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LTC2487
11
2487fd
PIN FUNCTIONS
GND – 0.3V to VCC + 0.3V. Within these limits, the two
selected inputs (IN+ and IN– ) provide a bipolar input range
VIN = (IN+ – IN–) from –0.5 VREF/Gain to 0.5 VREF/Gain.
Outside this input range, the converter produces unique
over-range and under-range output codes.
CH0 to CH3 (Pin 8-Pin 11): Analog Inputs. May be pro-
grammed for single-ended or differential mode.
VCC (Pin 12): Positive Supply Voltage. Bypass to GND with
a 10μF tantalum capacitor in parallel with a 0.1μF ceramic
capacitor as close to the part as possible.
REF+, REF– (Pin 13, Pin 14): Differential Reference Input.
The voltage on these pins can have any value between
GND and VCC as long as the reference positive input, REF+,
remains more positive than the negative reference input,
REF–, by at least 0.1V. The differential voltage (VREF = REF+
– REF–) sets the full-scale range (–0.5 VREF/Gain to 0.5
VREF/Gain) for all input channels. When performing an
on-chip temperature measurement, the minimum value
of REF = 2V.
Exposed Pad (Pin 15): Ground. This pin is ground and
must be soldered to the PCB ground plane. For prototyping
purposes, this pin may remain oating.
FUNCTIONAL BLOCK DIAGRAM
AUTOCALIBRATION
AND CONTROL
DIFFERENTIAL
3RD ORDER
Δ MODULATOR
DECIMATING FIR
ADDRESS
INTERNAL
OSCILLATOR
I2C
INTERFACE
GND
VCC
CH0
CH1
CH2
CH3
COM
MUX
IN+
IN–
CA0
SCL
REF+
REF–
CA1
SDA
fO
(INT/EXT)
2487 BD
+
–
1.7k
TEMP
SENSOR