5

LTC1454/LTC1454L

X1/X2 B, X1/ X2 A (Pins 1, 7): The Input Pin that Sets the

Gain for DAC A/B. When grounded the gain will be 2, i.e.,

output full scale will be

×2 REFHI. When connected to

to REFHI.

CLR (Pin 2): The Clear Pin for the DAC. Clears both DACs

to zero scale when pulled low. This pin should be tied to

CLK (Pin 3): The Serial Interface Clock Input.

latched into the shift register on the rising edge of the serial

clock. Data is loaded as one 24-bit word. The first 12 bits

are for DAC A, MSB-first and the second 12 bits are for

DAC B, MSB-first.

CS/LD (Pin 5): The Serial Interface Enable and Load

Control Input. When CS/LD is low the CLK signal is

enabled so the data can be clocked in. When CS/LD is

pulled high, data is loaded from the shift register into the

DAC register, updating the DAC output.

Becomes Valid on the Rising Edge of the Serial Clock.

quires a bypass capacitor to ground.

REFOUT (Pin 10): The Output of the Internal Reference.

REFHI A , REFHI B (Pins 11,14): The Inputs to the DAC

Resistor Ladder for DAC A/B.

REFLO (Pin 12): The Bottom of the DAC Resistor Ladder

for Both DACs. This can be used to offset zero-scale above

ground. REFLO should be connected to ground when no

offset is required.

GND (Pin 13): Ground.