10
LTC1591/LTC1597
15917fa
PIN FUNCTIONS
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LTC1591
REF (Pin 1): Reference Input and 4-Quadrant Resistor R2.
Typically
±10V, accepts up to ±25V. In 2-Quadrant mode
this is the reference input. In 4-quadrant mode, this pin is
driven by external inverting reference amplifier.
RCOM (Pin 2): Center Tap Point of the Two 4-Quadrant
Resistors R1 and R2. Normally tied to the inverting input
of an external amplifier in 4-quadrant operation, otherwise
shorted to the REF pin. See Figures 1a and 2a.
R1 (Pin 3): 4-Quadrant Resistor R1. In 2-quadrant opera-
tion short to the REF pin. In 4-quadrant mode tie to ROFS
(Pin 4).
ROFS (Pin 4): Bipolar Offset Resistor. Typically swings
±10V, accepts up to ±25V. In 2-quadrant operation tie to
RFB. In 4-quadrant operation tie to R1.
RFB (Pin 5): Feedback Resistor. Normally tied to the output
of the current to voltage converter op amp. Swings to
±VREF. VREF is typically ±10V.
IOUT1 (Pin 6): DAC Current Output. Tie to the inverting
input of the current to voltage converter op amp.
AGND (Pin 7): Analog Ground. Tie to ground.
LD (Pin 8): DAC Digital Input Load Control Input. When LD
is taken to a logic high, data is loaded from the input
register into the DAC register, updating the DAC output.
WR (Pin 9):DAC Digital Write Control Input. When WR is
taken to a logic low, data is loaded from the digital input
pins into the 14-bit wide input register.
DB13 to D2 (Pins 10 to 21): Digital Input Data Bits.
DGND (Pin 22): Digital Ground. Tie to ground.
VCC (Pin 23): The Positive Supply Input. 4.5V ≤ VCC ≥ 5.5V.
Requires a bypass capacitor to ground.
DB1, DB0 (Pins 24, 25): Digital Input Data Bits.
NC (Pins 26, 27): No Connect.
CLR (Pin 28):Digital Clear Control Function for the DAC.
When CLR is taken to a logic low, it sets the DAC output
and all internal registers to zero code for the LTC1591 and
midscale code for the LTC1591-1.
LTC1597
REF (Pin 1): Reference Input and 4-Quadrant Resistor R2.
Typically
±10V, accepts up to ±25V. In 2-Quadrant mode
this is the reference input. In 4-quadrant mode, this pin is
driven by external inverting reference amplifier.
RCOM (Pin 2): Center Tap Point of the Two 4-Quadrant
Resistors R1 and R2. Normally tied to the inverting input
of an external amplifier in 4-quadrant operation, otherwise
shorted to the REF pin. See Figures 1b and 2b.
R1 (Pin 3): 4-Quadrant Resistor R1. In 2-quadrant opera-
tion short to the REF pin. In 4-quadrant mode tie to ROFS
(Pin 4).
ROFS (Pin 4): Bipolar Offset Resistor. Typically swings
±10V, accepts up to ±25V. In 2-quadrant operation tie to
RFB. In 4-quadrant operation tie to R1.
RFB (Pin 5): Feedback Resistor. Normally tied to the output
of the current to voltage converter op amp. Swings to
±VREF. VREF is typically ±10V.
IOUT1 (Pin 6): DAC Current Output. Tie to the inverting
input of the current to voltage converter op amp.
AGND (Pin 7): Analog Ground. Tie to ground.
LD (Pin 8): DAC Digital Input Load Control Input. When LD
is taken to a logic high, data is loaded from the input
register into the DAC register, updating the DAC output.
WR (Pin 9):DAC Digital Write Control Input. When WR is
taken to a logic low, data is loaded from the digital input
pins into the 16-bit wide input register.
DB15 to D4 (Pins 10 to 21): Digital Input Data Bits.
DGND (Pin 22): Digital Ground. Tie to ground.
VCC (Pin 23): The Positive Supply Input. 4.5V ≤ VCC ≥ 5.5V.
Requires a bypass capacitor to ground.
DB3 to DB0 (Pins 24 to 27): Digital Input Data Bits.
CLR (Pin 28):Digital Clear Control Function for the DAC.
When CLR is taken to a logic low, it sets the DAC output
and all internal registers to zero code for the LTC1597 and
midscale code for the LTC1597-1.