LM9822 datasheet(5/22 Pages) NSC

5 / 22 page

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AC Electrical Characteristics

The following specifications apply for AGND=DGND=0V, VA=+5.0VDC, VD=+3.0 or +5.0VDC, fMCLK=12MHz, except where noted

otherwise. Boldface limits apply for A=TJ=TMIN to TMAX; all other limits TA=TJ=25°C. (Notes 7& 8)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional,

but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characte ristics. The guaranteed specifications apply

only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the list ed test conditions.

Note 2: All voltages are measured with respect to GND=AGND=DGND=0V, unless otherwise specified.

Note 3: When the input voltage (VIN) at any pin exceeds the power supplies (VIN<GND or VIN>VA or VD), the current at that pin should be limited to 25mA. The 50m

maximum package input current rating limits the number of pins that can simultaneously safely exceed the power supplies with an

input current of 25mA to two.

Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax, ΘJA and the ambient temperature, TA. The maximum allow-

able power dissipation at any temperature is P D = (TJmax - TA) / ΘJA. TJmax = 150°C for this device. The typical thermal resistance ( ΘJA) of this part when board mounted

is 69°C/W for the M28B SOIC package

Note 5: Human body model, 100pF capacitor discharged through a 1.5k

Ω resistor. Machine model, 200 pF capacitor discharged through a 0Ω resistor.

Note 6: See AN450 “Surface Mounting Methods and Their Effect on Product Reliability” or the section titled “Surface Mount” found in any National Semiconductor Linear

Data Book for other methods of soldering surface mount devices.

Note 7: Two diodes clamp the OS analog inputs to

AGND and VA as shown below. This input protection, in combination with the external clamp capacitor and the output

impedance of the sensor, prevents damage to the LM9822 from transients during power-up.

Note 8: To guarantee accuracy, it is required that VA and VD be connected to clean, low noise power supplies, with separate bypass capacitors at each supply pin. When

both VA and VD are operated at 5.0V, they must be powered by the same regulator, with separate power planes or traces and separate bypass capacitors at each supply pin.

Symbol

Parameter

Conditions

Typical

(Note 9)

Limits

(Note 10)

Units

(Limits)

fMCLK

Maximum MCLK frequency

MHz (min)

tMCLK

MCLK period

ns (min)

MCLK duty cycle

%(min)

%(max)

tSCLK

Serial Clock Period

tMCLK(min)

tSEN

Serial Enable high time

tMCLK(min)

tSSU

SDI setup time

ns (min)

tSH

SDI hold time

ns (min)

tSDDO

SCLK

edge to new valid data

VD = 5.0V

VD = 3.3V

8.5

ns (max)

tVSU

VSMP setup time

ns (min)

tVH

VSMP hold time

ns (min)

tCSU

CLMP setup time

ns (min)

tCH

CLMP hold time

ns (min)

tDDO

MCLK

edge to new valid data

VD = 5.0V

VD = 3.3V

ns (max)

OS Input

AGND

TO INTERNAL

CIRCUITRY

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