LTC2453

10

2453f

Discarding a Conversion Result and Initiating a New

Conversion

It is possible to start a new conversion without reading

the old result, as shown in Figure 7. Following a valid 7-bit

address, a read request (R) bit, and a valid ACK, a STOP

command will start a new conversion.

PRESERVING THE CONVERTER ACCURACY

The LTC2453 is designed to dramatically reduce the conver-

sion result’s sensitivity to device decoupling, PCB layout,

antialiasing circuits, line and frequency perturbations. Nev-

ertheless, in order to preserve the high accuracy capability

of this part, some simple precautions are desirable.

Digital Signal Levels

Due to the nature of CMOS logic, it is advisable to keep

rent leakage from the part.

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

SLEEP

7-BIT ADDRESS

(0010100)

SP

R

ACK

READ

DATA OUTPUT

CONVERSION

CONVERSION

2453 F05

Figure 5. The LTC2453 Coversion Sequence

SLEEP

SLEEP

SP

R

ACK

READ

READ

DATA OUTPUT

CONVERSION

CONVERSION

2453 F06

S

RP

ACK

CONVERSION

DATA OUTPUT

7-BIT ADDRESS

(0010100)

7-BIT ADDRESS

(0010100)

Figure 6. Consecutive Reading at the Same Configuration

Figure 7. Start a New Conversion without Reading Old Conversion Result

SLEEP

SP

R

ACK READ (OPTIONAL)

DATA OUTPUT

CONVERSION

CONVERSION

2453 F07

7-BIT ADDRESS

(0010100)

APPLICATIONS INFORMATION