AS1530/AS1531
Data Sheet - Detailed Description
Additionally the bandgap voltage can be adjusted about ±100mV by forcing a voltage to the REFADJ pin. The REFADJ
input impedance is typically 17kΩ. Figure 32 shows a possible arrangement.
Figure 32. Reference Adjust Circuit
+3.3V
24kΩ
510kΩ
AS1530/
12
100kΩ
REFADJ
AS1531
CLOAD
0.01µF
DGND
GND
External Reference
An external reference can be connected directly at pin REF. To use the external reference, the internal buffer must be
disabled by connecting pin REFADJ to pin VDD. The input resistance is typically 15kΩ.
During conversion, an external reference at pin REF must deliver up to 350µA DC load current and have 10Ω or less
output impedance. If the reference has a higher output impedance or is noisy, bypass it with a 4.7µF capacitor placed
as close to pin REF as possible.
Note: Using the REFADJ input makes buffering the external reference unnecessary.
www.austriamicrosystems.com
Revision 1.02
22 - 29
AMSCO [ AMS(艾迈斯) ]
