LTC2453

11

2453fb

internal high frequency decoupling with damping elements,

which reduce the ADC performance sensitivity to PCB

layout and external components. Nevertheless, the very

high accuracy of this converter is best preserved by careful

low and high frequency power supply decoupling.

A 0.1μF, high quality, ceramic capacitor in parallel with a

10μF ceramic capacitor should be connected between the

The 0.1μF capacitor should be placed closest to the ADC

package. It is also desirable to avoid any via in the circuit

these two decoupling capacitors, and returning to the

converter GND pin. The area encompassed by this circuit

path, as well as the path length, should be minimized.

Very low impedance ground and power planes, and star

15k

(TYP)

0.35pF

(TYP)

IN–

2453 F08

15k

(TYP)

15k

(TYP)

15k

(TYP)

Figure 8. LTC2453 Analog Input/Reference Equivalent Circuit

15k

(TYP)

0.35pF

(TYP)

+

–

2453 F09

15k

(TYP)

0.35pF

(TYP)

+

–

Figure 9. LTC2453 Input Drive Equivalent Circuit

first to the decoupling capacitors described above, the

second to the ground return for the input signal source,

and the third to the ground return for the power supply

voltage source.

in Figure 8. Like all other A/D converters, the LTC2453 is

only as accurate as the reference it is using. Therefore, it

is important to keep the reference line quiet by careful low

and high frequency power supply decoupling.

The LT6660 reference is an ideal match for driving the

×

2mm DFN package with 2.5V, 3V, 3.3V and 5V options.

A 0.1μF, high quality, ceramic capacitor in parallel with

a 10μF ceramic capacitor should be connected between

package. The 0.1μF capacitor should be placed closest

to the ADC.

The input drive requirements can best be analyzed using

both the actual generator source resistance and any

additional optional resistors connected to the input pins.

APPLICATIONS INFORMATION