Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - AD converter (ADC) External uMAX 8

General Description

The MAX144/MAX145 low-power, 12-bit analog-to-

digital 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 succes-

sive-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 (V

= +3.6V) at the

maximum sampling rate of 108ksps. At slower through-

put rates, the automatic shutdown (0.2µA) further

reduces power consumption.

The MAX144 provides 2-channel, single-ended opera-

tion 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 data-

through the 3-wire serial interface, which is SPI™,

QSPI™, and MICROWIRE™-compatible.

Excellent dynamic performance and low power, com-

bined with ease of use and small package size, make

these converters ideal for battery-powered and data-

acquisition applications, or for other circuits with

demanding power-consumption and space require-

ments. For pin-compatible 10-bit ADCs, see the

MAX157 and MAX159 data sheets.

Applications

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

PART

TEMP

RANGE

PIN-

PACKAGE

INL

(LSB)

PKG

CODE

MAX144ACUA

0°C to

+70°C

8 µMAX ±0.5 U8-1

MAX144BCUA

0°C to

+70°C

8 µMAX ±1 U8-1

MAX144ACPA

0°C to

+70°C

8 Plastic DIP ±0.5 P8-1

MAX144BCPA

0°C to

+70°C

8 Plastic DIP ±1 P8-1

MAX144BC/D

0°C to

+70°C

Dice* ±1 —

MAX144AEUA

-40°C to

+85°C

8 µMAX ±0.5 U8-1

MAX144BEUA

-40°C to

+85°C

8 µMAX ±1 U8-1

MAX144AEPA

-40°C to

+85°C

8 Plastic DIP ±0.5 P8-1

MAX144BEPA

-40°C to

+85°C

8 Plastic DIP ±1 P8-1

MAX144AMJA

-55°C to

+125°C

8 CERDIP** ±0.5 J8-2

MAX144BMJA

-55°C to

+125°C

8 CERDIP** ±1 J8-2

Ordering Information

CS/SHDN

REFGND

SCLK

DOUT

( ) ARE FOR MAX145 ONLY

CH0 (CH+)

CH1 (CH-)

µMAX/DIP

TOP VIEW

MAX144

MAX145

Pin Configuration

19-1387; Rev 2; 10/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

*Dice are specified at T

= +25°C, DC parameters only.

**Contact factory for availability.

Ordering Information continued at end of data sheet.

Battery-Powered Systems

Portable Data Logging

Isolated Data Acquisition

Process-Control Monitoring

Instrumentation

Test Equipment

Medical Instruments

System Supervision

µMAX is a registered trademark of Maxim Integrated Products, Inc.

SPI and QSPI are trademarks of Motorola, Inc.

MICROWIRE is a trademark of National Semiconductor Corp.

Summary of content (16 pages)

PAGE 1
9-1387; Rev 2; 10/05 +2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX Features ♦ Single-Supply Operation (+2.7V to +5.25V) 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.
PAGE 2
MAX144/MAX145 +2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX ABSOLUTE MAXIMUM RATINGS VDD to GND ..............................................................-0.3V to +6V CH0, CH1 (CH+, CH-) to GND ................. -0.3V to (VDD + 0.3V) REF to GND .............................................. -0.3V to (VDD + 0.3V) Digital Inputs to GND. ............................................. -0.3V to +6V DOUT to GND............................................ -0.3V to (VDD + 0.
PAGE 3
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX (V DD = +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, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VREF V ±1 µA ANALOG INPUTS Analog Input Voltage Range VIN Multiplexer Leakage Current Input Capacitance (Note 6) 0 On/off leakage current, VIN = 0 to VDD ±0.
PAGE 4
MAX144/MAX145 +2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX TIMING CHARACTERISTICS (Figure 7) (VDD = +2.7V to +5.25V, VREF = 2.5V, 0.1µF capacitor at REF, fSCLK = 2.17MHz, 16 clocks/conversion cycle (108ksps), CH-= GND for MAX145, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS Wake-Up Time MIN TYP MAX 2.
PAGE 5
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX SUPPLY CURRENT vs. TEMPERATURE 900 500 100 3.0 3.5 4.0 4.5 5.0 MAX144/5-02 0.1 -60 -40 -20 0 5.5 20 40 60 80 100 120 140 0.1 100 1k SAMPLING RATE (sps) SHUTDOWN CURRENT vs. SUPPLY VOLTAGE SHUTDOWN CURRENT vs. TEMPERATURE OFFSET ERROR vs. SUPPLY VOLTAGE 400 0 600 400 3.5 4.0 4.5 5.0 20 40 60 80 100 120 140 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) TEMPERATURE (°C) SUPPLY VOLTAGE (V) OFFSET ERROR vs.
PAGE 6
Typical Operating Characteristics (continued) (VDD = +3.0V, VREF = 2.5V, 0.1µF at REF, fSCLK = 2.17MHz, 16 clocks/conversion cycle (108ksps), CH- = GND for MAX145, TA = +25°C, unless otherwise noted.) INTEGRAL NONLINEARITY vs. OUTPUT CODE INTEGRAL NONLINEARITY vs. SUPPLY VOLTAGE 0 -0.05 -0.10 0.4 0.3 INL (LSB) INL (LSB) 0.05 MAX144/5-12 0.4 0.10 0.5 MAX144/5-11 0.15 INTEGRAL NONLINEARITY vs. TEMPERATURE 0.5 MAX144/5-10 0.20 INL (LSB) 0.2 0.1 0.3 0.2 0.1 -0.15 -0.
PAGE 7
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX MAX144/MAX145 VDD DOUT 6k DOUT 6k CL CL GND GND a) HIGH-Z TO V0H, V0L TO V0H, AND VOH TO HIGH-Z b) HIGH-Z TO V0L, V0H TO V0L, AND VOL TO HIGH-Z Figure 1.
PAGE 8
MAX144/MAX145 +2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX The capacitive digital-to-analog converter (DAC) adjusts during the remainder of the conversion cycle to restore node ZERO to 0V within the limits of 12-bit resolution. This action is equivalent to transferring a 16pF · [(VIN+) - (VIN-)] charge from CHOLD to the binary-weighted capacitive DAC, which in turn forms a digital representation of the analog input signal.
PAGE 9
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX Internal Clock (fSCLK < 100kHz or fSCLK > 2.17MHz) In internal clock mode, the MAX144/MAX145 run from an internal, laser-trimmed oscillator to within 20% of the 2MHz specified clock rate. This releases the system microprocessor from running the SAR conversion clock and allows the conversion results to be read back at the processor’s convenience, at any clock rate from 0 to 5MHz.
PAGE 10
MAX144/MAX145 +2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX Table 1.
PAGE 11
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX padded with three leading ones and the channel identification before the MSB. If the serial clock hasn’t been idled after the last LSB and CS/SHDN is kept low, DOUT sends trailing zeros. SPI and MICROWIRE Interface When using SPI (Figure 8a) or MICROWIRE (Figure 8b) interfaces, set CPOL = 0 and CPHA = 0. Conversion begins with a falling edge on CS/SHDN (Figure 8c).
PAGE 12
MAX144/MAX145 +2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX PIC16 with SSP Module and PIC17 Interface The MAX144/MAX145 are compatible with a PIC16/ PIC17 controller (µC), using the synchronous serial-port (SSP) module.
PAGE 13
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX MAX144/MAX145 SETTINGS CONTROL BIT SYNCHRONOUS SERIAL-PORT STATUS REGISTER (SSPSTAT) 0 SPI Data Input Sample Phase. Input data is sampled at the middle of the data output time. BIT6 1 SPI Clock Edge Select Bit. Data will be transmitted on the rising edge of the serial clock.
PAGE 14
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX MAX144/MAX145 Ordering Information (continued) PART POWER SUPPLIES +3V +3V GND MAX145ACUA R* = 10 W MAX145BCUA 1mF MAX145ACPA 0.1 mF V DD GND +3V DGND DIGITAL CIRCUITRY MAX144 MAX145 MAX145BCPA MAX145BC/D MAX145AEUA * OPTIONAL FILTER RESISTOR MAX145BEUA Figure 11.
PAGE 15
+2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX 8LUMAXD.EPS (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.
PAGE 16
Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) PDIPN.EPS MAX144/MAX145 +2.7V, Low-Power, 2-Channel, 108ksps, Serial 12-Bit ADCs in 8-Pin µMAX Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.