PI4S705, PI4S706x,PI4S707, PI4S708x, PI4S813L Low Cost µP Supervisor Circuts Description Product Features The PI4S70xxx/PI4S813L family microprocessor (µP) supervisory circuits are targeted to improve reliability and accuracy of power-supply circuitry in µP systems. These devices reduce the complexity and number of components required to monitor power-supply and battery functions. • Precision supply-voltage monitor - 4.63V (PI4S705, PI4S813L, PI4S707) - 4.38V (PI4S706, PI4S706H, PI4S708) - 3.08V (PI4S706T, PI4S706TH, PI4S708T) - 2.93V (PI4S706S, PI4S706SH, PI4S708S) - 2.63V (PI4S706R, PI4S706P, PI4S708R) The main functions are: • 200ms reset pulse width 1. Asserting reset output during power-µp, power-down and brownout conditions for µP systems. • Debounced TTL/CMOS-compatible manualreset input 2. Detecting power failure or low-battery conditions with a 1.25V threshold detector. • Independent watchdog timer with 1.6sec time-out (PI4S705, 706x, 706xH, and 813L ONLY ) 3. Generating an independent watchdog output that goes low if the watchdog input has not been toggled within 1.6 seconds. • Reset output signal: - Active-low only (PI4S705, 706, 706T, 706S, 706R) - Active-high only (PI4S813L, 706H, 706TH, 706SH, 706P) - Active-high and active-low (PI4S707, 708, 708T, 708S, 708R) 4. Asserting reset output with an active-low manual-reset input • Voltage monitor for power-fail or low battery warning • Automotive Systems • Guaranteed RESET/RESET valid at VCC = 1.2V • Printers Applications • Computers • Controllers • Intelligent Instruments • Critical Microprocessor Power Monitoring Product Pin Configuration MR 1 8 WDO MR 1 8 WDO MR 1 8 RESET VCC 2 7 RESET V CC 2 7 RESET V CC 2 7 RESET GND 3 6 WDI GND 3 6 WDI GND 3 6 NC PFI 4 5 PFO PFI 4 5 PFO PFI 4 5 PFO PI74S705 PI74S706 PI74S706T PI74S706S PI74S706R PI74S813L PI4S706H PI4S706TH PI4S706SH PI4S706P PI74S707 PI74S708 PI74S708T PI74S708S PI74S708R Top View 1 PS8703 09/23/03 PI4S705, PI4S706x, PI4S707, PI4S708x, PI4S813L µP Supervisor Circuts Pin Descriptiom Pin Name Type Description MR Input Manual-Reset: triggers a reset pulse when pulled below 0.8V, active low. It has an internal 250μA pull-up current and can be driven from a TTL or CMOS logic line as well as shorted to ground with a switch. VCC Power Power Supply GND Ground Ground Reference for all signals PFI Input Power-Fail Voltage Monitor Input: When PFI is less than 1.25V, PFO goes low. Connect PFI to GND or Vcc when not used. PFO Output Power-Fail Output: it gets low and sinks current when PFI is less than 1.25V; otherwise PFO stays high. Input Watchdog Input: If WDI remains high or low for 1.6sec, the internal watchdog timer runs out and WDO goes low. Floating WDI or connecting WDI to a high-impedance three-state buffer disables the watchdog feature. The internal watchdog timer clears whenever reset is asserted, WDI is three-stated, or WDI sees a rising or falling edge. WDI No Connect NC Output Reset Output pulses: low for 200ms when triggered, and stays low whenever Vcc is below the reset threshold. It remains low for 200ms after VCC rises above the reset threshold or MR goes from low to high. A watchdog timeout will not trigger RESET unless WDO is connected to MR. WDO Output Watchdog Output: pulls low when the internal watchdog timer finishes its 1.6sec count and does not go high again until the watchdog is cleared. WDO also goes low during low-line conditions. Whenever Vcc is below the reset threshold, WDO stays low; however, unlike RESET, WDO does not have minimum pulse width. As soon as VCC rises above the reset threshold, WDO goes high with no delay. RESET Output The inverse of RESET: active high. Whenever RESET is high, RESET is low. RESET 2 PS8703 09/23/03 PI4S705, PI4S706x, PI4S707, PI4S708x, PI4S813L µP Supervisor Circuts Block Diagram for PI7S705, PI4S706x, PI4S706xH, PI4S813L WDI Watchdog Transition Detector V cc 250uA Watchdog Timer WDO Timebase for Reset & Watchdog MR Reset Generator Vcc RESET (RESET) * V RST PFI PFO 1.25V *VRST = RESET Threshold Voltage Block Diagram for PI4S707, PI4S708x Vcc 250uA RESET MR Reset Generator Vcc RESET * V RST PFI PFO 1.25V *VRST = RESET Threshold Voltage 3 PS8703 09/23/03 PI4S705, PI4S706x, PI4S707, PI4S708x, PI4S813L µP Supervisor Circuts Watchdog Timer Functional Description The watchdog circuit monitors the µP’s activity. If the µP does not toggle the watchdog input (WDI) within 1.6sec and WDI is not in high impedance, WDO goes low. As long as RESET is asserted or the WDI input is in high impedance, the watchdog timer will stay cleared and will not count. As soon as reset is released and WDI is driven high or low, the timer will start counting. Pulses as short as 50ns can be detected. The PI4S70xxx/813L family can assert reset output during power-up, power-down and brownout conditions for uP system, detect power failure or low-battery conditions with a 1.25V threshold detector and have watchdog functions. Refer to Function Reference Table for their individual features. For the typical application see Figure 4. Reset Output Typically, WDO will be connected to the non-maskable interrupt input (NMI) of a µP. When VCC drops below the reset threshold, WDO will go low whether or not the watchdog timer has timed out yet. Normally this would trigger an NMI interrupt, but RESET goes low simultaneously, and thus overrides the NMI interrupt. If WDI is left unconnected, WDO can be used as a low-line output. Since floating WDI disables the internal timer, WDO goes low only when VCC falls below the reset threshold, thus functioning as a low-line output. The supervisory circuits can assert reset for a microprocessor during power-up, power-down and brownout to prevent code execution errors. On power-up, once VCC reaches about 1.2V, RESET is a guaranteed logic low of 0.4V or less. As VCC rises, RESET stays low. When VCC rises above the reset threshold, an internal timer releases RESET after about 200ms. RESET pulses low whenever VCC drops below the reset threshold (brownout condition). If brownout occurs in the middle of a previously initiated reset pulse, the pulse continues for at least another 140ms. Manual Reset The manual-reset input (MR) allows reset to be triggered by a pushbutton switch. The switch is effectively debounced by the 140ms minimum reset pulse width. MR is TTL/CMOS logic compatible, so it can be driven by any external logic line. On power-down, once VCC falls below the reset threshold, RESET stays low and is guaranteed to be 0.4V or less until Vcc drops below 1.2V. The PI4S706xH, PI4S707, PI4S708x and PI4S813L active-high RESET output is simply the complement of the RESET output, and is guaranteed to be valid with VCC down to 1.2V. Some µPs, such as Intel’s 80C51, require an active-high reset pulse. Power-Fail Comparator The power-fail comparator will send out a low signal once detects a voltage lowered than 1.25V. It can be used for various purposes because its output and non-inverting input are not internally connected. The inverting input is internally connected to a 1.25V reference. Typical Application Circuit Unregulated DC IN DC Linear Regulator µP OUT Vcc Vcc PFI MR RESET µP Supervisory Circuit WDI WDO PFO 4 RESET I/O Line NMI Interrupt PS8703 09/23/03 PI4S705, PI4S706x, PI4S707, PI4S708x, PI4S813L µP Supervisor Circuts Function Reference Table Reset Threshold Reset Active Low or High Nom. Reset Time (ms), tRS Nom. Watchdog Time (sec), tWD Power Fail Comp. Manual Reset Input PI4S705 4.63V LOW 200 1.6 1.25V detector Yes PI4S813L 4.63V HIGH 200 1.6 1.25V detector Yes PI4S707 4.63V LOW, HIGH 200 unavailable 1.25V detector Yes PI4S706 4.38V LOW 200 1.6 1.25V detector Yes PI4S706H 4.38V HIGH 200 1.6 1.25V detector Yes PI4S708 4.38V LOW, HIGH 200 unavailable 1.25V detector Yes PI4S706T 3.08V LOW 200 1.6 1.25V detector Yes PI4S706TH 3.08V HIGH 200 1.6 1.25V detector Yes PI4S708T 3.08V LOW, HIGH 200 unavailable 1.25V detector Yes PI4S706S 2.93V LOW 200 1.6 1.25V detector Yes PI4S706SH 2.93V HIGH 200 1.6 1.25V detector Yes PI4S708S 2.93V LOW, HIGH 200 unavailable 1.25V detector Yes PI4S706R 2.63V LOW 200 1.6 1.25V detector Yes PI4S706P 2.63V HIGH 200 1.6 1.25V detector Yes PI4S708R 2.63V LOW, HIGH 200 unavailable 1.25V detector Yes Part No. Absolute Maximum Ratings Storage Temperature .....................................................-65oC to +150oC Ambient Temperature with Power Applied .......................0oC to +70oC Supply Voltage to Ground Potential (VCC to GND) ....... -0.3V to +7.0V DC Input Voltage (All inputs except VCC and GND) ........ -0.3V to VCC+0.3V DC Output Current (All outputs) ................................................... 20mA Power Dissipation (W package) ................................................. 500mW Note: Stresses greater than those listed under MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. DC Electrical Characteristics (VCC =4.75V to 5.5V for PI4S705, PI4S813L, PI4S707 ; VCC = 4.5V to 5.5V for PI4S706, PI4S706H, PI4S708; VCC = 3.15V to 5.5V for PI4S706T, PI4S706TH, PI4S708T; VCC = 3.0V to 5.5V for PI4S706S, PI4S706SH, PI4S708S; VCC = 2.7V to 5.5V for PI4S706R, PI4S706P, PI4S708R; TA = 0ºC to 70°C; unless otherwise noted.) Symbol Description VCC Supply Voltage for PI4S70xxx, 813L VIH1 MR Input High Voltage VIH2 WDI Input High Voltage VIL1 MR Input Low Voltage VIL2 WDI Input Low Voltage TA Operating Temperature Test Conditions Min Typ 1.2 VCC > 4.0V 2 VCC ≤ 4.0V 0.7 x VCC Max Unit 5.5 2.4 V 0.7 x VCC VCC > 4.0V 0.8 VCC ≤ 4.0V 0.2 x VCC 0.3 x VCC 0 5 70 PS8703 ºC 09/23/03 PI4S705, PI4S706x, PI4S707, PI4S708x, PI4S813L µP Supervisor Circuts DC Electrical Characteristics (Continued) Symbol ICC VRST VRTH VOH VOL Description Operational Power Supply Current Reset Threshold Voltage * Test Conditions Min PI4S705, 706, 706H, 707, 708, 813L, VCC = 5V; PI4S706S, 706SH, 706T, 706TH, 708S, 708T, VCC = 3.3V; PI4S706P, 706R, 708R, VCC = 3.0V; Left WDI un-connected (No output load) Output LOW Voltage VPFT PFI Input Threshold IPFI PFI Input Current IWDI Average WDI Input Current** IMR MR Input Current Max Unit 30 200 µA PI4S705, 707, 813L 4.50 4.63 4.75 PI4S706, 706H, 708 4.25 4.38 4.50 PI4S706T, 706TH, 708T 3.00 3.08 3.15 PI4S706S, 706SH, 708S 2.85 2.93 3.00 PI4S706P, 706R, 708R 2.55 2.63 2.70 Reset Threshold Hysteresis * Output HIGH Voltage Typ 70 VCC > 4.5V Isource = 800μA VCC-1.5 VCC > 2.7V Isource = 500μA 0.8 x VCC VCC ≥ 1.2V Isource = 4μA 0.8 x VCC mV VCC > 4.5V Isink = 3.2mA 0.4 VCC > 2.7V Isink = 1.2mA 0.3 VCC ≥ 1.2V Isink = 50μA 0.3 VPFI varies from1.0V to 1.5V 1.20 1.25 PFI connected to VCC PFI connected to GND V V 1.30 2 -2 WDI connected to VCC 30 WDI connected to GND -100 -30 MR = 0, VCC = 5V -600 -250 100 µA -100 * Valid for both RESET and RESET. ** WDI is internally serviced within the watchdog period if WDI is left unconnected. 6 PS8703 09/23/03 PI4S705, PI4S706x, PI4S707, PI4S708x, PI4S813L µP Supervisor Circuts AC Electrical Characteristics (VCC =4.75V to 5.5V for PI4S705, PI4S813L, PI4S707 ; VCC = 4.5V to 5.5V for PI4S706, PI4S706H, PI4S708; VCC = 3.15V to 5.5V for PI4S706T, PI4S706TH, PI4S708T; VCC = 3.0V to 5.5V for PI4S706S, PI4S706SH, PI4S708S; VCC = 2.7V to 5.5V for PI4S706R, PI4S706P, PI4S708R; TA = 0ºC to 70°C; unless otherwise noted.) Symbol Description Test Conditions tRS Reset Pulse Width MR from low to High tWD Watchdog Timeout Period WDI and MR tied to VCC tMR MR Pulse Width tMD MR to RESET Output Delay tWP WDI Pulse Width Min Typ Max Units 140 200 280 ms 1 1.6 2.25 s 250 ns 150 VCC = 5.0V 50 Watchdog Timing Diagram tWP tWD tWD tWD 5V WDI 0V 5V WDO 0V Externally Triggered by MR RESET 5V 0V tRS 5V RESET 0V RESET, MR, and WDO Timing Diagram with WDI 3-stated. (RESET output is the inverse of RESET shown). V CC V RT V RT 5V tRS tRS 0V 5V RESET 0V MR 5V tMD 0V tMR 5V WDO 0V 7 PS8703 09/23/03 PI4S705, PI4S706x, PI4S707, PI4S708x, PI4S813L µP Supervisor Circuts Packaging Mechanical: 8-pin 150-mil wide plastic SOIC (W) 8 .149 .157 3.78 3.99 .0099 .0196 1 .189 .196 0.25 x 45˚ 0.50 .0075 .0098 0-8˚ 4.80 5.00 .016 .026 0.406 0.660 0.19 0.25 0.40 .016 1.27 .050 .2284 .2440 5.80 6.20 1.35 1.75 .053 .068 SEATING PLANE REF .050 BSC 1.27 .0040 0.10 .0098 0.25 .013 0.330 .020 0.508 X.XX DENOTES DIMENSIONS X.XX IN MILLIMETERS Ordering Information Ordering Code Packaging Code Package Type Reset Threshold PI4S705W PI4S813LW PI4S707W PI4S706W PI4S706HW PI4S708W PI4S706TW PI4S706THW PI4S708TW PI4S706SW PI4S706SHW PI4S708SW PI4S706RW PI4S706PW PI4S708RW W W W W W W W W W W W W W W W 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 8-pin, 150 mil wide plastic SOIC 4.63V 4.63V 4.63V 4.38V 4.38V 4.38V 3.08V 3.08V 3.08V 2.93V 2.93V 2.93V 2.63V 2.63V 2.63V Notes: 1. Thermal characteristics can be found on the company web site at http://www.pericom.com/packaging/mechanicals.php Pericom Semiconductor Corporation 2380 Bering Drive • San Jose, CA 95131 • 1-800-435-2336 • Fax (408) 435-1100 • http://www.pericom.com 8 PS8703 09/23/03