DS1239-5

DS1239 MicroManager Chip www.dalsemi.com FEATURES














Provides necessary control for start up and shutdown of power supply from keyboard Holds microprocessor in check during power transients Halts and restarts an out-of-control microprocessor Monitors push button for external override Warns microprocessor of an impending power failure Converts CMOS SRAM into nonvolatile memory Unconditionally write-protects memory when power supply is out of tolerance Consumes less than 100 nA of battery current Controls external power switch for high current applications Accurate 10% power supply monitoring Optional 5% power supply monitoring designated DS1239-5 Provides orderly shutdown in nonvolatile microprocessor applications Supplies necessary control for low-power “stop mode” in battery operate hand-held applications Standard 16-pin DIP or space-saving 16-pin SOIC Optional industrial temperature range -40°C to +85°C PIN ASSIGNMENT VBAT 1 16 PSO VCCO 2 15 RST VCC 3 14 PBRST GND 4 13 CEI PF 5 12 PF 6 11 WC/SC 7 10 PSI 8 9 VBAT VCCO CEO VCC GND ST PF NMI PF WC/SC IN PSI DS1239 16-Pin DIP (300-mil) See Mech. Drawings Section 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 PSO RST PBRST CEI CEO ST NMI IN DS1239 16-Pin SOIC (300-mil) See Mech. Drawings Section PIN DESCRIPTION VBAT VCCO VCC GND PF PF WC/ SC PSI IN NMI ST CEO CEI PBRST RST PSO - +3 Volt Battery Input - Switched SRAM Supply Output - +5 Volt Power Supply Input - Ground - Power Fail (Active High) - Power Fail (Active Low) - Wake-Up Control (Sleep) - Power Supply Control Input - Early Warning Input - Non-Maskable Interrupt - Strobe Input - Chip Enable Output - Chip Enable Input - Pushbutton Reset Input - Reset Output (Active low) - Power Supply Control Outputs DESCRIPTION The DS1239 MicroManager provides all the necessary functions for power supply control and monitoring, reset control, and memory backup in microprocessor-based systems. Using the DS1239, an AC power switch is no longer required for microprocessor-based systems. A keyboard control system for power supply start up and shutdown is provided through the use of the Power Supply Control Input and Output. In other respects, the DS1239 is functionally identical to a DS1236 in the NMOS mode. For a complete description of the other DS1239 features, refer to the DS1236 data sheet. Pin-out of the 1 of 4 111899 DS1239 DS1239 is identical to the DS1236 with two exceptions. The RC and RST pins have been replaced with PSI and PSO, respectively. Other pins and functions operate exactly as the DS1236 in NMOS mode. POWER SUPPLY CONTROL The DS1239 facilitates the power-up and power-down sequencing of a main power supply from a keyboard or pushbutton. The Power Supply Control Input ( PSI ) and Power Supply Control Output (PSO) are used for this purpose. Prior to establishing a voltage on VCC (+5V), the PSI is internally held at a high level at all times with the VBAT supply. When PSI is forced low via a keypad or other source, the PSO is connected to the VBAT to provide a high level. As shown in Figure 1, this active high signal can be wired directly to an optically isolated SCR to initiate an AC to DC power-up sequence. This in turn will provide the supply voltage for VCC. The timing is illustrated in Figure 2. Holding the PSI input low, the PSO output will supply a connection to the VBAT pin until the VCC reaches VBAT, or a maximum of 500 ms. If the supply voltage on VCC rises above the VBAT level before the tPSI timeout, the PSO pin will remain high and track the VCC input. If VCC does not rise above VBAT before either tPSI or PSI is allowed to return to a high level, the PSO output will return to tristate. Once the PSO output and VCC are set at a high level, a subsequent falling edge on PSI will tristate PSO to initiate a shut down condition. The 10 microamp current supplied by the PSI pin allows the use of a 0.1 µF capacitor as a simple pushbutton debounce circuit. The battery size for this application must be selected to provide the SCR on-current for the power supply response time and is consequently application-specific. POWER SUPPLY CONTROL Figure 1 2 of 4 DS1239 POWER SUPPLY CONTROL TIMING Figure 2 ABSOLUTE MAXIMUM RATINGS* Voltage on VCC Pin Relative to Ground Voltage on I/O Relative to Ground Operating Temperature Operating Temperature (Industrial Version) Storage Temperature Soldering Temperature * -0.5V to +7.0V -0.5V to VCC + 0.5V 0°C to 70°C -40°C to +85°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. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. These specifications reflect the power supply control feature of the DS1239. For complete electrical specifications, refer to the DS1236 data sheet. 3 of 4 DS1239 DC ELECTRICAL CHARACTERISTICS PARAMETER PSI Output Current (0°C to 70°C; VCC= 4.5V to 5.5V) SYMBOL IPSI MIN IPSO 10 PSO Output Current AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL TYP 3 MAX UNITS µA NOTES mA 3 (0°C to 70°C; VCC= 4.5V to 5.5V) MIN TYP MAX UNITS NOTES 1 PSI to Valid VCC tPSI 200 ms PSI to PSO Tri-state tPST 20 ns PSI to Valid PSO tPSO 100 ns PSO Pulse Width tPSP 500 ms 200 NOTES: 1. Minimum turn-on response time for AC-to-DC power supply. 2. PSO pulse width for VCC held below VBAT. 3. PSO will typically source 1.5 mA at 1.5V with VCC= 0V, VBAT= 3V. 4 of 4 2