SLAS708A September   2010  – September 2019 ADS7947 , ADS7948 , ADS7949

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     ADS794x Block Diagram
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions: ADS794x (12-, 10-, 8-Bit)
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics: ADS7947 (12-Bit)
    6. 7.6  Electrical Characteristics: ADS7948 (10-Bit)
    7. 7.7  Electrical Characteristics: ADS7949 (8-Bit)
    8. 7.8  Timing Requirements
    9. 7.9  Switching Characteristics
    10. 7.10 Typical Characteristics: ADS7947, ADS7948, ADS7949
    11. 7.11 Typical Characteristics: ADS7947 (12-Bit)
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Multiplexer and ADC Input
      2. 8.3.2 Reference
      3. 8.3.3 Clock
      4. 8.3.4 ADC Transfer Function
      5. 8.3.5 Power-Down
    4. 8.4 Device Functional Modes
      1. 8.4.1 Device Operation
    5. 8.5 Programming
      1. 8.5.1 16-Clock Frame
      2. 8.5.2 32-Clock Frame
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Driving an ADC Without a Driving Op Amp
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Related Links
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.7 Electrical Characteristics: ADS7949 (8-Bit)

minimum and maximum values at AVDD = 2.7 V to 5.5 V, DVDD = 1.65 V to AVDD, TA = –40°C to +125°C, and
fSAMPLE = 2 MSPS (unless otherwise noted); typical values at AVDD = 3 V, DVDD = 1.8 V, TA = +25°C, and fSAMPLE = 2 MSPS
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ANALOG INPUT
Input capacitance(4) 32 pF
Input leakage current At +125°C 1.5 nA
SYSTEM PERFORMANCE
Resolution 8 Bits
No missing codes 8 Bits
Integral linearity –0.3 ±0.06 0.3 LSB(1)
Differential linearity –0.3 ±0.06 0.3 LSB
Offset error(2) –0.3 ±0.06 0.3 LSB
Gain error –0.3 ±0.06 0.3 LSB
Transition noise 25 µVRMS
Power-supply rejection 60 dB
SAMPLING DYNAMICS
Conversion time 8.5 SCLK
Acquisition time 80 ns
Maximum sample rate (throughput rate) 34-MHz SCLK in 16-clock frame 2 MSPS
34-MHz SCLK and CS low for 8.5 clocks 3 MSPS
Aperture delay 5 ns
Aperture jitter 10 ps
Step response 80 ns
Overvoltage recovery 80 ns
DYNAMIC CHARACTERISTICS
Total harmonic distortion (THD)(3) 100 kHz –80 dB
Signal-to-noise ratio (SNR) 100 kHz 49 dB
Signal-to-noise and distortion ratio (SINAD) 100 kHz 49 dB
Spurious-free dynamic range (SFDR) 100 kHz 81 dB
Full-power bandwidth At –3 dB 15 MHz
DIGITAL INPUT/OUTPUT
Logic family CMOS
Logic level VIH 0.7DVDD V
VIL 0.3DVDD V
VOH ISOURCE = 200 µA DVDD – 0.2 V
VOL ISINK = 200 µA 0.4 V
Input leakage current IIH, IIL 0 <VIN < DVDD ±20 nA
POWER-SUPPLY REQUIREMENTS
AVDD supply current IDYNAMIC AVDD = 3.3 V, fSAMPLE = 2 MSPS 2.5 mA
AVDD = 5 V, fSAMPLE = 2 MSPS 3 3.5 mA
ISTATIC AVDD = 3.3 V, SCLK off 1.8 mA
AVDD = 5 V, SCLK off 1.9 2.5 mA
DVDD supply current(5) DVDD = 3.3 V, SCLK = 34 MHz,
SDO load 20 pF		 500 µA
Power-down state AVDD supply current IPD-DYNAMIC SCLK = 34 MHz 550 µA
IPD-STATIC SCLK off 2.5 µA
Power-up time 1 µs
(1) LSB means least significant bit.
(2) Measured relative to an ideal full-scale input.
(3) Calculated on the first nine harmonics of the input frequency.
(4) See Figure 40 for sampling circuit details.
(5) DVDD consumes only dynamic current. IDVDD = CLOAD × DVDD × number of 0→1 transitions in SDO × fSAMPLE. This current is load-dependent and there is no DVDD current when the output is not toggling.