1
For more information www.linear.com/LTC2640
Block Diagram
Features
applications
Description
Single 12-/10-/8-Bit SPI
V
OUT
DACs with
10ppm/°C Reference
The LTC
®
2640 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 10ppm/°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 50MHz.
The LTC2640 incorporates a power-on reset circuit. Op-
tions are available for Reset to Zero-Scale or Reset to
Mid-Scale after power-up.
Integral Nonlinearity (LTC2640A-LZ12)
n
Integrated Precision Reference
2.5V Full-Scale 10ppm/°C (LTC2640-L)
4.096V Full-Scale 10ppm/°C (LTC2640-H)
n
Maximum INL Error: 1LSB (LTC2640A-12)
n
Bidirectional Reference: Input or 10ppm/°C Output
n
Low Noise (0.7mVpp, 0.1Hz to 200kHz)
n
Guaranteed Monotonic Over Temperature
n
2.7V to 5.5V Supply Range (LTC2640-L)
n
Low Power Operation: 180µA at 3V
n
Power Down to 1.8µA Maximum (C and I Grades)
n
Asynchronous DAC Clear Pin (LTC2640-Z)
n
Power-On Reset to Zero or Mid-Scale options
n
Double-Buffered Data Latches
n
Guaranteed Operation from –40°C to 125°C (H-Grade)
n
8-Lead TSOT-23 (ThinSOT™) Package
n
Mobile Communications
n
Process Control and Industrial Automation
n
Automatic Test Equipment
n
Portable Equipment
n
Automotive
n
Optical Networking
L, LT, LT C, LTM , Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners. Protected by U.S. Patents, including 5396245, 5859606, 6891433,
6937178 and 7414561.
(LTC2640-Z)
DAC
REGISTER
RESISTOR
DIVIDER
INTERNAL
REFERENCE
INPUT
REGISTER
24-BIT
SHIFT
REGISTER
DAC
V
OUT
SWITCH
CONTROL
DECODE LOGIC
CS/LD
V
CC
REF
GND
CLR
DACREF
2640 TA01
SCK
SDI
CODE
0
INL (LSB)
0
0.5
4095
2640 TA01b
–0.5
–1.0
1024
2048
3072
1.0
V
CC
= 3V
V
FS
= 2.5V
