DS1920-F5+ Maxim Integrated Products, DS1920-F5+ Datasheet
DS1920-F5+
Specifications of DS1920-F5+
Related parts for DS1920-F5+
DS1920-F5+ Summary of contents
Page 1
... Measurements Simultaneously for All Devices on the Bus 2 Bytes of EEPROM to Be Used Either as Alarm Triggers or User Memory Alarm Search Directly Indicates Which Device Senses Alarming Temperatures ORDERING INFORMATION PART PIN-PACKAGE DS1920-F5+ + Denotes a lead(Pb)-free/RoHS-compliant package. F5 MicroCAN 5.89 0.51 A0 000000FBC52B ...
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... One control function command instructs the DS1920 to perform a temperature measurement. The result of this measurement will be placed in the DS1920’s scratchpad memory, and may be read by issuing a memory function command, which reads the contents of the scratchpad memory. The temperature alarm triggers TH and TL consist of 1 byte of EEPROM each ...
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... This problem is particularly acute if several DS1920s are on the same data line and attempting to convert simultaneously. The way to assure that the DS1920 has sufficient supply current is to provide a strong pullup on the data line whenever temperature conversion or copying to the EEPROM is taking place. This may be accomplished by using a MOSFET to connect the data line directly to the power supply as shown in Figure 2. The data line must be switched over to the strong pullup within 10µ ...
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... The DS1920 can measure temperature over the range of -55°C to +100°C in 0.5°C increments. For Fahrenheit usage, a lookup table or conversion factor must be used. Note that temperature is represented in the DS1920 in terms of a 1/2°C LSB, yielding the following 9-bit format: ...
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... COUNT_PER_ DIGITAL OUTPUT (BINARY) 00000000 11001000 00000000 00110010 00000000 00000001 00000000 00000000 11111111 11111111 11111111 11001110 11111111 10010010 DS1920 - COUNT_REMA IN) C SET/CLEAR LSB DIGITAL OUTPUT (HEX) 00C8h 0032h 0001h 0000h FFFFh FFCEh FF92h ...
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... Each DS1920 contains a unique ROM code that is 64 bits long. The first 8 bits are a 1-Wire family code (DS1920 code is 10h). The next 48 bits are a unique serial number. The last 8 bits are a CRC of the first 56 bits. (See Figure 4.) The 64-bit ROM and ROM Function Control section allow the DS1920 to operate as a 1-Wire device and follow the 1-Wire protocol detailed in the 1-Wire Bus System section ...
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... LASERED ROM Figure 4 8-BIT CRC CODE MSB ROM FUNCTIONS FLOWCHART Figure 5 48-BIT SERIAL NUMBER LSB MSB 8-BIT FAMILY CODE (10H) LSB MSB DS1920 LSB ...
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... CRC CODE Figure 6 MEMORY The DS1920’s memory is organized as shown in Figure 7. The memory consists of a scratchpad and 2 bytes of EEPROM that store the high and low temperature triggers TH and TL. The scratchpad helps insure data integrity when communicating over the 1-Wire bus. Data is first written to the scratchpad where it can be read back ...
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... BUS SYSTEM The 1-Wire bus is a system that has a single bus master and one or more slaves. The DS1920 behaves as a slave. The discussion of this bus system is broken down into three topics: hardware configuration, transaction sequence, and 1-Wire signaling (signal types and timing). ...
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... This command allows the bus master to read the DS1920’s 8-bit family code, unique 48-bit serial number, and 8-bit CRC. This command can only be used if there is a single DS1920 on the bus. If more than one slave is present on the bus, a data collision will occur when all slaves try to transmit at the same time (open drain will produce a wired-AND result) ...
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... The following command protocols are summarized in Table 2, and by the flowchart of Figure 9. Write Scratchpad [4Eh] This command writes to the scratchpad of the DS1920, starting at address 2. The next 2 bytes written will be saved in scratchpad memory, at address locations 2 and 3. Writing may be terminated at any point by issuing a reset. However reset occurs before both bytes have been completely sent, the contents of these bytes will be indeterminate. Bytes 2 and 3 can be read and written ...
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... MEMORY AND CONTROL FUNCTIONS FLOWCHART Figure DS1920 ...
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... MEMORY AND CONTROL FUNCTIONS FLOWCHART (continued) Figure 9 FROM FIGURE 9 FIRST PART DS1920 9 TO FIGURE THIRD PART ...
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... Strong Pullup. All these signals except Presence Pulse are initiated by the bus master. The initialization sequence required to begin any communication with the DS1920 is shown in Figure 10. A Reset Pulse followed by a Presence Pulse indicates the DS1920 is ready to accept a ROM command. The bus master transmits (Tx) a Reset Pulse (t and goes into receive mode (Rx) ...
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... DS1920. During write time slots, the delay circuit determines when the DS1920 will sample the data line. For a read data time slot transmitted, the delay circuit determines how long the DS1920 will hold the data line low overriding the 1 generated by the master. If the data bit the DS1920 will leave the read data time slot unchanged ...
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... As such, no other activity may take place on the 1-Wire bus for at least this period after a Convert Temperature command has been issued. 2. After receiving the Copy Scratchpad command, the data line for the DS1920 must be held high for at least 10ms to provide power during the copy process. As such, no other activity may take place on the 1-Wire bus for at least this period after a Copy Scratchpad command has been issued ...
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... MASTER DS1920 60µs ≤ t < t < 120µs LOW0 SLOT 1µs ≤ t < ∞ REC 60µs ≤ t < 120µs SLOT 1µs ≤ t < 15µs LOWR 0 ≤ t < 45µs RELEASE 1µs ≤ t < ∞ REC t = 15µs RDV t < 1µ DS1920 ...
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... Rx Reset Reset pulse(480–960µs) Presence Presence pulse 55h Issue “Match ROM” command Issue address for DS1920 44h Issue “Convert Temperature” command Data line is held high for at least 0.75 seconds by bus master to allow conversion to complete. Reset Reset pulse Presence ...
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... COPY -0.5V to +7.0V -55°C to +100°C -55°C to +100°C TYP MAX UNITS 5.0 6 0.8 V TYP MAX UNITS °C 1/2 µA 1000 1500 µA 5 0.4 V MAX UNITS 800 pF MAX UNITS 0.75 seconds 10 ms DS1920 NOTES NOTES 11 11 3,4 2 NOTES 9 NOTES 5 ...
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... CC may have to be reduced to as much as 0.5V to always ILMAX MAX UNITS NOTES µs 120 µs 15 µs 120 µs µs 45 µs 1 µs µs µs 4800 µs 60 µs 240 = 3.4V. PUP DS1920 ...
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... TYPICAL PERFORMANCE CURVE ERROR = READING - TRUE TEMPERATURE WHEN COLD, THE TRUE TEMPERATURE IS TYPICALLY COLDER THAN THE TEMPERATURE READING PACKAGE INFORMATION For the latest package outline information and land patterns www.maxim-ic.com/packages. PACKAGE TYPE F5 MicroCAN DS1920 TEMPERATURE iButton TRUE TEMPERATURE (°C) PACKAGE CODE IB+5NS DS1920 . ...
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... Extended the temperature conversion time from 0.5s to 0.75s 110806 maximum. Removed F3 MicroCAN drawing and ordering information; added 040108 lead-free DS1920-F5+ and removed leaded package from the Ordering Information table. Corrected the Ordering Information PART information (added hyphen to the part number). 8/09 Removed the UL#913 bullet from the Common iButton Features section ...