AS1538-BTST austriamicrosystems, AS1538-BTST Datasheet - Page 10

• Manufacturer Part Number: AS1538-BTST
• Description: IC ADC 12BIT 8CH 50K 16-TSSOP
• Manufacturer: austriamicrosystems

Specifications of AS1538-BTST

• Number Of Bits: 12
• Sampling Rate (per Second): 50k
• Data Interface: I²C, Serial
• Number Of Converters: 1
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AS1538/AS1540
Data Sheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1538/AS1540 successive approximation register (SAR) A/D converter architecture is based on capacitive
redistribution which inherently includes a sample-and- hold function.
The AS1538/AS1540 core is controlled by an internally generated free-running clock. When the device is not perform-
ing conversions or being addressed, the A/D converter-core and internal clock are powered off.
Figure 22. Simplified I/O Diagram
Analog Input
When the converter enters the hold mode, the voltage on the selected CHx pin is captured on the internal capacitor
array. The input current on the analog inputs depends on the conversion rate of the device. During the sample period,
the source must charge the internal sampling capacitor (typically 15pF). After the capacitor has been fully charged,
there is no further input current. The amount of charge transfer from the analog source to the converter is a function of
conversion rate.
Figure 23. Reference circuit
www.austriamicrosystems.com
1µF
REF
VIN
IN/OUT
COM
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
+
-
AS1538/
AS1540
10Ω
1µF
1nF
V
SDA
SCL
A0
A1
GND
DD
REF
CH0:CH7
+
IN/OUT
Revision 1.03
0.1 to
10µF
AS1538
2kΩ
V
SDA
DD
+
0.1 to
10µF
Microcontroller
+5.25V
+2.7 to
2kΩ
+5.25V
+2.7 to
0.1 to
10µF
+
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