Maxim MAX144BEUA, MAX144BEPA, MAX144BCUA, MAX144BCPA, MAX144BC-D Datasheet

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General Description

The MAX144/MAX145 low-power, 12-bit analog-to­digital converters (ADCs) are available in 8-pin µMAX
and DIP packages. Both devices operate with a single
+2.7V to +5.25V supply and feature a 7.4µs succes­sive-approximation ADC, automatic power-down, fast
wake-up (2.5µs), an on-chip clock, and a high-speed,
3-wire serial interface.

Power consumption is only 3.2mW (VDD= +3.6V) at the
maximum sampling rate of 108ksps. At slower through­put rates, the automatic shutdown (0.2µA) further
reduces power consumption.

The MAX144 provides 2-channel, single-ended opera­tion and accepts input signals from 0 to V

REF

. The
MAX145 accepts pseudo-differential inputs ranging
from 0 to V

REF

. An external clock accesses data­through the 3-wire serial interface, which is SPI™,
QSPI™, and MICROWIRE™-compatible.

Excellent dynamic performance and low power, com­bined with ease of use and small package size, make
these converters ideal for battery-powered and data­acquisition applications, or for other circuits with
demanding power-consumption and space require­ments. For pin-compatible 10-bit ADCs, see the
MAX157 and MAX159.

Applications

Battery-Powered Systems Instrumentation
Portable Data Logging Test Equipment
Isolated Data Acquisition Medical Instruments
Process-Control Monitoring System Supervision

Features

♦ Single-Supply Operation (+2.7V to +5.25V)
♦ Two Single-Ended Channels (MAX144)

One Pseudo-Differential Channel (MAX145)

♦ Low Power

0.9mA (108ksps, +3V Supply)
100µA (10ksps, +3V Supply)
10µA (1ksps, +3V Supply)

0.2µA (Power-Down Mode)

♦ Internal Track/Hold
♦ 108ksps Sampling Rate
♦ SPI/QSPI/MICROWIRE-Compatible 3-Wire

Serial Interface

♦ Space-Saving 8-Pin µMAX Package
♦ Pin-Compatible 10-Bit Versions Available

MAX144/MAX145

+2.7V, Low-Power, 2-Channel, 108ksps,

Serial 12-Bit ADCs in 8-Pin µMAX

________________________________________________________________

Maxim Integrated Products

1

CS/SHDN

REFGND

1
2

87SCLK

DOUT

( ) ARE FOR MAX145 ONLY

CH0 (CH+)

CH1 (CH-)

V

DD

µMAX/DIP

TOP VIEW

3

4

6

5

MAX144
MAX145

19-1387; Rev 0; 11/98

PART

MAX144ACUA

MAX144BCUA
MAX144ACPA 0°C to +70°C

0°C to +70°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

8 µMAX
8 µMAX
8 Plastic DIP

*

Dice are specified at TA= +25°C, DC parameters only.

**

Contact factory for availability.

Pin Configuration

Ordering Information

SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.

INL

(LSB)

±0.5
±1

±0.5
MAX144BCPA
MAX144BC/D
MAX144AEUA -40°C to +85°C

0°C to +70°C

0°C to +70°C 8 Plastic DIP

Dice*
8 µMAX

±1

±1

±0.5
MAX144BEUA
MAX144AEPA
MAX144BEPA -40°C to +85°C

-40°C to +85°C

-40°C to +85°C 8 µMAX
8 Plastic DIP
8 Plastic DIP

±1
±0.5

±1
MAX144AMJA
MAX144BMJA
MAX145ACUA

0°C to +70°C

-55°C to +125°C

-55°C to +125°C 8 CERDIP**
8 CERDIP**
8 µMAX

±0.5
±1

±0.5
MAX145BCUA 0°C to +70°C 8 µMAX ±1
MAX145ACPA
MAX145BCPA
MAX145BC/D 0°C to +70°C

0°C to +70°C

0°C to +70°C 8 Plastic DIP

8 Plastic DIP
Dice*

±0.5

±1

±1
MAX145AEUA
MAX145BEUA
MAX145AEPA -40°C to +85°C

-40°C to +85°C

-40°C to +85°C 8 µMAX
8 µMAX
8 Plastic DIP

±0.5
±1

±0.5
MAX145BEPA
MAX145AMJA
MAX145BMJA -55°C to +125°C

-55°C to +125°C

-40°C to +85°C 8 Plastic DIP
8 CERDIP**
8 CERDIP**

±1
±0.5
±1

MAX144/MAX145

+2.7V, Low-Power, 2-Channel, 108ksps,
Serial 12-Bit ADCs in 8-Pin µMAX

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +2.7V to +5.25V, V

REF

= 2.5V, 0.1µF capacitor at REF, f

SCLK

= 2.17MHz, 16 clocks/conversion cycle (108ksps),

CH- = GND for MAX145, T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

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.

VDDto GND..............................................................-0.3V to +6V

CH0, CH1 (CH+, CH-) to GND ................. -0.3V to (V

DD

+ 0.3V)

REF to GND .............................................. -0.3V to (V

DD

+ 0.3V)

Digital Inputs to GND. ............................................. -0.3V to +6V

DOUT to GND............................................ -0.3V to (V

DD

+ 0.3V)

DOUT Sink Current ........................................................... 25mA

Continuous Power Dissipation (T

A

= +70°C)

µMAX (derate 4.1mW/°C above +70°C) .................... 330mW

Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW

CERDIP (derate 8.00mW/°C above +70°C) ............... 640mW

Operating Temperature Ranges (T

A

)

MAX144/MAX145_C_A .......................................0°C to +70°C

MAX144/MAX145_E_A. ...................................-40°C to +85°C

MAX144/MAX145_M_A ................................ -55°C to +125°C

Storage Temperature Range.............................-65°C to +150°C

Lead Temperature (soldering, 10sec).............................+300°C

MAX14_A
MAX14_B
No missing codes over temperature

CONDITIONS

LSB

±0.5

INLRelative Accuracy (Note 2)

Bits

12

RESResolution

±1

LSB±0.75DNLDifferential Nonlinearity

UNITSMIN TYP MAXSYMBOLPARAMETER

ppm/°C±0.8Gain Temperature Coefficient

LSB±3

LSB±3Offset Error

Gain Error (Note 3)

LSB±0.05

Channel-to-Channel Offset
Matching

LSB±0.05

Channel-to-Channel Gain
Matching

-3dB rolloff

fIN= 65kHz, VIN= 2.5Vp-p (Note 4)

External clock, f

SCLK

= 2.17MHz,

16 clocks/conversion cycle

MHz1.0Full-Power Bandwidth

MHz2.25

dB-85Channel-to-Channel Crosstalk

Small-Signal Bandwidth

µs

7.4

t

CONV

Conversion Time (Note 5)

Total Harmonic Distortion
(including 5th-order harmonic)

dB70SINAD

Signal-to-Noise Plus
Distortion Ratio

dB-80THD
dB80SFDRSpurious-Free Dynamic Range

Internal clock mode, for data transfer only

External clock mode

Internal clock

05

MHz

0.1 2.17

f

SCLK

ps<50Aperture Jitter

Serial Clock Frequency

57

µs2.5t

ACQ

T/H Acquisition Time

ns25Aperture Delay

DC ACCURACY (Note 1)

DYNAMIC SPECIFICATIONS (f

IN(sine-wave)

= 10kHz, VIN= 2.5Vp-p, 108ksps, f

SCLK

= 2.17MHz, CH- = GND for MAX145)

CONVERSION RATE

MAX144/MAX145

+2.7V, Low-Power, 2-Channel, 108ksps,

Serial 12-Bit ADCs in 8-Pin µMAX

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +2.7V to +5.25V, V

REF

= 2.5V, 0.1µF capacitor at REF, f

SCLK

= 2.17MHz, 16 clocks/conversion cycle (108ksps),

CH- = GND for MAX145, T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

V

REF

= 2.5V

On/off leakage current, VIN= 0 to V

DD

kΩ18 25Input Resistance

µA100 140

V

0V

DD

+ 50mV

V

REF

Input Voltage Range (Note 7)
Input Current

µA0.01 10

CONDITIONS

Shutdown REF Input Current

µA±0.01 ±1Multiplexer Leakage Current

V0V

REF

V

IN

Analog Input Voltage Range
(Note 6)

pF16C

IN

Input Capacitance

UNITS

MIN TYP MAX

SYMBOLPARAMETER

Input Leakage Current I

IN

±1 µA

Input Hysteresis V

HYS

0.2 V

0.2 5 µA

Input High Voltage V

IH

2.0
V

3.0

Input Low Voltage V

IL

0.8 V

Positive Supply Current I

DD

0.9 2.0 mA

Three-State Output Capacitance C

OUT

15 pF

Positive Supply Voltage V

DD

2.7 5.25 V

Power-Supply Rejection
(Note 9)

Shutdown, CS/SHDN = GND

Operating mode

PSR ±0.15 mV

CS/SHDN = VDD(Note 8)

VDD= 2.7V to 5.25V,
V

REF

= 2.5V, full-scale input

Three-State Output Leakage
Current

±10 µA

Output High Voltage V

OH

VDD- 0.5 V

Output Low Voltage

Input Capacitance

VIN= 0 or V

DD

C

IN

15 pF

V

OL

0.4
V

0.5

VDD≤ 3.6V
VDD> 3.6V

CS/SHDN = V

DD

I

SOURCE

= 0.5mA

(Note 8)
I

SINK

= 5mA

I

SINK

= 16mA

ANALOG INPUTS

EXTERNAL REFERENCE

DIGITAL INPUTS (CS/SHDN) AND OUTPUT (DOUT)

POWER REQUIREMENTS

ns

MAX144/MAX145

+2.7V, Low-Power, 2-Channel, 108ksps,
Serial 12-Bit ADCs in 8-Pin µMAX

4 _______________________________________________________________________________________

TIMING CHARACTERISTICS (Figure 7)

(VDD= +2.7V to +5.25V, V

REF

= 2.5V, 0.1µF capacitor at REF, f

SCLK

= 2.17MHz, 16 clocks/conversion cycle (108ksps),

CH- = GND for MAX145, T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.)

Internal clock, SCLK for data transfer only
(Note 8)

External clock

Internal clock, SCLK for data transfer only

CL = 100pF, Figure 1

External clock

CL= 100pF

50

ns

215

t

CH

05

CL= 100pF, Figure 1
External clock

SCLK Pulse Width High

ns

215

CONDITIONS

t

CL

SCLK Pulse Width Low

ns

120

t

TR

CS/SHDN Rise to Output Disable

ns

120

t

DV

µs

2.5

t

WAKE

Wake-Up Time (Note 10)
CS/SHDN Fall to Output Enable

ns

20 120

t

DO

SCLK Fall to Output Data Valid

MHz

0.1 2.17

f

SCLK

SCLK Clock Frequency

UNITSMIN TYP MAXSYMBOLPARAMETER

Internal clock, SCLK for data transfer only
(Note 8)

50

ns

60

t

SCLKS

SCLK to CS/SHDN Setup

ns

60

t

CS

CS/SHDN Pulse Width

Note 1: Tested at VDD= +2.7V.
Note 2: Relative accuracy is the deviation of the analog value at any code from its theoretical value after full-scale range has been

calibrated.

Note 3: Offset nulled.
Note 4: “On” channel is grounded; sine wave applied to “off” channel (MAX144 only).
Note 5: Conversion time is defined as the number of clock cycles times the clock period; clock has 50% duty cycle.
Note 6: The common-mode range for the analog inputs is from GND to V

DD

(MAX145 only).

Note 7: ADC performance is limited by the converter’s noise floor, typically 300µVp-p.
Note 8: Guaranteed by design. Not subject to production testing.
Note 9: Measured as V

FS(2.7V)

- V

FS(5.25V)

.

Note 10: SCLK must remain stable during this time.

MAX144/MAX145

+2.7V, Low-Power, 2-Channel, 108ksps,

Serial 12-Bit ADCs in 8-Pin µMAX

_______________________________________________________________________________________

5

500

700

900

1100

1300

1500

2.5 3.0 3.5 4.0 4.5 5.55.0

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX144/5-01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

V

REF

= V

DD

RL = ∞
C

L

= 50pF

CODE = 101010100000

0

200

400

600

800

1000

-60 20 40-20 0-40 60 80 100 120 140

SHUTDOWN CURRENT

vs. TEMPERATURE

MAX144/5-05

TEMPERATURE (°C)

SHUTDOWN CURRENT (nA)

V

REF

= V

DD

500

750

1250

1000

1500

-60 -20 0 20 40-40 60 80 100 120 140

SUPPLY CURRENT

vs. TEMPERATURE

MAX144/5-02

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

V

REF

= V

DD

RL = ∞
C

L

= 50pF

CODE = 101010100000

0

200

400

600

800

1000

SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE

MAX144/5-04

SUPPLY VOLTAGE (V)

SHUTDOWN CURRENT (nA)

2.5 3.0 3.5 4.0 4.5 5.55.0

V

REF

= V

DD

Typical Operating Characteristics

(VDD= +3.0V, V

REF

= 2.5V, 0.1µF at REF, f

SCLK

= 2.17MHz, 16 clocks/conversion cycle (108ksps), CH- = GND for MAX145, TA= +25°C,

unless otherwise noted.)

SUPPLY CURRENT vs.

SAMPLING RATE

MAX144/5-03

SAMPLING RATE (sps)

SUPPLY CURRENT (µA)

10,000

0.1

1

10

100

1000

0.1 100 1k 10k1 10 100k

VDD = V

REF

CL = 20pF
CODE = 101010100000

0

0.2

0.4

0.6

0.8

1.0

2.5 3.0 3.5 4.0 4.5 5.0 5.5

OFFSET ERROR

vs. SUPPLY VOLTAGE

MAX144/5-06

SUPPLY VOLTAGE (V)

OFFSET ERROR (LSB)

0

0.2

0.1

0.4

0.3

0.6

0.5

0.7

0.9

0.8

1.0

OFFSET ERROR

vs. TEMPERATURE

MAX144/5-07

TEMPERATURE (°C)

OFFSET ERROR (LSB)

-60 -10 15-35 40 65 90 115 140

-0.5

-0.3

-0.4

-0.1

-0.2

0.1
0

0.2

0.4

0.3

0.5

2.5 3.53.0 4.0 4.5 5.0 5.5

GAIN ERROR

vs. SUPPLY VOLTAGE

MAX144/5-08

VDD (V)

GAIN ERROR (LSB)

-0.5

-0.3

-0.4

-0.1

-0.2

0.1
0

0.2

0.4

0.3

0.5

GAIN ERROR

vs. TEMPERATURE

MAX144/5-09

GAIN ERROR (LSB)

TEMPERATURE (°C)

-60 -10 15-35 40 65 90 115 140