LTC1407-1/LTC1407A-1
9
14071fb
TYPICAL PERFORMANCE CHARACTERISTICS
CH0+ (Pin 1): Noninverting Channel 0. CH0+ operates
fully differentially with respect to CH0–, with a –1.25V to
1.25V differential swing with respect to CH0– and a 0 to
VDD absolute input range.
CH0– (Pin 2):
Inverting Channel 0. CH0– operates fully
differentially with respect to CH0+, with a 1.25V to –1.25V
differential swing with respect to CH0+ and a 0 to VDD
absolute input range.
VREF (Pin 3): 2.5V Internal Reference. Bypass to GND and
a solid analog ground plane with a 10μF ceramic capacitor
(or 10μF tantalum in parallel with 0.1μF ceramic). Can be
overdriven by an external reference voltage ≥ 2.55V and
≤VDD.
CH1+ (Pin 4):
Noninverting Channel 1. CH1+ operates
fully differentially with respect to CH1–, with a –1.25V to
1.25V differential swing with respect to CH1– and a 0 to
VDD absolute input range.
CH1– (Pin 5):
Inverting Channel 1. CH1– operates fully
differentially with respect to CH1+, with a 1.25V to –1.25V
differential swing with respect to CH1+ and a 0 to VDD
absolute input range.
GND (Pins 6, 11): Ground and Exposed Pad. This single
ground pin and the Exposed Pad must be tied directly to
the solid ground plane under the part. Keep in mind that
analog signal currents and digital output signal currents
ow through these connections.
VDD (Pin 7): 3V Positive Supply. This single power pin
supplies 3V to the entire chip. Bypass to GND pin and
solid analog ground plane with a 10μF ceramic capacitor
(or 10μF tantalum) in parallel with 0.1μF ceramic. Keep in
mind that internal analog currents and digital output signal
currents ow through this pin. Care should be taken to
place the 0.1μF bypass capacitor as close to Pins 6 and 7
as possible.
SDO (Pin 8): Three-State Serial Data Output. Each pair of
output data words represent the two analog input channels
at the start of the previous conversion. The output format
is 2’s complement.
SCK (Pin 9): External Clock Input. Advances the conver-
sion process and sequences the output data on the rising
edge. One or more pulses wake from sleep.
CONV (Pin 10): Convert Start. Holds the two analog input
signals and starts the conversion on the rising edge. Two
pulses with SCK in xed high or xed low state starts nap
mode. Four or more pulses with SCK in xed high or xed
low state starts sleep mode.
VDD = 3V, TA = 25°C (LTC1407-1/LTC1407A-1)
Reference Voltage vs VDD
Reference Voltage
vs Load Current
PIN FUNCTIONS
VDD (V)
2.4890
V
REF
(V)
2.4894
2.4898
2.4902
2.4892
2.4896
2.4900
2.8
3.0
3.2
3.4
14071 G26
2.6
3.6
LOAD CURRENT (mA)
0.4
0.8
1.2
1.6
14071 G27
2.0
0.2
0
0.6
1.0
1.4
1.8
2.4890
V
REF
(V)
2.4894
2.4898
2.4902
2.4892
2.4896
2.4900