DS1990A MAXIM | Alldatasheet
Document overview
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Technical content
Features
♦ Can Be Read in Less Than 5ms ♦ Operating Range: 2.8V to 6.0V, -40°C to +85°C Common iButton Features ♦ Unique Factory-Lasered 64-Bit Registration Number Ensures Error-Free Device Selection and Absolute Traceability Because No Two Parts are Alike ♦ Built-In Multidrop Controller for 1-Wire Net ♦ Digital Identification by Momentary Contact ♦ Data Can Be Accessed While Affixed to Object ♦ Economically Communicates to Bus Master with a Single Digital Signal at 16.3kbps ♦ Button Shape is Self-Aligning with Cup-Shaped Probes ♦ Durable Stainless-Steel Case Engraved with Registration Number Withstands Harsh Environments ♦ Easily Affixed with Self-Stick Adhesive Backing, Latched by its Flange, or Locked with a Ring Pressed Onto its Rim DS1990A Serial Number iButton Pin Configurations
Ordering Information
Rev: 10/08 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. PART TEMP RANGE PIN-PACKAGE DS1990A-F5+ -40 °C to +85°C F5 i Button DS1990A-F3+ -40 °C to +85°C F3 i Button Examples of Accessories PART ACCESSORY DS9096P Self-Stick Adhesive Pad DS9101 Multipurpose Clip DS9093RA Mounting Lock Ring DS9093A Snap-In Fob DS9092 i Button Probe 16.25mm 5.89mm 0.51mm 3.10mm 0.51mm 17.35mm BRANDING F5 SIZE GNDGND IOIO F3 SIZE 89 01 000000FBC52B 1-Wire® iBut t o n® . com YYWW ZZZ DS1990A+FX iButton and 1-Wire are registered trademarks of Maxim Integrated Products, Inc. +Denotes a lead-free/RoHS-compliant package.
ELECTRICAL CHARACTERISTICS
(TA = -40°C to +85°C.) Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Note 1: All voltages are referenced to ground. Note 2: External pullup voltage. See Figure 4. Note 3: System requirement. Note 4: Full RPUP range is guaranteed by design and simulation and not production tested. Production testing performed at a fixed RPUP value. Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1- Wire recovery times. The specified value here applies to systems with only one device and with the minimum 1-Wire recov- ery times. For more heavily loaded systems, an active pullup such as that found in the DS2480B may be required. Note 5: Capacitance on the IO pin could be 800pF when power is first applied. If a 5kΩ resistor is used to pull up the IO line to V PUP, 5µs after power has been applied the parasite capacitance will not affect normal communications. Note 6: Guaranteed by design, simulation only. Not production tested. Note 7: Input load is to ground. PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS IO PIN: GENERAL DATA 1-Wire Pullup Voltage V PUP (Notes 1, 2) 2.8 6.0 V 1-Wire Pullup Resistance R PUP (Notes 3, 4) 0.6 5 k Input Capacitance C IO (Notes 5, 6) 100 800 pF Input Load Current I L (Note 7) 0.25 μA Input Low Voltage V IL (Notes 1, 3, 8) 0.3 V Input High Voltage V IH (Notes 1, 9) 2.2 V Output Low Voltage at 4mA V OL (Note 1) 0.4 V Operating Charge Q OP (Notes 6, 10) 30 nC Recovery Time t REC (Note 3) 1 μs Time Slot Duration t SLOT (Note 3) 61 μs IO PIN: 1-Wire RESET, PRESENCE-DETECT CYCLE Reset Low Time t RSTL (Notes 3, 11) 480 μs Reset High Time t RSTH (Notes 3, 12) 480 μs Presence-Detect High Time t PDH 15 60 μs Presence-Detect Low Time t PDL (Note 13) 60 240 μs Presence-Detect Sample Time t MSP (Note 3) 60 75 μs IO PIN: 1-Wire WRITE Write-Zero Low Time t W0L (Notes 3, 14) 60 120 μs Write-One Low Time t W1L (Notes 3, 14) 1 15 μs IO PIN: 1-Wire READ Read Low Time t RL (Notes 3, 15) 1 15 - μs Read Sample Time t MSR (Notes 3, 15) t RL + 15 μs
Note 8: The voltage on IO must be less than or equal to VILMAX whenever the master drives the line low. Note 9: VIH is a function of the internal supply voltage. Note 10: 30nC per 72 time slots at 5.0V pullup voltage with a 5kΩ pullup resistor and tSLOT ≤ 120µs. mask or conceal interrupt pulses if this device is used in parallel with a DS1994. Note 12: An additional reset or communication sequence cannot begin until the reset high time has expired. Note 13: Presence pulse is guaranteed only after a preceding reset pulse (tRSTL). maximum duration for the master to pull the line low is tW1LMAX + tF - ε and tW0LMAX + tF - ε, respectively. threshold of the bus master. The actual maximum duration for the master to pull the line low is tRLMAX + tF. SIZE See the Package Information section. Figure 1. Block Diagram
the 1-Wire bus has a maximum data rate of 16.3kbps. mately 2.2kΩ. The idle state for the 1-Wire bus is high.
- Initialization
- ROM Function Command Initialization All transactions on the 1-Wire bus begin with an initial- ization sequence. The initialization sequence consists of a reset pulse transmitted by the bus master followed by presence pulse(s) transmitted by the slave(s). The presence pulse lets the bus master know that the DS1990A is on the bus and is ready to operate. For more details, see the 1-Wire Signaling section. DS1990A Serial Number iButton Rx RPUP VPUP SIMPLE BUS MASTER DS2480B BUS MASTER OPEN-DRAIN PORT PIN 100Ω MOSFET Tx Rx Tx DATA DS1990A 1-Wire PORT Rx = RECEIVE Tx = TRANSMIT VDD POL RXDSERIAL IN SERIAL OUT TXD VPP GND N.C. 1-W TO 1-Wire DATA +5V HOST CPU SERIAL PORT DS2480B
Figure 4. Hardware Configuration
supports. All ROM function commands are 8 bits long. 48-bit serial number results in a mismatch of the CRC. detailed discussion, including an example. includes a Match ROM and a Skip ROM command. that do respond to Match ROM or Skip ROM. Figure 5. ROM Functions Flowchart
Figure 7. Read/Write Timing Diagram
A read-data time slot begins like a write-one time slot. The voltage on the data line must remain below V ILMAX until the read low time t RL is expired. During the t RL window, when responding with a 0, the DS1990A starts pulling the data line low; its internal timing generator determines when this pulldown ends and the voltage starts rising again. When responding with a 1, the DS1990A does not hold the data line low at all, and the voltage starts rising as soon as t RL is over. The sum of tRL + δ (rise time) on one side and the inter- nal timing generator of the DS1990A on the other side define the master sampling window (t MSRMIN to tMSRMAX) in which the master must perform a read from the data line. For most reliable communication, t RL should be as short as permissible and the master should read close to but no later than t MSRMAX. After reading from the data line, the master must wait until t SLOT is expired. This guarantees sufficient recovery time t REC for the DS1990A to get ready for the next time slot. DS1990A Serial Number iButton PACKAGE TYPE PACKAGE CODE DOCUMENT NO. F3 iButton — 56-G0CAN-F30 F5 iButton — 56-G0CAN-F50
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circu it patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Revision History
033005 Redid the formatting based on newer template style. Also deleted the 0F Read ROM command and added a note about presence pulse criteria. 1–8 Created newer template-style data s heet. All Updated Ordering Information with lead-free part numbers. 1 Deleted Meets UL 913 (4th Edit); Intrinsically Safe Apparatus: Approved Under Entity Concept for Use in Class I, Division I, Group A, B, C, and D from the Common i Button Features and iButton Can Physical Specification sections. 1, 3 Updated Electrical Characteristics table: Deleted Output High Voltage parameter. Moved 1-Wire Pullup voltage parameter from table header to table body. Changed VILMAX from 0.8V to 0.3V. Added Note 14 to the tW0L specification. Changed tW1LMAX from 15μs – to 15μs. Added the epsilon timing to the Write-Zero Time Slot in Figure 7. 8