MX574AKCWI+T - Maxim - Datasheet.Directory

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

�� Maxim Integrated Products 1

Functional Diagram

19-2765; Rev 3; 8/11

Ordering Information appears at end of data sheet.

For related parts and recommended products to use with this part, refer to www.maxim-ic.com/MAX174.related.

EVALUATION KIT AVAILABLE

General Description

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.

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.

Features

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

Digital Signal Processing

High-Accuracy Process Control

High-Speed Data Acquisition

Electro-Mechanical Systems

R

14

5kI

9.950kI

5kI

131211

VEE BIPOFF 10VIN 20VIN

2R

+10V

REF

9

8

10

REFIN

AGND

REFOUT

12-BIT

DAC

7

VCC

15

DGND

1

VL

SAR

12

LOW

NIBBLE

444

MIDDLE

NIBBLE

HIGH

NIBBLE

CLOCK

AND

CONTROL

LOGIC

212/8

A0

3

4

27 56282423201916

D0 D3 D4 D7 D8 D11 STS CE R/C

CS

MAX174

MX574A

MX674A

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.

�� Maxim Integrated Products 2

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

VCC to DGND ..............................................................0 to 16.5V

VEE to DGND ...............................................................0 to 16.5V

VL to DGND ......................................................................0 to 7V

DGND to AGND ................................................................... Q1V

Control Inputs to DGND

(CE, CS, A0, 12/8, R/C) ........................ -0.3V to (VCC + 0.3V)

Digital Output Voltage to DGND

(DB11–DB0, STS) ..................................... -0.3V to (VL + 0.3V)

Analog Inputs to AGND (REFIN, BIPOFF, 10VIN) ........... Q16.5V

20VIN to AGND ................................................................... Q24V

REFOUT ................................... Indefinite short to VCC or AGND

Power Dissipation (any package) to +75NC .................1000mW

Derates above +75NC .............................................. 10mW/NC

Operating Temperature Ranges

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)

PDIP, Wide SO .............................................................+260NC

PLCC ............................................................................+245NC

ABSOLUTE MAXIMUM RATINGS

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

(VL = +5V, VEE = +15V or +12V, VEE = -15V or -12V, TA = +25NC, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

ACCURACY

Resolution RES 12 Bits

Integral Nonlinearity INL

TA = +25°C MAX174A/B ±1/2

LSB

MAX174C ±1

TA = TMIN to TMAX

MAX174AC/BC ±1/2

MAX174AE/BE/AM/BM ±3/4

MAX174C ±1

Differential Nonlinearity DNL 12 bits, no missing codes over temperature ±1 LSB

Unipolar Offset Error (Note 1) MAX174A/B ±1 LSB

MAX174C ±2

Bipolar Offset Error (Notes 2, 3) MAX174A ±3 LSB

MAX174B/C ±4

Full-Scale Calibration Error (Note 3) ±0.25 %

TEMPERATURE COEFFICIENTS (Using Internal Reference) (Notes 2, 3, 4)

Unipolar Offset Change MAX174A/B ±1 LSB

MAX174C ±2

Bipolar Offset Change

MAX174AC/BC ±1

LSB

MAX174CC ±2

MAX174AE/AM ±1

MAX174BE/BM ±2

MAX174CE/CM ±4

�� Maxim Integrated Products 3

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

ELECTRICAL CHARACTERISTICS—MX574A, MX674A

(VL = + 5V, VEE = +15V or +12V, VEE = -15V or -12V, TA = +25NC, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS—MAX174 (continued)

(VL = +5V, VEE = +15V or +12V, VEE = -15V or -12V, TA = +25NC, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

ACCURACY

Resolution RES 12 Bits

Integral Nonlinearity INL

TA = +25°C

MX574AK/L/T/U,

MX674AK/L/T/U ±1/2

LSB

MX574AJ/S, MX674AJ/S ±1

TA = TMIN to TMAX

MX574AK/L/KE/LE ±1/2

MX674AK/L/KE/LE ±1/2

MX574AT/U, MX674AT/U ±3/4

MX574AJ/S, MX674AJ/S ±1

Differential Nonlinearity DNL 12 bits, no missing codes over temperature ±1 LSB

Unipolar Offset Error (Note 1) MX574AK/L/T/U, MX674AK/L/T/U ±1 LSB

MX574AJ/S, MX674AJ/S ±2

Bipolar Offset Error (Notes 2, 3) MX574AL/U, MX674AL/U ±3 LSB

MX574AJ/K/S/T, MX674AJ/K/S/T ±4

Full-Scale Calibration Error

(Note 3)

MX574AL/U ±0.125 %

MX574AJ/K/S/T, MX674A ±0.25

TEMPERATURE COEFFICIENTS (Using Internal Reference) (Notes 2, 3, 4)

Unipolar Offset Change MX574AK/L/T/U, MX674AK/L/T/U ±1 LSB

MX574AJ/S, MX674AJ/S ±2

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Full-Scale Calibration Change

MAX174AC ±2 (10)

LSB

(ppm/°C

MAX174BC ±5 (27)

MAX174CC ±9 (50)

MAX174AE ±7 (19)

MAX174BE ±10 (38)

MAX174CE ±20 (75)

MAX174AM ±5 (12)

MAX174BM ±10 (25)

MAX174CM ±20 (50)

INTERNAL REFERENCE

Output Voltage No load MAX174A 9.98 10.00 10.02 V

MAX174B/C 9.97 10.00 10.03

Output Current (Note 5) Available for external loads, in addition to

REFIN and BIPOFF load 2 mA

�� Maxim Integrated Products 4

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

ELECTRICAL CHARACTERISTICS—MX574A, MX674A (continued)

(VL = + 5V, VEE = +15V or +12V, VEE = -15V or -12V, TA = +25NC, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS—MAX174/MX574/MX674A

(VL = +5V, VCC = +15V or +12V, VEE = -15V or -12V, TA = +25NC, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Bipolar Offset Change

MX574AK/L, MX674AK/L ±1

LSB

MX574AJ, MX674AJ ±2

MX574AU/LE, MX674AU/LE ±1

MX574AT/KE, MX674AT/KE ±2

MX574AS/JE, MX674AS/JE ±4

Full-Scale Calibration Change

MX574AL, MX674AL ±2 (10)

LSB

(ppm/°C

MX574AK, MX674AK ±5 (27)

MX574AJ, MX674AJ ±9 (50)

MX574ALE, MX674ALE ±7 (19)

MX574AKE, MX674AKE ±10 (38)

MX574AJE, MX674AJE ±20 (75)

MX574AU, MX674AU ±5 (12)

MX574AT, MX674AT ±10 (25)

MX574AS, MX674AS ±20 (50)

INTERNAL REFERENCE

Output Voltage No load

MX574AL/U 9.99 10.00 10.01

VMX574AJ/K/S/T, MX674AL/U 9.98 10.00 10.02

MX674AJ/K/S/T 9.97 10.00 10.03

Output Current (Note 5) Available for external loads, in addition to

REFIN and BIPOFF load 2 mA

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

ANALOG INPUT

Bipolar Input Range Using 10V input ±5 V

Using 20V input ±10

Unipolar Input Range Using 10V input 0 +10 V

Using 20V input 0 +20

Input Impedance 10V input 3 5 7 kW

20V input 6 10 14

POWER-SUPPLY REJECTION (Max Change in Full-Scale Calibration)

VCC Only 15V ±1.5V or

12V ±0.6V

MAX174A/B, MX_74AK/L/TU ±1/8 ±1 LSB

MAX174C, MX_74AJ/S ±1/8 ±2

VEE Only 15V ±1.5V or 12V ±0.6V ±1/8 ±1/2 LSB

VL Only 5V ±0.5V ±1/8 ±1/2 LSB

LOGIC INPUTS

Input Low Voltage VIL CS, CE, R/C, A0, 12/80.8 V

Input High Voltage VIH CS, CE, R/C, A0, 12/82.0 V

�� Maxim Integrated Products 5

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

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 TA = +25°C to TMIN or TA = +25°C to TMAX.

Note 5: External load current should not change during a conversion. For Q12V supply operation, REFOUT need not be buffered

except when external load in addition to REFIN and BIPOFF inputs have to be driven.

ELECTRICAL CHARACTERISTICS—MAX174/MX574/MX674A (continued)

(VL = +5V, VCC = +15V or +12V, VEE = -15V or -12V, TA = +25NC, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Current IIN CS, CE, R/C, A0, 12/8, VIN = 0 to VL±5 µA

Input Capacitance CIN CS, CE, R/C, A0, 12/87 pF

LOGIC OUTPUTS

Output Low Voltage VOL DB11–DB0, STS ISINK = 1.6mA 0.4 V

Output High Voltage VOH DB11–DB0, STS ISOURCE = 500µA 4 V

Floating State Leakage Current ILKG DB11–DB0, STS VOUT = 0 to VL±10 µA

Floating State Output Capacitance COUT DB11–DB0 8 pF

CONVERSION TIME

12-Bit Cycle tCONV

MX574A 15 20 25

µsMX674A 9 12 15

MAX174 6 7 8

8-Bit Cycle tCONV

MX574A 10 14 18

µsMX674A 6 8 11

MAX174 4 5 6

POWER REQUIREMENTS

VCC Operating Range 11.4 16.5 V

VL Operating Range 4.5 5.5 V

VEE Operating Range -11.4 -16.5 V

VCC Supply Current (Note 5) ICC 3 5 mA

VL Supply Current (Note 5) IL3 8 mA

VEE Supply Current (Note 5) IEE 6 10 mA

Power Dissipation (Note 5) PDVCC = +15V and VEE = -15V 150 265 mW

�� Maxim Integrated Products 6

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Note 6: Timing specifications guaranteed by design. All input control signals specified with tR = tF = 5ns (10% to 90% of +5V) and

timed from a voltage level of +1.6V. See loading circuits in Figures 1 and 2.

TIMING CHARACTERISTICS—MAX174/MX574A/MX674A

(VL = +5V, VCC = +15V or +12V, VEE = -15V or -12V.)

(Note 6)

PARAMETER SYMBOL CONDITIONS TA = +25°C TA = -40°C TO +85°C

TA = 0°C TO +70° C TA = -55°C TO +125°C UNITS

MIN TYP MAX MIN TYP MAX MIN TYP MAX

CONVERT START TIMING—FULL CONTROL MODE

STS Delay from CE tDSC CL = 50pF 100 200 250 320 ns

CE Pulse Width tHEC 50 15 50 50 ns

CS to CE Setup tSSC 50 50 50 ns

CS Low During CE High tHSC 50 50 50 ns

R/C to CE Setup tSRC 50 50 50 ns

R/C Low During CE High tHRC 50 50 50 ns

A0 to CE Setup tSAC 0 0 0 ns

A0 Valid During CE High tHAC 50 50 50 ns

READ TIMING—FULL CONTROL MODE

Access Time (From CE) tDD CL = 100pF 60 120 150 200 ns

Data Valid After CE Low tHD 25 40 20 15 ns

Output Float Delay tHL 75 100 120 ns

CS to CE Setup tSSR 50 50 50 ns

R/C to CE Setup tSRR 0 0 0 ns

A0 to CE Setup tSAR 50 50 50 ns

CS Valid After CE Low tHSR 0 0 0 ns

R/C High After CE Low tHRR 0 0 0 ns

A0 Valid After CE Low tHAR 0 0 0 ns

STAND-ALONE MODE

Low R/C Pulse Width tHRL 50 15 50 50 ns

STS Delay from R/CtDS 115 200 250 320 ns

Data Valid After R/C Low tHDR 25 40 20 15 ns

STS Delay After Data Valid tHS

MX574A 300 600 1000 300 1000 300 1000

nsMX674A 30 320 600 30 600 30 600

MAX174 30 140 300 30 300 30 400

High R/C Pulse Width tHRH 150 150 200 ns

Data Access Time tDDR CL = 100pF 60 120 150 200 ns

�� Maxim Integrated Products 7

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Figure 2. Load Circuit for Output Float Delay TestFigure 1. Load Circuit for Access Time Test

Pin Configurations

Pin Description

PIN NAME FUNCTION

1 VLLogic Supply, +5V

212/8Data Mode Select Input

3 CS Chip-Select Input. Must be low to select device.

4 A0 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).

5R/CRead/Convert Input. When high, the device will be in the data-read mode. When low, the device will

be in the conversion start mode.

3kI

DN

100pF

HIGH-Z TO LOGIC 1

3kI

+5V

DN

100pF

HIGH-Z TO LOGIC 1

3kI

DN

100pF

LOGIC 1 TO HIGH - Z

3kI

+5V

DN

100pF

LOGIC 0 TO HIGH - Z

28

27

26

25

24

23

22

21

1

2

3

4

5

6

7

8

VLSTS

D11

D10

D9

D8

D7

D6

D5

TOP VIEW

CE

A0

VCC

REFOUT

20

19

9

10

D4

D3

AGND

REFIN

18

17

11

12

D2

D1

VEE

BIPOFF

16

15

13

14

D0

DGND

10VIN

20VIN

MAX174

MX574A

MX674A

DIP/SO

+

12/8

R/C

CS

12

BIPOFF

10VIN

20VIN

DGND

D0

D1

D2

A0

CS

12/8

VL

STS

D11

D10

D3VEE

D4REFIN

D5AGND

D6REFOUT

D7VCC

D8CE

D9R/C

13 14 15 16 17 18

123

42

62728

19

20

21

22

23

24

25

5

6

7

8

9

10

11

MAX174

MX574A

MX674A

PLCC

TOP VIEW

�� Maxim Integrated Products 8

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Pin Description (continued)

Detailed Description

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.

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.

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.

Digital Interface

CE, CS, and R/C control the operation of the MAX174/

MX574A/MX674A. While both CE and CS are asserted,

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

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.

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.

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.

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.

PIN NAME FUNCTION

6 CE Chip-Enable Input. Must be high to select device.

7 VCC +12V or +15V Supply

8 REFOUT +10V Reference Output

9 AGND Analog Ground

10 REFIN Reference Input

11 VEE -12V or -15V Supply

12 BIPOFF Bipolar Offset Input. Connect to REFOUT for bipolar input range.

13 10VIN 10V Span Input

14 20VIN 20V Span Input

15 DGND Digital Ground

16–27 D0–D11 Three-State Data Outputs

28 STS Status Output

�� Maxim Integrated Products 9

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Table 1. Truth Table

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.

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.

Note that the output cannot be forced to a right-justified for-

mat by rearranging the data lines on the 8-bit bus interface.

Figure 3. Analog Equivalent Circuit

Table 2. MAX174/MX574A/MX674A Data

Format for 8-Bit Bus

CE CS R/C12/8A0 OPERATION

0 X X X X None

X 1 X X X None

1 0 0 X 0 Initiate 12-bit conversion

1 0 0 X 1 Initiate 12-bit conversion

1 0 1 1 X Enable 12-bit conversion

1 0 1 0 0 Enable 8 MSBs

1 0 1 0 1 Enable 4 LSBs + 4

trailing 0s

D7 D6 D5 D4 D3 D2 D1 D0

High Byte

(A0 = 0) MSB D10 D9 D8 D7 D6 D5 D4

Low Byte

(A0 = 1) D3 D2 D1 D0 0 0 0 0

R*

2R* -50I

5kI

9.950kI

5kI

1.6kI

BIPOFF 10VIN

20VIN

REFIN

SAR

2.5kI

DAC

REFIN

2

27 (MSB)

26 (D10)

25 (D9)

24 (D8)

23 (D7)

22 (D6)

21 (D5)

20 (D4)

19 (D3)

18 (D2)

17 (D1)

16 (LSB)

HARDWIRING FOR 8-BIT DATA BUSES

D7

D6

D5

D4

D3

D2

D1

D0

DATA BUS

MAX174

MX574A

MX674A

�� Maxim Integrated Products 10

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Figure 4. Convert Start Timing Figure 5. Read Timing

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.

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

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.

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.

tHSC

tHEC

CE

A0

STS

D0–D11

tSSC

tHRC

tSRC

tHAC

tDSC tC

tSAC

HIGH IMPEDANCE

R/C

CS

tSSR

tSRR

tSAR tHAR

tHRR

tHSR

HIGH IMPEDANCE

tDD tHD,tHL

CE

A0

STS

D0–D11

R/C

CS

�� Maxim Integrated Products 11

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Figure 6. Low Pulse for R//C in Stand-Alone Mode

Figure 7. High Pulse for R//C in Stand-Alone Mode

Figure 8. Power-Supply Grounding Practice

Stand-Alone Operation

For systems which do not use or require full bus interfac-

ing, the MAX174/MX574A/MX674A can be operated in

a stand-alone mode directly linked through dedicated

input ports.

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.

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.

Analog Considerations

Application Hints

Physical Layout

For best system performance, PCBs should be used for

the MAX174/MX574A/MX674A. Wire wrap 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.

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.

tHDR tHS

tDS

tHRL

tC

R/C

STS

D0–11 HIGH IMPEDANCE

tHRH

tDS

R/C

STS

D0–11

tDDR tHDR

HIGH IMPEDANCE

S/H AND

ANALOG

CIRCUITRY

DIGITAL

CIRCUITRY

VEE GNDV

CC VEE AGND DGND DGND+5VVL

VCC

MAX174

MX574A

MX674A

ANALOG SUPPLY DIGITAL SUPPLY

-15V GND +15V +5V GND

�� Maxim Integrated Products 12

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Figure 9. Power-Supply Bypassing

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.

All power-supply pins should use supply decoupling capac-

itors connected with short lead length to the pins, as shown

in Figure 9. The VCC and VEE pins should be decoupled

directly to AGND. A 4.7µF tantalum type in parallel with a

0 1µF disc ceramic type is a suitable decoupling.

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.

Driving the Analog Input

The input leads to AGND and 10VIN or 20VIN should be

as short as possible to minimize noise pick up. If long

leads are needed, use shielded cables.

When using the 20VIN as the analog input, load capaci-

tance on the 10VIN pin must be minimized. Especially on

the faster MAX174, leave the 10VIN pin open to minimize

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.

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.

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.

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 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).

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.

VL

+5V

DIGITAL

GROUND

ANALOG

GROUND

+12V/15V

-12V/15V

VCC

VEE

DGND

RECOMMENDED

C1, C2, C4 – 0.1µF CERAMIC

C4, C5, C6 – 4.7µF

AGND

MAX174

MX574A

MX674A

C4C1

C5C2

C6C3

�� Maxim Integrated Products 13

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Table 3. Input Ranges and Ideal Digital Output Codes

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.

Figure 10. MX574/MX674A to AD585 Sample-and-Hold Interface

ANALOG INPUT VOLTAGE (V) DIGITAL OUTPUT

0 to +10V 0 to +20V ±5V ±10V MSB LSB

+10.0000 +20.0000 +5.0000 +10.0000 1111 1111 1111

+9.9963 +19.9927 +4.9963 +9.9927 1111 1111 1110*

+5.0012 +10.0024 +0.0012 +0.0024 1000 0000 0000*

+4.9988 +9.9976 -0.0012 -0.0024 0111 1111 1111*

+4.9963 +9.9927 -0.0037 -0.0073 0111 1111 1110*

+0.0012 +0.0024 -4.9988 -9.9976 0000 0000 0000*

0.0000 0.0000 -5.0000 -10.0000 0000 0000 0000

STS

20VIN

10VIN

BIPOFF

REFOUT

REFIN

-VS

VCC

+VIN

*ADDITIONAL PINS OMITTED FOR CLARITY

GND

0.1µF

ANALOG

INPUT

-15V

4.7µF

AGND DGND

HOLD

LREF

VOUT

-VIN

50I

HOLD

+15V

4.7µF

0.1µF

VEE -15V

4.7µF

0.1µF

VL+5V

4.7µF

0.1µF

AD585*

CONTROL

INPUTS

+VS

+15V

4.7µF 0.1µF

MX574A*

MX674A

D0–11

�� Maxim Integrated Products 14

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

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.

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.

For a 0 to +10V input range, the analog input is con-

nected between AGND and 10VIN. For a 0 to +20V input

range, the analog input is connected between AGND

and 20VIN. These ADCs can easily handle an input signal

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 10VIN. For a full-

scale input range of 20.48V, use a 500ω trimmer in series

with 20VIN. The nominal input impedance into 10VIN is

5kω and 10kω for 20VIN.

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.

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.

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.

STS

20VIN

10VIN

BIPOFF

REFOUT

REFIN

-VS

VCC

+VIN

*ADDITIONAL PINS OMITTED FOR CLARITY

GND

0.1µF

ANALOG

INPUT

-15V

4.7µF

AGND DGND

S/H

VOUT

-VIN

50I

+15V

4.7µF

0.1µF

VEE -15V

4.7µF

0.1µF

VL+5V

4.7µF

0.1µF

HA5320*

CONTROL

INPUTS

+VS

+15V

4.7µF 0.1µF

MAX174*

D0–11

�� Maxim Integrated Products 15

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Figure 13. Unipolar Input Connections

Figure 12. Ideal Unipolar Transfer Function

Figure 15. Bipolar Input Connections

Figure 14. Ideal Bipolar Transfer Function

REFOUT

GAIN

REFIN

BIPOFF

10VIN

*ADDITIONAL PINS OMITTED FOR CLARITY

100I

100kI

+12V TO +15V

-12V TO -15V

0 TO +10V

0 TO +20V

ANALOG

INPUTS

OFFSET

R1

100kI

R2

100I

20VIN

AGND

MAX174*

MX574A

MX674A

REFIN

GAIN

REFOUT

BIPOFF

10VIN

*ADDITIONAL PINS OMITTED FOR CLARITY

Q5V

Q10V

ANALOG

INPUTS

R2

100I

R1

100I

OFFSET

20VIN

AGND

MAX174*

MX574A

MX674A

0

OUTPUT CODE

1111 1111 1111

1111 1111 1110

1111 1111 1101

0000 0000 0011

0000 0000 0010

0000 0000 0001

0000 0000 0000 123 FS-1

FULL-SCALE

TRANSITION

FS = 4069 LSBs

FS

OUTPUT CODE

1111 1111 1111

1111 1111 1110

1111 1111 1101

1000 0000 0001

1000 0000 0000

0111 1111 1111

0111 1111 1110

0000 0000 0011

0000 0000 0010

0000 0000 0001

0000 0000 0000

ANALOG INPUT VOLTAGE IN LSBs

FS

2

-

FS = 4069 LSBs

FS

2

-+2 -2 -1 01

FS

22

FS

21

FS

2

FS

2

-+1

�� Maxim Integrated Products 16

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Ordering Information

+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.

PART PIN-

PACKAGE

LINEARITY

(LSB)

TEMPCO

(ppm/NC)

8µs Maximum Conversion Time

TEMP RANGE: 0NC to +70NC

MAX174ACPI+ 28 Plastic DIP ½ 10

MAX174BCPI+ 28 Plastic DIP ½ 27

MAX174CCPI+ 28 Plastic DIP 1 50

MAX174ACWI+ 28 Wide SO ½ 10

MAX174BCWI+ 28 Wide SO ½ 27

MAX174CCWI+ 28 Wide SO 1 50

MAX174BC/D Dice* 1/2 —

TEMP RANGE: -40NC to +85NC

MAX174AEPI+ 28 Plastic DIP ½ 19

MAX174BEPI+ 28 Plastic DIP ½ 38

MAX174CEPI+ 28 Plastic DIP 1 75

MAX174AEWI+ 28 Wide SO ½ 19

MAX174BEWI+ 28 Wide SO ½ 38

MAX174CEWI+ 28 Wide SO 1 75

TEMP RANGE: -55NC to +125NC

MAX174AMJI 28 CERDIP ¾ 12

MAX174BMJI 28 CERDIP ¾ 25

MAX174CMJ 28 CERDIP 1/21 50

15µs Maximum Conversion Time

TEMP RANGE: 0NC to +70NC

MX674AJN+ 28 Plastic DIP 1 50

MX674AKN+ 28 Plastic DIP ½ 27

MX674ALN+ 28 Plastic DIP ½ 10

MX674AJCWI+ 28 Wide SO 1 50

MX674AKCWI+ 28 Wide SO ½ 27

MX674ALCWI+ 28 Wide SO ½ 10

MX674AK/D Dice* ½ —

TEMP RANGE: -40NC to +85NC

MX674AJEPI+ 28 Plastic DIP 1 75

MX674AKEPI+ 28 Plastic DIP ½ 38

MX674ALEPI+ 28 Plastic DIP ½ 19

MX674AJEWI+ 28 Wide SO 1 75

MX674AKEWI+ 28 Wide SO ½ 38

MX674ALEWI+ 28 Wide SO ½ 19

PART PIN-

PACKAGE

LINEARITY

(LSB)

TEMPCO

(ppm/NC)

TEMP RANGE: -55NC to +125NC

MX674ASQ 28 CERDIP* 1 50

MX674ATQ 28 CERDIP* ¾ 25

MX674AUQ 28 CERDIP* ¾ 12

MX674ASD 28 Ceramic SB 1 50

MX674ATD 28 Ceramic SB ¾ 25

MX674AUD 28 Ceramic SB ¾ 12

25µs Maximum Conversion Time

TEMP RANGE: 0NC to +70NC

MX574AJN+ 28 Plastic DIP 1 50

MX574AKN+ 28 Plastic DIP ½ 27

MX574ALN+ 28 Plastic DIP ½ 10

MX574AJCWI+ 28 Wide SO 1 50

MX574AKCWI+ 28 Wide SO ½ 27

MX574ALCWI+ 28 Wide SO ½ 10

MX574AJP+ 28 PLCC 1 50

MX574AKP+ 28 PLCC ½ 27

MX574ALP+ 28 PLCC ½ 10

MX574AK/D Dice* ½ —

TEMP RANGE: -40NC to +85NC

MX574AJEPI+ 28 Plastic DIP 1 75

MX574AKEPI+ 28 Plastic DIP ½ 38

MX574ALEPI+ 28 Plastic DIP ½ 19

MX574AJEWI+ 28 Wide SO 1 75

MX574AKEWI+ 28 Wide SO ½ 38

MX574ALEWI+ 28 Wide SO ½ 19

TEMP RANGE: -55NC to +125NC

MX574ASQ 28 CERDIP* 1 50

MX574ATQ 28 CERDIP* ¾ 25

MX574AUQ 28 CERDIP* ¾ 12

MX574ASD 28 Ceramic SB 1 50

MX574ATD 28 Ceramic SB ¾ 25

MX574AUD 28 Ceramic SB ¾ 12

�� Maxim Integrated Products 17

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

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.

Chip Information

PROCESS: BiCMOS

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

28 PDIP P28+2 21-0044 —

28 PLCC Q28+3 21-0049 90-0235

28 Wide SO W28+2 21-0042 90-0109

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

MAX174/MX574A/MX674A

Industry-Standard, Complete 12-Bit ADCs

Revision History

REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

0 3/90 Initial release —

1 8/11 Updated the Electrical Characteristics and Ordering Information. Added

Revision History.2–4