THS4521 Datasheet, PDF (47/65 Pages) Texas Instruments – VERY LOW POWER, NEGATIVE RAIL INPUT, RAIL-TO-RAIL OUTPUT, FULLY DIFFERENTIAL AMPLIFIER

www.ti.com
THS4521, THS4522, THS4524
SBOS458H – DECEMBER 2008 – REVISED JUNE 2015
9.2.2 ADC Driver Performance: THS4521 and ADS1278 Combined Performance
The THS4521 provides excellent performance when driving high-performance ΔΣ and successive approximation
register (SAR) ADCs in audio and industrial applications using a single 3-V to 5-V power supply. To show
achievable performance, the THS4521 is tested as the drive amplifier for the ADS1278 24-bit ADC. The
ADS1278 offers excellent ac and DC performance, with four selectable operating
modes from 10 kSPS to 128 kSPS to enable the user to fine-tune performance and power for specific application
needs. The circuit shown in Figure 85 was used to test the performance. Data were taken using the High-
Resolution mode (52 kSPS) of the ADS1278 with input frequencies at 1 kHz and 10 kHz and signal levels 1/2 dB
below full-scale (–0.5 dBFS). FFT plots showing the spectral performance are given in Figure 87 and Figure 88;
tabulated ac analysis results are shown in Table 11 and compared to the ADS1278 data sheet typical
performance specifications.
1 kW
1.5 nF
5V
V_IN+
V_IN-
1 kW
1 kW
49.9 W
THS4521
V_OCM
1.5 nF
49.9 W
0.1 mF
2.2 nF
AINN1
ADS1278 (CH 1)
AINP1 V_COM
x1
1/2
OPA2350
0.1 mF
1 kW
Figure 85. THS4521 and ADS1278 (Ch 1) Test Circuit
9.2.2.1 Design Requirements
Configuration
THS4521 and
ADS1278
ADS1278 Data
sheet (typ)
Tone
1 kHz
10 kHz
1 kHz
Table 11. AC Analysis
Signal (dBFS)
–0.5
–0.5
SNR (dBc)
109
102
THD (dBc)
–108
–110
–0.5
110
–108
SINAD (dBc)
105
101
—
SFDR (dBc)
114
110
109
Copyright © 2008–2015, Texas Instruments Incorporated
Submit Documentation Feedback
47
Product Folder Links: THS4521 THS4522 THS4524