LTC2494CUHF-PBF LINER [Linear Technology], LTC2494CUHF-PBF Datasheet - Page 10

• Manufacturer Part Number: LTC2494CUHF-PBF
• Description: 16-Bit 8-/16-Channel ?? ADC with PGA and Easy Drive Input Current Cancellation
• Manufacturer: LINER [Linear Technology]

PIN FUNCTIONS
LTC2494
TYPICAL PERFORMANCE CHARACTERISTICS
GND (Pins 1, 3, 4, 5, 6, 31, 32, 33): Ground. Multiple
ground pins internally connected for optimum ground cur-
rent fl ow and V
pins to a common ground plane through a low impedance
connection. All eight pins must be connected to ground
for proper operation.
NC (Pin 2): No Connection, this pin can be left fl oating
or tied to GND.
COM (Pin 7): The common negative input (IN
single-ended multiplexer confi gurations. The voltage on
CH0 to CH15 and COM pins can have any value between
GND – 0.3V to V
selected inputs (IN
V
Outside this input range, the converter produces unique
over-range and under-range output codes.
CH0 to CH15 (Pins 8 to 23): Analog Inputs. May be pro-
grammed for single-ended or differential mode.
MUXOUTP (Pin 24): Positive Multiplexer Output. Used
to drive an external buffer/amplifi er or can be shorted
directly to ADCINP.
ADCINP (Pin 25): Positive ADC Input. Tie to the output
of a buffer/amplifi er driven by MUXOUTP or tie directly
to MUXOUTP.
10
IN
= (IN
+
– IN
–
CC
) from –0.5 • V
–100
–140
–120
–20
–40
–60
–80
CC
decoupling. Connect each one of these
+
0
and IN
0
PSRR vs Frequency at V
(2x Speed Mode)
+ 0.3V. Within these limits, the two
V
REF
REF
IN
IN
F
T
O
CC
A
+
–
20
= GND
= 25°C
+
–
= GND
= GND
= 4.1V DC ±1.4V
= 2.5V
= GND
40 60
–
FREQUENCY AT V
) provide a bipolar input range
REF
80
100
/Gain to 0.5 • V
120
140
CC
(Hz)
160
CC
180
200
2494 G37
REF
–
220
) for all
/Gain.
ADCINN (Pin 26): Negative ADC Input. Tie to the output
of a buffer/amplifi er driven by MUXOUTN or tie directly
to MUXOUTN.
MUXOUTN (Pin 27): Negative Multiplexer Output. Used
to drive an external buffer/amplifi er or can be shorted
directly to ADCINN.
V
a 10μF tantalum capacitor in parallel with a 0.1μF ceramic
capacitor as close to the part as possible.
REF
The voltage on these pins can have any value between
GND and V
remains more positive than the negative reference input,
REF
– REF
• V
on-chip temperature measurement, the minimum value
of REF = 2V.
SDI (Pin 34): Serial Data Input. This pin is used to select the
gain, line frequency rejection mode, 1x or 2x speed mode,
temperature sensor, as well as the input channel. The serial
data input is applied under control of the serial clock (SCK)
during the data output/input operation. The fi rst conversion
following a new input or mode change is valid.
CC
REF
(Pin 28): Positive Supply Voltage. Bypass to GND with
–
+
, by at least 0.1V. The differential voltage V
(Pin 29), REF
–
/Gain) for all input channels. When performing an
–120
–140
–100
) sets the full-scale range (–0.5 • V
–20
–60
–40
–80
30600
0
CC
PSRR vs Frequency at V
(2x Speed Mode)
V
REF
REF
IN
IN
F
T
O
A
CC
+
–
as long as the reference positive input, REF
= GND
= 25°C
+
–
= GND
= GND
= 4.1V DC ±0.7V
= 2.5V
= GND
30650
FREQUENCY AT V
–
(Pin 30): Differential Reference Input.
30700
CC
(Hz)
30750
CC
2494 G38
30800
REF
/Gain to 0.5
REF
= (REF
2494fb
+
+
,