19-2000; Rev 1; 1/99 Open-Drain SOT µP Reset Circuit ____________________________Features The MAX6315 low-power CMOS microprocessor (µP) supervisory circuit is designed to monitor power supplies in µP and digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments. The MAX6315 also provides a debounced manual reset input. ♦ Small SOT143 Package This device performs a single function: it asserts a reset signal whenever the VCC supply voltage falls below a preset threshold or whenever manual reset is asserted. Reset remains asserted for an internally programmed interval (reset timeout period) after VCC has risen above the reset threshold or manual reset is deasserted. The MAX6315’s open-drain RESET output can be pulled up to a voltage higher than VCC. The MAX6315 comes with factory-trimmed reset threshold voltages in 100mV increments from 2.5V to 5V. Preset timeout periods of 1ms, 20ms, 140ms, and 1120ms (minimum) are also available. The device comes in a SOT143 package. For microcontrollers (µCs) and µPs with bidirectional reset pins, see the MAX6314 data sheet. ________________________Applications ♦ Open-Drain RESET Output Can Exceed VCC ♦ Precision, Factory-Set VCC Reset Thresholds: 100mV Increments from 2.5V to 5V ♦ ±1.8% Reset Threshold Accuracy at TA = +25°C ♦ ±2.5% Reset Threshold Accuracy Over Temp. ♦ Four Reset Timeout Periods Available: 1ms, 20ms, 140ms, or 1120ms (minimum) ♦ Immune to Short VCC Transients ♦ 5µA Supply Current ♦ Pin-Compatible with MAX811 Ordering and Marking Information appear at end of data sheet. Computers Controllers Intelligent Instruments Critical µP and µC Power Monitoring __________Typical Operating Circuit Portable/Battery-Powered Equipment VCC __________________Pin Configuration VCC LASERTRIMMED RESISTORS TOP VIEW GND 1 4 VCC µP MAX6315 MR RESET 2 3 MR RESET CIRCUITRY RESET RESET MAX6315 GND SOT143 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX6315 ________________General Description MAX6315 Open-Drain SOT µP Reset Circuit ABSOLUTE MAXIMUM RATINGS VCC ........................................................................-0.3V to +6.0V RESET....................................................................-0.3V to +6.0V All Other Pins..............................................-0.3V to (VCC + 0.3V) Input Current (VCC) .............................................................20mA Output Current (RESET)......................................................20mA Rate of Rise (VCC) ...........................................................100V/µs Continuous Power Dissipation (TA = +70°C) SOT143 (derate 4mW/°C above +70°C) ........................320mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°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 specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = +2.5V to +5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Operating Voltage Range SYMBOL VCC VCC Supply Current ICC Reset Threshold (Note 1) VTH Reset Threshold Tempco VCC to Reset Delay ∆VTH/°C Reset Timeout Period tRP CONDITIONS TA = -40°C to +85°C VCC = 5.5V, no load VCC = 3.6V, no load TA = +25°C TA = -40°C to +85°C VCC = falling at 1mV/µs MAX6315US_ _D1-T MAX6315US_ _D2-T MAX6315US_ _D3-T MAX6315US_ _D4-T MIN TYP MAX UNITS V 5 4 VTH 5.5 12 10 VTH + 1.8% VTH + 2.5% 1.0 VTH - 1.8% VTH - 2.5% 1 20 140 1120 60 35 1.4 28 200 1570 µA V ppm/°C µs 2 40 280 2240 ms MANUAL RESET INPUT MR Input Threshold VIL VIH VIL VIH VTH > 4.0V VTH < 4.0V MR Minimum Input Pulse 0.8 2.4 0.3 x VCC V 0.7 x VCC 1 µs MR Glitch Rejection 100 ns MR to Reset Delay 500 ns MR Pull-Up Resistance RESET Output Voltage 32 VOL 63 0.4 VCC > 2.5V, ISINK = 1.2mA 0.3 VCC > 1.2V, ISINK = 0.5mA VCC > 1.0V, ISINK = 80µA RESET Output Leakage Current 100 VCC > 4.25V, ISINK = 3.2mA VCC > VTH, RESET deasserted kΩ V 0.3 1 µA Note 1: The MAX6315 monitors VCC through an internal factory-trimmed voltage divider that programs the nominal reset threshold. Factory-trimmed reset thresholds are available in 100mV increments from 2.5V to 5V (see Ordering and Marking Information). 2 _______________________________________________________________________________________ Open-Drain SOT µP Reset Circuit SUPPLY CURRENT vs. SUPPLY VOLTAGE 3 VCC = 3V 2 TA = +85°C 3 TA = +25°C 2 TA = -40°C -30 -10 10 30 50 70 1 0 90 3 2 NORMALIZED RESET TIMEOUT PERIOD vs. TEMPERATURE (VCC RISING) 1.02 1.01 1.00 0.99 0.98 0.97 0.96 30 50 TEMPERATURE (°C) VTH = 3.00V 10 -50 -30 70 90 -10 10 30 50 90 70 MAX6315-05 MAXIMUM TRANSIENT DURATION vs. RESET COMPARATOR OVERDRIVE 1.004 1.002 1.000 0.998 0.996 100 TA = +25°C RESET OCCURS ABOVE CURVE 80 VTH = 4.63V 60 40 20 VT = 3.00V 0 0.994 10 20 TEMPERATURE (°C) 1.006 NORMALIZED RESET THRESHOLD 1.03 -10 VTH = 4.63V NORMALIZED RESET THRESHOLD vs. TEMPERATURE (VCC FALLING) MAX6315-04 1.04 -30 30 SUPPLY VOLTAGE (V) TEMPERATURE (°C) -50 40 0 5 4 MAXIMUM TRANSIENT DURATION (µs) -50 NORMALIZED RESET TIMEOUT PERIOD VCC FALLING AT 1mV/µs 0 0 MAX6315-03 MAX6315-02 4 1 VCC = 1V 1 50 POWER-DOWN RESET DELAY (µs) VCC = 5V 4 5 SUPPLY CURRENT (µA) 5 SUPPLY CURRENT (µA) 6 MAX6315-01 6 POWER-DOWN RESET DELAY vs. TEMPERATURE MAX6315-06 SUPPLY CURRENT vs. TEMPERATURE -50 -30 -10 10 30 50 70 TEMPERATURE (°C) 90 10 100 1000 RESET COMP. OVERDRIVE, VTH - VCC (mV) ______________________________________________________________Pin Description PIN NAME FUNCTION 1 GND 2 RESET 3 MR Manual Reset Input. A logic low on MR asserts reset. Reset remains asserted as long as MR is low, and for the reset timeout period (tRP) after the reset conditions are terminated. Connect to VCC if not used. 4 VCC Supply Voltage and Reset Threshold Monitor Input Ground Active-Low Open-Drain Output. Connect to an external pull-up resistor. Can be pulled up to a voltage higher than VCC, but less than 6V. _______________________________________________________________________________________ 3 MAX6315 __________________________________________Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) MAX6315 Open-Drain SOT µP Reset Circuit _______________Detailed Description Reset Output A microprocessor’s (µP’s) reset input starts the µP in a known state. The MAX6315 asserts reset to prevent code-execution errors during power-up, power-down, or brownout conditions. RESET is guaranteed to be a logic low for VCC > 1V (see Electrical Characteristics). Once VCC exceeds the reset threshold, the internal timer keeps reset asserted for the reset timeout period (tRP); after this interval RESET goes high. If a brownout condition occurs (monitored voltage dips below its programmed reset threshold), RESET goes low. Any time VCC dips below the reset threshold, the internal timer resets to zero and RESET goes low. The internal timer starts when VCC returns above the reset threshold, and RESET remains low for the reset timeout period. The MAX6315’s RESET output structure is a simple open-drain N-channel MOSFET switch. Connect a pullup resistor to any supply in the 0V to +6V range. Select a resistor value large enough to register a logic low when RESET is asserted (see Electrical Characteristics), and small enough to register a logic high while supplying all input current and leakage paths connected to the RESET line. A 10kΩ pull-up is sufficient in most applications. Often, the pull-up connected to the MAX6315’s RESET output will connect to the supply voltage monitored at the IC’s VCC pin. However, some systems may use the open-drain output to level-shift from the monitored supply to reset circuitry powered by some other supply (Figure 1). This is one useful feature of an open-drain output. Keep in mind that as the MAX6315’s V CC decreases below 1V, so does the IC’s ability to sink current at RESET. Finally, with any pull-up, RESET will be pulled high as VCC decays toward 0V. The voltage where this occurs depends on the pull-up resistor value and the voltage to which it connects (see Electrical Characteristics). Manual-Reset Input Many µP-based products require manual-reset capability, allowing the operator, a test technician, or external logic circuitry to initiate a reset. A logic low on MR asserts reset. Reset remains asserted while MR is low, and for the reset active timeout period after MR returns high. MR has an internal 63kΩ pull-up resistor, so it can be left open if not used. Connect a normally open momentary switch from MR to GND to create a manual reset function; external debounce circuitry is not required. 4 +3.3V +5.0V VCC 10k MR RESET 5V SYSTEM MAX6315 GND Figure 1. MAX6315 Open-Drain RESET Output Allows Use with Multiple Supplies If MR is driven from long cables or if the device is used in a noisy environment, connecting a 0.1µF capacitor from MR to ground provides additional noise immunity. __________Applications Information Negative-Going VCC Transients In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, these devices are relatively immune to short-duration negative-going transients (glitches). The Typical Operating Characteristics show the Maximum Transient Duration vs. Reset Threshold Overdrive, for which reset pulses are not generated. The graph was produced using negativegoing pulses, starting at VRST max and ending below the programmed reset threshold by the magnitude indicated (reset threshold overdrive). The graph shows the maximum pulse width that a negative-going VCC transient may typically have without causing a reset pulse to be issued. As the transient amplitude increases (i.e., goes farther below the reset threshold), the maximum allowable pulse width decreases. A 0.1µF bypass capacitor mounted close to V CC provides additional transient immunity. _______________________________________________________________________________________ Open-Drain SOT µP Reset Circuit NOMINAL VTH (V) PART† MAX6315US50D1-T MAX6315US49D1-T MAX6315US48D1-T MAX6315US47D1-T MAX6315US46D1-T MAX6315US45D1-T MAX6315US44D1-T††† MAX6315US43D1-T MAX6315US42D1-T MAX6315US41D1-T MAX6315US40D1-T MAX6315US39D1-T MAX6315US38D1-T MAX6315US37D1-T MAX6315US36D1-T MAX6315US35D1-T MAX6315US34D1-T MAX6315US33D1-T MAX6315US32D1-T MAX6315US31D1-T MAX6315US30D1-T MAX6315US29D1-T MAX6315US28D1-T MAX6315US27D1-T MAX6315US26D1-T††† MAX6315US25D1-T 5.00 4.90 4.80 4.70 4.63 4.50 4.39 4.30 4.20 4.10 4.00 3.90 3.80 3.70 3.60 3.50 3.40 3.30 3.20 3.08 3.00 2.93 2.80 2.70 2.63 2.50 MIN tRP (ms) SOT TOP MARK†† PART† 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 FX_ _ FY_ _ FZ_ _ GA_ _ GB_ _ GC_ _ GD_ _ GE_ _ GF_ _ GG_ _ GH_ _ GI_ _ GJ_ _ GK_ _ GL_ _ GM_ _ GN_ _ GO_ _ GP_ _ GQ_ _ GR_ _ GS_ _ GT_ _ GU_ _ GV_ _ GW_ _ MAX6315US50D2-T MAX6315US49D2-T MAX6315US48D2-T MAX6315US47D2-T MAX6315US46D2-T MAX6315US45D2-T MAX6315US44D2-T††† MAX6315US43D2-T MAX6315US42D2-T MAX6315US41D2-T MAX6315US40D2-T MAX6315US39D2-T MAX6315US38D2-T MAX6315US37D2-T MAX6315US36D2-T MAX6315US35D2-T MAX6315US34D2-T MAX6315US33D2-T MAX6315US32D2-T MAX6315US31D2-T MAX6315US30D2-T MAX6315US29D2-T MAX6315US28D2-T MAX6315US27D2-T MAX6315US26D2-T††† MAX6315US25D2-T NOMINAL VTH (V) 5.00 4.90 4.80 4.70 4.63 4.50 4.39 4.30 4.20 4.10 4.00 3.90 3.80 3.70 3.60 3.50 3.40 3.30 4.20 3.08 3.00 2.93 2.80 2.70 2.63 2.50 MIN tRP (ms) SOT TOP MARK†† 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 GX_ _ GY_ _ GZ_ _ HA_ _ HB_ _ HC_ _ HD_ _ HE_ _ HF_ _ HG_ _ HH_ _ HI_ _ HJ_ _ HK_ _ HL_ _ HM_ _ HN_ _ HO_ _ HP_ _ HQ_ _ HR_ _ HS_ _ HT_ _ HU_ _ HV_ _ HW_ _ †The MAX6315 is available in a SOT143 package, -40°C to +85°C temperature range. ††The first two letters in the package top mark identify the part, while the remaining two letters are the lot tracking code. †††Sample stocks generally held on the bolded products; also, the bolded products have 2,500 piece minimum-order quantities. Non-bolded products have 10,000 piece minimum-order quantities. Contact factory for details. Note: All devices available in tape-and-reel only. Contact factory for availability. _______________________________________________________________________________________ 5 MAX6315 ________________________________________________________Ordering Information MAX6315 Open-Drain SOT µP Reset Circuit ___________________________________________Ordering Information (continued) PART† MAX6315US50D3-T MAX6315US49D3-T MAX6315US48D3-T MAX6315US47D3-T MAX6315US46D3-T††† MAX6315US45D3-T MAX6315US44D3-T††† MAX6315US43D3-T MAX6315US42D3-T MAX6315US41D3-T MAX6315US40D3-T MAX6315US39D3-T MAX6315US38D3-T MAX6315US37D3-T MAX6315US36D3-T MAX6315US35D3-T MAX6315US34D3-T MAX6315US33D3-T MAX6315US32D3-T MAX6315US31D3-T††† MAX6315US30D3-T MAX6315US29D3-T††† MAX6315US28D3-T MAX6315US27D3-T MAX6315US26D3-T††† MAX6315US25D3-T NOMINAL VTH (V) 5.00 4.90 4.80 4.70 4.63 4.50 4.39 4.30 4.20 4.10 4.00 3.90 3.80 3.70 3.60 3.50 3.40 3.30 3.20 3.08 3.00 2.93 2.80 2.70 2.63 2.50 MIN tRP (ms) SOT TOP MARK†† 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 140 HX_ _ HY_ _ HZ_ _ IA_ _ IB_ _ IC_ _ ID_ _ IE_ _ IF_ _ IG_ _ IH_ _ II_ _ IJ_ _ IK_ _ IL_ _ IM_ _ IN_ _ IO_ _ IP_ _ IQ_ _ IR_ _ IS_ _ IT_ _ IU_ _ IV_ _ IW_ _ PART† NOMINAL VTH (V) MIN tRP (ms) SOT TOP MARK†† MAX6315US50D4-T 5.00 1120 IX_ _ MAX6315US49D4-T MAX6315US48D4-T MAX6315US47D4-T MAX6315US46D4-T MAX6315US45D4-T MAX6315US44D4-T††† MAX6315US43D4-T MAX6315US42D4-T MAX6315US41D4-T MAX6315US40D4-T MAX6315US39D4-T MAX6315US38D4-T MAX6315US37D4-T MAX6315US36D4-T MAX6315US35D4-T MAX6315US34D4-T MAX6315US33D4-T MAX6315US32D4-T MAX6315US31D4-T MAX6315US30D4-T MAX6315US29D4-T MAX6315US28D4-T MAX6315US27D4-T MAX6315US26D4-T††† MAX6315US25D4-T 4.90 4.80 4.70 4.63 4.50 4.39 4.30 4.20 4.10 4.00 3.90 3.80 3.70 3.60 3.50 3.40 3.30 3.20 3.08 3.00 2.93 2.80 2.70 2.63 2.50 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 1120 IY_ _ IZ_ _ JA_ _ JB_ _ JC_ _ JD_ _ JE_ _ JF_ _ JG_ _ JH_ _ JI_ _ JJ_ _ JK_ _ JL_ _ JM_ _ JN_ _ JO_ _ JP_ _ JQ_ _ JR_ _ JS_ _ JT_ _ JU_ _ JV_ _ JW_ _ †The MAX6315 is available in a SOT143 package, -40°C to +85°C temperature range. ††The first two letters in the package top mark identify the part, while the remaining two letters are the lot tracking code. †††Sample stocks generally held on the bolded products; also, the bolded products have 2,500 piece minimum-order quantities. Non-bolded products have 10,000 piece minimum-order quantities. Contact factory for details. Note: All devices available in tape-and-reel only. Contact factory for availability. 6 _______________________________________________________________________________________ Open-Drain SOT µP Reset Circuit TRANSISTOR COUNT: 519 SOT1434.EPS ________________________________________________________Package Information _______________________________________________________________________________________ 7 MAX6315 ___________________Chip Information MAX6315 Open-Drain SOT µP Reset Circuit NOTES 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.