DS1210 MAXIM | Alldatasheet
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Technical content
FEATURES
Converts CMOS RAMs into Nonvolatile Memories Unconditionally Write Protects when VCC is Out-of-Tolerance Automatically Switches to Battery when Power-Fail Occurs Space-Saving 8-Pin PDIP or 16-Pin SO Packages Consumes <100nA of Battery Current Tests Battery Condition on Power up Provides for Redundant Batteries Optional 5% or 10% Power-Fail Detection Low Forward Voltage Drop on the V CC Switch Optional Industrial (N) Temperature Range of -40°C to +85°C PIN ASSIGNMENT PIN DESCRIPTION VCCO - RAM Supply VBAT1 - + Battery 1 TOL - Power Supply Tolerance GND - Ground CE - Chip Enable Input CEO - Chip Enable Output VBAT2 - + Battery 2 VCCI - + Supply NC - No Connect
DESCRIPTION
The DS1210 Nonvolatile Controller Chip is a CMOS circuit which solves the application problem of converting CMOS RAM into nonvolatile memory. Incoming power is monitored for an out -of-tolerance condition. When such a condition is detected, chip enable is inhibited to accomplish write protection and the battery is switched on to supply the RAM with uninterrupted power. Special circuitry uses a low - leakage CMOS process which affords precise voltage detection at extremely low battery consumption. The 8 -pin DIP package keeps PC board real estate requirements to a minimum. By combining the DS1210 Nonvolatile Controller Chip with a CMOS memory and batteries, nonvolatile RAM operati on can be achieved. DS1210 Nonvolatile Controller Chip VCCO VBAT1 TOL GND VCCI VBAT2 CEO CE DS1210 8-pin PDIP (300 mils) NC VCCO NC VBAT1 NC TOL NC GND NC VCCI NC VBAT2 NC CEO NC CE DS1210S 16-pin SO (300 mils) 19-6294; Rev 6/12
The DS1210 nonvolatile controller performs five circuit functions required to battery back up a RAM. First, a switch is provided to direct power from the battery or the incoming supply (VCCI) depending on which is greater. This switch has a voltage drop of less than 0.3V. The second function which the nonvolatile controller provides is power-fail detection. The DS1210 constantly monitors the incoming supply. When the supply goes out of tolerance, a precision comparator detects power-fail and inhibits chip enable ( CEO ). The third function of write protection is accomplished by holding the CEO output signal to within 0.2 volts of the VCCI or battery supply. If CE input is low at the time power-fail detection occurs, the CEO output is kept in its present state until CE is returned high. The delay of write protection until the current memory cycle is completed prevents the corruption of data. Power-fail detection occurs in the range of 4.75 volts to 4.5 volts with the tolerance (TOL) pin grounded. If TOL in connected to VCCO, then power- fail detection occurs in the range of 4.5 volts to 4.25 volts. During nominal supply conditions CEO will follow CE with a maximum propagation delay of 20ns. The fourth function the DS1210 performs is a battery status warning so that potential data loss is avoided. Each time that the circuit is powered up the battery voltage is checked with a precision comparator. If the battery voltage is less than 2.0 volts, the second memory cycle is inhibited. Battery status can, therefore, be determined by performing a read cycle after power-up to any location in memory, verifying that memory location content. A subsequent write cycle can then be executed to the same memory location altering the data. If the next read cycle fails to verify the written data, then the batteries are less than 2.0V and data is in danger of being corrupted. The fifth function of the nonvolatile controller provides for battery redundancy. In many applications, data integrity is paramount. In these applications it is often desirable to use two batteries to ensure reliability. The DS1210 controller provides an internal isolation switch which allows the connection of two batteries. During battery backup operation the battery with the highest voltage is selected for use. If one battery should fail, the other will take over the load. The switch to a redundant battery is transparent to circuit operation and to the user. A battery status warning will occur when the battery in use falls below 2.0 volts. A grounded V BAT2 pin will not activate a battery-fail warning. In applications where battery redundancy is not required, a single battery should be connected to the BAT1 pin, and the BAT2 battery pin must be grounded. The nonvolatile controller contains circuitry to turn off the battery backup. This is to maintain the battery(s) at its highest capacity until the equipment is powered up and valid data is written to the SRAM. While in the freshness seal mode the CEO and VCCO will be forced to VOL. When the batteries are first attached to one or both of the VBAT pins, VCCO will not provide battery back-up until VCCI exceeds VCCTP, as set by the TOL pin, and then falls below VBAT. Figure 1 shows a typical application incorporating the DS1210 in a microprocessor-based system. Section A shows the connections necessary to write protect the RAM when V CC is less than 4.75 volts and to back up the supply with batteries. Section B shows the use of the DS1210 to halt the processor when VCC is less than 4.75 volts and to delay its restart on power-up to prevent spurious writes.
SECTION A - BATTERY BACKUP Figure 1 BATTERY BACKUP CURRENT DRAIN EXAMPLE CONSUMPTION DS1210 IBAT 100 nA RAM ICC02 10 µA Total Drain 10.1 µA SECTION B - PROCESSOR RESET
Voltage Range on Any Pin Relative to Ground -0.3V to +7.0V Operating Temperature Range 0°C to +70°C, -40°C to +85°C for N parts Storage Temperature Range -55°C to +125°C Soldering Temperature (reflow, SO) +260°C Lead Temperature (soldering, 10s) +300°C 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. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. PACKAGE THERMAL CHARACTERISTICS (Note 1) PDIP SO Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board for the SO. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. RECOMMENDED OPERATING CONDITIONS (Note 10) PARAMETER SYMBOL 4B MIN TYP MAX UNITS 0B NOTES TOL = GND Supply Voltage VCCI 4.75 5.0 5.5 V 2 TOL = VCCO Supply Voltage VCCI 4.5 5.0 5.5 V 2 Logic 1 Input VIH 2.2 VCC+0.3 V 2 Logic 0 Input VIL -0.3 +0.8 V 2 Battery Input VBAT1, VBAT2 2.0 4.0 V 2, 3 DC ELECTRICAL CHARACTERISTICS (Note 10; VCCI = 4.75 to 5.5V, TOL = GND) (VCCI = 4.5 to 5.5V, TOL = VCCO) PARAMETER SYMBOL MIN TYP MAX UNITS 1B NOTES Supply Current ICCI 5 mA 4 Supply Voltage VCCO VCC-0.2 V 2 Supply Current ICCO1 80 mA 5 Input Leakage IIL -1.0 +1.0 µA Output Leakage ILO -1.0 +1.0 µA CEO Output @ 2.4V IOH -1.0 mA 6 CEO Output @ 0.4V IOL 4.0 mA 6 VCC Trip Point (TOL=GND) VCCTP 4.50 4.62 4.74 V 2 VCC Trip Point (TOL=VCCO) VCCTP 4.25 4.37 4.49 V 2 CEO Output VOHL VBAT-0.2 V 8 VBAT1 or VBAT2 Battery Current IBAT 100 nA 3, 4 Battery Backup Current @ VCCO = VBAT – 0.3V ICCO2 50 µA 7, 8
CAPACITANCE (TA = +25°C) PARAMETER SYMBOL MIN TYP MAX UNITS 2B NOTES Input Capacitance CIN 5 pF Output Capacitance COUT 7 pF AC ELECTRICAL CHARACTERISTICS (Note 10; VCCI = 4.75V to 5.5V, TOL = GND) (VCCI = 4.5V to 5.5V, TOL = VCCO) PARAMETER SYMBOL MIN TYP MAX UNITS 3B NOTES CE Propagation Delay tPD 5 10 20 ns 6 CE High to Power-Fail tPF 0 ns AC ELECTRICAL CHARACTERISTICS (Note 10; VCCI = 4.75V, TOL = GND) (VCCI < 4.5, TOL = VCCO) Recovery at Power Up tREC 2 80 125 ms VCC Slew Rate Power-Down tF 300 µs VCC Slew Rate Power-Down tFB 10 µs VCC Slew Rate Power-Up tR 0 µs CE Pulse Width tCE 1.5 µs 9 NOTES: 2. All voltages are referenced to ground. 3. Only one battery input is required. Unused battery inputs must be grounded. 4. Measured with VCCO and CEO open. 5. ICC01 is the maximum average load which the DS1210 can supply to the memories. 6. Measured with a load as shown in Figure 2. 7. I CC02 is the maximum average load current which the DS1210 can supply to the memories in the battery backup mode. 8. t CE max must be met to ensure data integrity on power loss. 9. CEO can only sustain leakage current in the battery backup mode. 10. All AC and DC electrical characteristics are valid for the full temperature range. For commercial products, this range is 0 to +70°C. For industrial products (N), this range is -40°C to +85°C. 11. DS1210 is recognized by Underwriters Laboratories (UL) under file E99151.
TIMING DIAGRAM: POWER-UP TIMING DIAGRAM: POWER-DOWN OUTPUT LOAD Figure 2
ORDERING INFORMATION
DS1210+ 0°C to +70°C 8 PDIP DS1210N+ -40°C to +85°C 8 PDIP DS1210S+ 0°C to +70°C 16 SO DS1210SN+ -40°C to +85°C 16 SO +Denotes a lead(Pb)-free/RoHS-compliant package.
PACKAGE INFORMATION
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
8 PDIP P8+4 21-0043
16 SO W16+2 21-0042 90-0107
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, Inc. 160 Rio Robles , San Jose, CA 95134 USA 1-408 -601 -1000 © 2012 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
REVISION HISTORY
Added lead temperature and soldering temperature information to the Absolute Maximum Ratings section; changed “Pin 3” to “TOL” in multiple places; added the Package Thermal Characteristics section; added the Ordering Information and Package Information sections 1, 2, 4, 5, 8