AS1542-BTSU ams, AS1542-BTSU Datasheet - Page 26

• Manufacturer Part Number: AS1542-BTSU
• Description: Analog to Digital Converters - ADC
• Manufacturer: ams

Specifications of AS1542-BTSU

• Rohs: yes
• Number Of Channels: 16/8
• Architecture: SAR
• Conversion Rate: 1 MSPs
• Resolution: 12 bit
• Input Type: Single-Ended/Differential
• Snr: 71 dB
• Interface Type: QSPI, SPI
• Operating Supply Voltage: 2.7 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-28
• Maximum Power Dissipation: 18.4 mW
• Minimum Operating Temperature: - 40 C
• Number Of Converters: 1

AS1542
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
Grounding and Layout Considerations
The AS1542 has excellent immunity to noise on the power supplies as can be seen by the
Frequency graph on page
www.austriamicrosystems.com
- The PCB should be designed such that the analog and digital sections are confined to separate areas of the
- Pins AGND and GND should be tied to the analog ground plane. Pin DGND should be tied to the digital ground
- Digital and analog ground planes should be joined at only one place. If the AS1542 is in a system where multiple
- Avoid running digital lines under the device as these will couple noise onto the die.
- The analog ground plane should be allowed to run under the AS1542 to avoid noise coupling.
- The power supply lines to the AS1542 should use as large a trace as possible to provide low-impedance paths
- Fast-switching signals (e.g., clocks) should be shielded with digital ground to avoid radiating noise to other sec-
- Clock signals should not be run near the analog inputs.
- Avoid crossover of digital and analog signals.
- Traces on opposite sides of the board should run at right angles to each other. This will reduce the effects of
- All analog input channels and the reference input voltage should be decoupled to the ground pin of AGND.
- All analog supplies should be decoupled with 10µF tantalum in parallel with 0.1µF capacitors to GND. To achieve
board. This facilitates the use of ground planes that can be separated easily. A minimum etch technique is gener-
ally best for ground planes as it gives the best shielding.
plane.
devices require an AGND-to-DGND connection, the connection should be made at one point – a star ground
point which should be established as close as possible to the AS1542.
and reduce the effects of glitches on the power supply line.
tions of the PCB.
feedthrough through the board. A microstrip technique is the best but is not always possible with a double-sided
board. In this technique, the component side of the board is dedicated to ground planes while signals are placed
on the solder side.
the best from these decoupling components, they must be placed as close as possible to the device, ideally right
up against the device. The 0.1µF capacitors should be low ESR and ESI (e.g., common ceramic or surface
mount types) which provide a low impedance path to ground at high frequencies to handle transient currents due
to internal logic switching.
11, however, the following should be considered regarding grounding and PCB layout:
Revision 1.00
PSRR vs. Supply Signal
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