LTC2640
1
2640fd
For more information www.linear.com/LTC2640
BLOCK DIAGRAM
FEATURES
APPLICATIONS
DESCRIPTION
Single 12-/10-/8-Bit SPI
VOUT 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 , LT M, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Analog Devices, Inc. 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 VOUT
SWITCH
CONTROL
DECODE LOGIC
CS/LD
VCC 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 VCC = 3V
VFS = 2.5V
LTC2640
2
2640fd
For more information www.linear.com/LTC2640
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC) ................................... –0.3V to 6V
CLR, CS/LD, REF_SEL, SCK, SDI ................. –0.3V to 6V
VOUT, REF .........................–0.3V to Min(VCC + 0.3V, 6V)
Operating Temperature Range
LTC2640C ................................................ 0°C to 70°C
LTC2640I ............................................. –40°C to 85°C
LTC2640H .......................................... –40°C to 125°C
(Notes 1, 2)
PIN CONFIGURATION
Maximum Junction Temperature .......................... 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ...................300°C
LTC2640-Z LTC2640-M
CS/LD 1
SCK 2
SDI 3
GND 4
8 CLR
7 VOUT
6 REF
5 VCC
TOP VIEW
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 150°C (NOTE 5), θJA = 195°C/W
CS/LD 1
SCK 2
SDI 3
GND 4
8 REF_SEL
7 VOUT
6 REF
5 VCC
TOP VIEW
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
TJMAX = 150°C (NOTE 5), θJA = 195°C/W
LTC2640
3
2640fd
For more information www.linear.com/LTC2640
LTC2640 A C TS8 –L M 12 #TRM PBF
LEAD FREE DESIGNATOR
TAPE AND REEL
TR = 2,500-Piece Tape and Reel
TRM = 500-Piece Tape and Reel
RESOLUTION
12 = 12-Bit
10 = 10-Bit
8 = 8-Bit
POWER-ON RESET
M = Reset to Mid-Scale
Z = Reset to Zero-Scale
FULL-SCALE VOLTAGE, INTERNAL REFERENCE MODE
L = 2.5V
H = 4.096V
PACKAGE TYPE
TS8 = 8-Lead Plastic TSOT-23
TEMPERATURE GRADE
C = Commercial Temperature Range (0°C to 70°C)
I = Industrial Temperature Range (–40°C to 85°C)
H = Automotive Temperature Range (–40°C to 125°C)
ELECTRICAL GRADE (OPTIONAL)
A = ±1LSB Maximum INL (12-Bit)
PRODUCT PART NUMBER
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
ORDER INFORMATION
http://www.linear.com/product/LTC2640#orderinfo
LTC2640
4
2640fd
For more information www.linear.com/LTC2640
PRODUCT SELECTION GUIDE
PART NUMBER
PART MARKING*
VFS WITH INTERNAL
REFERENCE
POWER-ON RESET
TO CODE
PIN 8
RESOLUTION
VCC
MAXIMUM INL
LTC2640A-LM12
LTC2640A-LZ12
LTC2640A-HM12
LTC2640A-HZ12
LTDHV
LTDHW
LTDHX
LTDHY
2.5V • (4095/4096)
2.5V • (4095/4096)
4.096V • (4095/4096)
4.096V • (4095/4096)
Mid-Scale
Zero
Mid-Scale
Zero
REF_SEL
CLR
REF_SEL
CLR
12-Bit
12-Bit
12-Bit
12-Bit
2.7V – 5.5V
2.7V – 5.5V
4.5V – 5.5V
4.5V – 5.5V
±1LSB
±1LSB
±1LSB
±1LSB
LTC2640-LM12
LTC2640-LM10
LTC2640-LM8
LTDHV
LTDHZ
LTDJF
2.5V • (4095/4096)
2.5V • (1023/1024)
2.5V • (255/256)
Mid-Scale
Mid-Scale
Mid-Scale
REF_SEL
REF_SEL
REF_SEL
12-Bit
10-Bit
8-Bit
2.7V – 5.5V
2.7V – 5.5V
2.7V – 5.5V
±2.5LSB
±1LSB
±0.5LSB
LTC2640-LZ12
LTC2640-LZ10
LTC2640-LZ8
LTDHW
LTDJB
LTDJG
2.5V • (4095/4096)
2.5V • (1023/1024)
2.5V • (255/256)
Zero
Zero
Zero
CLR
CLR
CLR
12-Bit
10-Bit
8-Bit
2.7V – 5.5V
2.7V – 5.5V
2.7V – 5.5V
±2.5LSB
±1LSB
±0.5LSB
LTC2640-HM12
LTC2640-HM10
LTC2640-HM8
LTDHX
LTDJC
LTDJH
4.096V • (4095/4096)
4.096V • (1023/1024)
4.096V • (255/256)
Mid-Scale
Mid-Scale
Mid-Scale
REF_SEL
REF_SEL
REF_SEL
12-Bit
10-Bit
8-Bit
4.5V – 5.5V
4.5V – 5.5V
4.5V – 5.5V
±2.5LSB
±1LSB
±0.5LSB
LTC2640-HZ12
LTC2640-HZ10
LTC2640-HZ8
LTDHY
LTDJD
LTDJJ
4.096V • (4095/4096)
4.096V • (1023/1024)
4.096V • (255/256)
Zero
Zero
Zero
CLR
CLR
CLR
12-Bit
10-Bit
8-Bit
4.5V – 5.5V
4.5V – 5.5V
4.5V – 5.5V
±2.5LSB
±1LSB
±0.5LSB
*The temperature grade is identified by a label on the shipping container.
LTC2640
5
2640fd
For more information www.linear.com/LTC2640
ELECTRICAL CHARACTERISTICS
LTC2640-8 LTC2640-10 LTC2640-12 LTC2640A-12
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
DC Performance
Resolution l8 10 12 12 Bits
Monotonicity VCC = 3V, Internal Ref. (Note 3) l8 10 12 12 Bits
DNL Differential
Nonlinearity
VCC = 3V, Internal Ref. (Note 3) l±0.5 ±0.5 ±1 ±1 LSB
INL Integral
Nonlinearity
VCC = 3V, Internal Ref. (Note 3) l±0.05 ±0.5 ±0.2 ±1 ±1 ±2.5 ±0.5 ±1 LSB
ZSE Zero-Scale Error VCC = 3V, Internal Ref.,
Code = 0
l0.5 5 0.5 5 0.5 5 0.5 5 mV
VOS Offset Error VCC = 3V, Internal Ref. (Note 4) l±0.5 ±5 ±0.5 ±5 ±0.5 ±5 ±0.5 ±5 mV
VOSTC VOS Temperature
Coefficient
VCC = 3V, Internal Ref. (Note 4) ±10 ±10 ±10 ±10 µV/°C
FSE Full-Scale Error VCC = 3V, Internal Ref. (Note 10) l±0.08 ±0.4 ±0.08 ±0.4 ±0.08 ±0.4 ±0.08 ±0.4 %FSR
VFSTC Full-Scale Voltage
Temperature
Coefficient
VCC = 3V, Internal Ref. (Note 9)
C-Grade
I-Grade
H-Grade
±10
±10
±10
±10
±10
±10
±10
±10
±10
±10
±10
±10
ppm/°C
ppm/°C
ppm/°C
Load Regulation Internal Ref., Mid-Scale,
VCC = 3V ±10%,
–5mA ≤ IOUT ≤ 5mA,
VCC = 5V ±10%,
–10mA ≤ IOUT ≤ 10mA
l
l
0.009
0.009
0.016
0.016
0.035
0.035
0.064
0.064
0.14
0.14
0.256
0.256
0.14
0.14
0.256
0.256
LSB/mA
LSB/mA
ROUT DC Output
Impedance
Internal Ref., Mid-Scale,
VCC = 3V ±10%,
–5mA ≤ IOUT ≤ 5mA,
VCC = 5V ±10%,
–10mA ≤ IOUT ≤ 10mA
l
l
0.09
0.09
0.156
0.156
0.09
0.09
0.156
0.156
0.09
0.09
0.156
0.156
0.09
0.09
0.156
0.156
Ω
Ω
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VOUT unloaded unless otherwise specified.
LTC2640-LM12/-LM10/-LM8/-LZ12/-LZ10/-LZ8, LTC2640A-LM12/-LZ12 (VFS = 2.5V)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOUT DAC Output Span External Reference
Internal Reference
0 to VREF
0 to 2.5
V
V
PSR Power Supply Rejection VCC = 3V ±10% or 5V ±10% –80 dB
ISC Short-Circuit Output Current (Note 5)
Sinking
Sourcing
VFS = VCC = 5.5V
Zero-Scale; VOUT shorted to VCC
Full-Scale; VOUT shorted to GND
l
l
27
–28
48
–48
mA
mA
Power Supply
VCC Positive Supply Voltage For Specified Performance l2.7 5.5 V
ICC Supply Current (Note 6) VCC = 3V, VREF = 2.5V, External Reference
VCC = 3V, Internal Reference
VCC = 5V, VREF = 2.5V, External Reference
VCC = 5V, Internal Reference
l
l
l
l
150
180
160
190
200
240
210
260
µA
µA
µA
µA
ISD Supply Current in Power-Down Mode
(Note 6)
VCC = 5V, C-Grade, I-Grade
VCC = 5V, H-Grade
l
l
0.6
0.6
1.8
4
µA
µA
LTC2640
6
2640fd
For more information www.linear.com/LTC2640
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V, VOUT unloaded unless otherwise specified.
LTC2640-LM12/-LM10/-LM8/-LZ12/-LZ10/-LZ8, LTC2640A-LM12/-LZ12 (VFS = 2.5V)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Reference Input
Input Voltage Range l0 VCC V
Resistance l160 190 220 kΩ
Capacitance 7.5 pF
IREF Reference Current, Power-Down Mode DAC Powered Down l0.005 0.1 µA
Reference Output
Output Voltage l1.240 1.250 1.260 V
Reference Temperature Coefficient ±10 ppm/°C
Output Impedance 0.5 kΩ
Capacitive Load Driving 10 µF
Short-Circuit Current VCC = 5.5V; REF Shorted to GND 2.5 mA
Digital I/O
VIH Digital Input High Voltage VCC = 3.6V to 5.5V
VCC = 2.7V to 3.6V
l
l
2.4
2
V
V
VIL Digital Input Low Voltage VCC = 4.5V to 5.5V
VCC = 2.7V to 4.5V
l
l
0.8
0.6
V
V
ILK Digital Input Leakage VIN = GND to VCC l±1 µA
CIN Digital Input Capacitance (Note 7) l2.5 pF
AC Performance
tSSettling Time VCC = 3V (Note 8)
±0.39% (±1LSB at 8-Bits)
±0.098% (±1LSB at 10-Bits)
±0.024% (±1LSB at 12-Bits)
3.2
3.8
4.1
µs
µs
µs
Voltage Output Slew Rate 1 V/µs
Capacitance Load Driving 500 pF
Glitch Impulse At Mid-Scale Transition 2.1 nV•s
Multiplying Bandwidth External Reference 300 kHz
enOutput Voltage Noise Density At f = 1kHz, External Reference
At f = 10kHz, External Reference
At f = 1kHz, Internal Reference
At f = 10kHz, Internal Reference
140
130
160
150
nV√Hz
nV√Hz
nV√Hz
nV√Hz
Output Voltage Noise 0.1Hz to 10Hz, External Reference
0.1Hz to 10Hz, Internal Reference
0.1Hz to 200kHz, External Reference
0.1Hz to 200kHz, Internal Reference,
CREF = 0.33µF
20
20
650
670
µVP-P
µVP-P
µVP-P
µVP-P
LTC2640
7
2640fd
For more information www.linear.com/LTC2640
TIMING CHARACTERISTICS
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VCC = 2.7V to 5.5V. (See Figure 1) (Note 7).
LTC2640-LM12/-LM10/-LM8/-LZ12/-LZ10/-LZ8, LTC2640A-LM12/-LZ12 (VFS = 2.5V)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t1SDI Valid to SCK Setup l4 ns
t2SDI Valid to SCK Hold l4 ns
t3SCK High Time l9 ns
t4SCK Low Time l9 ns
t5CS/LD Pulse Width l10 ns
t6LSB SCK High to CS/LD High l7 ns
t7CS/LD Low to SCK High l7 ns
t9CLR Pulse Width l20 ns
t10 CS/LD High to SCK Pos. Edge l7 ns
SCK Frequency 50% Duty Cycle l50 MHz
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 4.5V to 5.5V, VOUT unloaded unless otherwise specified.
LTC2640-HM12/-HM10/-HM8/-HZ12/-HZ10/-HZ8, LTC2640A-HM12/-HZ12 (VFS = 4.096V)
LTC2640-8 LTC2640-10 LTC2640-12 LTC2640A-12
SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
DC Performance
Resolution l8 10 12 12 Bits
Monotonicity VCC = 5V, Internal Ref. (Note 3) l8 10 12 12 Bits
DNL Differential
Nonlinearity
VCC = 5V, Internal Ref. (Note 3) l±0.5 ±0.5 ±1 ±1 LSB
INL Integral
Nonlinearity
VCC = 5V, Internal Ref. (Note 3) l±0.05 ±0.5 ±0.2 ±1 ±1 ±2.5 ±0.5 ±1 LSB
ZSE Zero-Scale Error VCC = 5V, Internal Ref.,
Code = 0
l0.5 5 0.5 5 0.5 5 0.5 5 mV
VOS Offset Error VCC = 5V, Internal Ref. (Note 4) l±0.5 ±5 ±0.5 ±5 ±0.5 ±5 ±0.5 ±5 mV
VOSTC VOS Temperature
Coefficient
VCC = 5V, Internal Ref. (Note 4) ±10 ±10 ±10 ±10 µV/°C
FSE Full-Scale Error VCC = 5V, Internal Ref. (Note 10) l±0.08 ±0.4 ±0.08 ±0.4 ±0.08 ±0.4 ±0.08 ±0.4 %FSR
VFSTC Full-Scale Voltage
Temperature
Coefficient
VCC = 5V, Internal Ref. (Note 9)
C-Grade
I-Grade
H-Grade
±10
±10
±10
±10
±10
±10
±10
±10
±10
±10
±10
±10
ppm/°C
ppm/°C
ppm/°C
Load Regulation VCC = 5V ±10%,
Internal Ref. Mid-Scale,
–10mA ≤ IOUT ≤ 10mA
l0.006 0.01 0.022 0.04 0.09 0.16 0.09 0.16 LSB/mA
ROUT DC Output
Impedance
VCC = 5V ±10%,
Internal Ref. Mid-Scale,
–10mA ≤ IOUT ≤ 10mA
l0.09 0.156 0.09 0.156 0.09 0.156 0.09 0.156 Ω
LTC2640
8
2640fd
For more information www.linear.com/LTC2640
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 4.5V to 5.5V, VOUT unloaded unless otherwise specified.
LTC2640-HM12/-HM10/-HM8/-HZ12/-HZ10/-HZ8, LTC2640A-HM12/-HZ12 (VFS = 4.096V)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VOUT DAC Output Span External Reference
Internal Reference
0 to VREF
0 to 4.096
V
V
PSR Power Supply Rejection VCC = 5V ±10% –80 dB
ISC Short-Circuit Output Current (Note 5)
Sinking
Sourcing
VFS = VCC = 5.5V
Zero-Scale; VOUT shorted to VCC
Full-Scale; VOUT shorted to GND
l
l
27
–28
48
–48
mA
mA
Power Supply
VCC Positive Supply Voltage For Specified Performance l4.5 5.5 V
ICC Supply Current (Note 6) VCC = 5V, VREF = 4.096V, External Reference
VCC = 5V, Internal Reference
l
l
160
200
220
270
µA
µA
ISD Supply Current in Power-Down Mode
(Note 6)
VCC = 5V, C-Grade, I-Grade
VCC = 5V, H-Grade
l
l
0.6
0.6
1.8
4
µA
µA
Reference Input
Input Voltage Range l0 VCC V
Resistance l160 190 220 kΩ
Capacitance 7.5 pF
IREF Reference Current, Power-Down
Mode
DAC Powered Down l0.005 0.1 µA
Reference Output
Output Voltage l2.032 2.048 2.064 V
Reference Temperature Coefficient ±10 ppm/°C
Output Impedance 0.5 kΩ
Capacitive Load Driving 10 µF
Short-Circuit Current VCC = 5.5V; REF Shorted to GND 4.3 mA
Digital I/O
VIH Digital Input High Voltage l2.4 V
VIL Digital Input Low Voltage l0.8 V
ILK Digital Input Leakage VIN = GND to VCC l±1 µA
CIN Digital Input Capacitance (Note 7) l2.5 pF
AC Performance
tSSettling Time VCC = 5V (Note 8)
±0.39% (±1LSB at 8 Bits)
±0.098% (±1LSB at 10 Bits)
±0.024% (±1LSB at 12 Bits)
3.7
4.2
4.6
µs
µs
µs
Voltage Output Slew Rate 1 V/µs
Capacitance Load Driving 500 pF
Glitch Impulse At Mid-Scale Transition 3.0 nV•s
Multiplying Bandwidth External Reference 300 kHz
LTC2640
9
2640fd
For more information www.linear.com/LTC2640
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 4.5V to 5.5V, VOUT unloaded unless otherwise specified.
LTC2640-HM12/-HM10/-HM8/-HZ12/-HZ10/-HZ8, LTC2640A-HM12/-HZ12 (VFS = 4.096V)
TIMING CHARACTERISTICS
The l denotes the specifications which apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VCC = 4.5V to 5.5V. (See Figure 1) (Note 7).
LTC2640-HM12/-HM10/-HM8/-HZ12/-HZ10/-HZ8, LTC2640A-HM12/-HZ12 (VFS = 4.096V)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t1SDI Valid to SCK Setup l4 ns
t2SDI Valid to SCK Hold l4 ns
t3SCK High Time l9 ns
t4SCK Low Time l9 ns
t5CS/LD Pulse Width l10 ns
t6LSB SCK High to CS/LD High l7 ns
t7CS/LD Low to SCK High l7 ns
t9CLR Pulse Width l20 ns
t10 CS/LD High to SCK Pos. Edge l7 ns
SCK Frequency 50% Duty Cycle l50 MHz
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All voltages are with respect to GND.
Note 3: Linearity and monotonicity are defined from code kL to code
2N – 1, where N is the resolution and kL is given by kL = 0.016 • (2N/ VFS),
rounded to the nearest whole code. For VFS = 2.5V and N = 12, kL = 26
and linearity is defined from code 26 to code 4,095. For VFS = 4.096V
and N = 12, kL = 16 and linearity is defined from code 16 to code 4,095.
Note 4: Inferred from measurement at code 16 (LTC2640-12), code 4
(LTC2640-10) or code 1 (LTC2640-8), and at full-scale.
Note 5: This IC includes current limiting that is intended to protect the
device during momentary overload conditions. Junction temperature can
exceed the rated maximum during current limiting. Continuous operation
above the specified maximum operating junction temperature may impair
device reliability.
Note 6: Digital inputs at 0V or VCC.
Note 7: Guaranteed by design and not production tested.
Note 8: Internal Reference mode. DAC is stepped 1/4 scale to 3/4 scale
and 3/4 scale to 1/4 scale. Load is 2k in parallel with 100pF to GND.
Note 9: Temperature coefficient is calculated by dividing the maximum
change in output voltage by the specified temperature range.
Note 10: Full-scale error is determined using the reference voltage
measured at the REF pin.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
enOutput Voltage Noise Density At f = 1kHz, External Reference
At f = 10kHz, External Reference
At f = 1kHz, Internal Reference
At f = 10kHz, Internal Reference
140
130
210
200
nV√Hz
nV√Hz
nV√Hz
nV√Hz
Output Voltage Noise 0.1Hz to 10Hz, External Reference
0.1Hz to 10Hz, Internal Reference
0.1Hz to 200kHz, External Reference
0.1Hz to 200kHz, Internal Reference,
CREF = 0.33µF
20
20
650
670
µVP-P
µVP-P
µVP-P
µVP-P
LTC2640
10
2640fd
For more information www.linear.com/LTC2640
TYPICAL PERFORMANCE CHARACTERISTICS
Integral Nonlinearity (INL)
Differential Nonlinearity (DNL)
INL vs Temperature
DNL vs Temperature
Full-Scale Output Voltage
vs Temperature
Settling to ±1LSB
Settling to ±1LSB
LTC2640-L12 (Internal Reference, VFS = 2.5V)
CODE
0
INL (LSB)
0
0.5
4095
2640 G01
–0.5
–1.0 1024 2048 3072
1.0 VCC = 3V
CODE
0
DNL (LSB)
0
0.5
4095
2640 G02
–0.5
–1.0 1024
VCC = 3V
2048 3072
1.0
Reference Output Voltage
vs Temperature
TEMPERATURE (°C)
–50 –25 25 75 125
VREF (V)
1.250
1.255
150
2640 G03
1.245
1.240 050 100
1.260
VCC = 3V
TEMPERATURE (°C)
–50 –25 25 75 125
INL (LSB)
0
0.5
150
2640 G04
–0.5
–1.0 050 100
1.0
VCC = 3V
INL (POS)
INL (NEG)
TEMPERATURE (°C)
–50 –25 25 75 125
DNL (LSB)
0
0.5
150
2640 G05
–0.5
–1.0 050 100
1.0
VCC = 3V
DNL (POS)
DNL (NEG)
TEMPERATURE (°C)
–50 –25 25 75 125
FS OUTPUT VOLTAGE (V)
2.50
2.51
150
2640 G06
2.49
2.48 050 100
2.52
VCC = 3V
2µs/DIV
2640 G07
VOUT
1LSB/DIV
1/4 SCALE TO 3/4 SCALE STEP
VCC = 3V, VFS = 2.5V
RL = 2k, CL = 100pF
AVERAGE OF 256 EVENTS
CS/LD
2V/DIV
3.6µs
2µs/DIV
2640 G08
VOUT
1LSB/DIV
3/4 SCALE TO 1/4 SCALE STEP
VCC = 3V, VFS = 2.5V
RL = 2k, CL = 100pF
AVERAGE OF 256 EVENTS
CS/LD
2V/DIV
4.1µs
TA = 25°C, unless otherwise noted.
LTC2640
11
2640fd
For more information www.linear.com/LTC2640
TYPICAL PERFORMANCE CHARACTERISTICS
Integral Nonlinearity (INL)
Differential Nonlinearity (DNL)
INL vs Temperature
DNL vs Temperature
Full-Scale Output Voltage
vs Temperature
Settling to ±1LSB
Settling to ±1LSB
LTC2640-H12 (Internal Reference, VFS = 4.096V)
CODE
0
INL (LSB)
0
0.5
4095
2640 G09
–0.5
–1.0 1024 2048 3072
1.0
VCC = 5V
CODE
0
DNL (LSB)
0
0.5
4095
2640 G10
–0.5
–1.0 1024 2048 3072
1.0
VCC = 5V
Reference Output Voltage
vs Temperature
TEMPERATURE (°C)
–50 –25 25 75 125
VREF (V)
2.048
2.058
150
2640 G11
2.038
2.028 050 100
2.068
VCC = 5V
TEMPERATURE (°C)
–50 –25 25 75 125
INL (LSB)
0
0.5
150
2640 G12
–0.5
–1.0 050 100
1.0
VCC = 5V
INL (POS)
INL (NEG)
TEMPERATURE (°C)
–50 –25 25 75 125
DNL (LSB)
0
0.5
150
2640 G13
–0.5
–1.0 050 100
1.0
VCC = 5V
DNL (POS)
DNL (NEG)
TEMPERATURE (°C)
–50 –25 25 75 125
FS OUTPUT VOLTAGE (V)
4.095
4.105
150
2640 G14
4.085
4.075 050 100
4.115
VCC = 5V
2µs/DIV
2640 G15
VOUT
1LSB/DIV
1/4 SCALE TO 3/4 SCALE STEP
VCC = 5V, VFS = 4.095V
RL = 2k, CL = 100pF
AVERAGE OF 256 EVENTS
CS/LD
5V/DIV
3.9µs
2µs/DIV
2640 G16
VOUT
1LSB/DIV
CS/LD
5V/DIV
4.6µs
3/4 SCALE TO 1/4 SCALE STEP
VCC = 5V, VFS = 4.095V
RL = 2k, CL = 100pF
AVERAGE OF 256 EVENTS
TA = 25°C, unless otherwise noted.
LTC2640
12
2640fd
For more information www.linear.com/LTC2640
TYPICAL PERFORMANCE CHARACTERISTICS
LTC2640-10
Integral Nonlinearity (INL)
Differential Nonlinearity (DNL)
Integral Nonlinearity (INL)
Differential Nonlinearity (DNL)
Load Regulation
Current Limiting
Offset Error vs Temperature
LTC2640-8
LTC2640
CODE
0
INL (LSB)
0
0.5
1023
2640 G17
–0.5
–1.0 256 512 768
1.0
VCC = 5V
VFS = 4.096V
INTERNAL REF.
CODE
0
DNL (LSB)
0
0.5
1023
2640 G18
–0.5
–1.0 256 512 768
1.0 VCC = 5V
VFS = 4.096V
INTERNAL REF.
CODE
0
INL (LSB)
0
0.5
255
2640 G19
–0.5
–1.0 64 128 192
1.0 VCC = 3V
VFS = 2.5V
INTERNAL REF.
CODE
0
DNL (LSB)
0
0.25
255
2640 G20
–0.25
–0.50 64 128 192
0.50
VCC = 3V
VFS = 2.5V
INTERNAL REF.
IOUT (mA)
–30 –20 –10 0 10 20 30
ΔVOUT (mV)
0
2
4
6
8
2630 G21
–6
–4
–2
–8
–10
10
INTERNAL REF.
CODE = MIDSCALE
VCC = 5V (LTC2640-H)
VCC = 5V (LTC2640-L)
VCC = 3V (LTC2640-L)
IOUT (mA)
–30 –20 –10 0 10 20 30
∆V
OUT
(V)
–0.05
0
0.05
0.10
0.15
2630 G22
–0.20
–0.15
–0.10
0.20
INTERNAL REF.
CODE = MIDSCALE
VCC = 5V (LTC2640-H)
VCC = 5V (LTC2640-L)
VCC = 3V (LTC2640-L)
TEMPERATURE (°C)
–50 –25 0 25 50 75 100 125 150
OFFSET ERROR (mV)
0
1
2
2640 G23
–1
–2
–3
3
TA = 25°C, unless otherwise noted.
LTC2640
13
2640fd
For more information www.linear.com/LTC2640
TYPICAL PERFORMANCE CHARACTERISTICS
LTC2640
Large-Signal Response
Mid-Scale-Glitch Impulse
Power-On Reset Glitch
Headroom at Rails
vs Output Current
Exiting Power-Down to Mid-Scale
Supply Current vs Logic Voltage
Hardware CLR
2µs/DIV
VOUT
0.5V/DIV
2640 G26
VFS = VCC = 5V
1/4 SCALE TO 3/4 SCALE
2µs/DIV
LTC2640-H12, VCC = 5V:
3.0nV-s TYP
LTC2640-L12, VCC = 3V:
2.1nV-s TYP
VOUT
5mV/DIV
2640 G27
CS/LD
5V/DIV
200µs/DIV
VCC
2V/DIV
2640 G28
LTC2640-L
VOUT
2mV/DIV
ZERO-SCALE
IOUT (mA)
0 1 2 3 4 5 6 7 8 9 10
V
OUT
(V)
2.5
2.0
3.5
3.0
4.0
2640 G29
1.5
1.0
0.5
0
5.0
4.5 5V SOURCING
3V (LTC2640-L) SOURCING
3V (LTC2640-L) SINKING
5V SINKING
4µs/DIV
2640 G30
LTC2640-H
CS/LD
2V/DIV
VOUT
0.5V/DIV
LOGIC VOLTAGE (V)
0
ICC (mA)
1.4
1.2
0.8
0.4
1.0
0.6
0.2
0.0 42
2640 G31
531
VCC = 5V
VCC = 3V
(LTC2640-L)
SWEEP SCK, SDI, CS/LD
AND CLR BETWEEN
0V AND VCC
1µs/DIV
2640 G32
LTC2640-LZ
VOUT
1V/DIV
CLR
5V/DIV
Gain Error vs VCC
Gain Error vs Temperature
VCC (V)
2.5 3 3.5 4 4.5 5 5.5
GAIN ERROR (%FSR)
0.1
0.2
0.3
2640 G24
0.0
–0.3
–0.2
–0.1
–0.4
0.4
EXTERNAL REF.
VREF = 2.5V
TEMPERATURE (°C)
–50 –25 0 25 50 75 100 125 150
GAIN ERROR (%FSR)
0.1
0.2
0.3
2640 G25
0.0
–0.3
–0.2
–0.1
–0.4
0.4
EXTERNAL REF.
VREF = 2.5V
TA = 25°C, unless otherwise noted.
LTC2640
14
2640fd
For more information www.linear.com/LTC2640
TYPICAL PERFORMANCE CHARACTERISTICS
LTC2640
Multiplying Bandwidth
Noise Voltage vs Frequency
0.1Hz to 10Hz Voltage Noise
PIN FUNCTIONS
CS/LD (Pin 1): Serial Interface Chip Select/Load Input.
When CS/LD is low, SCK is enabled for shifting data on
SDI into the register. When CS/LD is taken high, SCK
is disabled and the specified command (see Table 1) is
executed.
SCK (Pin 2): Serial Interface Clock Input. CMOS and TTL
compatible.
SDI (Pin 3): Serial Interface Data Input. Data on SDI
is clocked into the DAC on the rising edge of SCK. The
LTC2640 accepts input word lengths of either 24- or 32-bits.
GND (Pin 4): Ground.
VCC (Pin 5): Supply Voltage Input. 2.7V ≤ VCC ≤ 5.5V
(LTC2640-L) or 4.5V ≤ VCC ≤ 5.5V (LTC2640-H). Bypass
to GND with a 0.1µF capacitor.
REF (Pin 6): Reference Voltage Input or Output. When
External Reference mode is selected, REF is an input
(0V ≤ VREF ≤ VCC) where the voltage supplied sets the
full-scale voltage. When Internal Reference is selected,
the 10ppm/°C 1.25V (LTC2640-L) or 2.048V (LTC2640-H)
internal reference is available at the pin. This output may
be bypassed to GND with up to 10µF (0.33µF is recom-
mended), and must be buffered when driving external DC
load current.
VOUT (Pin 7): DAC Analog Voltage Output.
CLR (Pin 8, LTC2640-Z): Asynchronous Clear Input. A
logic low at this level-triggered input clears all registers
and causes the DAC voltage output to reset to Zero. CMOS
and TTL compatible.
REF_SEL (Pin 8, LTC2640-M): Selects default Reference
at power-up. Tie to VCC to select the Internal Reference,
or GND to select an External Reference. After power-up,
the logic state at this pin is ignored and the reference may
be changed only by software command.
FREQUENCY (Hz)
100
NOISE VOLTAGE (nV/√Hz)
200
300
1M
2640 G34
100
01k 10k 100k
500
400
INTERNAL REF.
CODE = MIDSCALE
LTC2640-H
(VCC = 5V)
LTC2640-L
(VCC = 4V)
1s/DIV
10µV/DIV
2640 G35
LTC2640-L, VCC = 4V
INTERNAL REF.
CODE = MIDSCALE
FREQUENCY (Hz)
1k
dB
0
–2
–6
–8
–14
–4
–12
–10
–16
–18 100k
2640 G33
1000k10k
VCC = 5V
VREF(DC) = 2V
VREF(AC) = 0.2VP-P
CODE = FULL SCALE
TA = 25°C, unless otherwise noted.
LTC2640
15
2640fd
For more information www.linear.com/LTC2640
BLOCK DIAGRAMS
2640 BD
DAC
REGISTER
RESISTOR
DIVIDER
INTERNAL
REFERENCE
INPUT
REGISTER
24-BIT
SHIFT
REGISTER
DAC VOUT
SWITCH
CONTROL
DECODE LOGIC
CS/LD
VCC REF
GNDCLR
DACREF
SCK
SDI
DAC
REGISTER
RESISTOR
DIVIDER
INTERNAL
REFERENCE
INPUT
REGISTER
24-BIT
SHIFT
REGISTER
DAC VOUT
REF_SEL
SWITCH
CONTROL
DECODE LOGIC
CS/LD
VCC REF
GND
DACREF
SCK
SDI
LTC2640-Z
LTC2640-M
LTC2640
17
2640fd
For more information www.linear.com/LTC2640
The LTC2640 is a family of single voltage-output DACs
in 8-lead ThinSOT packages. Each DAC can operate rail-
to-rail using an external reference, or with its full-scale
voltage set by an integrated reference. 12 combinations of
accuracy (12-, 10-, and 8-bit), power-on reset value (zero
or mid-scale), and full-scale voltage (2.5V or 4.096V) are
available. The LTC2640 is controlled using a 3-wire SPI/
MICROWIRE compatible interface.
Power-On Reset
The LTC2640-HZ/LTC2640-LZ clear the output to zero-
scale when power is first applied, making system initializa-
tion consistent and repeatable.
For some applications, downstream circuits are active
during DAC power-up, and may be sensitive to nonzero
outputs from the DAC during this time. The LTC2640
contains circuitry to reduce the power-on glitch: the
analog output typically rises less than 5mV above zero-
scale during power on if the power supply is ramped
to 5V in 1ms or more. In general, the glitch amplitude
decreases as the power supply ramp time is increased.
See “Power-On Reset Glitch” in the Typical Performance
Characteristics section.
The LTC2640-HM/LTC2640-LM provide an alternative
reset, setting the output to mid-scale when power is first
applied.
Default reference mode selection is described in the Refer-
ence Modes section.
Power Supply Sequencing
The voltage at REF (Pin 6) should be kept within the range
–0.3V ≤ VREF ≤ VCC + 0.3V (see Absolute Maximum Rat-
ings). Particular care should be taken to observe these
limits during power supply turn-on and turn-off sequences,
when the voltage at VCC (Pin 5) is in transition.
Transfer Function
The digital-to-analog transfer function is:
VOUT(IDEAL) =k
2
N
VREF
where k is the decimal equivalent of the binary DAC input
code, N is the resolution, and VREF is either 2.5V (LTC2640-
LM/LTC2640-LZ) or 4.096V (LTC2640-HM/LTC2640-HZ)
when in Internal Reference mode, and the voltage at REF
(Pin 6) when in External Reference mode.
OPERATION
Figure 2. Command and Data Input Format
2640 F02
C3
COMMAND 4 DON'T-CARE BITS
MSB
MSB
MSB
LSB
LSB
LSB
DATA (12 BITS + 4 DON'T-CARE BITS)
C2 C1 C0 X X X X D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 XXXX
C3
COMMAND 4 DON'T-CARE BITS DATA (10 BITS + 6 DON'T-CARE BITS)
C2 C1 C0 X X X X D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 XXXXXX
C3
COMMAND
INPUT WORD (LTC2640-12)
INPUT WORD (LTC2640-10)
INPUT WORD (LTC2640-8)
4 DON'T-CARE BITS DATA (8 BITS + 8 DON'T-CARE BITS)
C2 C1 C0 X X X X D7 D6 D5 D4 D3 D2 D1 D0 XXXXXXXX
LTC2640
18
2640fd
For more information www.linear.com/LTC2640
OPERATION
Serial Interface
The CS/LD input is level triggered. When this input is
taken low, it acts as a chip-select signal, enabling the
SDI and SCK buffers and the input shift register. Data
(SDI input) is transferred at the next 24 rising SCK edges.
The 4-bit command, C3-C0, is loaded first, followed by
4 don’t-cares bits, and finally the 16-bit data word. The
data word comprises the 12-, 10- or 8-bit input code, or-
dered MSB-to-LSB, followed by 4, 6 or 8 don’t-cares bits
(LTC2640-12, LTC2640-10 and LTC2640-8 respectively;
see Figure 2). Data can only be transferred to the device
when the CS/LD signal is low, beginning on the first rising
edge of SCK. SCK may be high or low at the falling edge
of CS/LD. The rising edge of CS/LD ends the data transfer
and causes the device to execute the command specified
in the 24-bit input sequence. The complete sequence is
shown in Figure 3a.
The command (C3-C0) assignments are shown in Table 1.
The first three commands in the table consist of write and
update operations. A Write operation loads a 16-bit data
word from the 24-bit shift register into the input register.
In an Update operation, the input register is copied to the
DAC register and converted to an analog voltage at the
DAC output. Write to and Update combines the first two
commands. The Update operation also powers up the
DAC if it had been in power-down mode. The data path
and registers are shown in the Block Diagram.
Table 1. Command Codes
COMMAND*
C3 C2 C1 C0
0 0 0 0 Write to Input Register
0 0 0 1 Update (Power-Up) DAC Register
0 0 1 1 Write to and Update (Power-Up) DAC Register
0 1 0 0 Power Down
0 1 1 0 Select Internal Reference
0 1 1 1 Select External Reference
*Command codes not shown are reserved and should not be used
While the minimum input sequence is 24-bits, it may
optionally be extended to 32-bits to accommodate micro-
processors that have a minimum word width of 16-bits
(2-bytes). To use the 32-bit width, 8 don’t-cares bits are
transferred to the device first, followed by the 24-bit se-
quence described. Figure 3b shows the 32-bit sequence.
The 16-bit data word is ignored for all commands that do
not include a Write operation.
Reference Modes
For applications where an accurate external reference is not
available, the LTC2640 has a user-selectable, integrated
reference. The LTC2640-LM/LTC2640-LZ provide a full-
scale output of 2.5V. The LTC2640-HM/LTC2640-HZ
provide a full-scale output of 4.096V. The internal reference
can be useful in applications where the supply voltage is
poorly regulated. Internal Reference mode can be selected
by using command 0110, and is the power-on default for
LTC2640-HZ/LTC2640-LZ, as well as for LTC2640-HM/
LTC2640-LM when REF_SEL is tied high.
The 10ppm/°C, 1.25V (LTC2640-LM/LTC2640-LZ) or
2.048V (LTC2640-HM/LTC2640-HZ) internal reference
is available at the REF pin. Adding bypass capacitance
to the REF pin will improve noise performance; 0.33µF
is recommended, and up to 10µF can be driven without
oscillation. This output must be buffered when driving an
external DC load current.
Alternatively, the DAC can operate in External Reference
mode using command 0111. In this mode, an input voltage
supplied externally to the REF pin provides the reference
(0V ≤ VREF ≤ VCC) and the supply current is reduced. External
Reference mode is the power-on default for LTC2640-HM/
LTC2640-LM when REF_SEL is tied low.
The reference mode of LTC2640-HZ/LTC2640-LZ can be
changed only by software command. The same is true for
LTC2640-HM/LTC2640-LM after power-on, after which
the logic state on REF_SEL is ignored.
Power-Down Mode
For power-constrained applications, the LTC2640’s power-
down mode can be used to reduce the supply current
whenever the DAC output is not needed. When in power-
down, the buffer amplifier, bias circuit, and reference
circuit are disabled and draw essentially zero current. The
DAC output is put into a HIGH-impedance state, and the
output pin is passively pulled to ground through a 200k
LTC2640
19
2640fd
For more information www.linear.com/LTC2640
OPERATION
resistor. Input and DAC register contents are not disturbed
during power-down.
The DAC can be put into power-down mode by using
command 0100. The supply current is reduced to 1.8µA
maximum (C and I grades) and the REF pin becomes HIGH
impedance (typically > 1GΩ).
Normal operation resumes after executing any command
that includes a DAC update, as shown in Table 1. The DAC
is powered up and its voltage output is updated. Normal
settling is delayed while the bias, reference, and ampli-
fier circuits are re-enabled. When the REF pin output is
bypassed to GND with 1nF or less, the power-up delay
time is 20µs for settling to 12-bits. This delay increases
to 200µs for 0.33µF, and 10ms for 10µF.
Voltage Output
The LTC2640’s integrated rail-to-rail amplifier has guar-
anteed load regulation when sourcing or sinking up to
10mA at 5V, and 5mA at 3V.
Load regulation is a measure of the amplifier’s ability to
maintain the rated voltage accuracy over a wide range of
load current. The measured change in output voltage per
change in forced load current is expressed in LSB/mA.
DC output impedance is equivalent to load regulation, and
may be derived from it by simply calculating a change in
units from LSB/mA to ohms. The amplifier’s DC output
impedance is 0.1Ω when driving a load well away from
the rails.
When drawing a load current from either rail, the output
voltage headroom with respect to that rail is limited by
the 50Ω typical channel resistance of the output devices
(e.g., when sinking 1mA, the minimum output voltage is
50Ω • 1mA, or 50mV). See the graph “Headroom at Rails
vs. Output Current” in the Typical Performance Charac-
teristics section.
The amplifier is stable driving capacitive loads of up to
500pF.
Rail-to-Rail Output Considerations
In any rail-to-rail voltage output device, the output is limited
to voltages within the supply range.
Since the analog output of the DAC cannot go below ground,
it may limit the lowest codes, as shown in Figure 4b.
Similarly, limiting can occur near full-scale when the REF
pin is tied to VCC. If VREF = VCC and the DAC full-scale error
(FSE) is positive, the output for the highest codes limits
at VCC, as shown in Figure 4c. No full-scale limiting can
occur if VREF is less than VCC – FSE.
Offset and linearity are defined and tested over the region
of the DAC transfer function where no output limiting can
occur.
Board Layout
The PC board should have separate areas for the analog and
digital sections of the circuit. A single, solid ground plane
should be used, with analog and digital signals carefully
routed over separate areas of the plane. This keeps digital
signals away from sensitive analog signals and minimizes
the interaction between digital ground currents and the
analog section of the ground plane. The resistance from
the LTC2640 GND pin to the ground plane should be as
low as possible. Resistance here will add directly to the
effective DC output impedance of the device (typically
0.1Ω). Note that the LTC2640 is no more susceptible to
this effect than any other parts of this type; on the con-
trary, it allows layout-based performance improvements
to shine rather than limiting attainable performance with
excessive internal resistance.
Another technique for minimizing errors is to use a sepa-
rate power ground return trace on another board layer.
The trace should run between the point where the power
supply is connected to the board and the DAC ground pin.
Thus the DAC ground pin becomes the common point for
analog ground, digital ground, and power ground. When
the LTC2640 is sinking large currents, this current flows
out the ground pin and directly to the power ground trace
without affecting the analog ground plane voltage.
It is sometimes necessary to interrupt the ground plane
to confine digital ground currents to the digital portion of
the plane. When doing this, make the gap in the plane only
as long as it needs to be to serve its purpose and ensure
that no traces cross over the gap.
LTC2640
20
2640fd
For more information www.linear.com/LTC2640
OPERATION
Figure 3a. LTC2640-12 24-Bit Load Sequence (Minimum Input Word).
LTC2640-10 SDI Data Word: 10-Bit Input Code + 6 Don’t-Cares Bits;
LTC2640-8 SDI Data Word: 8-Bit Input Code + 8 Don’t-Cares Bits
Figure 3b. LTC2640-12 32-Bit Load Sequence
LTC2640-10 SDI Data Word: 10-Bit Input Code + 6 Don’t-Cares Bits;
LTC2640-8 SDI Data Word: 8-Bit Input Code + 8 Don’t-Cares Bits
12345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24
C2 C1 C0 X X X X D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X XC3
CS/LD
SCK
SDI
COMMAND WORD 4 DON’T-CARE BITS DATA WORD
24-BIT INPUT WORD
2640 F03a
12345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
C2 C1 C0 X X X X D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X X XC3XXXXXXXX
CS/LD
SCK
SDI
COMMAND WORD DATA WORD
8 DON’T-CARE BITS 4 DON’T-CARE BITS
2640 F03b
32-BIT INPUT WORD
LTC2640
21
2640fd
For more information www.linear.com/LTC2640
OPERATION
Figure 4. Effects of Rail-to-Rail Operation on a DAC Transfer Curve (Shown for 12-Bits)
(a) Overall Transfer Function
(b) Effect of Negative Offset for Codes Near Zero
(c) Effect of Positive Full-Scale Error for Codes Near Full-Scale
2640 F04
INPUT CODE
(b)
OUTPUT
VOLTAGE
NEGATIVE
OFFSET
0V
0V 2,0480 4,095
INPUT CODE
OUTPUT
VOLTAGE
(a)
VREF = VCC
VREF = VCC
(c)
INPUT CODE
OUTPUT
VOLTAGE
POSITIVE
FSE
LTC2640
22
2640fd
For more information www.linear.com/LTC2640
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC2640#packaging for the most recent package drawings.
1.50 – 1.75
(NOTE 4)
2.80 BSC
0.22 – 0.36
8 PLCS (NOTE 3)
DATUM ‘A’
0.09 – 0.20
(NOTE 3)
TS8 TSOT-23 0710 REV A
2.90 BSC
(NOTE 4)
0.65 BSC
1.95 BSC
0.80 – 0.90
1.00 MAX 0.01 – 0.10
0.20 BSC
0.30 – 0.50 REF
PIN ONE ID
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.40
MAX
0.65
REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
1.4 MIN
2.62 REF
1.22 REF
TS8 Package
8-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1637 Rev A)
LTC2640
23
2640fd
For more information www.linear.com/LTC2640
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER
C 10/13 Updated TS8 package drawing to Rev A. 22
D 06/17 Removed Note 3. 9
(Revision history begins at Rev C)
LTC2640
24
2640fd
For more information www.linear.com/LTC2640
LINEAR TECHNOLOGY CORPORATION 2008
LT 0617 REV D • PRINTED IN USA
www.linear.com/LTC2640
RELATED PARTS
TYPICAL APPLICATION
PART NUMBER DESCRIPTION COMMENTS
LTC1663 Single 10-Bit VOUT DAC in SOT-23 VCC = 2.7V to 5.5V, 60µA, Internal Reference, SMBus Interface
LTC1669 Single 10-Bit VOUT DAC in SOT-23 VCC = 2.7V to 5.5V, 60µA, Internal Reference, I2C Interface
LTC2360/LTC2362/
LTC2365/LTC2366
12-Bit SAR ADCs in TSOT23-6/TSOT23-8 Packages 100ksps/250ksps/500ksps/1Msps/3Msps Output Rates
LTC2450/LTC2452 16-Bit Single-Ended/Differential Delta Sigma ADCs SPI Interface, Tiny DFN Packages, 60Hz Output Rate
LTC2451/LTC2453 16-Bit Single-Ended/Differential Delta Sigma ADCs I2C Interface, Tiny DFN and TSOT23-8 Packages, 60Hz Output Rate
LTC2600/LTC2610/LTC2620 Octal 16-/14-/12-Bit VOUT DACs in 16-Lead SSOP 250µA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output,
SPI Serial Interface
LTC2601/LTC2611/LTC2621 Single 16-/14-/12-Bit VOUT DACs in 10-Lead DFN 300µA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output,
SPI Serial Interface
LTC2602/LTC2612/LTC2622 Dual 16-/14-/12-Bit VOUT DACs in 8-Lead MSOP 300µA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output,
SPI Serial Interface
LTC2604/LTC2614/LTC2624 Quad 16-/14-/12-Bit VOUT DACs in 16-Lead SSOP 250µA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output,
SPI Serial Interface
LTC2605/LTC2615/LTC2625 Octal 16-/14-/12-Bit VOUT DACs with I2C Interface 250µA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output,
I2C Interface
LTC2606/LTC2616/LTC2626 Single 16-/14-/12-Bit VOUT DACs with I2C Interface 270µA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output,
I2C Interface
LTC2609/LTC2619/LTC2629 Quad 16-/14-/12-Bit VOUT DACs with I2C Interface 250µA per DAC, 2.5V to 5.5V Supply Range, Rail-to-Rail Output with
Separate VREF Pins for Each DAC
LTC2630 Single 12-/10-/8-Bit VOUT DACs with 10ppm/°C
Reference in SC70
180µA per DAC, 2.7V to 5.5V Supply Range, 10ppm/°C Reference,
Rail-to-Rail Output, SPI Interface
LTC2631 Single 12-/10-/8-Bit I2C VOUT DACs with 10ppm/°C
Reference in ThinSOT
180µA per DAC, 2.7V to 5.5V Supply Range, 10ppm/°C Reference,
Selectable External Ref. Mode, Rail-to-Rail Output, I2C Interface
Programmable ±5V Output
SDI
SCK
CS/LD
0.1µF
VOUT = ±5V
VCC REF
VOUT
SERIAL
BUS LTC2640A
-LM12
2640 TA03
–
+
LTC2054
GND
REF_SEL
8
3
2
1
4
5 6
7
5V
5V
–10V
10V
5
4
6
7
8
9
10
1
2
3
5
4
3
1
2
LT1991
M9
M3
M1
P1
P3
P9
VEE
VCC
OUT
REF
0.1µF
0.1µF
0.1µF
