Linduino  1.3.0
Linear Technology Arduino-Compatible Demonstration Board

LTC2640: Single 12-/10-/8-Bit Rail-to-Rail DACs with 10ppm/C Reference. More...

Detailed Description

LTC2640: Single 12-/10-/8-Bit Rail-to-Rail DACs with 10ppm/C Reference.

LTC2630: Single 12-/10-/8-Bit Rail-to-Rail DACs with Integrated Reference in SC70.

The LTC2640 is a family of 12-, 10-, and 8-bit voltage-output DACs with an
integrated, high-accuracy, low-drift reference in an 8-lead TSOT-23 package. It
has a rail-to-rail output buffer that is guaranteed monotonic.

The LTC2640-L has a full-scale output of 2.5V, and operates from a single 2.7V
to 5.5V supply. The LTC2640-H has a full-scale output of 4.096V, and operates
from a 4.5V to 5.5V supply. A 10 ppm/C reference output is available at the REF
pin.

Each DAC can also operate in External Reference mode, in which a voltage
supplied to the REF pin sets the full- scale output. The LTC2640 DACs use a
SPI/MICROWIRE compatible 3-wire serial interface which operates at clock rates
up to 50 MHz.

The LTC2640 incorporates a power-on reset circuit. Options are available for
Reset to Zero Scale or Reset to Midscale after power-up.

SPI DATA FORMAT (MSB First):

            Byte #1                            Byte #2          Byte #3
(LTC2640-12)
Data In  :  C3 C2 C1 C0 X X X X    D11 D10 D9 D8 D7 D6 D5 D4    D3 D2 D1 D0 X X X X
(LTC2640-10)
Data In  :  C3 C2 C1 C0 X X X X    D9  D8  D7 D6 D5 D4 D3 D2    D1 D0 X  X  X X X X
(LTC2640-8)
Data In  :  C3 C2 C1 C0 X X X X    D7  D6  D5 D4 D3 D2 D1 D0    X  X  X  X  X X X X

Cx   : DAC Command Code
Dx   : Data Bits
X    : Don't care

Example Code:

Set DAC to 1V for 12-bit DAC.


    shift_count = 4; // Set shift count for 12-bit DAC

    dac_voltage = 1.0;  // Set dac voltage variable to 1V;
    dac_code = LTC2640_voltage_to_code(dac_voltage, LTC2640_lsb, LTC2640_offset); // Calculates DAC code from desired voltage

    LTC2640_write(LTC2640_CS, LTC2640_CMD_WRITE_UPDATE, dac_code << shift_count);

http://www.linear.com/product/LTC2640 http://www.linear.com/product/LTC2630

http://www.linear.com/product/LTC2640#demoboards http://www.linear.com/product/LTC2630#demoboards

Copyright 2018(c) Analog Devices, Inc.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

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  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Header for LTC2640 Single 12-/10-/8-Bit Rail-to-Rail DACs with 10ppm/C Reference

Definition in file LTC2640.h.

Go to the source code of this file.

Functions

void LTC2640_write (uint8_t cs, uint8_t dac_command, uint16_t dac_code)
 Write the dac_command and 16-bit dac_code to the LTC2640. More...
 
uint16_t LTC2640_voltage_to_code (float dac_voltage, float LTC2640_lsb, int16_t LTC2640_offset)
 Calculate the LTC2640 DAC code given the desired output voltage. More...
 
float LTC2640_code_to_voltage (uint16_t dac_code, float LTC2640_lsb, int16_t LTC2640_offset)
 Calculate the LTC2640 DAC output voltage given the DAC code, offset, and LSB value. More...
 
void LTC2640_calibrate (uint16_t dac_code1, uint16_t dac_code2, float voltage1, float voltage2, float *LTC2640_lsb, int16_t *LTC2640_offset)
 Calculate the LTC2640 offset and LSB voltages given two measured voltages and their corresponding codes. More...
 

Macros

#define LTC2640_CS   QUIKEVAL_CS
 Define the SPI CS pin. More...
 
LTC2640 Command Codes (C3-C0)
#define LTC2640_CMD_WRITE   0x00
 
#define LTC2640_CMD_UPDATE   0x10
 
#define LTC2640_CMD_WRITE_UPDATE   0x30
 
#define LTC2640_CMD_POWER_DOWN   0x40
 
#define LTC2640_CMD_INTERNAL_REFERENCE   0x60
 
#define LTC2640_CMD_EXTERNAL_REFERENCE   0x70
 

Function Documentation

◆ LTC2640_calibrate()

void LTC2640_calibrate ( uint16_t  dac_code1,
uint16_t  dac_code2,
float  voltage1,
float  voltage2,
float *  LTC2640_lsb,
int16_t *  LTC2640_offset 
)

Calculate the LTC2640 offset and LSB voltages given two measured voltages and their corresponding codes.

Returns
Void
Parameters
dac_code1First DAC code
dac_code2Second DAC code
voltage1First voltage
voltage2Second voltage
LTC2640_lsbReturns resulting LSB (volts)
LTC2640_offsetReturns resulting Offset (volts)

Definition at line 123 of file LTC2640.cpp.

◆ LTC2640_code_to_voltage()

float LTC2640_code_to_voltage ( uint16_t  dac_code,
float  LTC2640_lsb,
int16_t  LTC2640_offset 
)

Calculate the LTC2640 DAC output voltage given the DAC code, offset, and LSB value.

Returns
Calculated voltage
Parameters
dac_codeDAC code
LTC2640_lsbLSB value (volts)
LTC2640_offsetOffset (volts)

Definition at line 115 of file LTC2640.cpp.

◆ LTC2640_voltage_to_code()

uint16_t LTC2640_voltage_to_code ( float  dac_voltage,
float  LTC2640_lsb,
int16_t  LTC2640_offset 
)

Calculate the LTC2640 DAC code given the desired output voltage.

Returns
Code to send to DAC
Parameters
dac_voltageVoltage to send to DAC
LTC2640_lsbLSB value (volts)
LTC2640_offsetOffset (volts)

Definition at line 101 of file LTC2640.cpp.

◆ LTC2640_write()

void LTC2640_write ( uint8_t  cs,
uint8_t  dac_command,
uint16_t  dac_code 
)

Write the dac_command and 16-bit dac_code to the LTC2640.

The dac_code must be left aligned before calling this function.

Returns
Void
Parameters
csChip Select Pin
dac_commandCommand code nibble
dac_code12-bit DAC code, left justified

Definition at line 87 of file LTC2640.cpp.

Macro Definition Documentation

◆ LTC2640_CMD_EXTERNAL_REFERENCE

#define LTC2640_CMD_EXTERNAL_REFERENCE   0x70

Definition at line 115 of file LTC2640.h.

◆ LTC2640_CMD_INTERNAL_REFERENCE

#define LTC2640_CMD_INTERNAL_REFERENCE   0x60

Definition at line 114 of file LTC2640.h.

◆ LTC2640_CMD_POWER_DOWN

#define LTC2640_CMD_POWER_DOWN   0x40

Definition at line 113 of file LTC2640.h.

◆ LTC2640_CMD_UPDATE

#define LTC2640_CMD_UPDATE   0x10

Definition at line 111 of file LTC2640.h.

◆ LTC2640_CMD_WRITE

#define LTC2640_CMD_WRITE   0x00

Definition at line 110 of file LTC2640.h.

◆ LTC2640_CMD_WRITE_UPDATE

#define LTC2640_CMD_WRITE_UPDATE   0x30

Definition at line 112 of file LTC2640.h.

◆ LTC2640_CS

#define LTC2640_CS   QUIKEVAL_CS

Define the SPI CS pin.

Definition at line 105 of file LTC2640.h.