MAX19505ETM+ Maxim Integrated Products, MAX19505ETM+ Datasheet - Page 31

• Manufacturer Part Number: MAX19505ETM+
• Description: IC ADC 8BIT 1CH 65MSPS 48TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX19505ETM+

• Number Of Bits: 8
• Sampling Rate (per Second): 65M
• Data Interface: Serial, Parallel
• Number Of Converters: 1
• Power Dissipation (max): 99mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 17. Integrated Voltage Regulator
Figure 18. Transformer-Coupled Input Drive for Input
Frequencies Up to Nyquist
Figure 19. Transformer-Coupled Input Drive for Input Frequencies Beyond Nyquist
V
IN
0.1µF
N.C.
MINI-CIRCUITS
1
5
3
ADT1-1WT
(PINS 1, 12, 13, 48)
T1
V
IN
6
2
4
0.1µF
N.C.
______________________________________________________________________________________
N.C.
36.5Ω
36.5Ω
AVDD
0.5%
0.5%
GND
MINI-CIRCUITS
1
5
3
ADT1-1WT
T1
0.1µF
6
2
4
N.C.
REFERENCE
Dual-Channel, 8-Bit, 65Msps ADC
IN_+
CM_
IN_-
MAX19505
75Ω
0.5%
75Ω
0.5%
N.C.
MINI-CIRCUITS
1
5
3
ADT1-1WT
T2
6
2
4
N.C.
The MAX19505 provides better SFDR and THD with
fully differential input signals than a single-ended input
drive. In differential input mode, even-order harmonics
are lower as both inputs are balanced, and each of the
ADC inputs only require half the signal swing compared
to single-ended input mode.
An RF transformer (Figure 18) provides an excellent
solution for converting a single-ended signal to a fully
differential signal. Connecting the center tap of the
transformer to CM_ provides a common-mode voltage.
The transformer shown has an impedance ratio of 1:1.4.
Alternatively, a different step-up transformer can be
selected to reduce the drive requirements. A reduced
signal swing from the input driver can also improve the
overall distortion. The configuration of Figure 18 is good
for frequencies up to Nyquist (f
Transformer-Coupled Differential Analog Input
110Ω
0.5%
110Ω
0.5%
IN
2.3V TO 3.5V
ENABLE
0.1µF
REGULATOR
Applications Information
1.8V
OUT
IN_+
CM_
IN_-
MAX19505
CLK
INTERNAL
CIRCUITS
ANALOG
/2).
Analog Inputs
31