Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsDS1722S+T&R

DS1722

Digital Thermometer with

SPI/3-Wire Interface

www.maxim-ic.com

FEATURES

 Temperature Measurements Require No

External Components

1 of 14 022008

 Measures Temperatures from -55°C to

+120°C. Fahrenheit Equivalent is -67°F to

+248°F

 Thermometer Accuracy is ±2.0°C

 Thermometer Resolution is Configurable

from 8 to 12 bits (1.0°C to 0.0625°C

Resolution)

 Data is Read From/Written to Via a Motorola

Serial Peripheral Interface (SPI) or Standard

3-Wire Serial Interface

 Wide Analog Power Supply Range (2.65V -

5.5V)

 Separate Digital Supply Allows for 1.8V

Logic

 Available in an 8-Pin SO (150mil) and 8-Pin

μMAX package

PIN ASSIGNMENT

DDD

PIN DESCRIPTION

SERMODE - Serial Interface Mode

CE - Chip Enable

SCLK - Serial Clock

GND - Ground

DDA

- Analog Supply Voltage

SDO - Serial Data Out

SDI - Serial Data In

DDD

- Digital Supply Voltage

DESCRIPTION

The DS1722 Digital Thermometer and Thermostat with SPI/3-Wire Interface provides temperature

readings which indicate the temperature of the device. No additional components are required; the device

is truly a temperature-to-digital converter. Temperature readings are communicated from the DS1722

over a Motorola SPI interface or a standard 3-wire serial interface. The choice of interface standard is

selectable by the user.

For applications that require greater temperature resolution, the user can adjust the readout resolution

from 8 to 12 bits. This is particularly useful in applications where thermal runaway conditions must be

detected quickly.

For application flexibility, the DS1722 features a wide analog supply rail of 2.65V - 5.5V. A separate

digital supply allows a range of 1.8V to 5.5V.

The DS1722 is available in an 8-pin SO (150mil) and 8-pin μMAX package.

Applications for the DS1722 include personal computers/servers/workstations, cellular telephones, office

equipment, or any thermally-sensitive system.

SCLK

GND

DDA

DS1722S

n SO (150mil)

1 8

2 7

3 6

4 5

8-Pi

SERMODE

SDI

SDO

DS1722U

8-PIN

MAX

DDA

SERMODE

SDI

SDO

DDD

SCLK

GND

Summary of content (14 pages)

PAGE 1
DS1722 Digital Thermometer with SPI/3-Wire Interface www.maxim-ic.com FEATURES Temperature Measurements Require No External Components Measures Temperatures from -55°C to +120°C. Fahrenheit Equivalent is -67°F to +248°F Thermometer Accuracy is ±2.0°C Thermometer Resolution is Configurable from 8 to 12 bits (1.0°C to 0.0625°C Resolution) Data is Read From/Written to Via a Motorola Serial Peripheral Interface (SPI) or Standard 3-Wire Serial Interface Wide Analog Power Supply Range (2.65V 5.
PAGE 2
DS1722 ORDERING INFORMATION Table 1 PART DS1722S DS1722S/T&R MARKING DS1722 DS1722 DS1722S+ DS1722 (See note) DS1722 (See note) 1722 1722 DS1722S+T&R DS1722U DS1722U/T&R DS1722U+ DESCRIPTION DS1722 in 150mil 8-Pin SO DS1722 in 150mil 8-Pin SO, 2500 Piece Tape-andReel DS1722 in Lead-Free 150mil 8-Pin SO DS1722 in Lead-Free 150mil 8-Pin SO, 2500 Piece Tape-and-Reel DS1722 in 8-Pin µMAX DS1722 in 8-Pin µMAX, 3000 Piece Tape-andReel DS1722 in Lead-Free 8-Pin µMAX 1722 (See note) DS1722U+T&R 1722 DS1722 i
PAGE 3
DS1722 OVERVIEW A block diagram of the DS1722 is shown in Figure 1. The DS1722 consists of four major components: 1. Precision temperature sensor 2. Analog-to-digital converter 3. SPI/3-wire interface electronics 4. Data registers The factory-calibrated temperature sensor requires no external components. The DS1722 is in a powerconserving shutdown state upon power-up.
PAGE 4
DS1722 FUNCTIONAL BLOCK DIAGRAM Figure 1 DS1722 OPERATION-Measuring Temperature The core of DS1722 functionality is its direct-to-digital temperature sensor. The DS1722 measures temperature through the use of an on-chip temperature measurement technique with an operating range from -55° to +120°C. The device powers up in a power-conserving shutdown mode. After power-up, the DS1722 may be placed in a continuous conversion mode or in a one-shot conversion mode.
PAGE 5
DS1722 Temperature/Data Relationships Table 3 Address Location S 26 25 24 23 21 (unit = °C) MSb 2-1 22 2-2 2-3 2-4 0 20 02h LSb 0 0 0 01h TEMPERATURE +120°C DIGITAL OUTPUT (BINARY) 0111 1000 0000 0000 DIGITAL OUTPUT (HEX) 7800h +25.0625°C 0001 1001 0001 0000 1910h +10.125°C 0000 1010 0010 0000 0A20h +0.5°C 0000 0000 1000 0000 0080h 0°C 0000 0000 0000 0000 0000h -0.5°C 1111 1111 1000 0000 FF80h -10.125°C 1111 0101 1110 0000 F5E0h -25.
PAGE 6
DS1722 CONFIGURATION/STATUS REGISTER Figure 2 1 MSb 1 1 1SHOT R2 R1 R0 SD LSb 1SHOT = One-shot temperature conversion bit. If the SD bit is "1", (continuous temperature conversions are not taking place), a "1" written to the 1SHOT bit will cause the DS1722 to perform one temperature conversion and store the results in the temperature register at addresses 01h (LSB) and 02h (MSB). The bit will clear itself to "0" upon completion of the temperature conversion.
PAGE 7
DS1722 inactive clock is determined by sampling SCLK when CE becomes active. Therefore, either SCLK polarity can be accommodated. Input data (SDI) is latched on the internal strobe edge and output data (SDO) is shifted out on the shift edge (See Table 6 and Figure 3). There is one clock for each bit transferred. Address and data bits are transferred in groups of eight, MSB first.
PAGE 8
DS1722 SPI SINGLE BYTE WRITE Figure 4 SPI SINGLE-BYTE READ Figure 5 The address byte is always the first byte entered after CE is driven high. The most significant bit (A7) of this byte determines if a read or write will take place. If A7 is "0", one or more read cycles will occur. If A7 is "1", one or more write cycles will occur. Data transfers can occur 1 byte at a time in multiple-byte burst mode. After CE is driven high an address is written to the DS1722.
PAGE 9
DS1722 3-WIRE SERIAL DATA BUS The 3-wire communication mode operates similar to the SPI mode. However, in 3-wire mode, there is one bi-directional I/O instead of separate data in and data out signals. The 3-wire consists of the I/O (SDI and SDO pins tied together), CE, and SCLK pins. In 3-wire mode, each byte is shifted in LSB first unlike SPI mode where each byte is shifted in MSB first.
PAGE 10
DS1722 ABSOLUTE MAXIMUM RATINGS* Voltage on V DD , Relative to Ground Voltage on any other pin, Relative to Ground Operating Temperature Storage Temperature Soldering Temperature -0.3V to +6.0V -0.3V to +6.0V -55°C to +125°C -55°C to +125°C 260°C for 10 seconds * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied.
PAGE 11
DS1722 ELECTRICAL CHARACTERISTICS: DIGITAL THERMOMETER (-55°C to +120°C, 2.65V ≤ VDDA ≤ 5.5V) PARAMETER Thermometer Error Resolution Conversion Time SYMBOL TERR CONDITION -40°C to +85°C -55°C to +120°C MIN TYP 8 tCONVT 8-bit conversions 9-bit conversions 10-bit conversions 11-bit conversions 12-bit conversions 67.5 125 250 500 1000 MAX UNITS NOTES °C ±2.0 ±3.0 12 bits ms 75 150 300 600 1200 AC ELECTRICAL CHARACTERISTICS: 3-WIRE INTERFACE (-55°C to +120°C, 2.65V ≤ VDD ≤ 5.
PAGE 12
TIMING DIAGRAM: 3-WIRE WRITE DATA TRANSFER Figure 10 DS1722 *I/O is SDI and SDO tied together. AC ELECTRICAL CHARACTERISTICS: SPI Interface (-55°C to +120°C, 2.65V ≤ VDD ≤ 5.5V) PARAMETER Data to SCLK Setup SCLK to Data Hold SCLK to Data Valid SCLK Low Time SCLK High Time SCLK Frequency SCLK Rise and Fall CE to SCLK Setup SCLK to CE Hold CE Inactive Time CE to Output High Z SYMBOL tDC tCDH tCDD tCL tCH tCLK tR, tF tCC tCCH tCWH tCDZ CONDITION MIN 35 35 TYP MAX 80 100 100 DC 5.
PAGE 13
TIMING DIAGRAM: SPI WRITE DATA TRANSFER Figure 12 DS1722 *SCLK can be either polarity, timing shown for CPOL = 1. NOTES: 1. All voltages are referenced to ground. 2. Logic 0 voltages are specified at a sink current of 3 mA. 3. Logic 1 voltages are specified at a source current of 1 mA. 4. ICC specified with SCLK=VDDD and CE=GND. Typical ICC1 is 0.25 µA and ICC is 0.3 mA at 25°C and VDDD = 2.65V. 5. Measured at VIH =0.7 VDDD or VIL=0.2 VDDD and 10 ms maximum rise and fall time. 6.
PAGE 14
DS1722 TYPICAL DS1722 THERMOMETER ERROR 2 1.75 1.5 1.25 1 +3σ 0.75 Error(C) 0.5 Mean 0.25 0 -0.25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 -0.5 -0.75 -1 -1.25 -1.5 -1.75 -2 Ref Temp(C) REVISION HISTORY REVISION DATE 052307 103007 022008 DESCRIPTION Initial release. Various changes. Deleted all references to flip-chip package. 14 of 14 PAGES CHANGED 1, 2, 11, 13, 14.