LTC1287

3

1287fa

AC CHARACTERISTICS

LTC1287B/LTC1287C

ELECTRICAL C

C

HARA TER STICS

DIGITAL A D

I

DC

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

Note 2: All voltage values are with respect to ground (unless otherwise

noted).

= 2.5V, 1LSB = 2.5V/4096 = 0.61mV.

Note 5: Integral nonlinearity error is defined as the deviation of a code

from a straight line passing through the actual endpoints of the transfer

curve. The deviation is measured from the center of the quantization band.

Note 6: Recommended operating conditions.

LTC1287B/LTC1287C

Note 7: Two on-chip diodes are tied to each analog input which will

conduct for analog voltages one diode drop below GND or one diode drop

inputs can cause this input diode to conduct, especially at elevated

temperature, and cause errors for inputs near full scale. This spec allows

50mV forward bias of either diode. This means that as long as the analog

input does not exceed the supply voltage by more than 50mV, the output

code will be correct.

Note 8: Channel leakage current is measured after the channel selection.

Note 9: Increased leakage currents at elevated temperatures cause the

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Time Output Data Remains Valid After CLK

↓

50

ns

See Test Circuits

q

40

100

ns

See Test Circuits

q

40

100

ns

CLK High Time

600

ns

CLK Low Time

800

ns

Setup Time, CS

↓ Before CLK↑

100

ns

CS High Time Between Data Transfer Cycles

5.0

µs

CS Low Time During Data Transfer

14

CLK Cycles

Input Capacitance

Analog Inputs On Channel

100

pF

Analog Inputs Off Channel

5

pF

Digital Inputs

5

pF

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

High Level Input Voltage

q

2.1

V

Low Level Input Voltage

q

0.45

V

High Level Input Current

q

2.5

µA

Low Level Input Current

q

–2.5

µA

High Level Output Voltage

2.90

V

q

2.7

2.85

V

Low Level Output Voltage

0.05

V

q

0.10

0.3

V

High Z Output Leakage

q

3

µA

q

–3

µA

Output Source Current

–10

mA

Output Sink Current

9mA

Positive Supply Current

CS High

q

1.5

5

mA

Reference Current

q

10

50

µA