Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - AD converter (ADC) Internal SOIC 8 N

__________________General Description

The MAX1240/MAX1241 low-power, 12-bit analog-to-

digital converters (ADCs) are available in 8-pin pack-

ages. The MAX1240 operates with a single +2.7V to

+3.6V supply, and the MAX1241 operates with a single

+2.7V to +5.25V supply. Both devices feature a 7.5µs

successive-approximation ADC, a fast track/hold

(1.5µs), an on-chip clock, and a high-speed, 3-wire ser-

ial interface.

Power consumption is only 37mW (V

= 3V) at the

73ksps maximum sampling speed. A 2µA shutdown

mode reduces power at slower throughput rates.

The MAX1240 has an internal 2.5V reference, while the

MAX1241 requires an external reference. The MAX1241

accepts signals from 0V to V

REF

, and the reference

input range includes the positive supply rail. An exter-

nal clock accesses data from the 3-wire interface,

which connects directly to standard microcontroller I/O

ports. The interface is compatible with SPI™, QSPI™,

and MICROWIRE™.

Excellent AC characteristics and very low power com-

bined with ease of use and small package size make

these converters ideal for remote-sensor and data-

acquisition applications, or for other circuits with

demanding power consumption and space require-

ments. The MAX1240/MAX1241 are available in 8-pin

PDIP and SO packages.

Applications

Battery-Powered Systems

Portable Data Logging

Isolated Data Acquisition

Process Control

Instrumentation

________________________________Features

♦ Single-Supply Operation:

+2.7V to +3.6V (MAX1240)

+2.7V to +5.25V (MAX1241)

♦ 12-Bit Resolution

♦ Internal 2.5V Reference (MAX1240)

♦ Small Footprint: 8-Pin PDIP/SO Packages

♦ Low Power: 3.7µW (73ksps, MAX1240)

3mW (73ksps, MAX1241)

66µW (1ksps, MAX1241)

5µW (power-down mode)

♦ Internal Track/Hold

♦ SPI/QSPI/MICROWIRE 3-Wire Serial Interface

♦ Internal Clock

MAX1240/MAX1241

+2.7V, Low-Power,

12-Bit Serial ADCs in 8-Pin SO

________________________________________________________________ Maxim Integrated Products 1

19-1155; Rev 5; 8/10

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

Ordering Information continued at end of data sheet.

TOP VIEW

SCLK

DOUT

GND

REF

SHDN

AIN

PDIP/SO

MAX1240

MAX1241

Pin Configuration

Ordering Information

EVALUATION KIT

AVAILABLE

Functional Diagram

AIN

T/H

DOUT

OUTPUT

SHIFT

CONTROL

LOGIC

INT

CLOCK

12-BIT

SAR

REF

SHDN

2.5V REFERENCE

(MAX1240 ONLY)

GND

SCLK

MAX1240

MAX1241

*Dice are specified at T

= +25°C, DC parameters only.

**Future product—contact factory for availability.

/V denotes an automotive qualified part.

+Denotes a lead(Pb)-free/RoHS-compliant package.

PART*

TEMP RANGE

PIN -

PA C K A G E

INL

(LSB)

MAX1240ACPA+

0°C to +70°C

8 PDIP

±1/2

MAX1240BCPA+

0°C to +70°C

8 PDIP ±1

MAX1240CCPA+

0°C to +70°C

8 PDIP ±1

MAX1240ACSA+

0°C to +70°C

8 SO

±1/2

MAX1240BCSA+

0°C to +70°C

8 SO ±1

MAX1240CCSA+

0°C to +70°C

8 SO ±1

MAX1240CC/D

0°C to +70°C

Dice* ±1

MAX1240AESA/V+** -40°C to +85°C

8 SO

±1/2

MAX1240BESA/V+

-40°C to +85°C

8 SO ±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.

Summary of content (15 pages)

PAGE 1
9-1155; Rev 5; 8/10 KIT ATION EVALU E L B AVAILA +2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO ________________________________Features The MAX1240/MAX1241 low-power, 12-bit analog-todigital converters (ADCs) are available in 8-pin packages. The MAX1240 operates with a single +2.7V to +3.6V supply, and the MAX1241 operates with a single +2.7V to +5.25V supply. Both devices feature a 7.5µs successive-approximation ADC, a fast track/hold (1.
PAGE 2
MAX1240/MAX1241 +2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO ABSOLUTE MAXIMUM RATINGS VDD to GND .............................................................-0.3V to +6V AIN 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 + 0.3V) DOUT Current .....
PAGE 3
+2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO (VDD = +2.7V to +3.6V (MAX1240); VDD = +2.7V to +5.25V (MAX1241); 73ksps, fSCLK = 2.1MHz (50% duty cycle); MAX1240—4.7µF capacitor at REF pin, MAX1241—external reference; VREF = 2.500V applied to REF pin; TA = TMIN to TMAX; unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 2.480 2.500 2.
PAGE 4
MAX1240/MAX1241 +2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO ELECTRICAL CHARACTERISTICS (continued) (VDD = +2.7V to +3.6V (MAX1240); VDD = +2.7V to +5.25V (MAX1241); 73ksps, fSCLK = 2.1MHz (50% duty cycle); MAX1240—4.7µF capacitor at REF pin, MAX1241—external reference; VREF = 2.500V applied to REF pin; TA = TMIN to TMAX; unless otherwise noted.) PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS POWER REQUIREMENTS Supply Voltage VDD MAX1240 2.7 3.6 MAX1241 2.7 5.
PAGE 5
+2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO MAX1240/MAX1241 +2.7V 6k DOUT DOUT 6k CLOAD = 50pF CLOAD = 50pF DGND DGND a) High-Z to VOH and VOL to VOH b) High-Z to VOL and VOH to VOL Figure 1. Load Circuits for DOUT Enable Time +2.7V 6k DOUT DOUT 6k CLOAD = 50pF CLOAD = 50pF DGND DGND a) VOH to High-Z b) VOLto High-Z Figure 2. Load Circuits for DOUT Disable Time __________________________________________Typical Operating Characteristics (VDD = 3.0V, VREF = 2.5V, fSCLK = 2.
PAGE 6
____________________________Typical Operating Characteristics (continued) (VDD = 3.0V, VREF = 2.5V, fSCLK = 2.1MHz, CL = 20pF, TA = +25°C, unless otherwise noted.) SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE 2.0 1.5 1.0 0.5 4.0 3.5 3.0 2.5 2.0 1.5 3.25 3.75 4.25 4.75 -20 20 60 100 TEMPERATURE (°C) GAIN ERROR vs. SUPPLY VOLTAGE GAIN ERROR vs. TEMPERATURE -55 140 -30 -5 20 45 70 95 120 145 MAX1240 INTERNAL REFERENCE VOLTAGE vs. SUPPLY VOLTAGE 2.5020 MAX1241-08 0.8 MAX1241-07 0.7 0.
PAGE 7
+2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO INTEGRAL NONLINEARITY vs. CODE FFT PLOT 0.4 MAX1241-TOC12A 20 MAX1241-11A/NEW 0.6 fAIN = 10kHz, 2.5VP-P fSAMPLE = 73ksps 0 -20 AMPLITUDE (dB) INL (LSB) 0.2 0 -0.2 -40 -60 -80 -100 -0.4 -120 -140 -0.6 0 1024 2048 CODE 3072 4096 0 18.75 37.50 FREQUENCY (kHz) _______________________________________________________________________Pin Description PIN NAME FUNCTION 1 VDD Positive Supply Voltage: 2.7V to 3.6V, (MAX1240); 2.7V to 5.
PAGE 8
MAX1240/MAX1241 +2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO +2.7V to +3.6V* * VDD,MAX = +5.25V (MAX1241) ** 4.7μF (MAX1240) 0.1μF (MAX1241) 4.7μF 0.1μF 1 ANALOG INPUT 0V TO VREF 2 SHUTDOWN INPUT 3 REFERENCE INPUT (MAX1241 ONLY) 4 VDD SCLK AIN MAX1240 CS MAX1241 SHDN REF DOUT GND 8 7 AIN SERIAL INTERFACE COMPARATOR TRACK INPUT CHOLD HOLD ZERO - + 16pF CSWITCH 6 9k RIN HOLD TRACK 5 C** AT THE SAMPLING INSTANT, THE INPUT SWITCHES FROM AIN TO GND. GND Figure 4.
PAGE 9
+2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO Analog Input Protection Internal protection diodes, which clamp the analog input to VDD and GND, allow the input to swing from GND - 0.3V to VDD + 0.3V without damage. However, for accurate conversions near full scale, the input must not exceed VDD by more than 50mV, or be lower than GND by 50mV. If the analog input exceeds 50mV beyond the supplies, limit the input current to 2mA.
PAGE 10
Using SHDN to Reduce Supply Current VDD = VREF = 3.0V RLOAD = ∞, CLOAD = 50pF CODE = 010101010000 1 SUPPLY CURRNET (mA) MAX1241 FIG. 06a 10 Power consumption can be reduced significantly by shutting down the MAX1240/MAX1241 between conversions. Figure 6 shows a plot of average supply current versus conversion rate.
PAGE 11
+2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO … tCS0 SCLK tDO tCONV tDV … DOUT tAPR INTERNAL T/H tCH … tCL B2 tTR B1 B0 tSTR (TRACK/ACQUIRE) … (HOLD) (TRACK/ACQUIRE) Figure 9. Detailed Serial-Interface Timing End of conversion (EOC) is signaled by DOUT going high. DOUT’s rising edge can be used as a framing signal. SCLK shifts the data out of this register any time after the conversion is complete. DOUT transitions on SCLK’s falling edge.
PAGE 12
MAX1240/MAX1241 +2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO 5) With CS = high, wait the minimum specified time, tCS, before initiating a new conversion by pulling CS low. If a conversion is aborted by pulling CS high before the conversion’s end, wait for the minimum acquisition time, tACQ, before starting a new conversion. CS must be held low until all data bits are clocked out. Data can be output in two bytes or continuously, as shown in Figure 8.
PAGE 13
+2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO MAX1240/MAX1241 1ST BYTE READ 2ND BYTE READ SCLK CS tCONV D11 DOUT* D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 MSB HIGH-Z D0 LSB EOC *WHEN CS IS HIGH, DOUT = HIGH -Z Figure 12. SPI/MICROWIRE Serial Interface Timing (CPOL = CPHA = 0) SCLK CS tCONV D11 MSB DOUT* D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 LSB HIGH-Z EOC *WHEN CS IS HIGH, DOUT = HIGH -Z Figure 13.
PAGE 14
MAX1240/MAX1241 +2.
PAGE 15
2.7V, Low-Power, 12-Bit Serial ADCs in 8-Pin SO REVISION NUMBER REVISION DATE 3 3/10 4 6/10 Future product note removed from one part in the Ordering Information 1 5 8/10 Removed MAX1240BC/D and add MAX1240CC/D 1 DESCRIPTION Added automotive grade to data sheet PAGES CHANGED 1, 2, 3, 7, 9, 14, 15, 16 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.