Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsData collecting ICsData acquisition IC - AD converter (ADC) External , Internal TSSOP 16

General Description

The MAX1253/MAX1254 are stand-alone, 10-channel (8

external, 2 internal) 12-bit system monitor ADCs with

internal reference. A programmable single-ended/dif-

ferential mux accepts voltage and remote-diode tem-

perature-sensor inputs. These devices independently

monitor the input channels without microprocessor

interaction and generate an interrupt when any variable

exceeds user-defined limits. The MAX1253/MAX1254

configure both high and low limits, as well as the num-

ber of fault cycles allowed, before generating an inter-

rupt. These ADCs can also perform recursive data

averaging for noise reduction. Programmable wait inter-

vals between conversion sequences allow the selection

of the sample rate.

At the maximum sampling rate of 94ksps (auto mode,

single channel enabled), the MAX1253 consumes only

5mW (1.7mA at 3V). AutoShutdown

reduces supply

current to 190µA at 2ksps and to less than 8µA at 50sps.

Stand-alone operation, combined with ease of use in a

small package (16-pin TSSOP), makes the MAX1253/

MAX1254 ideal for multichannel system-monitoring

applications. Low power consumption also makes

these devices a good fit for hand-held and battery-pow-

ered applications.

Applications

System Supervision

Remote Telecom Networks

Server Farms

Remote Data Loggers

Features

♦ Monitor 10 Signals Without Processor

Intervention

♦ Eight External Channels Programmable as

Temperature or Voltage Monitors

♦ Intelligent Circuitry for Reliable Autonomous

Measurement

Programmable Digital Averaging Filter

Programmable Fault Counter

♦ Precision Measurements

12-Bit Resolution

±1 LSB INL, ±1 LSB DNL

±0.75°C Temperature Accuracy (typ)

♦ Flexible

Automatic Channel Scan Sequencer with

Programmable Intervals

Programmable Inputs: Single Ended/Differential,

Voltage/Temperature

Programmable Wait State

♦ Internal 2.5V/4.096V Reference

(MAX1253/MAX1254)

♦ Remote Temperature Sensing Up to 10m

(Differential Mode)

♦ Single 3V or 5V Supply Operation

♦ Small 16-Pin TSSOP Package

MAX1253/MAX1254

Stand-Alone, 10-Channel, 12-Bit System Monitors

with Internal Temperature Sensor and V

Monitor

________________________________________________________________ Maxim Integrated Products 1

Selector Guide

19-2838; Rev 0; 4/03

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.

*Future product—contact factory for availability.

Typical Application Circuit appears at end of data sheet.

AutoShutdown is a trademark of Maxim Integrated Products, Inc.

PART INL (LSB)

TEMP

ERROR (°C)

SUPPLY

VOLTAGE (V)

MAX1253AEUE*

±1 ±1.0

2.7 to 3.6

MAX1253BEUE

±1 ±3.0

2.7 to 3.6

MAX1254AEUE*

±1 ±1.0

4.5 to 5.5

MAX1254BEUE

±1 ±2.5

4.5 to 5.5

AIN0

SCLK

DIN

GND

DOUT

INT

REF

TOP VIEW

MAX1253

MAX1254

16 TSSOP

AIN1

AIN2

AIN5

AIN3

AIN4

AIN6

AIN7

Pin Configuration

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX1253AEUE* -40°C to +85°C

16 TSSOP

MAX1253BEUE -40°C to +85°C

16 TSSOP

MAX1254AEUE* -40°C to +85°C

16 TSSOP

MAX1254BEUE -40°C to +85°C

16 TSSOP

Summary of content (29 pages)

PAGE 1
9-2838; Rev 0; 4/03 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Stand-alone operation, combined with ease of use in a small package (16-pin TSSOP), makes the MAX1253/ MAX1254 ideal for multichannel system-monitoring applications. Low power consumption also makes these devices a good fit for hand-held and battery-powered applications.
PAGE 2
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor ABSOLUTE MAXIMUM RATINGS VDD to GND .............................................................-0.3V to +6V Analog Inputs to GND (AIN0–AIN7, REF) ... -0.3V to (VDD + 0.3V) Digital Inputs to GND (DIN, SCLK, CS) .... -0.3V to (VDD + 0.3V) Digital Outputs to GND (DOUT, INT) ........ -0.3V to (VDD + 0.3V) Digital Outputs Sink Current .............................................
PAGE 3
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor (VDD = +2.7V to +3.6V (MAX1253), VDD = +4.5V to +5.5V (MAX1254), VREF = +2.5V (MAX1253), VREF = +4.096V (MAX1254), fSCLK = 10MHz (50% duty cycle), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor ELECTRICAL CHARACTERISTICS (continued) (VDD = +2.7V to +3.6V (MAX1253), VDD = +4.5V to +5.5V (MAX1254), VREF = +2.5V (MAX1253), VREF = +4.096V (MAX1254), fSCLK = 10MHz (50% duty cycle), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 5
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor (VDD = +2.7V to +3.6V (MAX1253), VDD = +4.5V to +5.5V (MAX1254), TA = TMIN to TMAX, unless otherwise noted.) (Figures 1, 2, and 4) MIN TYP SCLK Clock Period PARAMETER SYMBOL tCP CONDITIONS 100 0.
PAGE 6
Typical Operating Characteristics (VDD = +3V, VREF = 2.5V (MAX1253); VDD = 5V, VREF = 4.096V (MAX1254); fSCLK = 10MHz, CREF = 0.1µF, TA = +25°C, unless otherwise noted.) 0.6 0.2 0.2 0 -0.2 0 -0.2 -0.4 -0.4 -0.6 -0.6 -0.8 -0.8 -1.0 -1.0 1024 2048 3072 4096 2.505 2.504 2.503 2.502 2.501 2.500 1024 0 2048 3072 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 4096 INTERNAL REFERENCE VOLTAGE vs. SUPPLY VOLTAGE REFERENCE VOLTAGE vs. TEMPERATURE REFERENCE VOLTAGE vs. TEMPERATURE 4.077 2.
PAGE 7
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor 9 VOLTAGE CHANNELS AND 1 TEMPERATURE CHANNEL 3.5 3.1 2.5 2.4 2.7 2.3 2.3 2.2 2.1 1.9 1.8 1.6 3.1 3.5 3.9 4.3 4.7 5.1 5.5 2.0 5 20 35 50 65 80 -40 -25 -10 5 20 35 50 65 600 500 400 300 200 100 MAX1253 VDD = 3V 0.80 3.5 3.9 4.3 4.7 5.1 0.60 OFFSET ERROR 0.40 0.20 0 MAX1253 -0.20 MAX1254 -0.40 GAIN ERROR -0.60 -1.00 -40 -25 -10 5.5 SINGLE ENDED -0.80 0 3.
PAGE 8
Typical Operating Characteristics (continued) (VDD = +3V, VREF = 2.5V (MAX1253); VDD = 5V, VREF = 4.096V (MAX1254); fSCLK = 10MHz, CREF = 0.1µF, TA = +25°C, unless otherwise noted.) EXTERNAL TEMPERATURE SENSOR TEMPERATURE ERROR 1.2 0 -0.4 -0.8 -1.6 -2 -3 -4 EXTERNAL SENSOR, SINGLE-ENDED INPUT EXTERNAL DIODE DIFFERENTIAL TEMPERATURE MEASUREMENT MODE -5 -2.0 -6 -20 0 20 40 60 80 10 1 100 1000 TEMPERATURE (°C) INTERCONNECT CAPACITANCE (pF) SAMPLING ERROR vs.
PAGE 9
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor VDD REF REFERENCE INPUT CHANNEL REGISTER TEMP SENSOR INPUT CONFIGURATION REGISTER MAX1253 MAX1254 STEP-UP REGISTER ALARM REGISTER 12-BIT ADC WITH T/H AIN1 DOUT AIN2 MUX AIN3 SERIAL INTERFACE AIN4 SCAN AND CONVERSION CONTROL AIN5 AIN6 AIN7 POR INTERNAL TEMP VDD/2 AIN0 DIN SCLK CS AVERAGING DIGITAL COMPARATOR POWERGOOD AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 INT AIN7 ACCUMULATOR ACCUMULATOR ACCUMU
PAGE 10
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor VDD VDD 100nA DOUT 100nA DOUT 100nA DOUT CLOAD = 100pF GND a) VOL TO VOH CLOAD = 100pF GND b) HIGH-Z TO VOL AND VOH TO VOL Figure 1. Load Circuits for DOUT Enable Time and SCLK to DOUT Delay Time Detailed Description The MAX1253/MAX1254 are precision-monitoring integrated circuit systems specifically intended for standalone operation.
PAGE 11
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor MAX1253/MAX1254 VDD AIN0 INPUT REGISTERS AIN1 UPPER THRESHOLD CURRENT DATA LOWER THRESHOLD AIN2 AIN3 # FAULT CYCLES MUX 12-BIT ADC WITH T/H AVERAGE DIGITAL COMPARATOR INT CONFIGURATION/ STATUS REGISTERS AIN4 AIN5 SCAN AND CONVERSION CONTROL AIN6 AIN7 SERIAL INTERFACE TEMP SENSE DIN DOUT SCLK CS Figure 3.
PAGE 12
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor INCREMENT CHANNEL COUNTER IS CHANNEL ENABLED? NO YES SAMPLE CHANNEL CONVERT CHANNEL AVERAGE CONVERTED CHANNEL DATA INCREMENT FAULT COUNTER YES SAME FAULT AS PREVIOUS? NO RESET FAULT COUNTER IS AVG DATA > UPPER? YES YES NO IS AVG DATA < LOWER? NO IS FAULT CNT > FAULT REG? NO YES SET ALARM REGISTER Figure 4.
PAGE 13
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor VDD T T CHOLDP 8-TO-1 DIFFERENTIAL MUX MAX1253/MAX1254 VDD CHOLD ADC H 8-TO-1 DIFFERENTIAL MUX ADC H CHOLDN T T T H T H H TEMP TEMP VAZ DIFFERENTIAL INPUT EQUIVALENT INPUT CIRCUIT VAZ SINGLE-ENDED INPUT EQUIVALENT INPUT CIRCUIT Figure 5.
PAGE 14
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor CS tCSW tCSS tCH tCL tCSH tCP SCLK tDS tDH DIN tDOV HIGH-Z tDOD HIGH-Z tDOE DOUT Figure 6. Detailed Serial Interface Timing Diagram Clock pulses on SCLK shift data into DIN on the rising edge of the SCLK and out of DOUT on the falling edge of SCLK. Data transfers require a logic low on CS. A high-to-low transition of CS marks the beginning of a data transfer.
PAGE 15
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor COMMAND WORD MAX1253/MAX1254 Table 2.
PAGE 16
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Read Alarm Register (Command Code 0001) Read Current Data Register for All Channels (Command Code 0011) The Read Alarm Register command, 0001, outputs the current status of the alarm register (see Table 11). The address bits in this command are ignored. The alarm register is 24 bits long and outputs in 3 bytes. Table 12 illustrates the encoding of the alarm register.
PAGE 17
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Clear Alarm Register for All Channels (Command Code 1001) The Read Global Configuration Register command, 0101, outputs the global configuration registers. The address bits following this command are ignored.
PAGE 18
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Write-Selected Channel Configuration Registers (Command Code 1100) The Write-Selected Channel Configuration Register command, 1100, writes to the three channel configuration registers for the addressed channel (see Table 3).
PAGE 19
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Setup Register: Sample Wait Bits (B7, B6, B5) These 3 bits in the setup register (Table 8) set the wait time between conversion scans. The following are examples of how the MAX1253/MAX1254 begin a sample sequence (see the Setup Register: Reference Selection Bits (B1, B0) section).
PAGE 20
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Setup Register: Scan Mode Bit (B2) The scan mode bit selects between automatic scanning and manual conversion mode. When set (B2 = 1), the MAX1253/MAX1254 enter automatic scanning mode and convert every enabled channel starting with the internal temperature sensor, followed by the VDD monitor, then sequencing through AIN0 to AIN7.
PAGE 21
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor B7 (MSB) B6 B5 B4 B3 B2 B1 B0 (LSB) Fault B3 Fault B2 Fault B1 Fault B0 Ave B3 Ave B2 Ave B1 Ave B0 Table 14. Conversion Average Encoding CODE N 0000 1, no averaging 0001 2 0010 4 0011 8 0100 16 0101 32 fault occurs and the next scan finds the input within the normal range defined by the thresholds, the fault counter resets.
PAGE 22
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Upper Threshold Register A conversion result greater than the value stored in the upper threshold register results in a fault, increasing the internal fault counter by one. When the fault count exceeds the value stored in fault bits B7–B4 of the channel configuration register, the channel’s alarm bits in the alarm register are set, resulting in an interrupt on INT.
PAGE 23
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor VDD value can be calculated from the digitized data with the following equation: 1) Disable autoscan (set up register scan mode bit to zero), if necessary. 2) Pull CS low. V  VDD = 2 x (current _ data _ register _ content) x  REF   4096  3) Initiate a conversion by issuing a Manually Triggered Conversion command (0000, followed by the address bits of the channel to be converted).
PAGE 24
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor The temperature measurement process is fully automated in the MAX1253/MAX1254. All steps are sequenced and executed by the MAX1253/MAX1254 each time an input channel (or an input channel pair) configured for temperature measurement is scanned. The resulting 12-bit, two’s complement number represents the sensor temperature in degrees Celsius, with 1 LSB = +0.125°C.
PAGE 25
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Input Configuration Register Power-Up/Reset Defaults At power-on or after a RESET command, the input configuration register resets to 00 hex, configuring AIN0–AIN7 for single-ended voltage measurement. Alarm Register Power-Up/Reset Defaults At power-on or after a RESET command, the alarm register is reset to 000000 hex, indicating that no alarm condition exists.
PAGE 26
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Automatic Reference Shutdown The MAX1253/MAX1254 enter an automatic shutdown mode when in reference mode 00 or when the sample wait is greater than 80µs in reference mode 01. Using either of these reference modes and a sample wait period as long as the application allows results in the lowest power consumption.
PAGE 27
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor 011....111 011....110 000....010 000....001 000....000 111....111 FS = VREF 2 011....111 011....110 ZS = 0 -V -FS = REF 2 V 1 LSB = REF 4096 000....010 000....001 000....000 111....111 111....110 111....101 111....110 111....101 100....001 100....000 100....001 100....000 -FS MAX1253/MAX1254 OUTPUT CODE OUTPUT CODE 0 +FS - 1 LSB INPUT VOLTAGE (LSB) Figure 11.
PAGE 28
MAX1253/MAX1254 Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor Gain Error The gain error is the difference between the ideal and actual value of the analog input difference between the first and last transitions of the ADC output. The first transition is from digital code 0 to code 1, and the last from code (2N-2) to code (2N-1), where N = number of ADC bits for straight binary output code.
PAGE 29
Stand-Alone, 10-Channel, 12-Bit System Monitors with Internal Temperature Sensor and VDD Monitor POWER SUPPLY +V -5V +5V µC +3V VDD VREF REFERENCE GLOBAL REGISTERS TEMP SENSOR INT SPI INTERFACE AIN0 SPI I/F ADC AIN1 DIGITAL BLOCK 48V AIN2 AIN3 AIN4 MUX MAX1253 MAX1254 AIN5 AIN6 CHANNEL REGISTERS AIN7 GND REMOTE TEMP Chip Information TRANSISTOR COUNT: 89,473 PROCESS: 0.