Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - AD converter (ADC) External , Internal SSOP 20

General Description

The MAX1202/MAX1203 are 12-bit data-acquisition sys-

tems specifically designed for use in applications with

mixed +5V (analog) and +3V (digital) supply voltages.

They operate with a single +5V analog supply or dual ±5V

analog supplies, and combine an 8-channel multiplexer,

high-bandwidth track/hold, and serial interface with high

conversion speed and low power consumption.

A 4-wire serial interface connects directly to SPI/

MICROWIRE® devices without external logic, and a serial

strobe output allows direct connection to TMS320-family

digital signal processors. The MAX1202/MAX1203 use

either the internal clock or an external serial-interface clock

to perform successive approximation analog-to-digital con-

versions. The serial interface operates at up to 2MHz.

The MAX1202 features an internal 4.096V reference,

while the MAX1203 requires an external reference. Both

parts have a reference-buffer amplifier that simplifies gain

trim. They also have a V

pin that is the power supply for

the digital outputs. Output logic levels (3V, 3.3V, or 5V) are

determined by the value of the voltage applied to this pin.

These devices provide a hard-wired SHDN pin and two

software-selectable power-down modes. Accessing the

serial interface automatically powers up the devices. A

quick turn-on time enables the MAX1202/MAX1203 to

be shut down between conversions, allowing the user

to optimize supply currents. By customizing power-down

between conversions, supply current can drop below

10μA at reduced sampling rates.

The MAX1202/MAX1203 are available in 20-pin SSOP

and PDIP packages, and are specified for the commercial

and extended temperature ranges.

Applications

● 5V/3V Mixed-Supply Systems

● Data Acquisition

● High-Accuracy Process Control

● Battery-Powered Instruments

● Medical Instruments

Features

● 8-Channel Single-Ended or 4-Channel Differential

Inputs

● Operates from Single +5V or Dual ±5V Supplies

● User-Adjustable Output Logic Levels

(2.7V to 5.25V)

● Low Power: 1.5mA (Operating Mode)

2μA (Power-Down Mode)

● Internal Track/Hold, 133kHz Sampling Rate

● Internal 4.096V Reference (MAX1202)

● SPI/MICROWIRE/TMS320-Compatible

4-Wire Serial Interface

● Software-Configurable Unipolar/Bipolar Inputs

● 20-Pin PDIP/SSOP

Typical Operating Circuit appears at end of data sheet.

MICROWIRE is a registered trademark of National

Semiconductor Corp.

19-1173; Rev 3; 3/12

Ordering Information continued at end of data sheet.

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

PART TEMP RANGE

PIN-

PACKAGE

INL

(LSB)

MAX1202ACPP+ 0ºC to +70ºC 20 PDIP ±1/2

MAX1202BCPP+ 0ºC to +70ºC 20 PDIP ±1

MAX1202ACAP+ 0ºC to +70ºC 20 SSOP ±1/2

MAX1202BCAP+ 0ºC to +70ºC 20 SSOP ±1

TOP VIEW

PDIP/SSOP

SCLK

DIN

SSTRB

DOUT

GND

REFADJ

REF

SHDN

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

MAX1202

MAX1203

MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs

with 3V Digital Interface

Pin Conguration

Ordering Information

EVALUATION KIT AVAILABLE

Summary of content (24 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX1202/MAX1203 General Description The MAX1202/MAX1203 are 12-bit data-acquisition systems specifically designed for use in applications with mixed +5V (analog) and +3V (digital) supply voltages. They operate with a single +5V analog supply or dual ±5V analog supplies, and combine an 8-channel multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and low power consumption.
PAGE 2
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Absolute Maximum Ratings VDD to GND.............................................................-0.3V to +6V VL.............................................................. -0.3V to (VDD + 0.3V) VSS to GND..............................................................+0.3V to -6V VDD to VSS.............................................................-0.3V to +12V CH0–CH7 to GND.......................... (VSS - 0.3V) to (VDD + 0.
PAGE 3
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Electrical Characteristics (continued) (VDD = +5V ±5%, VL = 2.7V to 3.6V; VSS = 0V or -5V ±5%; fSCLK = 2.0MHz, external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); MAX1202—4.7μF capacitor at REF pin; MAX1203—external reference, VREF = 4.096V applied to REF pin; TA = TMIN to TMAX, unless otherwise noted.
PAGE 4
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Electrical Characteristics (continued) (VDD = +5V ±5%, VL = 2.7V to 3.6V; VSS = 0V or -5V ±5%; fSCLK = 2.0MHz, external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); MAX1202—4.7μF capacitor at REF pin; MAX1203—external reference, VREF = 4.096V applied to REF pin; TA = TMIN to TMAX, unless otherwise noted.
PAGE 5
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Electrical Characteristics (continued) (VDD = +5V ±5%, VL = 2.7V to 3.6V; VSS = 0V or -5V ±5%; fSCLK = 2.0MHz, external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); MAX1202—4.7μF capacitor at REF pin; MAX1203—external reference, VREF = 4.096V applied to REF pin; TA = TMIN to TMAX, unless otherwise noted.
PAGE 6
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface TIMING CHARACTERISTICS (VDD = +5V ±5%, VL = 2.7V to 3.6V, VSS = 0V or -5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER Acquisition Time SYMBOL CONDITIONS MIN TYP MAX UNITS tACQ 1.
PAGE 7
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Typical Operating Characteristics (VDD = 5V ±5%; VL = 2.7V to 3.6V; VSS = 0V; fSCLK = 2.0MHz, external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); MAX1202—4.7μF capacitor at REF pin; MAX1203—external reference, VREF = 4.096V applied to REF pin; TA = +25°C, unless otherwise noted.) 1.6 MAX1202 1.4 1.2 4.7 4.9 5.1 2.0 MAX1202 1.5 MAX1203 1.0 0.5 5.3 0 5.
PAGE 8
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Typical Operating Characteristics (continued) (VDD = 5V ±5%; VL = 2.7V to 3.6V; VSS = 0V; fSCLK = 2.0MHz, external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); MAX1202—4.7μF capacitor at REF pin; MAX1203—external reference, VREF = 4.096V applied to REF pin; TA = +25°C, unless otherwise noted.) INTEGRAL NONLINEARITY vs. DIGITAL 0.8 0.6 AMPLITUDE (dB) INL (LSB) 0.4 0.2 0 -0.2 -0.4 -20 -40 -60 -80 -0.
PAGE 9
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface +3.3V 3kΩ DOUT DOUT 3kΩ CLOAD CLOAD GND GND a. High-Z to VOH and VOL to VOH b. High-Z to VOL and VOH to VOL Figure 1. Load Circuits for Enable Time +3.3V DOUT DOUT 3kΩ CLOAD GND a.
PAGE 10
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Track/Hold The T/H enters tracking mode on the falling clock edge after the fifth bit of the 8-bit control word is shifted in. The T/H enters hold mode on the falling clock edge after the eighth bit of the control word is shifted in. IN- is connected to GND if the converter is set up for single-ended inputs, and the converter samples the “+” input.
PAGE 11
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Table 1a. Unipolar Full Scale and Zero Scale ZERO SCALE FULL SCALE 0V +4.096V at REFADJ 0V at REF 0V VREFADJ x A* REFERENCE Internal External VREF *A = 1.68 for the MAX1202, 1.64 for the MAX1203. Table 1b. Bipolar Full Scale, Zero Scale, and Negative Full Scale REFERENCE Internal at External REFADJ at REF NEGATIVE FULL SCALE ZERO SCALE FULL SCALE +4.096V/2 0V +4.
PAGE 12
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Table 2. Control-Byte Format BIT 7 (MSB) BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT1 BIT 0 (LSB) START SEL 2 SEL 1 SEL 0 UNI/BIP SGL/DIF PD1 PD0 BIT NAME 7 (MSB) START The first logic 1 bit after CS goes low defines the beginning of the control byte. 6 5 4 SEL2 SEL1 SEL0 These three bits select which of the eight channels is used for the conversion (Tables 3 and 4). 3 UNI/BIP 1 = unipolar, 0 = bipolar.
PAGE 13
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Simple Software Interface Digital Output Make sure the CPU’s serial interface runs in master mode so the CPU generates the serial clock. Choose a clock frequency from 100kHz to 2MHz. In unipolar-input mode, the output is straight binary (Figure 15); for bipolar inputs, the output is two’s complement (Figure 16). Data is clocked out at SCLK’s falling edge in MSB-first format.
PAGE 14
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface ••• CS tCSH tCSS tCL tCH SCLK tCSH ••• tDS tDH DIN ••• tDV tDO DOUT tTR ••• Figure 7. Detailed Serial-Interface Timing CS ••• ••• tSTR tSDV SSTRB ••• ••• tSSTRB SCLK ••• tSSTRB ••• PD0 CLOCKED IN Figure 8. External Clock Mode SSTRB Detailed Timing the next CS falling edge, SSTRB outputs a logic low. Figure 8 shows SSTRB timing in external clock mode.
PAGE 15
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface CS SCLK 1 DIN 2 3 4 SEL2 SEL1 SEL0 7 8 UNI/ SGL/ BIP DIF PD1 PD0 5 6 9 10 11 12 18 19 20 21 22 23 24 START SSTRB tCONV B11 MSB B10 DOUT ADC STATE ACQUISITION CONVERSION 1.5s 10s MAX (SCLK = 2MHz) IDLE B9 B2 B1 FILLED WITH B0 LSB ZEROS IDLE Figure 9.
PAGE 16
MAX1202/MAX1203 Figure 11a shows the serial-interface timing necessary to perform a conversion every 15 SCLK cycles in external clock mode. If CS is low and SCLK is continuous, guarantee a start bit by first clocking in 16 zeros. Most microcontrollers (μCs) require that data transfers occur in multiples of eight clock cycles; 16 clocks per conversion is typically the fastest that a μC can drive the MAX1202/MAX1203.
PAGE 17
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface CS 1 8 1 8 1 SCLK DIN S S CONTROL BYTE 0 DOUT B11 B10 B9 B8 S CONTROL BYTE 1 B7 B6 B5 B4 B3 B2 B1 B0 B11 B10 B9 B8 B7 B6 CONTROL BYTE 2 B5 B4 B3 B2 B1 B0 CONVERSION RESULT 1 CONVERSION RESULT 0 SSTRB Figure 11a.
PAGE 18
MAX1202/MAX1203 CLOCK MODE 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface INTERNAL EXTERNAL EXTERNAL SHDN SETS FAST POWER-DOWN MODE SETS EXTERNAL CLOCK MODE DIN S X X X X X 1 1 SETS EXTERNAL CLOCK MODE SX X XX X 0 1 DOUT DATA VALID (12 DATA BITS) MODE POWERED UP S XX XXX 1 1 DATA VALID (12 DATA BITS) DATA INVALID FAST POWER-DOWN FULL POWERDOWN POWERED UP POWERED UP Figure 12a. Timing Diagram for Power-Down Modes, External Clock Table 5.
PAGE 19
MAX1202/MAX1203 CLOCK MODE 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface INTERNAL CLOCK MODE SETS FULL POWER-DOWN SETS INTERNAL CLOCK MODE DIN S X X X X X 1 0 SX X XX X 0 0 DOUT S DATA VALID DATA VALID CONVERSION SSTRB CONVERSION FULL POWER-DOWN POWERED UP MODE POWERED UP Figure 12b.
PAGE 20
MAX1202/MAX1203 MAX1202/MAX1203 FAST POWER-DOWN 8 CHANNELS 100 1 CHANNEL 10 1 0 50 100 150 200 250 300 350 400 450 500 10,000 AVERAGE SUPPLY CURRENT (µA) 2ms FASTPD WAIT 400kHz EXTERNAL CLOCK INTERNAL COMPENSATION MAX186-14A FULL POWER-DOWN 1000 AVERAGE SUPPLY CURRENT (µA) 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface 8 CHANNELS 1000 100 10 CONVERSIONS PER CHANNEL PER SECOND Figure 14a. MAX1202 Supply Current vs.
PAGE 21
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface OUTPUT CODE OUTPUT CODE FULL-SCALE TRANSITION 11 . . . 111 011 . . . 111 11 . . . 110 FS = +2.048V 011 . . . 110 1LSB = +4.096V 4096 11 . . . 101 000 . . . 010 000 . . . 001 FS = +4.096V 1LSB = + 4.096V 4096 111 . . . 111 111 . . . 110 111 . . . 101 00 . . . 011 00 . . . 010 100 . . . 001 00 . . . 001 00 . . . 000 000 . . . 000 100 . . . 000 0 1 2 3 INPUT VOLTAGE (LSBs) FS (“star” ground point) at GND.
PAGE 22
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface TMS320CL3x to MAX1202/ MAX1203 Interface 3) Write an 8-bit word (1XXXXX11) to the MAX1202/ MAX1203 to initiate a conversion and place the device into external clock mode. Refer to Table 2 to select the proper XXXXX bit values for your specific application. Figure 19 shows an application circuit to interface the MAX1202/MAX1203 to the TMS320 in external clock mode. Figure 20 shows the timing diagram for this interface circuit.
PAGE 23
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Chip Information Ordering Information (continued) INL (LSB) ±1/2 PROCESS: BiCMOS PART TEMP RANGE MAX1202AEPP+ -40ºC to +85ºC PINPACKAGE 20 PDIP MAX1202BEPP+ -40ºC to +85ºC 20 PDIP ±1 MAX1202AEAP+ -40ºC to +85ºC 20 SSOP ±1/2 MAX1202BEAP+ -40ºC to +85ºC 20 SSOP ±1 MAX1203ACPP+ 0ºC to +70ºC 20 PDIP ±1/2 MAX1203BCPP+ 0ºC to +70ºC 20 PDIP ±1 MAX1203ACAP+ 0ºC to +70ºC 20 SSOP ±1/2 PACKAGE TYPE PACKAGE CO
PAGE 24
MAX1202/MAX1203 5V, 8-Channel, Serial, 12-Bit ADCs with 3V Digital Interface Package Information REVISION NUMBER REVISION DATE PAGES CHANGED 0 1/97 Initial release 1 3/97 Added MAX1203 to the data sheet 1–24 2 5/98 Corrected gain error limit 2, 20 3 3/12 Removed military grade packages and updated style throughout data sheet DESCRIPTION — 1–10, 13, 16, 18, 22, 23 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s