Specifications

ManualsBrandsADC ManualsPower Supply10

________________General Description

The MAX192 is a low-cost, 10-bit data-acquisition system

that combines an 8-channel multiplexer, high-bandwidth

track/hold, and serial interface with high conversion

speed and ultra-low power consumption. The device

operates with a single +5V supply. The analog inputs are

software configurable for single-ended and differential

(unipolar/bipolar) operation.

The 4-wire serial interface connects directly to SPI™,

QSPI™, and Microwire™ devices, without using external

logic. A serial strobe output allows direct connection to

TMS320 family digital signal processors. The MAX192

uses either the internal clock or an external serial-

interface clock to perform successive approximation A/D

conversions. The serial interface can operate beyond

4MHz when the internal clock is used. The MAX192 has

an internal 4.096V reference with a drift of ±30ppm typi-

cal. A reference-buffer amplifier simplifies gain trim and

two sub-LSBs reduce quantization errors.

The MAX192 provides a hardwired SHDN pin and two

software-selectable power-down modes. Accessing the

serial interface automatically powers up the device, and

the quick turn-on time allows the MAX192 to be shut

down between conversions. By powering down

between conversions, supply current can be cut to

under 10µA at reduced sampling rates.

The MAX192 is available in 20-pin DIP and SO pack-

ages, and in a shrink-small-outline package (SSOP)

that occupies 30% less area than an 8-pin DIP. The

data format provides hardware and software compati-

bility with the MAX186/MAX188. For anti-aliasing filters,

consult the data sheets for the MAX291–MAX297.

________________________Applications

Automotive

Pen-Entry Systems

Consumer Electronics

Portable Data Logging

Robotics

Battery-Powered Instruments, Battery

Management

Medical Instruments

____________________________Features

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

Inputs

♦ Single +5V Operation

♦ Low Power: 1.5mA (operating)

2µA (power-down)

♦ Internal Track/Hold, 133kHz Sampling Rate

♦ Internal 4.096V Reference

♦ 4-Wire Serial Interface is Compatible

with SPI, QSPI, Microwire, and TMS320

♦ 20-Pin DIP, SO, SSOP Packages

♦ Pin-Compatible 12-Bit Upgrade (MAX186/MAX188)

_______________Ordering Information

MAX192

Low-Power, 8-Channel,

Serial 10-Bit ADC

________________________________________________________________ Maxim Integrated Products

TOP VIEW

DIP/SO/SSOP

SCLK

DIN

SSTRB

DOUT

DGND

AGND

REFADJ

VREFSHDN

AGND

CH7

CH6

CH5

CH4

CH3

CH2

CH1

CH0

MAX192

___________________Pin Configuration

SPI and QSPI are trademarks of Motorola Corp.

Microwire is a trademark of National Semiconductor Corp.

19-0247; Rev. 1; 4/97

PART TEMP. RANGE

MAX192ACPP 0°C to +70°C

MAX192BCPP 0°C to +70°C

MAX192ACWP 0°C to +70°C 20 Wide SO

20 Plastic DIP

PIN-PACKAGE

MAX192BCWP 0°C to +70°C 20 Wide SO

MAX192ACAP 0°C to +70°C 20 SSOP

MAX192BCAP 0°C to +70°C 20 SSOP

±1/2

±1

±1/2

INL (LSB)

±1

±1/2

±1

MAX192AEPP -40°C to +85°C 20 Plastic DIP ±1/2

MAX192BEPP -40°C to +85°C 20 Plastic DIP ±1

MAX192AEWP -40°C to +85°C 20 Wide SO ±1/2

MAX192BEWP -40°C to +85°C 20 Wide SO ±1

MAX192AEAP -40°C to +85°C 20 SSOP ±1/2

MAX192BEAP -40°C to +85°C 20 SSOP ±1

MAX192AMJP -55°C to +125°C 20 CERDIP ±1/2

MAX192BMJP -55°C to +125°C 20 CERDIP ±1

See last page for Typical Operating Circuit.

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

For small orders, phone 408-737-7600 ext. 3468.

Summary of content (24 pages)

PAGE 1
9-0247; Rev. 1; 4/97 Low-Power, 8-Channel, Serial 10-Bit ADC The MAX192 is a low-cost, 10-bit data-acquisition system that combines an 8-channel multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and ultra-low power consumption. The device operates with a single +5V supply. The analog inputs are software configurable for single-ended and differential (unipolar/bipolar) operation.
PAGE 2
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC ABSOLUTE MAXIMUM RATINGS VDD to AGND........................................................... -0.3V to +6V AGND to DGND.................................................... -0.3V to +0.3V CH0–CH7 to AGND, DGND ...................... -0.3V to (VDD + 0.3V) CH0–CH7 Total Input Current.......................................... ±20mA VREF to AGND .......................................... -0.3V to (VDD + 0.3V) REFADJ to AGND......................................
PAGE 3
Low-Power, 8-Channel, Serial 10-Bit ADC (VDD = 5V ±5%, fCLK = 2.0MHz, external clock (50% duty cycle), 15 clocks/conversion cycle (133ksps), 4.7µF capacitor at VREF pin, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL External Clock Frequency CONDITIONS MIN External compensation, 4.7µF 0.1 Internal compensation (Note 5) 0.1 Used for data transfer only TYP MAX UNITS 2.0 0.
PAGE 4
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC ELECTRICAL CHARACTERISTICS (continued) (VDD = 5V ±5%, fCLK = 2.0MHz, external clock (50% duty cycle), 15 clocks/conversion cycle (133ksps), 4.7µF capacitor at VREF pin, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 5
Low-Power, 8-Channel, Serial 10-Bit ADC (VDD = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN Acquisition Time tAZ 1.
PAGE 6
Low-Power, 8-Channel, Serial 10-Bit ADCs MAX192 Pin Description PIN NAME FUNCTION 1–8 CH0–CH7 9, 13 AGND Analog Ground. Also IN- Input for single-enabled conversions. Connect both AGND pins to analog ground. 10 SHDN Three-Level Shutdown Input. Pulling SHDN low shuts the MAX192 down to 10µA (max) supply current, otherwise the MAX192 is fully operational. Pulling SHDN high puts the reference-buffer amplifier in internal compensation mode.
PAGE 7
Low-Power, 8-Channel, Serial 10-Bit ADC 18 19 DIN 17 SHDN 10 CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7 1 AGND AGND 13 MAX192 CS SCLK CAPACITIVE DAC 2 3 4 5 6 INPUT SHIFT REGISTER CONTROL LOGIC OUTPUT SHIFT REGISTER ANALOG INPUT MUX REFADJ 12 VREF 11 15 16 DOUT SSTRB T/H OUT 20k A ≈ 1.65 +4.096V CH3 20 14 VDD DGND MAX192 CH6 CH7 COMPARATOR CHOLD INPUT MUX – + ZERO 16pF 10k RS CH2 CH5 REF +2.
PAGE 8
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC Track/Hold The T/H enters its tracking mode on the falling clock edge after the fifth bit of the 8-bit control word has been shifted in. The T/H enters its hold mode on the falling clock edge after the eighth bit of the control word has been shifted in. If the converter is set up for single-ended inputs, IN- is connected to AGND, and the converter samples the “+” input.
PAGE 9
Low-Power, 8-Channel, Serial 10-Bit ADC MAX192 Table 2. Channel Selection in Differential Mode (SGL/DIF = 0) SEL2 SEL1 SEL0 CH0 CH1 0 0 0 + – 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 – CH2 CH3 + – CH4 CH5 + – CH6 CH7 + – – + + – + – + Table 3.
PAGE 10
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC Table 4a. Unipolar Full Scale and Zero Scale ZERO SCALE FULL SCALE 0V +4.096V at REFADJ 0V VREFADJ (1.678) at VREF 0V VREF REFERENCE Internal Reference External Reference Example: Simple Software Interface 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. 1) 2) Set up the control byte for external clock mode, call it TB1.
PAGE 11
Low-Power, 8-Channel, Serial 10-Bit ADC MAX192 VDD +5V OSCILLOSCOPE 0.1µF DGND AGND AGND MAX192 0V TO 4.096V ANALOG 0.01µF INPUT SCLK SSTRB CH7 CS DOUT* SCLK +5V DIN 2MHz OSCILLATOR CH1 CH2 CH3 CH4 DOUT C2 0.01µF REFADJ SSTRB VREF SHDN N.C. C1 4.7µF +2.5V +2.5V REFERENCE ** * FULL-SCALE ANALOG INPUT, CONVERSION RESULT = $FFF (HEX) **OPTIONAL. A POTENTIOMETER MAY BE USED IN PLACE OF THE REFERENCE FOR TEST PURPOSES. Figure 5.
PAGE 12
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC CS tACQ SCLK 1 4 8 12 16 RB1 DIN UNI/ BIP START SEL2 SEL1 SEL0 20 RB2 SGL/ DIF PD1 24 RB3 PD0 SSTRB B9 MSB B8 B7 ACQUISITION IDLE A/D STATE RB3 RB2 RB1 DOUT B6 B5 B4 B3 B2 B1 B0 LSB S1 SO FILLED WITH ZEROS CONVERSION IDLE 1.5µs (CLK = 2MHz) Figure 6.
PAGE 13
Low-Power, 8-Channel, Serial 10-Bit ADC ••• tSTR tSDV SSTRB ••• ••• tSSTRB tSSTRB •• • • SCLK MAX192 ••• CS •••• PD0 CLOCKED IN Figure 8. External Clock Mode SSTRB Detailed Timing CS SCLK DIN 1 2 3 4 5 START SEL2 SEL1 SEL0 UNI/ BIP 7 8 SGL/ PD1 DIF PD0 6 9 10 11 12 18 19 20 21 22 23 24 SSTRB tCONV B9 MSB DOUT A/D STATE IDLE ACQUISITION CONVERSION 10µs MAX B8 B7 B0 LSB S1 S0 FILLED WITH ZEROS IDLE 1.5µs (CLK = 2MHz) Figure 9.
PAGE 14
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC CS tCONV tCSS tSCK tCSH SSTRB tSSTRB SCLK PD0 CLOCK IN NOTE: FOR BEST NOISE PERFORMANCE, KEEP SCLK LOW DURING CONVERSION. Figure 10. Internal Clock Mode SSTRB Detailed Timing CS 1 8 1 8 1 SCLK S DIN CONTROL BYTE 0 S CONTROL BYTE 2 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 S1 S0 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 S1 S0 DOUT S CONTROL BYTE 1 CONVERSION RESULT 1 CONVERSION RESULT 0 SSTRB Figure 11a.
PAGE 15
Low-Power, 8-Channel, Serial 10-Bit ADC INTERNAL MAX192 CLOCK MODE EXTERNAL EXTERNAL SHDN SETS FAST POWER-DOWN MODE SETS EXTERNAL CLOCK MODE DIN S X X X X X 1 1 DOUT S X X X X X 0 1 S X X X X X 1 1 DATA VALID (10 + 2 DATA BITS) DATA VALID (10 + 2 DATA BITS) POWERED UP MODE SETS EXTERNAL CLOCK MODE FAST POWER-DOWN VALID DATA INVALID POWERED UP POWERED UP FULL POWERDOWN Figure 12a.
PAGE 16
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC Table 5. Worst-Case Power-Up Delay Times Reference Buffer ReferenceBuffer Compensation Mode VREF Capacitor (µF) PowerDown Mode Power-Up Delay (sec) Maximum Sampling Rate (ksps) Enabled Internal Fast 5µ 26 Enabled Internal Enabled External 4.7 Full 300µ 26 Fast See Figure 14c 133 Enabled External 4.7 Full See Figure 14c 133 Disabled Fast 2µ 133 Disabled Full 2µ 133 Table 6.
PAGE 17
Low-Power, 8-Channel, Serial 10-Bit ADC MAX192 COMPLETE CONVERSION SEQUENCE 2ms WAIT CH1 (ZEROS) DIN 1 00 1 FULLPD 01 1 11 FASTPD (ZEROS) CH7 1 00 NOPD 1 FULLPD 01 FASTPD 2.5V REFADJ 0V τ = RC = 20kΩ x CREFADJ 4V VREF 0V tBUFFEN ≈ 15µs Figure 13. FULLPD/FASTPD Power-Up Sequence FULL POWER-DOWN FAST POWER-DOWN 8 CHANNELS 100 1 CHANNEL 10 2ms FASTPD WAIT 400kHz EXTERNAL CLOCK INTERNAL COMPENSATION 1 MAX192-14B MAX192-14A 10,000 AVG. SUPPLY CURRENT (µA) AVG.
PAGE 18
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC OUTPUT CODE OUTPUT CODE FULL-SCALE TRANSITION 11 . . . 111 011 . . . 111 11 . . . 110 011 . . . 110 11 . . . 101 000 . . . 010 FS = +4.096 2 1LSB = +4.096 1024 000 . . . 001 FS = +4.096V 1LSB = FS 1024 000 . . . 000 111 . . . 111 111 . . . 110 111 . . . 101 00 . . . 011 00 . . . 010 100 . . . 001 00 . . . 001 100 . . . 000 00 . . .
PAGE 19
Low-Power, 8-Channel, Serial 10-Bit ADC MAX192 +5V SUPPLIES MAX192 +5V GND 510k 100k 12 REFADJ R* = 10Ω 0.01µF 24k VDD AGND MAX192 DGND +5V DGND DIGITAL CIRCUITRY * OPTIONAL Figure 17. Reference-Adjust Circuit Figure 18. Power-Supply Grounding Connection Layout, Grounding, Bypassing High-Speed Digital Interfacing For best performance, use printed circuit boards. Wire-wrap boards are not recommended.
PAGE 20
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC +5V VDDI, VDDE, VDDSYN, VSTBY ANALOG INPUTS 1 CH0 VDD 20 2 CH1 SCLK 19 3 CH2 CS 18 4 CH3 5 CH4 SSTRB 16 6 CH5 DOUT 15 7 CH6 DGND 14 8 CH7 AGND 13 9 AGND REFADJ 12 10 SHDN VREF 11 MAX192 0.1µF 4.7µF SCK PCS0 DIN 17 MC68HC16 MOSI MISO 0.01µF 0.1µF + 4.7µF VSSI VSSE * CLOCK CONNECTIONS NOT SHOWN Figure 19.
PAGE 21
Low-Power, 8-Channel, Serial 10-Bit ADC INITQSPI: ;This routine sets up the QSPI microsequencer to operate on its own. ;The sequencer will read all eight channels of a MAX192 each time ;it is triggered. The A/D converter results will be left in the ;receive data RAM. Each 16 bit receive data RAM location will ;have a leading zero, 10 + 2 bits of conversion result and three zeros.
PAGE 22
MAX192 Low-Power, 8-Channel, Serial 10-Bit ADC LDD #$0800 STD SPCR2 ;set ENDQP to $8 for 9 transfers ***** Initialize QSPI Command RAM ***** LDAA #$80 ;CONT=1,BITSE=0,DT=0,DSCK=0,PCS0=ACTIVE STAA $FD40 ;store first byte in COMMAND RAM LDAA #$C0 ;CONT=1,BITSE=1,DT=0,DSCK=0,PCS0=ACTIVE STAA $FD41 STAA $FD42 STAA $FD43 STAA $FD44 STAA $FD45 STAA $FD46 STAA $FD47 LDAA #$40 ;CONT=0,BITSE=1,DT=0,DSCK=0,PCS0=ACTIVE STAA $FD48 ***** Initialize QSPI Transmit RAM ***** LDD #$008F LDD #$00CF LDD #$009F LDD #$0
PAGE 23
Low-Power, 8-Channel, Serial 10-Bit ADC MAX192 CS •••• •••• SCLK •••• SSTRB DIN •••• Figure 21. QSPI Assembly-Code Timing CS XF SCLK CLKX TMS320 MAX192 CLKR DX DIN DR DOUT FSR SSTRB Figure 22. MAX192 to TMS320 Serial Interface CS SCLK DIN START SEL2 SEL1 SEL0 UNI/BIP SGL/DIF PD1 PD0 HIGH IMPEDANCE SSTRB DOUT MSB B10 S1 S0 HIGH IMPEDANCE Figure 23.
PAGE 24
Low-Power, 8-Channel, Serial 10-Bit ADC MAX192 Typical Operating Circuit Chip Information TRANSISTOR COUNT: 2278 +5V CH0 0V to 4.096V ANALOG INPUTS VDD VDD DGND AGND C3 0.1µF C4 0.1µF CPU CH7 MAX192 AGND CS SCLK VREF C1 4.7µF DIN DOUT REFADJ C2 0.01µF I/O SCK (SK)* MOSI (SO) MISO (SI) SSTRB SHDN VSS SSOP.EPS Package Information Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.