MAX5123BEEE [MAXIM]

+5V/+3V, 12-Bit, Serial, Force/Sense DACs with 10ppm/∑C Internal Reference; + 5V / + 3V , 12位,串行,加载/感应DAC与为10ppm / ° C内部参考
MAX5123BEEE
型号: MAX5123BEEE
厂家: MAXIM INTEGRATED PRODUCTS    MAXIM INTEGRATED PRODUCTS
描述:

+5V/+3V, 12-Bit, Serial, Force/Sense DACs with 10ppm/∑C Internal Reference
+ 5V / + 3V , 12位,串行,加载/感应DAC与为10ppm / ° C内部参考

转换器 数模转换器 光电二极管
文件: 总20页 (文件大小:286K)
中文:  中文翻译
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19-1446; Rev 0; 3/99  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
Ge n e ra l De s c rip t io n  
Fe a t u re s  
The MAX5122/MAX5123 low-power, 12-bit, voltage-out-  
put, digital-to-analog converters (DACs) feature an inter-  
nal precision bandgap reference and output amplifier.  
Single-Supply Operation  
+5V (MAX5122)  
+3V (MAX5123)  
The MAX5122 operates on a single +5V supply with an  
internal +2.5V reference, and offers a configurable output  
amplifier. If necessary, the user can override the on-chip,  
<10ppm/°C voltage reference with an external reference.  
The MAX5123 has the same features as the MAX5122 but  
operates from a single +3V supply and has an internal  
+1.25V precision reference. The user-accessible inverting  
input and output of the amplifier allows specific gain con-  
figurations, remote sensing, and high output drive capa-  
bility for a wide range of force/sense applications. Both  
d e vic e s d ra w only 500µA of s up p ly c urre nt, whic h  
reduces to 3µA in power-down mode. In addition, their  
power-up reset feature allows for a user-selectable initial  
output state of either 0V or midscale and reduces output  
glitches during power-up.  
Built-In 10ppm/°C max Precision Bandgap Reference  
+2.5V (MAX5122)  
+1.25V (MAX5123)  
SPI/QSPI/MICROWIRE-Compatible, 3-Wire Serial  
Interface  
Pin-Programmable Shutdown Mode and Power-  
Up Reset (0 or Midscale Output Voltage)  
Buffered Output Capable of Driving 5k100pF  
or 4–20mA Loads  
Space-Saving 16-Pin QSOP Package  
Pin-Compatible 13-Bit Upgrades Available  
The serial interface is compatible with SPI™, QSPI™, and  
MICROWIRE™, which makes the MAX5122/MAX5123  
suitable for cascading multiple devices. Each DAC has  
a double-buffered input organized as an input register  
followed by a DAC register. A 16-bit shift register loads  
data into the input register. The DAC register may be  
updated independently or simultaneously with the input  
register.  
(MAX5132/MAX5133)  
Pin-Compatible 14-Bit Upgrades Available  
(MAX5171/MAX5173)  
Ord e rin g In fo rm a t io n  
PIN-  
PACKAGE  
INL  
(LSB)  
Both devices are available in a 16-pin QSOP package  
and are specified for the extended-industrial (-40°C to  
+85°C) operating temperature range. For pin-compatible  
14-bit upgrades, see the MAX5171/MAX5173 data sheet;  
for the pin-compatible 13-bit version, see the MAX5132/  
MAX5133 data sheet.  
PART  
TEMP. RANGE  
MAX5122AEEE  
MAX5122BEEE  
MAX5123AEEE  
MAX5123BEEE  
-40°C to +85°C  
-40°C to +85°C  
-40°C to +85°C  
-40°C to +85°C  
16 QSOP  
16 QSOP  
16 QSOP  
16 QSOP  
±0.5  
±1  
±1  
±2  
Ap p lic a t io n s  
Industrial Process Control  
P in Co n fig u ra t io n  
Automatic Test Equipment  
TOP VIEW  
FB  
1
2
3
4
5
6
7
8
16 V  
DD  
Digital Offset and Gain Adjustment  
Motion Control  
OUT  
15 REFADJ  
14 REF  
RSTVAL  
PDL  
Microprocessor-Controlled Systems  
MAX5122  
MAX5123  
13 AGND  
12 PD  
CLR  
CS  
11 UPO  
10 DOUT  
DIN  
SCLK  
9 DGND  
SPI and QSPI are trademarks of Motorola, Inc.  
MICROWIRE is a trademark of National Semiconductor Corp.  
QSOP  
________________________________________________________________ Maxim Integrated Products  
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.  
For small orders, phone 1-800-835-8769.  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
ABSOLUTE MAXIMUM RATINGS  
V
DD  
to AGND, DGND...............................................-0.3V to +6V  
Continuous Power Dissipation (T = +70°C)  
A
AGND to DGND.....................................................-0.3V to +0.3V  
Digital Inputs to DGND.............................................-0.3V to +6V  
QSOP (derate 8.00mW/°C above +70°C).....................667mW  
Operating Temperature Range ...........................-40°C to +85°C  
Storage Temperature Range .............................-65°C to +150°C  
Lead Temperature (soldering, 10sec) .............................+300°C  
Digital Outputs (DOUT, UPO) to DGND.....-0.3V to (V + 0.3V)  
DD  
FB, OUT to AGND ......................................-0.3V to (V + 0.3V)  
DD  
REF, REFADJ to AGND ..............................-0.3V to (V + 0.3V)  
DD  
Maximum Current into Any Pin............................................50mA  
Stresses beyond those listed under Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional  
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to  
absolute maximum rating conditions for extended periods may affect device reliability.  
ELECTRICAL CHARACTERISTICS—MAX5122 (+5V)  
(V = +5V ±10%, AGND = DGND, 33nF capacitor at REFADJ, internal reference, R = 5k, C = 100pF, output amplifier configured  
DD  
L
L
in unity-gain, T = T  
to T  
, unless otherwise noted. Typical values are at T = +25°C.)  
A
MIN  
MAX  
A
PARAMETER  
STATIC PERFORMANCE  
Resolution  
SYMBOL  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
/MAX5123  
N
12  
-0.5  
-1  
Bits  
MAX5122A  
MAX5123B  
0.5  
1
Integral Nonlinearity (Note 1)  
INL  
LSB  
Differential Nonlinearity  
Offset Error (Note 2)  
Gain Error  
DNL  
-1  
1
LSB  
mV  
mV  
V
OS  
-10  
-3  
10  
3
GE  
-0.2  
3
MAX5122A  
MAX5123B  
10  
30  
250  
Full-Scale Temperature  
Coefficient (Note 3)  
TCV  
ppm/°C  
µV/V  
FS  
10  
20  
Power-Supply Rejection Ratio  
REFERENCE  
PSRR  
4.5V V 5.5V  
DD  
Output Voltage  
V
T
= +25°C  
2.475  
2.5  
3
2.525  
V
REF  
A
MAX5122A  
MAX5122B  
Output Voltage Temperature  
Coefficient  
TCV  
ppm/°C  
REF  
10  
0.1  
4
Reference External Load Regulation  
Reference Short-Circuit Current  
REFADJ Current  
V
/I  
0 I  
100µA (sourcing)  
1
7
µV/µA  
mA  
OUT OUT  
OUT  
REFADJ = V  
3.3  
µA  
DD  
DIGITAL INPUT  
Input High Voltage  
V
3
V
V
IH  
Input Low Voltage  
V
IL  
0.8  
1
Input Hysteresis  
V
HYS  
200  
0.001  
8
mV  
µA  
pF  
Input Leakage Current  
Input Capacitance  
I
IN  
V
IN  
= 0 or V  
-1  
DD  
C
IN  
DIGITAL OUTPUTS  
Output High Voltage  
Output Low Voltage  
V
I
= 2mA  
V - 0.5  
DD  
V
V
OH  
SOURCE  
V
OL  
I
= 2mA  
0.13  
0.4  
SINK  
2
_______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
ELECTRICAL CHARACTERISTICS—MAX5122 (+5V) (continued)  
(V = +5V ±10%, AGND = DGND, 33nF capacitor at REFADJ, internal reference, R = 5k, C = 100pF, output amplifier configured  
DD  
L
L
in unity-gain, T = T  
to T  
, unless otherwise noted. Typical values are at T = +25°C.)  
A
MIN  
MAX  
A
PARAMETER  
DYNAMIC PERFORMANCE  
Voltage Output Slew Rate  
Output Settling Time  
SYMBOL  
CONDITIONS  
MIN  
-0.1  
4.5  
TYP  
MAX  
UNITS  
SR  
0.6  
20  
V/µs  
µs  
To ±0.5LSB, V  
= 2.5V  
STEP  
Output Voltage Swing (Note 4)  
Current into FB  
0 to V  
V
DD  
0
2
0.1  
µA  
ms  
Time Required to Exit Shutdown  
CS = V , f  
= 100kHz,  
DD SCLK  
Digital Feedthrough  
5
nV-sec  
V
SCLK  
= 5Vp-p  
POWER REQUIREMENTS  
Power-Supply Voltage (Note 5)  
Power-Supply Current (Note 5)  
Power-Supply Current in Shutdown  
V
DD  
5.5  
600  
20  
V
I
DD  
500  
3
µA  
µA  
I
SHDN  
ELECTRICAL CHARACTERISTICS—MAX5123 (+3V)  
(V = +3V ±10%, AGND = DGND, 33nF capacitor at REFADJ, internal reference, R = 5k, C = 100pF, output amplifier connected  
DD  
L
L
in unity-gain, T = T  
to T , unless otherwise noted. Typical values are at T = +25°C.)  
MAX A  
A
MIN  
PARAMETER  
STATIC PERFORMANCE  
Resolution  
SYMBOL  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
N
12  
-1  
Bits  
MAX5123A  
MAX5123B  
1
2
Integral Nonlinearity (Note 1)  
INL  
LSB  
-2  
Differential Nonlinearity  
Offset Error (Note 2)  
Gain Error  
DNL  
-1  
1
LSB  
mV  
mV  
V
OS  
-10  
-5  
10  
5
GE  
-0.2  
3
MAX5123A  
MAX5123B  
10  
30  
250  
Full-Scale Temperature  
Coefficient (Note 3)  
TCV  
ppm/°C  
µV/V  
FS  
10  
20  
Power-Supply Rejection Ratio  
REFERENCE  
PSRR  
2.7V V 3.3V  
DD  
Output Voltage  
V
T
= +25°C  
1.237  
1.25  
3
1.263  
V
REF  
A
MAX5123A  
MAX5123B  
Output Voltage Temperature  
Coefficient  
TCV  
ppm/°C  
REF  
10  
0.1  
4
Reference External Load Regulation  
Reference Short-Circuit Current  
REFADJ Current  
V
/I  
0 I  
100µA (sourcing)  
1
7
µV/µA  
mA  
OUT OUT  
OUT  
REFADJ = V  
3.3  
µA  
DD  
DIGITAL INPUT  
Input High Voltage  
V
2.2  
V
V
IH  
Input Low Voltage  
V
IL  
0.8  
Input Hysteresis  
V
HYS  
200  
mV  
_______________________________________________________________________________________  
3
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
ELECTRICAL CHARACTERISTICS—MAX5123 (+3V) (continued)  
(V = +3V ±10%, AGND = DGND, 33nF capacitor at REFADJ, internal reference, R = 5k, C = 100pF, output amplifier connected  
DD  
L
L
in unity-gain, T = T  
to T , unless otherwise noted. Typical values are at T = +25°C.)  
MAX A  
A
MIN  
PARAMETER  
Input Leakage Current  
Input Capacitance  
SYMBOL  
CONDITIONS  
MIN  
TYP  
0.001  
8
MAX  
UNITS  
µA  
I
IN  
V
IN  
= 0 or V  
DD  
-1  
1
C
pF  
IN  
DIGITAL OUTPUTS  
Output High Voltage  
V
I
= 2mA  
V - 0.5  
DD  
V
V
OH  
SOURCE  
Output Low Voltage  
V
OL  
I
= 2mA  
0.13  
0.4  
0.1  
SINK  
DYNAMIC PERFORMANCE  
Voltage Output Slew Rate  
Output Settling Time  
SR  
0.6  
20  
V/µs  
µs  
To ±0.5LSB, V  
= 1.25V  
STEP  
Output Voltage Swing (Note 4)  
Current into FB  
0 to V  
V
DD  
-0.1  
0
2
µA  
ms  
Time Required to Exit Shutdown  
/MAX5123  
CS = V , f  
= 100kHz,  
DD SCLK  
Digital Feedthrough  
5
nV-sec  
V
SCLK  
= 3Vp-p  
POWER REQUIREMENTS  
Power-Supply Voltage (Note 5)  
Power-Supply Current (Note 5)  
Power-Supply Current in Shutdown  
V
2.7  
3.6  
600  
20  
V
DD  
I
DD  
500  
3
µA  
µA  
I
SHDN  
TIMING CHARACTERISTICS—MAX5122 (+5V)  
(V = +5V ±10%, AGND = DGND, 33nF capacitor at REFADJ, internal reference, R = 5k, C = 100pF, output amplifier connected  
DD  
L
L
in unity-gain, T = T  
to T  
, unless otherwise noted. Typical values are at T = +25°C.)  
A
MIN  
MAX  
A
PARAMETER  
SCLK Clock Period  
SYMBOL  
CONDITIONS  
MIN  
100  
40  
40  
40  
0
TYP  
MAX  
UNITS  
ns  
t
CP  
SCLK Pulse Width High  
SCLK Pulse Width Low  
CS Fall to SCLK Rise Setup Time  
SCLK Rise to CS Rise Hold Time  
SDI Setup Time  
t
ns  
CH  
t
ns  
CL  
t
ns  
CSS  
CSH  
t
ns  
t
DS  
40  
0
ns  
SDI Hold Time  
t
ns  
DH  
SCLK Rise to DOUT Valid  
Propagation Delay Time  
t
C
C
= 200pF  
80  
80  
ns  
ns  
DO1  
DO2  
LOAD  
LOAD  
SCLK Fall to DOUT Valid  
Propagation Delay Time  
t
= 200pF  
t
10  
40  
ns  
ns  
ns  
SCLK Rise to CS Fall Delay Time  
CS Rise to SCLK Rise Hold Time  
CS Pulse Width High  
CS0  
t
CS1  
t
100  
CSW  
4
_______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
TIMING CHARACTERISTICS—MAX5123 (+3V)  
(V = +3V ±10%, AGND = DGND, 33nF capacitor at REFADJ, internal reference, R = 5k, C = 100pF, output amplifier connected  
DD  
L
L
in unity-gain, T = T  
to T , unless otherwise noted. Typical values are at T = +25°C.)  
MAX A  
A
MIN  
PARAMETER  
SCLK Clock Period  
SYMBOL  
CONDITIONS  
MIN  
150  
75  
75  
60  
0
TYP  
MAX  
UNITS  
ns  
t
CP  
SCLK Pulse Width High  
SCLK Pulse Width Low  
CS Fall to SCLK Rise Setup Time  
SCLK Rise to CS Rise Hold Time  
SDI Setup Time  
t
ns  
CH  
t
ns  
CL  
t
ns  
CSS  
CSH  
t
ns  
t
DS  
60  
0
ns  
SDI Hold Time  
t
ns  
DH  
SCLK Rise to DOUT Valid  
Propagation Delay Time  
t
C
C
= 200pF  
200  
200  
ns  
ns  
DO1  
DO2  
LOAD  
LOAD  
SCLK Fall to DOUT Valid  
Propagation Delay Time  
t
= 200pF  
t
10  
75  
ns  
ns  
ns  
SCLK Rise to CS Fall Delay Time  
CS Rise to SCLK Rise Hold Time  
CS Pulse Width High  
CS0  
t
CS1  
t
150  
CSW  
Note 1: Accuracy is guaranteed by the following table:  
Accuracy Guaranteed  
From Code: To Code:  
16 4095  
33 4095  
V
DD  
(V)  
5
3
Note 2: Offset is measured at the code closest to 10mV.  
Note 2: The temperature coefficient is determined by the “box” method, in which the maximum V  
over the temperature range  
OUT  
is divided by T and the typical reference voltage.  
Note 4: Accuracy is better than 1.0LSB for V = 10mV to (V - 180mV). Guaranteed by PSR test on end points.  
OUT  
DD  
Note 5: R  
= and digital inputs are at either V or DGND.  
DD  
LOAD  
_______________________________________________________________________________________  
5
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s  
(V = +5V, R = 5k, C = 100pF, output amplifier in unity-gain configuration, T = +25°C, unless otherwise noted.)  
DD  
L
L
A
MAX5122  
MAX5122  
MAX5122  
INTEGRAL NONLINEARITY vs.  
DIGITAL INPUT CODE  
DIFFERENTIAL NONLINEARITY vs.  
DIGITAL INPUT CODE  
REFERENCE VOLTAGE vs. TEMPERATURE  
0.20  
2.510  
2.505  
2.500  
2.495  
2.490  
0.20  
0.15  
0.10  
0.05  
0
0.15  
0.10  
0.05  
0
-0.05  
-0.10  
-0.15  
-0.20  
-0.05  
-0.10  
-0.15  
-0.20  
0
1,000  
2,000  
3,000  
4,000  
5,000  
-60 -40 -20  
0
20 40 60 80 100  
0
1,000  
2,000  
3,000  
4,000  
5,000  
/MAX5123  
DIGITAL INPUT CODE  
TEMPERATURE (°C)  
DIGITAL INPUT CODE  
MAX5122  
MAX5122  
MAX5122  
SHUTDOWN CURRENT vs. TEMPERATURE  
SUPPLY CURRENT vs. TEMPERATURE  
SUPPLY CURRENT vs. SUPPLY VOLTAGE  
500  
450  
400  
350  
300  
250  
200  
2.00  
1.75  
1.50  
1.25  
500  
450  
400  
350  
300  
250  
(CODE = AAA HEX)  
(CODE = 000 HEX)  
(CODE = AAA HEX)  
(CODE = 000 HEX)  
1.00  
0.75  
0.50  
0.25  
0
-60 -40 -20  
0
20 40 60 80 100  
4.0  
4.5  
5.0  
5.5  
6.0  
-60 -40 -20  
0
20 40 60 80 100  
TEMPERATURE (°C)  
SUPPLY VOLTAGE (V)  
TEMPERATURE (°C)  
MAX5122  
FULL-SCALE OUTPUT VOLTAGE  
vs. TEMPERATURE  
MAX5122  
MAX5122  
FULL-SCALE OUTPUT ERROR vs. RESISTIVE LOAD  
DYNAMIC RESPONSE RISE TIME  
MAX5122/23-09  
2.510  
2.505  
R = 5k  
L
0.25  
CS  
5V/div  
C = 100pF  
L
-0.50  
2.500  
2.495  
2.490  
OUT  
1V/div  
-1.25  
-2.00  
2µs/div  
0.1  
1
10  
100  
-60 -40 -20  
0
20 40 60 80 100  
R (k)  
L
TEMPERATURE (°C)  
6
_______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )  
(V = +5V, R = 5k, C = 100pF, output amplifier in unity-gain configuration, T = +25°C, unless otherwise noted.)  
DD  
L
L
A
MAX5122  
DIGITAL FEEDTHROUGH (SCLK, OUT)  
MAX5122  
MAJOR CARRY TRANSITION  
MAX5122  
DYNAMIC RESPONSE FALL TIME  
MAX5122/23-11  
MAX5122/23-12  
MAX5122/23-10  
SCLK  
2V/div  
CS  
2V/div  
CS  
5V/div  
OUT  
1V/div  
OUT  
OUT  
1mV/div  
AC COUPLED  
100mV/div  
AC COUPLED  
2µs/div  
5µs/div  
2µV/div  
MAX5123  
MAX5123  
DIFFERENTIAL NONLINEARITY vs.  
DIGITAL INPUT CODE  
INTEGRAL NONLINEARITY vs.  
DIGITAL INPUT CODE  
MAX5123  
REFERENCE VOLTAGE vs. TEMPERATURE  
0.25  
0.15  
0.10  
0.05  
0
1.260  
1.255  
1.250  
1.245  
1.240  
0.20  
0.15  
0.10  
0.05  
0
-0.05  
-0.10  
-0.15  
-0.20  
-0.25  
-0.05  
-0.10  
-0.15  
-0.20  
0
1,000  
2,000  
3,000  
4,000  
5,000  
0
1,000  
2,000  
3,000  
4,000  
5,000  
-60 -40 -20  
0
20 40 60 80 100  
DIGITAL INPUT CODE  
DIGITAL INPUT CODE  
TEMPERATURE (°C)  
MAX5123  
MAX5123  
MAX5123  
SHUTDOWN CURRENT vs. TEMPERATURE  
SUPPLY CURRENT vs. TEMPERATURE  
SUPPLY CURRENT vs. SUPPLY VOLTAGE  
400  
350  
300  
250  
0.5  
0.4  
400  
350  
300  
(CODE = AAA HEX)  
(CODE = AAA HEX)  
0.3  
0.2  
0.1  
(CODE = 000 HEX)  
(CODE = 000 HEX)  
250  
200  
200  
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
2.50  
2.75  
3.00  
3.25  
3.50  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
SUPPLY VOLTAGE (V)  
_______________________________________________________________________________________  
7
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )  
(V = +5V, R = 5k, C = 100pF, output amplifier in unity-gain configuration, T = +25°C, unless otherwise noted.)  
DD  
L
L
A
MAX5123  
MAX5123  
MAX5123  
DYNAMIC-RESPONSE RISE TIME  
FULL-SCALE OUTPUT VOLTAGE  
vs. TEMPERATURE  
FULL-SCALE OUTPUT ERROR  
vs. RESISTIVE LOAD  
MAX5122/23-21  
1.260  
0
-1  
-2  
CS  
2V/div  
1.255  
1.250  
1.245  
1.240  
OUT  
400mV/div  
-3  
-4  
/MAX5123  
-60 -40 -20  
0
20 40 60 80 100  
1µs/div  
0.01  
0.1  
1
10  
100  
TEMPERATURE (°C)  
R (k)  
L
MAX5123  
DYNAMIC-RESPONSE FALL TIME  
MAX5123  
DIGITAL FEEDTHROUGH (SCLK, OUT)  
MAX5123  
MAJOR CARRY TRANSITION  
MAX5122/23-22  
MAX5122/23-23  
MAX5122/23-24  
SCLK  
2V/div  
CS  
2V/div  
CS  
2V/div  
OUT  
500µV/div  
AC COUPLED  
OUT  
100mV/div  
AC COUPLED  
OUT  
400mV/div  
1µs/div  
2µs/div  
5µV/div  
8
_______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
P in De s c rip t io n  
PIN  
1
NAME  
FUNCTION  
FB  
Amplifier Inverting Sense Input (Analog Input)  
2
OUT  
Analog Output Voltage. High impedance if part is in shutdown.  
Reset Value Input (Digital Input).  
3
RSTVAL  
1: Connect to V to select midscale as the output reset value.  
DD  
0: Connect to DGND to select 0V as the output reset value.  
Power-Down Lockout (Digital Input).  
1: Normal operation.  
0: Disallows shutdown (device cannot be powered down).  
4
5
PDL  
CLR  
Reset DAC Input (Digital Input). Clears the DAC to its predetermined (RSTVAL) output state. Clearing the  
DAC will cause it to exit a software shutdown state.  
6
7
Active-Low Chip-Select Input (Digital Input)  
Serial Data Input. Data is clocked in on the rising edge of SCLK.  
Serial Clock Input  
CS  
DIN  
8
SCLK  
DGND  
DOUT  
UPO  
9
Digital Ground  
10  
11  
Serial Data Output  
User-Programmable Output (Digital Output)  
Power-Down Input (Digital Input). Pulling PD high when PDL = V places the IC into shutdown with a maxi-  
mum shutdown current of 20µA.  
DD  
12  
13  
PD  
AGND  
Analog Ground  
Buffered Reference Output/Input. In internal reference mode, the reference buffer provides a +2.5V  
(MAX5122) or +1.25V (MAX5123) nominal output, externally adjustable at REFADJ. In external reference  
14  
REF  
mode, disable the internal reference by pulling REFADJ to V and applying the external reference to REF.  
DD  
Analog Reference Adjust Input. Bypass with a 33nF capacitor to AGND. Connect to V when using an  
DD  
external reference.  
15  
16  
REFADJ  
V
DD  
Positive Power Supply. Bypass with a 0.1µF capacitor in parallel with a 4.7µF capacitor to AGND.  
_______________________________________________________________________________________  
9
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
DIN  
V
DD  
AGND DGND  
CS  
SCLK  
PDL  
PD  
SR  
CONTROL  
16-BIT  
SHIFT REGISTER  
DOUT  
UPO  
LOGIC  
OUTPUT  
RSTVAL  
CLR  
DECODE  
CONTROL  
FB  
12  
INPUT  
REGISTER  
DAC  
REGISTER  
MAX5122  
MAX5123  
DAC  
OUT  
/MAX5123  
2X  
(X1)  
2.5V (1.25V)  
BANDGAP 1.25V  
REFERENCE  
4k  
REFERENCE  
BUFFER  
REFADJ  
REF  
( ) ARE FOR MAX5123 ONLY.  
Figure 1. Simplified Functional Diagram  
_______________De t a ile d De s c rip t io n  
The MAX5122/MAX5123 12-bit, force/sense DACs are  
easily configured with a 3-wire serial interface. They  
include a 16-bit data-in/data-out shift register and have  
a double-buffered digital input consisting of an input  
register and a DAC register. In addition, these devices  
employ precision bandgap references, as well as an  
output amplifier with accessible feedback and output  
pins that can be used to set the gain externally (Figure  
1) or for forcing and sensing applications. These DACs  
are designed with an inverted R-2R ladder network  
(Figure 2) that produces a weighted voltage proportion-  
al to the digital input code.  
FB  
OUT  
R
R
R
2R  
D0  
2R  
D9  
2R  
D10  
2R  
2R  
D11  
REF*  
In t e rn a l Re fe re n c e  
Both devices use an on-board precision bandgap ref-  
e re nc e with a low te mp e ra ture c oe ffic ie nt of only  
10ppm/°C (max) to generate an output voltage of +2.5V  
(MAX5122) or +1.25V (MAX5123). The REF pin can  
source up to 100µA and may become unstable with  
capacitive loads exceeding 100pF. REFADJ can be  
used for minor adjustments to the reference voltage.  
AGND  
*INTERNAL REFERENCE: +2.5V (MAX5122),  
+1.25V (MAX5123); OR EXTERNAL REFERENCE  
NOTE: SHOWN FOR ALL 1s ON DAC.  
Figure 2. Simplified Inverted R-2R DAC Structure  
10 ______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
The circuit in Figure 3 achieves a nominal reference  
Ou t p u t Am p lifie r  
The MAX5122/MAX5123s DAC outp ut is inte rna lly  
buffered by a precision amplifier with a typical slew rate  
of 0.6V/µs. Access to the output amplifiers inverting  
inp ut (FB) p rovid e s the us e r g re a te r fle xib ility with  
a mp lifie r g a in s e tting a nd s ig na l c ond itioning (s e e  
Applications Information).  
adjustment range of ±1%. Connect a 33nF capacitor  
from REFADJ to AGND to establish low-noise DAC  
operation. Larger capacitor values may be used, but  
will result in increased start-up delay. The time constant  
(τ) for the start-up delay is determined by the REFADJ  
input impedance of 4kand C  
:
REFADJ  
τ= 4k· C  
The output amplifier typically settles to ±0.5LSB from a  
full-scale transition within 20µs when it is connected in  
REFADJ  
Ex t e rn a l Re fe re n c e  
An external reference may be applied to the REF pin.  
Disable the internal reference by pulling REFADJ to  
unity gain and loaded with 5kΩ  
100pF. Loads less  
than 1kmay result in degraded performance.  
V
. This allows an external reference signal (AC- or  
P o w e r-Do w n Mo d e  
DD  
DC-based) to be fed into the REF pin. For proper oper-  
ation, do not exceed the input voltage range limits of 0  
to (V - 1.4V) for V  
These devices feature software- and hardware-pro-  
grammable (PD pin) shutdown modes that reduce the  
typical supply current to 3µA. To enter software shut-  
down mode, program the control sequence for the DAC  
as shown in Table 1.  
.
DD  
REF  
Determine the output voltage using the following equa-  
tion (REFADJ = V ):  
DD  
In shutdown mode, the amplifier output becomes high-  
impedance and the serial interface remains active.  
Da ta in the inp ut re g is te rs is s a ve d , a llowing the  
MAX5122/MAX5123 to recall the output state prior to  
entering shutdown when returning to normal operation.  
To exit shutdown mode, load both input and DAC regis-  
ters simultaneously or update the DAC register from the  
input register. When returning from shutdown to normal  
operation, wait 2ms for the reference to settle. When  
using an external reference, the DAC requires only  
20µs for the output to stabilize.  
V
= V  
[(NB / 4096) G]  
OUT  
REF  
whe re NB is the nume ric va lue of the MAX5122/  
MAX5123 input code (0 to 4095), V is the external  
re fe re nc e volta g e , a nd G is the g a in of the outp ut  
amplifier, set by an external resistor-divider. The REF  
pin has a minimum input resistance of 40kand is  
code-dependent.  
REF  
+3V  
+5V  
15k  
MAX5123  
90k  
MAX5122  
400k  
400k  
100k  
100k  
REFADJ  
REFADJ  
33nF  
33nF  
Figure 3a. MAX5122 Reference Adjust Circuit  
Figure 3b. MAX5123 Reference Adjust Circuit  
______________________________________________________________________________________ 11  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
Table 1. Serial-Interface Programming Commands  
16-BIT SERIAL WORD  
S0*  
S0*  
FUNCTION  
C2  
C1  
C0  
D11 ............... D0  
0
0
0
0
1
1
1
1
1
0
0
1
1
0
0
1
1
1
0
1
0
1
1
0
0
1
1
XXXXXXXXXXXX  
12-Bit DAC Data  
12-Bit DAC Data  
XXXXXXXXXXXX  
XXXXXXXXXXXX  
XXXXXXXXXXXX  
XXXXXXXXXXXX  
1XXXXXXXXXXX  
00XXXXXXXXXX  
0
0
0
0
0
0
0
0
0
No operation.  
Load input register; DAC register unchanged.  
Simultaneously load input and DAC registers; exit shutdown.  
Update DAC register from input register; exit shutdown.  
Shutdown DAC (provided PDL = 1).  
UPO goes low (default).  
UPO goes high.  
Mode 1; DOUT clocked out on SCLK’s rising edge.  
Mode 0; DOUT clocked out on SCLK’s falling edge (default).  
X = Dont care * S0 is a sub-bit and always zero.  
/MAX5123  
Power-Down Lockout Input (PDL)  
The power-down lockout pin (PDL) disables shutdown  
when low. When in shutdown mode, a high-to-low tran-  
sition on PDL will wake up the DAC with its output still  
set to the state prior to power-down. PDL can also be  
used to wake up the device asynchronously.  
V
DD  
SS  
DIN  
MOSI  
SCK  
Power-Down Input (PD)  
Pulling PD high places the MAX5122/MAX5123 in shut-  
d own. Pulling PD low will not re turn the MAX5122/  
MAX5123 to normal operation. A high-to-low transition  
on PDL or appropriate commands (Table 1) via the ser-  
ial interface are required to exit power-down mode.  
SPI/QSPI  
PORT  
(PIC16/PIC17)  
MAX5122  
MAX5123  
SCLK  
CS  
I/O  
S e ria l-In t e rfa c e Co n fig u ra t io n  
(S P I/QS P I/MICROWIRE/P IC1 6 /P IC1 7 )  
The MAX5122/MAX5123 3-wire serial interface is com-  
patible with SPI, QSPI, PIC16/PIC17 (Figure 4) and  
MICROWIRE (Figure 5) interface standards. The 2-  
byte-long serial input word contains three control bits,  
12 data bits in MSB-first format, and one sub-bit, which  
is always zero (Table 2).  
CPOL = 0, CPHA = 0  
(CKE = 1, CKP = 0, SMP= 0  
SSPM3 - SSPM0 = 0001)  
( ) ARE FOR PIC16/PIC17 ONLY.  
Figure 4. SPI/QSPI Interface Connections (PIC16/PIC17)  
The MAX5122/MAX5123s digital inputs are double  
buffered, which allows the user to:  
SK  
SO  
I/O  
SCLK  
DIN  
CS  
Load the input register without updating the DAC  
register,  
MICROWIRE  
PORT  
MAX5122  
MAX5123  
Update the DAC register with data from the input  
register,  
Update the input and DAC registers concurrently.  
Figure 5. MICROWIRE Interface Connections  
12 ______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
The 16-bit input word may be sent in two 1-byte pack-  
MAX5122 a nd 6.6MHz for the MAX5123. Fig ure 7  
depicts a more detailed timing diagram of the serial  
interface.  
ets (SPI-, MICROWIRE-, and PIC16/PIC17-compatible),  
with CS low during this period. The control bits C2, C1,  
and C0 (table 1) determine:  
P IC1 6 w it h S S P Mo d u le  
a n d P IC1 7 In t e rfa c e  
The clock edge on which DOUT transitions,  
The state of the user-programmable logic output,  
The configuration of the device after shutdown.  
The MAX5122/MAX5123 a re c omp a tib le with a  
PIC16/PIC17 microcontroller (µC), using the synchro-  
nous serial port (SSP) module. To establish SPI commu-  
nication, connect the controller as shown in Figure 4  
and configure the PIC16/PIC17 as system master by ini-  
tializing its synchronous serial port control register (SSP-  
CON) a nd s ync hronous s e ria l p ort s ta tus re g is te r  
(SSPSTAT) to the bit patterns shown in Tables 3 and 4.  
The general timing diagram in Figure 6 illustrates how  
data is acquired. CS must be low for the part to receive  
data. With CS low, data at DIN is clocked into the regis-  
ter on the rising edge of SCLK. When CS transitions  
high, data is latched into the input and/or DAC regis-  
ters, depending on the setting of the three control bits  
C2, C1, and C0. The maximum serial clock frequency  
g ua ra nte e d for p rop e r op e ra tion is 10MHz for the  
In SPI mode, the PIC16/PIC17 µCs allow eight bits of  
data to be synchronously transmitted and received  
simultaneously. Two consecutive 8-bit writings (Figure  
6) are necessary to feed the DAC with three control bits,  
12 data bits, and one sub-bit. DIN data transitions on  
the serial clocks falling edge and is clocked into the  
DAC on SCLKs rising edge. The first eight bits of DIN  
contain the three control bits (C2, C1, C0) and the first  
five data bits (D11–D7). The second 8-bit data stream  
contains the remaining bits (D6–D0), and the sub-bit S0.  
Table 2. Serial Data Format  
MSB ............................................................................... LSB  
16 BITS OF SERIAL DATA  
Control Bits  
C2, C1, C0  
MSB ..... Data Bits ..... LSB  
D11................................D0  
Sub-Bit  
S0  
CS  
COMMAND  
EXECUTED  
SCLK  
DIN  
1
8
9
16  
D5 D4 D3 D2 D1 D0 S0  
C1  
C0  
D10 D9  
C2  
D11  
D8 D7  
D6  
Figure 6. Serial-Interface Timing  
t
CSW  
CS  
t
CSH  
t
t
CSS  
CS0  
t
CS1  
SCLK  
t
CH  
t
CL  
t
CP  
DIN  
t
DS  
t
DH  
t
t
DO1  
DO2  
DOUT  
Figure 7. Detailed Serial-Interface Timing  
______________________________________________________________________________________ 13  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
Table 3. Detailed SSPCON Register Contents  
MAX5122/MAX5123  
SETTINGS  
SYNCHRONOUS SERIAL-PORT CONTROL REGISTER  
(SSPCON)  
CONTROL BIT  
WCOL  
BIT7  
BIT6  
X
X
Write Collision Detection Bit  
Receive Overflow Detect Bit  
SSPOV  
Synchronous Serial Port Enable Bit.  
0: Disables serial port and configures these pins as I/O port pins.  
1: Enables serial port and configures SCK, SDO and SCI as serial-  
port pins.  
SSPEN  
BIT5  
1
CKP  
BIT4  
BIT3  
BIT2  
BIT1  
BIT0  
0
0
0
0
1
Clock Polarity Select Bit. CKP = 0 for SPI master-mode selection.  
SSPM3  
SSPM2  
SSPM1  
SSPM0  
Synchronous Serial Port Mode Select Bit. Sets SPI master mode  
and selects f  
= f  
/ 16  
CLK  
OSC  
X = Dont care  
/MAX5123  
Table 4. Detailed SSPSTAT Register Contents  
MAX5130/MAX5131  
SYNCHRONOUS SERIAL-PORT CONTROL REGISTER  
(SSPSTAT)  
CONTROL BIT  
SETTINGS  
SPI Data Input Sample Phase. Input data is sampled at the mid-  
dle of the data output time.  
SMP  
CKE  
BIT7  
BIT6  
0
1
SPI Clock Edge Select Bit. Data will be transmitted on the rising  
edge of the serial clock.  
D/A  
P
BIT5  
BIT4  
BIT3  
BIT2  
BIT1  
BIT0  
X
X
X
X
X
X
Data Address Bit  
Stop Bit  
S
Start Bit  
R/W  
UA  
BF  
Read/Write Bit Information  
Update Address  
Buffer Full Status Bit  
X = Dont care  
S e ria l Da t a Ou t p u t  
Us e r-P ro g ra m m a b le Ou t p u t (UP O)  
The UPO feature allows an external device to be con-  
trolled through the serial-interface setup (Table 1) there-  
by reducing the number of microcontroller I/O ports  
required. During power-down, this output will retain the  
last digital state before shutdown. With CLR pulled low,  
UPO will reset to the default state after wake-up.  
The contents of the internal shift-register are output  
serially on DOUT which allows for daisy-chaining of  
multiple devices (see Applications Information) as well  
as data readback. The MAX5122/MAX5123 may be  
programmed to shift data out of DOUT on the serial  
clocks rising edge (Mode 1) or on the falling edge  
(Mode 0). The latter is the default during power-up and  
provides a lag of 16 clock cycles, maintaining SPI,  
QSPI, MICROWIRE, and PIC16/PIC17 compatibility. In  
Mode 1, the output data lags DIN by 15.5 clock cycles.  
During power-down, DOUT retains its last digital state  
prior to shutdown.  
14 ______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
1LSB. If the magnitude of the DNL is less than or equal  
to 1LSB, the DAC guarantees no missing codes and is  
monotonic.  
__________Ap p lic a t io n s In fo rm a t io n  
De fin it io n s  
Integral Nonlinearity (INL)  
Integral nonlinearity (Figure 8a) is the deviation of the  
values on an actual transfer function from a straight  
line. This straight line can be either a best-straight-line  
fit (closest approximation to the actual transfer curve)  
or a line drawn between the endpoints of the transfer  
function, once offset and gain errors have been nulli-  
fied. For a DAC, the deviations are measured at every  
single step.  
Offset Error  
The offset error (Figure 8c) is the difference between  
the ideal and the actual offset point. For a DAC, the off-  
set point is the step value when the digital input is zero.  
This error affects all codes by the same amount and  
can usually be compensated for by trimming.  
Gain Error  
Gain error (Figure 8d) is the difference between the  
ideal and the actual full-scale output voltage on the  
transfer curve, after nullifying the offset error. This error  
a lte rs the s lop e of the tra ns fe r func tion a nd c orre -  
sponds to the same percentage error in each step.  
Differential Nonlinearity (DNL)  
Differential nonlinearity (Figure 8b) is the difference  
between an actual step height and the ideal value of  
7
6
ACTUAL  
DIAGRAM  
3
2
1
0
5
4
IDEAL DIAGRAM  
OFFSET ERROR  
AT STEP  
O11 (1/2 LSB )  
3
2
1
0
(+1 1/4 LSB)  
AT STEP  
001 (1/4 LSB )  
ACTUAL  
OFFSET POINT  
IDEAL OFFSET  
POINT  
000 001 010 011 100 101 110 111  
DIGITAL INPUT CODE  
000  
001  
010  
011  
DIGITAL INPUT CODE  
Figure 8a. Integral Nonlinearity  
Figure 8c. Offset Error  
IDEAL FULL-SCALE OUTPUT  
6
5
4
7
GAIN ERROR  
(-1 1/4 LSB)  
1 LSB  
6
5
DIFFERENTIAL LINEARITY  
ERROR (-1/4 LSB)  
IDEAL DIAGRAM  
3
ACTUAL  
FULL-SCALE  
OUTPUT  
1 LSB  
2
1
0
DIFFERENTIAL  
4
0
LINEARITY ERROR (+1/4 LSB)  
000  
001  
010  
011  
100  
101  
000 100  
101  
110  
111  
DIGITAL INPUT CODE  
DIGITAL INPUT CODE  
Figure 8b. Differential Nonlinearity  
______________________________________________________________________________________ 15  
Figure 8d. Gain Error  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
Settling Time  
The settling time is the amount of time required from the  
+5V/+3V  
start of a transition until the DAC output settles to its  
REF  
new output value within the converters specified accu-  
racy.  
V
DD  
50k  
50k  
MAX5122  
MAX5123  
Digital Feedthrough  
Digital feedthrough is noise generated on the DACs  
output when any digital input transitions. Proper board  
la yout a nd g round ing will s ig nific a ntly re d uc e this  
nois e , b ut the re will a lwa ys b e s ome fe e d throug h  
caused by the DAC itself.  
FB  
DAC  
OUT  
AGND  
DGND  
Un ip o la r Ou t p u t  
Figure 9 shows the MAX5122/MAX5123 setup for unipo-  
lar, Rail-to-Rail operation with a closed- loop gain of  
NOTE: GAIN = +2V/V  
®
2V/V. With its internal reference of +2.5V, the MAX5122  
provides a convenient unipolar output range of 0 to  
+4.99878V, while the MAX5123 offers an output range of  
0 to +2.49939V with its on-board +1.25V reference.  
Table 5 lists example codes for unipolar output voltages.  
Figure 9. Unipolar Output Circuit Using Internal  
(+1.25V/+2.5V) or External Reference. With external reference,  
pull REFADJ to V  
/MAX5123  
.
DD  
Bip o la r Ou t p u t  
The MAX5122/MAX5123 can be configured for unity-  
gain bipolar operation (FB = OUT) using the circuit  
+5V/+3V  
50k  
FB  
50k  
V+  
REF  
V
DD  
shown in Figure 10. The output voltage V  
is then  
OUT  
given by the following equation:  
MAX5122  
MAX5123  
V
OUT  
= V [{G (NB / 4096)} - 1]  
REF  
where NB is the numeric value of the DACs binary  
input code, V is the voltage of the internal (or exter-  
V
OUT  
DAC  
REF  
OUT  
nal) precision reference, and G is the overall gain. The  
application circuit in Figure 10 uses a low-cost op amp  
(MAX4162) e xte rna l to the MAX5122/MAX5123.  
Together with the MAX5122/MAX5123 this circuit offers  
an overall gain of +2V/V. Table 6 lists example codes  
for bipolar output voltages.  
MAX4162  
V-  
AGND  
DGND  
Figure 10. Unity-Gain Bipolar Output Circuit Using Internal  
(+1.25V/+2.5V) or External Reference. With external reference,  
Re s e t (RS TVAL) a n d  
pull REFADJ to V  
.
DD  
CLR  
Cle a r (  
) Fu n c t io n s  
The MAX5122/MAX5123 DACs feature a clear pin (CLR),  
which resets the output to a certain value, depending  
upon how RSTVAL is set. RSTVAL = DGND selects an  
Da is y-Ch a in in g De vic e s  
Any number of MAX5122/MAX5123s may be daisy-  
chained by simply connecting the serial data output pin  
(DOUT) of one device to the serial data input pin (DIN)  
of the following device in the chain (Figure 11).  
output of 0, and RSTVAL = V selects a midscale out-  
DD  
put when CLR is pulled low.  
The CLR pin has a minimum input resistance of 40kin  
series with a diode to the supply voltage (V ). If the  
DD  
Anothe r c onfig ura tion (Fig ure 12) a llows s e ve ra l  
MAX5122/MAX5123 DACs to share one common DIN  
signal line. In this configuration, the data bus is common  
to all devices; data is not shifted through a daisy-chain.  
However, more I/O lines are required in this configura-  
tion, because each IC needs a dedicated CS line.  
digital voltage is higher than the supply voltage for the  
part, a small input current may flow, but this current will  
be limited to (V  
- V - 0.5V) / 40k.  
CLR  
DD  
Note: Clearing the DAC will also cause the part to exit  
a software shutdown (PD = 0).  
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.  
16 ______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
Table 5. Unipolar Code Table (Gain = +1.6384V/V)  
DAC CONTENTS  
ANALOG OUTPUT  
INTERNAL REFERENCE  
MAX5122 MAX5123  
SUB-BIT  
S0  
EXTERNAL REFERENCE  
MAX5122/MAX5123  
MSB  
LSB  
1111 1111 1111  
0
0
0
0
0
0
+4.99878V  
+2.50122V  
+2.5V  
+2.49939V  
+1.25061V  
+1.25V  
V
(4095 / 4096) 2  
(2049 / 4096) 2  
(2048 / 4096) 2  
(2047 / 4096) 2  
REF  
1000 0000 0001  
1000 0000 0000  
0111 1111 1111  
0000 0000 0001  
0000 0000 0000  
V
REF  
V
REF  
+2.49878V  
+1.2207mV  
0V  
+1.24939V  
+610.35µV  
0V  
V
REF  
V
(1 / 4096) 2  
0
REF  
Table 6. Bipolar Code Table (Figure 10)  
DAC CONTENTS  
ANALOG OUTPUT  
INTERNAL REFERENCE  
SUB-BIT  
S0  
EXTERNAL REFERENCE  
MAX5122/MAX5123  
MSB  
LSB  
MAX5122  
+2.49878V  
+1.2207mV  
0V  
MAX5123  
+1.24939V  
+610.35µV  
0V  
1111 1111 1111  
0
0
0
0
0
0
V
[ {2 (4095 / 4096)} - 1]  
[ {2 (2049 / 4096)} - 1]  
[ {2 (2048 / 4096)} - 1]  
[ {2 (2047 / 4096)} - 1]  
REF  
1000 0000 0001  
1000 0000 0000  
0111 1111 1111  
0000 0000 0001  
0000 0000 0000  
V
REF  
V
REF  
-1.2207mV  
-2.49878V  
-2.5V  
-610.35µV  
-1.24939V  
-1.25V  
V
REF  
V
REF  
[ {2 (1 / 4096)} - 1]  
-V  
REF  
SCLK  
SCLK  
SCLK  
I
II  
III  
MAX5122  
MAX5123  
MAX5122  
MAX5123  
MAX5122  
MAX5123  
DIN  
DOUT  
DIN  
CS  
DOUT  
DIN  
CS  
DOUT  
CS  
TO OTHER  
SERIAL DEVICES  
Figure 11. Daisy-Chaining Multiple Devices with the Digital I/Os DIN/DOUT  
______________________________________________________________________________________ 17  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
V
). Bypass the power supply (V ) with a 4.7µF  
DD  
Us in g a n Ex t e rn a l Re fe re n c e  
w it h AC Co m p o n e n t s  
The MAX5122/MAX5123 have multiplying capabilities  
within the reference input voltage range specifications.  
Figure 13 shows a technique for applying a sinusoidal  
input to REF, where the AC signal is offset before being  
applied to the reference input.  
DD  
capacitor in parallel with a 0.1µF capacitor to AGND.  
Minimize lead lengths to reduce lead inductance.  
La yo u t Co n s id e ra t io n s  
Digital and AC signals coupling to AGND can create  
noise at the output. Connect AGND to the highest quali-  
ty ground available. Use proper grounding techniques,  
s uc h a s a multila ye r b oa rd with a low-ind uc ta nc e  
ground plane. Wire-wrapped boards and sockets are  
not recommended. If noise becomes an issue, shield-  
ing may be required.  
P o w e r-S u p p ly a n d Byp a s s in g  
Co n s id e ra t io n s  
On power-up, the input and DAC registers are cleared to  
either zero (RSTVAL = DGND) or midscale (RSTVAL =  
DIN  
SCLK  
CS1  
/MAX5123  
CS2  
TO OTHER  
SERIAL DEVICES  
CS3  
I
II  
III  
CS  
CS  
CS  
MAX5122  
MAX5123  
MAX5122  
MAX5123  
MAX5122  
MAX5123  
SCLK  
SCLK  
SCLK  
DIN  
DIN  
DIN  
Figure 12. Multiple Devices Share One Common Digital Input (DIN)  
___________________Ch ip In fo rm a t io n  
+5V/  
+3V  
TRANSISTOR COUNT: 3308  
+5V/+3V  
26k  
AC  
REFERENCE  
SUBSTRATE CONNECTED TO AGND  
MAX495  
INPUT  
10k  
500mVp-p  
V
DD  
REF  
FB  
DAC  
OUT  
MAX5122  
MAX5123  
AGND  
DGND  
Figure 13. External Reference with AC Components  
18 ______________________________________________________________________________________  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
/MAX5123  
P a c k a g e In fo rm a t io n  
______________________________________________________________________________________ 19  
+5 V/+3 V, 1 2 -Bit , S e ria l, Fo rc e /S e n s e DACs  
w it h 1 0 p p m /°C In t e rn a l Re fe re n c e  
NOTES  
/MAX5123  
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are  
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.  
20 ____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0  
© 1999 Maxim Integrated Products  
Printed USA  
is a registered trademark of Maxim Integrated Products.  

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