VCM
400
0.1μF
624678 F04
REFIN
10μF
AVP
5V
500
REFOUT
10μF
1μF
CNVST PD
LTC2393-16
SAMPLE CLOCK
0.1μF
DVP
RESET
5V
GND
4.7μF
1.8V TO 5V
OGND
OVP
BYTESWAP
INTERFACE
PARALLEL
SERIAL
SER/PAR
OR
OB/2C
BUSY
625234 F03
RD
CS
16 BIT
625234f