MX674ALEWI+T [MAXIM]
ADC, Successive Approximation, 12-Bit, 1 Func, Parallel, Word Access, BICMOS, PDSO28, SO-28;
| 型号： | MX674ALEWI+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | ADC, Successive Approximation, 12-Bit, 1 Func, Parallel, Word Access, BICMOS, PDSO28, SO-28 信息通信管理 光电二极管 转换器 |
| 文件： | 总18页 (文件大小：1427K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2765; Rev 3; 8/11
E V A L U A T I O N K I T A V A I L A B L E
General Description
Features
The MAX174/MX574A/MX674A are complete 12-bit
analog-to-digital converters (ADCs) that combine high
speed, low-power consumption, and on-chip clock and
voltage reference. The maximum conversion times are
8µs (MAX174), 15µs (MX674A), and 25µs (MX574A).
Maxim’s BiCMOS construction reduces power dissipa-
tion 3 times (150mW) over comparable devices. The
internal buried zener reference provides low-drift and
low-noise performance. External component require-
ments are limited to only decoupling capacitors and fixed
resistors. The versatile analog input structure allows for
0 to +10V or 0 to +20V unipolar or ±5V or ±10V bipolar
input ranges with pin strapping.
S Complete ADC with Reference and Clock
S 12-Bit Resolution and Linearity
S No Missing Codes Over Temperature
S 150mW Power Dissipation
S 8µs (MAX174), 15µs (MX674A), and 25µs (MX574A)
Max Conversion Times
S Precision Low TC Reference: 10ppm/NC
S Monolithic BiCMOS Construction
S 150ns Maximum Data Access Time
Applications
The MAX174/MX574A/MX674A use standard micropro-
cessor interface architectures and can be interfaced to
8-, 12-, and 16-bit wide buses. Three-state data outputs
are controlled by CS, CE, and R/C logic inputs.
Digital Signal Processing
High-Accuracy Process Control
High-Speed Data Acquisition
Electro-Mechanical Systems
Ordering Information appears at end of data sheet.
Functional Diagram
V
R
DGND
15
V
V
BIPOFF
12
10V
20V
L
CC
7
EE
IN
IN
1
11
13
14
5kI
2R
9.950kI
10
REFIN
5kI
12-BIT
DAC
9
8
AGND
12
SAR
+10V
REF
REFOUT
2
3
4
12/8
CS
CLOCK
AND
CONTROL
LOGIC
4
4
4
MAX174
MX574A
MX674A
LOW
NIBBLE
MIDDLE
NIBBLE
HIGH
NIBBLE
A0
16
D0
19 20
D3 D4
23 24
D7 D8
27
28
6
5
D11
STS CE R/C
For related parts and recommended products to use with this part, refer to www.maxim-ic.com/MAX174.related.
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1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
ABSOLUTE MAXIMUM RATINGS
V
V
V
to DGND..............................................................0 to 16.5V
to DGND...............................................................0 to 16.5V
to DGND......................................................................0 to 7V
Power Dissipation (any package) to +75NC .................1000mW
Derates above +75NC ..............................................10mW/NC
Operating Temperature Ranges
CC
EE
L
MAX174_C, MX_74AJ/K/L...................................... 0 to +70NC
MAX174_E, MX_74AJE/KE/LE ........................ -40NC to +85NC
MAX174_M, MX_74AS/T/U............................ -55NC to +125NC
Storage Temperature Range............................ -55NC to +160NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow)
DGND to AGND ................................................................... Q1V
Control Inputs to DGND
(CE, CS, A0, 12/8, R/C) ........................ -0.3V to (V
+ 0.3V)
CC
Digital Output Voltage to DGND
(DB11–DB0, STS)..................................... -0.3V to (V + 0.3V)
L
Analog Inputs to AGND (REFIN, BIPOFF, 10V )........... Q16.5V
IN
PDIP, Wide SO.............................................................+260NC
PLCC............................................................................+245NC
20V to AGND................................................................... Q24V
IN
REFOUT................................... Indefinite short to V
or AGND
CC
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion 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—MAX174
(V = +5V, V = +15V or +12V, V = -15V or -12V, T = +25NC, unless otherwise noted.)
L
EE
EE
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ACCURACY
Resolution
12
Bits
RES
INL
MAX174A/B
MAX174C
±1/2
±1
T
T
= +25°C
A
A
Integral Nonlinearity
MAX174AC/BC
±1/2
±3/4
±1
LSB
= T
to T
MAX174AE/BE/AM/BM
MAX174C
MIN
MAX
Differential Nonlinearity
12 bits, no missing codes over temperature
±1
LSB
LSB
DNL
MAX174A/B
MAX174C
MAX174A
±1
Unipolar Offset Error (Note 1)
±2
±3
Bipolar Offset Error (Notes 2, 3)
Full-Scale Calibration Error (Note 3)
LSB
%
MAX174B/C
±4
±0.25
TEMPERATURE COEFFICIENTS (Using Internal Reference) (Notes 2, 3, 4)
MAX174A/B
±1
±2
±1
±2
±1
±2
±4
Unipolar Offset Change
MAX174C
LSB
LSB
MAX174AC/BC
MAX174CC
Bipolar Offset Change
MAX174AE/AM
MAX174BE/BM
MAX174CE/CM
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2
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
ELECTRICAL CHARACTERISTICS—MAX174 (continued)
(V = +5V, V = +15V or +12V, V = -15V or -12V, T = +25NC, unless otherwise noted.)
L
EE
EE
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX174AC
MAX174BC
MAX174CC
MAX174AE
MAX174BE
MAX174CE
MAX174AM
MAX174BM
MAX174CM
±2 (10)
±5 (27)
±± (50)
±7 (1±)
±10 (38)
±20 (75)
±5 (12)
±10 (25)
±20 (50)
LSB
(ppm/°C
Full-Scale Calibration Change
INTERNAL REFERENCE
MAX174A
MAX174B/C
±.±8
±.±7
10.00
10.00
10.02
10.03
Output Voltage
No load
V
Available for external loads, in addition to
REFIN and BIPOFF load
Output Current (Note 5)
2
mA
ELECTRICAL CHARACTERISTICS—MX574A, MX674A
(V = + 5V, V = +15V or +12V, V = -15V or -12V, T = +25NC, unless otherwise noted.)
L
EE
EE
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ACCURACY
Resolution
12
Bits
RES
INL
MX574AK/L/T/U,
MX674AK/L/T/U
±1/2
T
T
= +25°C
A
A
MX574AJ/S, MX674AJ/S
MX574AK/L/KE/LE
±1
±1/2
±1/2
±3/4
±1
Integral Nonlinearity
LSB
MX674AK/L/KE/LE
= T
to T
MAX
MIN
MX574AT/U, MX674AT/U
MX574AJ/S, MX674AJ/S
Differential Nonlinearity
12 bits, no missing codes over temperature
MX574AK/L/T/U, MX674AK/L/T/U
MX574AJ/S, MX674AJ/S
±1
LSB
LSB
DNL
±1
Unipolar Offset Error (Note 1)
±2
MX574AL/U, MX674AL/U
±3
Bipolar Offset Error (Notes 2, 3)
LSB
%
MX574AJ/K/S/T, MX674AJ/K/S/T
MX574AL/U
±4
±0.125
±0.25
Full-Scale Calibration Error
(Note 3)
MX574AJ/K/S/T, MX674A
TEMPERATURE COEFFICIENTS (Using Internal Reference) (Notes 2, 3, 4)
MX574AK/L/T/U, MX674AK/L/T/U
Unipolar Offset Change
±1
±2
LSB
MX574AJ/S, MX674AJ/S
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3
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
ELECTRICAL CHARACTERISTICS—MX574A, MX674A (continued)
(V = + 5V, V = +15V or +12V, V = -15V or -12V, T = +25NC, unless otherwise noted.)
L
EE
EE
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
±1
UNITS
MX574AK/L, MX674AK/L
MX574AJ, MX674AJ
±2
Bipolar Offset Change
MX574AU/LE, MX674AU/LE
MX574AT/KE, MX674AT/KE
MX574AS/JE, MX674AS/JE
MX574AL, MX674AL
±1
LSB
±2
±4
±2 (10)
±5 (27)
±± (50)
±7 (1±)
±10 (38)
±20 (75)
±5 (12)
±10 (25)
±20 (50)
MX574AK, MX674AK
MX574AJ, MX674AJ
MX574ALE, MX674ALE
MX574AKE, MX674AKE
MX574AJE, MX674AJE
MX574AU, MX674AU
MX574AT, MX674AT
LSB
(ppm/°C
Full-Scale Calibration Change
MX574AS, MX674AS
INTERNAL REFERENCE
MX574AL/U
±.±±
±.±8
±.±7
10.00
10.00
10.00
10.01
10.02
10.03
Output Voltage
No load
MX574AJ/K/S/T, MX674AL/U
MX674AJ/K/S/T
V
Available for external loads, in addition to
REFIN and BIPOFF load
Output Current (Note 5)
2
mA
ELECTRICAL CHARACTERISTICS—MAX174/MX574/MX674A
(V = +5V, V
= +15V or +12V, V = -15V or -12V, T = +25NC, unless otherwise noted.)
L
CC
EE
A
PARAMETER
ANALOG INPUT
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Using 10V input
Using 20V input
Using 10V input
Using 20V input
10V input
±5
±10
+10
+20
7
Bipolar Input Range
Unipolar Input Range
Input Impedance
V
V
0
0
3
6
5
kW
20V input
10
14
POWER-SUPPLY REJECTION (Max Change in Full-Scale Calibration)
MAX174A/B, MX_74AK/L/TU
MAX174C, MX_74AJ/S
±1/8
±1/8
±1/8
±1
±2
15V ±1.5V or
12V ±0.6V
V
Only
LSB
CC
V
Only
15V ±1.5V or 12V ±0.6V
5V ±0.5V
±1/2
LSB
LSB
EE
V Only
L
±1/8
±1/2
LOGIC INPUTS
Input Low Voltage
Input High Voltage
V
V
0.8
V
V
CS, CE, R/C, A0, 12/8
CS, CE, R/C, A0, 12/8
IL
2.0
IH
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4
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
ELECTRICAL CHARACTERISTICS—MAX174/MX574/MX674A (continued)
(V = +5V, V
= +15V or +12V, V = -15V or -12V, T = +25NC, unless otherwise noted.)
EE A
L
CC
PARAMETER
Input Current
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
µA
I
±5
CS, CE, R/C, A0, 12/8, V = 0 to V
IN
IN
L
Input Capacitance
C
7
pF
CS, CE, R/C, A0, 12/8
IN
LOGIC OUTPUTS
Output Low Voltage
V
DB11–DB0, STS
DB11–DB0, STS
DB11–DB0, STS
DB11–DB0
I
I
= 1.6mA
0.4
V
V
OL
SINK
Output High Voltage
V
= 500µA
4
OH
SOURCE
Floating State Leakage Current
Floating State Output Capacitance
CONVERSION TIME
I
V
= 0 to V
L
±10
µA
pF
LKG
OUT
C
8
OUT
MX574A
MX674A
MAX174
MX574A
MX674A
MAX174
15
±
20
12
7
25
15
8
12-Bit Cycle
t
µs
µs
CONV
CONV
6
10
6
14
8
18
11
6
8-Bit Cycle
t
4
5
POWER REQUIREMENTS
V
Operating Range
11.4
4.5
16.5
5.5
-16.5
5
V
V
CC
V Operating Range
L
V
Operating Range
-11.4
V
EE
V
Supply Current (Note 5)
I
3
3
mA
mA
mA
mW
CC
CC
V Supply Current (Note 5)
I
8
L
L
V
Supply Current (Note 5)
I
6
10
EE
EE
Power Dissipation (Note 5)
P
V
= +15V and V = -15V
150
265
D
CC
EE
Note 1: Adjustable to zero.
Note 2: With 50ω fixed resistor from REFOUT to BIPOFF. Adjustable to zero.
Note 3: With 50ω fixed resistor from REFOUT to REFIN. Adjustable to zero.
Note 4: Maximum change in specification from T = +25°C to T
Note 5: External load current should not change during a conversion. For Q12V supply operation, REFOUT need not be buffered
or T = +25°C to T
.
A
MIN
A
MAX
except when external load in addition to REFIN and BIPOFF inputs have to be driven.
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5
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
TIMING CHARACTERISTICS—MAX174/MX574A/MX674A (Note 6)
(V = +5V, V
= +15V or +12V, V = -15V or -12V.)
EE
L
CC
T
T
= -40°C TO +85°C
= 0°C TO +70° C
A
T
= +25°C
T = -55°C TO +125°C
A
A
PARAMETER
SYMBOL CONDITIONS
UNITS
A
MIN TYP MAX MIN TYP MAX
MIN
TYP MAX
CONVERT START TIMING—FULL CONTROL MODE
STS Delay from CE
CE Pulse Width
t
t
C = 50pF
100
15
200
250
320
ns
ns
ns
ns
ns
ns
ns
ns
DSC
L
50
50
50
50
50
0
50
50
50
50
50
0
50
50
50
50
50
0
HEC
t
CS to CE Setup
SSC
t
CS Low During CE High
R/C to CE Setup
HSC
t
SRC
HRC
t
R/C Low During CE High
A0 to CE Setup
t
SAC
A0 Valid During CE High
t
50
50
50
HAC
READ TIMING—FULL CONTROL MODE
Access Time (From CE)
Data Valid After CE Low
Output Float Delay
t
t
C = 100pF
L
60
40
120
75
150
100
200
120
ns
ns
ns
ns
ns
ns
ns
ns
ns
DD
HD
25
20
15
t
HL
t
t
50
0
50
0
50
0
CS to CE Setup
R/C to CE Setup
A0 to CE Setup
SSR
SRR
SAR
t
t
50
0
50
0
50
0
CS Valid After CE Low
R/C High After CE Low
A0 Valid After CE Low
STAND-ALONE MODE
Low R/C Pulse Width
STS Delay from R/C
HSR
HRR
HAR
t
t
0
0
0
0
0
0
t
50
15
115
40
50
20
50
ns
ns
ns
HRL
t
200
250
320
DS
t
25
300
30
15
300
30
Data Valid After R/C Low
HDR
MX574A
MX674A
MAX174
600 1000 300
1000
600
1000
600
STS Delay After Data Valid
t
320
140
600
300
30
30
ns
HS
30
300
30
400
t
t
150
150
200
ns
ns
High R/C Pulse Width
HRH
DDR
Data Access Time
C = 100pF
60
120
150
200
L
Note 6: Timing specifications guaranteed by design. All input control signals specified with t = t = 5ns (10% to ±0% of +5V) and
R
F
timed from a voltage level of +1.6V. See loading circuits in Figures 1 and 2.
����������������������������������������������������������������� Maxim Integrated Products
6
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
+5V
+5V
3kI
3kI
DN
DN
DN
DN
3kI
100pF
100pF
3kI
100pF
100pF
LOGIC 1 TO HIGH - Z
LOGIC 0 TO HIGH - Z
HIGH-Z TO LOGIC 1
HIGH-Z TO LOGIC 1
Figure 1. Load Circuit for Access Time Test
Figure 2. Load Circuit for Output Float Delay Test
Pin Configurations
TOP VIEW
+
V
L
1
2
3
4
5
6
7
8
9
28 STS
27 D11
26 D10
25 D9
24 D8
23 D7
22 D6
21 D5
20 D4
19 D3
18 D2
17 D1
16 D0
15 DGND
TOP VIEW
12/8
CS
4
3
2
1
28 27 26
A0
5
6
7
8
9
R/C
CE
25 D9
24 D8
R/C
CE
MAX174
MX574A
MX674A
V
CC
D7
23
V
CC
MAX174
MX574A
MX674A
REFOUT
AGND
22 D6
REFOUT
AGND
D5
D4
D3
21
20
19
REFIN 10
REFIN 10
11
V
11
EE
V
EE
12 13 14 15 16 17 18
BIPOFF 12
10VIN 13
20VIN 14
PLCC
DIP/SO
Pin Description
PIN
1
NAME
FUNCTION
V
L
Logic Supply, +5V
2
Data Mode Select Input
12/8
3
CS
Chip-Select Input. Must be low to select device.
Byte Address/Short-Cycle Input. When starting a conversion, controls number of bits converted (low = 12
bits, high = 8 bits). When reading data, if 12/8 = low, enables low byte (A0 = high) or high byte (A0 = low).
4
5
A0
Read/Convert Input. When high, the device will be in the data-read mode. When low, the device will
be in the conversion start mode.
R/C
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7
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
Pin Description (continued)
PIN
6
NAME
FUNCTION
Chip-Enable Input. Must be high to select device.
+12V or +15V Supply
CE
7
V
CC
8
REFOUT
AGND
+10V Reference Output
±
Analog Ground
10
11
12
13
14
15
16–27
28
REFIN
Reference Input
V
-12V or -15V Supply
EE
BIPOFF
Bipolar Offset Input. Connect to REFOUT for bipolar input range.
10V Span Input
10V
20V
IN
20V Span Input
IN
DGND
D0–D11
STS
Digital Ground
Three-State Data Outputs
Status Output
the state of R/C selects whether a conversion (R/C = 0) or
a data read (R/C = 1) is in progress. The register control
Detailed Description
inputs, 12/8 and A0, select the data format and conver-
sion length. A0 is usually tied to the LSB of the address
bus. To perform a full 12-bit conversion, set A0 low during
a convert start. For a shorter 8-bit conversion, A0 must be
high during a convert start.
Converter Operation
The MAX174/MX574A/MX674A use a successive approx-
imation technique to convert an unknown analog input to
a 12-bit digital output code. The control logic provides
easy interface to most microprocessors. Most applica-
tions require only a few external passive components to
perform the analog-to-digital (A/D) function.
Output Data Format
During a data read, A0 also selects whether the three-
state buffers contain the 8 MSBs (A0 = 0) or the 4 LSBs
(A0 = 1) of the digital result. The 4 LSBs are followed by
4 trailing 0s.
The internal voltage output DAC is controlled by a suc-
cessive approximation register (SAR) and has an output
impedance of 2.5kω. The analog input is connected to
the DAC output with a 5kω resistor for the 10V input and
10kω resistor for the 20V input. The comparator is essen-
tially a zero-crossing detector, and its output is fed back
to the SAR input.
Output data is formatted according to the 12/8 pin. If
this input is low, the output will be a word broken into
two 8-bit bytes. This allows direct interlace to 8-bit buses
without the need for external three-state buffers. If 12/8 is
high, the output will be one 12-bit word. A0 can change
state while a data-read operation is in effect.
The SAR is set to half-scale as soon as a conversion starts.
The analog input is compared to 1/2 of the full-scale volt-
age. The bit is kept if the analog input is greater than half-
scale or dropped if smaller. The next bit, bit 10, is then set
with the DAC output either at 1/4 scale, if the most signifi-
cant bit (MSB) is dropped, or 3/4 scale if the MSB is kept.
The conversion continues in this manner until the least
significant bit (LSB) is tried. At the end of the conversion,
the SAR output is latched into the output buffers.
To begin a conversion, the microprocessor must write
to the ADC address. Then, since a conversion usually
takes longer than a single clock cycle, the microproces-
sor must wait for the ADC to complete the conversion.
Valid data will be made available only at the end of the
conversion, which is indicated by STS. STS can be ether
polled or used to generate an interrupt upon completion.
Or, the microprocessor can be kept idle by inserting the
appropriate number of No Operation (NOP) instructions
between the conversion-start and data-read commands.
Digital Interface
CE, CS, and R/C control the operation of the MAX174/
MX574A/MX674A. While both CE and CS are asserted,
����������������������������������������������������������������� Maxim Integrated Products
8
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
BIPOFF
20V
10V
IN
IN
REFIN
5kI
2R* -50I
9.950kI
R*
DAC
2.5kI
5kI
1.6kI
REFIN
2
SAR
Figure 3. Analog Equivalent Circuit
Table 1. Truth Table
Table 2. MAX174/MX574A/MX674A Data
Format for 8-Bit Bus
CE
0
A0
X
OPERATION
CS
X
R/C 12/8
D7
D6
D5
D4 D3 D2 D1
D0
X
X
0
0
1
1
X
X
X
X
1
0
None
None
X
1
X
High Byte
(A0 = 0)
MSB D10 D±
D8 D7 D6 D5
D4
1
0
0
Initiate 12-bit conversion
Initiate 12-bit conversion
Enable 12-bit conversion
Enable 8 MSBs
1
0
1
Low Byte
(A0 = 1)
D3
D2
D1
D0
0
0
0
0
1
0
X
1
0
0
Enable 4 LSBs + 4
trailing 0s
1
0
1
0
1
27 (MSB)
26 (D10)
25 (D9)
24 (D8)
23 (D7)
22 (D6)
21 (D5)
20 (D4)
19 (D3)
18 (D2)
17 (D1)
16 (LSB)
D7
After the conversion is completed, data can be obtained
by the microprocessor. The ADCs have the required
logic for 8-, 12-, and 16-bit bus interfacing, which is
determined by the 12/8 input. If 12/8 is high, the ADCs
are configured for a 16-bit bus. Data lines D0–D11 may
be connected to the bus as either the 12 MSBs or the 12
LSBs. The other 4 bits must be masked out in software.
D6
D5
D4
D3
D2
D1
D0
MAX174
MX574A
MX674A
For 8-bit bus operation, 12/8 is set low. The format is left
justified, and the even address, A0 low, contains the 8
MSBs. The odd address, A0 high, contains the 4 LSBs,
which is followed by 4 trailing 0s. There is no need to
use a software mask when the ADCs are connected to
an 8-bit bus.
HARDWIRING FOR 8-BIT DATA BUSES
Note that the output cannot be forced to a right-justified for-
mat by rearranging the data lines on the 8-bit bus interface.
����������������������������������������������������������������� Maxim Integrated Products
9
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
cannot be prematurely terminated or restarted. However,
if the state of A0 is changed after the beginning of the
conversion, any additional start conversion transitions
will latch the new state of A0, possibly resulting in an
incorrect conversion length (8 bits vs. 12 bits) for that
conversion.
Timing and Control
Convert Start Timing—Full Control Mode
R/C must be low before asserting both CE and CS. If it
is high, a brief read operation occurs possibly resulting
in system bus contention. To initiate a conversion, use
either CE or CS. CE is recommended since it is shorter
by one propagation delay than CS and is the faster input
of the two. CE is used to begin the conversion in Figure 4.
Read Timing—Full Control Mode
Figure 5 illustrates the read-cycle timing. While reading
data, access time is measured from when CE and R/C
are both high. Access time is extended 10ns if CS is used
to initiate a read.
The STS output is high during the conversion indicating
the ADC is busy. During this period, additional convert
start commands will be ignored, so that the conversion
t
HEC
CE
CE
CS
t
t
t
HSC
HRC
HAC
t
t
HSR
SSR
t
t
SSC
CS
t
t
t
SRR
HRR
HAR
SRC
R/C
A0
R/C
A0
t
SAR
t
SAC
t
t
C
DSC
STS
STS
t
t
t
HD, HL
DD
D0–D11
HIGH IMPEDANCE
D0–D11
HIGH IMPEDANCE
Figure 4. Convert Start Timing
Figure 5. Read Timing
���������������������������������������������������������������� Maxim Integrated Products 10
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
Stand-Alone Operation
For systems which do not use or require full bus interfac-
t
HRL
ing, the MAX174/MX574A/MX674A can be operated in
a stand-alone mode directly linked through dedicated
input ports.
R/C
STS
t
t
C
DS
When configured in the stand-alone mode, conversion is
controlled by R/C. In addition, CS and A0 are wired low;
CE and 12/8 are wired high. To enable the three-state
buffers, set R/C low. A conversion starts when R/C is set
high. This allows either a high- or a low-pulse control sig-
nal. Shown in Figure 6 is the operation with a low pulse. In
this mode, the outputs, in response to the falling edge of
R/C, are forced into the high-impedance state and return
to valid logic-levels after the conversion is complete. The
STS output goes high following the R/C falling edge and
returns low when the conversion is complete.
t
t
HS
HDR
HIGH IMPEDANCE
D0–11
Figure 6. Low Pulse for R//C in Stand-Alone Mode
t
HRH
A high-pulse conversion initiation is illustrated in Figure 7.
When R/C is high, the data lines are enabled. The next con-
version starts with the falling edge of R/C. The data lines
return and remain in high impedance state until another
R/C high pulse.
R/C
t
DS
STS
t
HDR
Analog Considerations
t
DDR
HIGH IMPEDANCE
Application Hints
D0–11
Physical Layout
For best system performance, PCBs should be used for
the MAX174/MX574A/MX674A. Wirewrap boards are not
recommended. The layout of the board should ensure
that digital and analog signal lines are kept separated
from each other as much as possible. Care should be
taken not to run analog and digital lines parallel to each
other or digital lines underneath the MAX174/MX574A/
MX674A.
Figure 7. High Pulse for R//C in Stand-Alone Mode
ANALOG SUPPLY
GND
DIGITAL SUPPLY
-15V
+15V
+5V
GND
Grounding
The recommended power-supply grounding practice is
shown in Figure 8. The ground reference point for the on-
chip reference is AGND. It should be connected directly
to the analog reference point of the system. The analog
and digital grounds should be connected together at the
package in order to gain all of the accuracy possible
from the MAX174/MX574A/MX674A in high digital noise
environments. In situations permitting, they can be con-
nected to the most accessible ground-reference point.
The preference is analog power return.
V
GND
V
CC
V
AGND
V
V
L
DGND
+5V DGND
EE
EE
CC
S/H AND
ANALOG
CIRCUITRY
DIGITAL
CIRCUITRY
MAX174
MX574A
MX674A
Figure 8. Power-Supply Grounding Practice
���������������������������������������������������������������� Maxim Integrated Products 11
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
When using the 20V as the analog input, load capaci-
IN
Power-Supply Bypassing
The MAX174/MX574A/MX674A power supplies must be
filtered, well regulated, and free from high-frequency
noise, or unstable output codes will result. Unless great
care is taken in filtering any switching spikes present in
the output, switching power supplies is not suggested for
applications requiring 12-bit resolution. Take note that a
few millivolts of noise converts to several error counts in
a 12-bit ADC.
tance on the 10V pin must be minimized. Especially on
IN
the faster MAX174, leave the 10V pin open to minimize
IN
capacitance and to prevent linearity errors caused by
inadequate settling time.
The amplifier driving the analog input must have low
enough DC output impedance for low full-scale error.
Furthermore, low AC output impedance is also required
since the analog input current is modulated at the clock
rate during the conversion. The output impedance of an
amplifier is the open-loop output impedance divided by
the loop gain at the frequency of interest.
All power-supply pins should use supply decoupling capac-
itors connected with short lead length to the pins, as shown
in Figure ±. The V
and V pins should be decoupled
CC
EE
directly to AGND. A 4.7µF tantalum type in parallel with a
0 1µF disc ceramic type is a suitable decoupling.
MX574A and MX674A—The approximate internal clock
rate is 600kHz and 1MHz, respectively, and amplifiers
like the MAX400 can be used to drive the input.
Internal Reference
The MAX174/MX574A/MX674A have an internal buried
zener reference that provides a 10V, low-noise and low-
temperature drift output. An external reference voltage
can also be used for the ADC. When using ±15V sup-
plies, the internal reference can source up to 2mA in
addition to the BIPOFF and REFIN inputs over the entire
operating temperature range. With ±12V supplies, the
reference can drive the BIPOFF and REFIN inputs over
temperature, but it CANNOT drive an additional load.
MAX174—The internal clock rate is 2MHz and faster
amplifiers like the OP-27, AD711, or OP-42 are required.
Track-and-Hold Interface
The analog input to the ADC must be stable to within
1/2 LSB during the entire conversion for specified 12-bit
accuracy. This limits the input signal bandwidth to a
couple of hertz for sinusoidal inputs even with the faster
MAX174. For higher bandwidth signals, a track-and-hold
amplifier should be used.
Driving the Analog Input
The STS output may be used to provide the Hold signal
to the track-and-hold amplifier. However, since the A/D’s
DAC is switched at approximately the same time as the
conversion is initiated, the switching transients at the out-
put of the T/H caused by the DAC switching may result in
code dependent errors. It is recommended that the Hold
signal to the T/H amplifier precede a conversion or be
coincident with the conversion start.
The input leads to AGND and 10V or 20V should be
IN
IN
as short as possible to minimize noise pick up. If long
leads are needed, use shielded cables.
+5V
V
L
C
C
1
4
The first bit decision by the A/D is made approximately
1.5 clock cycles after the start of the conversion. This is
2.5µs, 1.5µs, and 0.8µs for the MX574A, MX674A, and
MAX174, respectively. The T/H hold settling time must
be less than this time. For the MX574A and MX674A, the
AD585 sample-and-hold is recommended (Figure 10).
For the MAX174, a faster T/H amplifier, like the HA5320
or HA5330, should be used (Figure 11).
DIGITAL
GROUND
DGND
MAX174
MX574A
MX674A
RECOMMENDED
V
+12V/15V
CC
C
C
C
C
5
6
2
3
ANALOG
GROUND
AGND
Input Configurations
The MAX174/MX574A/MX674A input range can be set
using pin strapping. Table 3 shows the possible input
ranges and ideal transition voltages. End-point errors can
be adjusted in all ranges.
V
EE
-12V/15V
C , C , C – 0.1µF CERAMIC
1
2
4
C , C , C – 4.7µF
4
5
6
Figure 9. Power-Supply Bypassing
���������������������������������������������������������������� Maxim Integrated Products 12
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
Table 3. Input Ranges and Ideal Digital Output Codes
ANALOG INPUT VOLTAGE (V)
0 to +20V 5V
DIGITAL OUTPUT
MSB LSB
0 to +10V
+10.0000
+±.±±63
+5.0012
+4.±±88
+4.±±63
+0.0012
0.0000
10V
+10.0000
+±.±±27
+0.0024
-0.0024
-0.0073
-±.±±76
-10.0000
+20.0000
+1±.±±27
+10.0024
+±.±±76
+±.±±27
+0.0024
0.0000
+5.0000
+4.±±63
+0.0012
-0.0012
-0.0037
-4.±±88
-5.0000
1111 1111 1111
1111 1111 1110*
1000 0000 0000*
0111 1111 1111*
0111 1111 1110*
0000 0000 0000*
0000 0000 0000
Note 7: For unipolar input ranges, output coding is straight binary.
Note 8: For bipolar input ranges, output coding is offset binary.
Note 9: For 0 to + 10V or ±5V ranges, 1 LSB = 2.44mV.
Note 10: For 0 to +20V or ±10V ranges, 1 LSB = 4.88mV.
*The digital outputs will be flickering between the Indicated code and the indicated code plus one.
CONTROL
INPUTS
+V
HOLD
LREF
+15V
4.7µF
STS
S
0.1µF
AD585*
D0–11
MX574A*
MX674A
HOLD
VOUT
20V
10V
IN
IN
V
+15V
4.7µF
CC
0.1µF
0.1µF
0.1µF
-V
-15V
4.7µF
S
0.1µF
-V
IN
BIPOFF
REFOUT
REFIN
V
EE
-15V
50I
50I
4.7µF
+V
IN
ANALOG
INPUT
GND
V
L
+5V
4.7µF
AGND
DGND
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 10. MX574/MX674A to AD585 Sample-and-Hold Interface
���������������������������������������������������������������� Maxim Integrated Products 13
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
CONTROL
INPUTS
+V
S/H
+15V
4.7µF
STS
S
0.1µF
D0–11
HA5320*
MAX174*
20V
10V
IN
IN
V
+15V
4.7µF
CC
VOUT
0.1µF
0.1µF
0.1µF
-V
S
-15V
4.7µF
0.1µF
-V
IN
BIPOFF
REFOUT
REFIN
V
-15V
EE
50I
50I
4.7µF
+V
IN
ANALOG
INPUT
GND
V
L
+5V
4.7µF
AGND
DGND
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 11. MAX174 to HA5320 Sample-and-Hold Interface
Unipolar Input Operation
The unipolar transfer function and input connections are
shown in Figures 12 and 13.
Offset and Full-Scale Adjustment
In applications where the offset and full-scale range
have to be adjusted, use the circuit shown in Figure 12.
The offset should be adjusted first. Apply 1/2 LSB at the
analog input and adjust R1 until the digital output code
flickers between 0000 0000 0000 and 0000 0000 0001.
To adjust the full-scale range, apply FS - 3/2 LSB at the
analog input and adjust R2 until the output code changes
between 1111 1111 1110 and 1111 1111 1111.
Because all internal resistors of the MAX174/MX574A/
MX674A are trimmed for absolute calibration, additional
trimming is not necessary for most applications. The
absolute accuracy for each grade is given in the speci-
fication tables.
If the offset trim is not needed, BIPOFF can be tied direct-
ly to AGND. The two resistors and trimmer for BIPOFF
can then be discarded. A 50ω ±1% metal film resistor
should be attached between REFOUT and REFIN.
Bipolar Input Operation
The bipolar transfer function is shown in Figure 14, and
input connections are shown in Figure 15. One or both
of the trimmers can be exchanged with a 50ω ±1% fixed
resistor if the offset and gain specifications suffice.
For a 0 to +10V input range, the analog input is con-
nected between AGND and 10V . For a 0 to +20V input
IN
range, the analog input is connected between AGND
Offset and Full-Scale Adjustment
To begin bipolar calibration, a signal 1/2 LSB above neg-
ative full-scale is applied. R1 is trimmed until the digital
output flickers between 0000 0000 0000 and 0000 0000
0001. Next, a signal 3/2 LSB below positive full scale
is applied. Then, R2 is trimmed until the output flickers
between 1111 1111 1110 and 1111 1111 1111.
and 20V . These ADCs can easily handle an input signal
IN
beyond the supplies. If full-scale trim is not needed, the
gain trimmer, R2, should be swapped with a 50ω resis-
tor. Should a 10.24V input range be selected, a 200ω
trimmer should be inserted in series with 10V . For a full-
IN
scale input range of 20.48V, use a 500ω trimmer in series
with 20V . The nominal input impedance into 10V is
IN
IN
5kω and 10kω for 20V .
IN
���������������������������������������������������������������� Maxim Integrated Products 14
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
OUTPUT CODE
FS = 4069 LSBs
1111 1111 1111
1111 1111 1110
OUTPUT CODE
FS = 4069 LSBs
1111 1111 1101
1000 0000 0001
1000 0000 0000
1111 1111 1111
1111 1111 1110
1111 1111 1101
0000 0000 0011
0000 0000 0010
0000 0000 0001
0000 0000 0000
0111 1111 1111
FULL-SCALE
TRANSITION
0111 1111 1110
0000 0000 0011
0000 0000 0010
0000 0000 0001
0000 0000 0000
0
1
2
3
FS-1 FS
FS
2
FS
2
FS
2
FS
2
+2
-2 -1
0
1
2
-
-
FS
2
FS
2
+1
1
-
ANALOG INPUT VOLTAGE IN LSBs
Figure 12. Ideal Unipolar Transfer Function
Figure 14. Ideal Bipolar Transfer Function
GAIN
MAX174*
MX574A
MX674A
MAX174*
MX574A
MX674A
GAIN
REFOUT
REFIN
R
2
R
2
100I
+12V TO +15V
100I
REFIN
REFOUT
BIPOFF
100kI
OFFSET
BIPOFF
R
1
100kI
R
1
100I
100I
-12V TO -15V
OFFSET
0 TO +10V
0 TO +20V
10V
20V
IN
IN
Q5V
10V
20V
IN
ANALOG
INPUTS
ANALOG
INPUTS
Q10V
IN
AGND
AGND
*ADDITIONAL PINS OMITTED FOR CLARITY
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 15. Bipolar Input Connections
Figure 13. Unipolar Input Connections
���������������������������������������������������������������� Maxim Integrated Products 15
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
Ordering Information
PIN-
PACKAGE
LINEARITY
(LSB)
TEMPCO
(ppm/NC)
PIN-
PACKAGE
LINEARITY
(LSB)
TEMPCO
(ppm/NC)
PART
PART
8µs Maximum Conversion Time
TEMP RANGE: 0NC to +70NC
TEMP RANGE: -55NC to +125NC
MX674ASQ
MX674ATQ
MX674AUQ
MX674ASD
MX674ATD
MX674AUD
28 CERDIP*
28 CERDIP*
1
¾
¾
1
50
25
12
50
25
12
MAX174ACPI+
MAX174BCPI+
MAX174CCPI+
MAX174ACWI+
MAX174BCWI+
MAX174CCWI+
MAX174BC/D
28 Plastic DIP
28 Plastic DIP
28 Plastic DIP
28 Wide SO
28 Wide SO
28 Wide SO
Dice*
½
½
1
10
27
50
10
27
50
—
28 CERDIP*
28 Ceramic SB
28 Ceramic SB
28 Ceramic SB
½
½
1
¾
¾
25µs Maximum Conversion Time
TEMP RANGE: 0NC to +70NC
1/2
TEMP RANGE: -40NC to +85NC
MX574AJN+
MX574AKN+
MX574ALN+
MX574AJCWI+
MX574AKCWI+
MX574ALCWI+
MX574AJP+
MX574AKP+
MX574ALP+
MX574AK/D
28 Plastic DIP
28 Plastic DIP
28 Plastic DIP
28 Wide SO
28 Wide SO
28 Wide SO
28 PLCC
1
½
½
1
50
27
10
50
27
10
50
27
10
—
MAX174AEPI+
MAX174BEPI+
MAX174CEPI+
MAX174AEWI+
MAX174BEWI+
MAX174CEWI+
28 Plastic DIP
28 Plastic DIP
28 Plastic DIP
28 Wide SO
28 Wide SO
28 Wide SO
½
½
1
1±
38
75
1±
38
75
½
½
1
½
½
1
TEMP RANGE: -55NC to +125NC
28 PLCC
½
½
½
MAX174AMJI
MAX174BMJI
MAX174CMJ
28 CERDIP
28 CERDIP
28 CERDIP
¾
¾
12
25
50
28 PLCC
Dice*
1/21
TEMP RANGE: -40NC to +85NC
15µs Maximum Conversion Time
TEMP RANGE: 0NC to +70NC
MX574AJEPI+
MX574AKEPI+
MX574ALEPI+
MX574AJEWI+
MX574AKEWI+
MX574ALEWI+
28 Plastic DIP
28 Plastic DIP
28 Plastic DIP
28 Wide SO
28 Wide SO
28 Wide SO
1
75
38
1±
75
38
1±
½
½
1
MX674AJN+
MX674AKN+
MX674ALN+
MX674AJCWI+
MX674AKCWI+
MX674ALCWI+
MX674AK/D
28 Plastic DIP
28 Plastic DIP
28 Plastic DIP
28 Wide SO
28 Wide SO
28 Wide SO
Dice*
1
50
27
10
50
27
10
—
½
½
1
½
½
½
½
½
TEMP RANGE: -55NC to +125NC
MX574ASQ
MX574ATQ
MX574AUQ
MX574ASD
MX574ATD
MX574AUD
28 CERDIP*
28 CERDIP*
1
50
25
12
50
25
12
¾
¾
1
TEMP RANGE: -40NC to +85NC
28 CERDIP*
MX674AJEPI+
MX674AKEPI+
MX674ALEPI+
MX674AJEWI+
MX674AKEWI+
MX674ALEWI+
28 Plastic DIP
28 Plastic DIP
28 Plastic DIP
28 Wide SO
28 Wide SO
28 Wide SO
1
½
½
1
75
38
1±
75
38
1±
28 Ceramic SB
28 Ceramic SB
28 Ceramic SB
¾
¾
½
½
+Denotes a lead(Pb)-free/RoHS-compliant package.
*Maxim reserves the right to ship Ceramic SB in lieu of CERDIP packages.
**Consult factory for dice specifications.
���������������������������������������������������������������� Maxim Integrated Products 16
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
Chip Information
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PROCESS: BiCMOS
PACKAGE
TYPE
PACKAGE OUTLINE
LAND
PATTERN NO.
CODE
P28+2
Q28+3
W28+2
NO.
28 PDIP
28 PLCC
21-0044
21-0049
21-0042
—
90-0235
90-0109
28 Wide SO
���������������������������������������������������������������� Maxim Integrated Products 17
MAX174/MX574A/MX674A
Industry-Standard, Complete 12-Bit ADCs
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
3/±0
Initial release
—
Updated the Electrical Characteristics and Ordering Information. Added
Revision History.
1
8/11
2–4
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. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
18
©
2011 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
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