LTC1857/LTC1858/LTC1859
U W
TYPICAL PERFOR A CE CHARACTERISTICS
LTC1859 Power Supply
Feedthrough vs Ripple Frequency
Supply Current vs Supply Voltage
Supply Current vs Temperature
9.0
8.5
8.0
7.5
7.0
–10
–20
–30
–40
–50
–60
–70
–80
9.0
8.5
8.0
7.5
f
= 100kHz
= 60mV
f
= 100kHz
f
= 100kHz
SAMPLE
RIPPLE
SAMPLE
SAMPLE
V
7.0
5
5.25
4.5
5.5
100
1k
10k
100k
1M
4.75
–50 –25
0
25
50
75
100
RIPPLE FREQUENCY (Hz)
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
1859 G10
1859 G11
1859 G12
U
U
U
PI FU CTIO S
AGND1 (Pin 14): Analog Ground.
COM (Pin 1): Common Input. This is the reference point
for all single-ended inputs. It must be free of noise and is
usually connected to the analog ground plane.
V
REF (Pin 15): 2.5V Reference Output. Bypass to analog
ground with a 1µF tantalum capacitor.
CH0 (Pin 2): Analog MUX Input.
CH1 (Pin 3): Analog MUX Input.
CH2 (Pin 4): Analog MUX Input.
CH3 (Pin 5): Analog MUX Input.
CH4 (Pin 6): Analog MUX Input.
CH5 (Pin 7): Analog MUX Input.
CH6 (Pin 8): Analog MUX Input.
CH7 (Pin 9): Analog MUX Input.
REFCOMP (Pin 16): Reference Buffer Output. Bypass to
analog ground with a 10µF tantalum and a 0.1µF ceramic
capacitor. Nominal output voltage is 4.096V.
AGND2 (Pin 17): Analog Ground.
AGND3 (Pin 18): Analog Ground. This is the substrate
connection.
AVDD (Pin19):5VAnalogSupply.Bypasstoanalogground
with a 0.1µF ceramic and a 10µF tantalum capacitor.
DVDD (Pin20):5VDigitalSupply. Bypasstodigitalground
with a 0.1µF ceramic and a 10µF tantalum capacitor.
MUXOUT+ (Pin 10): Positive MUX Output. Output of the
analogmultiplexer.ConnecttoADC+ fornormaloperation.
OVDD (Pin 21): Positive Supply for the Digital Output
Buffers (3V to 5V). Bypass to digital ground with a 0.1µF
ceramic and a 10µF tantalum capacitor.
MUXOUT– (Pin 11): Negative MUX Output. Output of the
analogmultiplexer.ConnecttoADC– fornormaloperation.
ADC+ (Pin 12): Positive Analog Input to the Analog-to-
Digital Converter.
BUSY (Pin 22): Output shows converter status. It is low
when a conversion is in progress.
ADC– (Pin 13): Negative Analog Input to the Analog-to-
Digital Converter.
SDO (Pin 23): Serial Data Output.
185789f
7
Linear Systems [ Linear Systems ]
