1999 imp, inc. 408-432-9100/www.impweb.com 1 key features applications u set-top boxes u cellular phones u pdas u energy management systems u embedded control systems u printers u single board computers u improved dallas ds1815 replacement ?over 50% lower maximum supply current u low supply current ?20? maximum (5.5v) ?15? maximum (3.6v) u automatically restarts a microprocessor after power failure u 150ms reset delay after v cc returns to an in-tolerance condition u active low power-up reset u precision temperature-compensated voltage reference and comparator u eliminates external components u low-cost to-92 package u compact surface mount sot-23 package u push-pull output for minimum current drain u operating temperature 40 c to +85 c block diagram + 1815_01.eps v cc 1 reset gnd 3 2 supply tolerance bias imp1815 delay 150ms typical reference imp1 imp1 8 8 1 1 5 5 p ower m anagement lo lo w p w p o o w w er er , 3.3v/3.0v , 3.3v/3.0v p r p r eset eset C a C a ctiv ctiv e l e l o o w w , push-pull output , push-pull output the imp1815 supply voltage monitor is an improved, low-power replacement for the dallas semiconductor ds1815. maximum supply current over temperature is a low 15 m a, representing over 50 percent lower power as compared to the ds1815. the imp1815 issues an active low reset signal whenever the monitored supply is out-of-tolerance. a precision reference and comparator circuit monitor power supply (v cc ) level. tolerance level options are 5-, 10- and 20-percent. when an out-of-tolerance condition is detected, an internal power-fail signal is generated which forces an active low reset signal. after v cc returns to an in-tolerance condition, the reset signal remains active for 150ms to allow the power supply and system microprocessor to stabilize. the imp1815 is designed with a push-pull output stage and operates over the extended industrial temperature range. devices are available in compact surface mount sot-23 packages and 3-lead to-92 packages. other low power products in this family include the imp1810/11/12/16/17, imp1233d and imp1233m. typical application imp1815 microprocessor reset reset 1815_02.eps v cc gnd t r a p e g a t l o v t e s e r ) v ( e m i t t e s e r ) s m ( t u p t u o e g a t s t e s e r y t i r a l o p 0 1 8 1 p m i0 2 1 . 4 , 0 7 3 . 4 , 0 2 6 . 40 5 1l l u p - h s u pw o l 1 1 8 1 p m i0 3 1 . 4 , 0 5 3 . 4 , 0 2 6 . 40 5 1n i a r d - n e p ow o l 2 1 8 1 p m i0 3 1 . 4 , 0 5 3 . 4 , 0 2 6 . 40 5 1l l u p - h s u ph g i h 5 1 8 1 p m i0 5 5 . 2 , 0 8 8 . 2 , 0 6 0 . 30 5 1l l u p - h s u pw o l 6 1 8 1 p m i0 5 5 . 2 , 0 8 8 . 2 , 0 6 0 . 30 5 1n i a r d - n e p ow o l 7 1 8 1 p m i0 5 5 . 2 , 0 8 8 . 2 , 0 6 0 . 30 5 1l l u p - h s u ph g i h d 3 3 2 1 p m i5 2 1 . 4 , 5 7 3 . 4 , 5 2 6 . 40 5 3n i a r d - n e p ow o l m 3 3 2 1 p m i0 2 7 . 2 , 5 7 3 . 4 , 5 2 6 . 40 5 3n i a r d - n e p ow o l family selection guide
2 408-432-9100/www .impweb.com 1999 imp , inc. pin configuration imp1 imp1 8 8 1 1 5 5 pin descriptions pin n umber n ame f unction 1 reset active low reset output 2 v cc power supply input 3 gnd ground imp1815-x reset v cc gnd 3 1 2 1815_03.eps package marking code ordering infor mation 1815_04.eps 1 2 3 imp1815-x so t23 t o-92* 1815_05a.eps 3 1 2 a b c d 3 2 - t o s e g a k c a p e d o c r e t t e l t r a p e p y t 3 2 - t o s e g a k c a p e d o c r e t t e l t e s e r e c n a r e l o t a b c d 8 1 5 5 1 8 1 p m i a % 5 b % 0 1 d % 0 2 s p e . 2 0 t _ 5 1 8 1 * add /s to part number for straight (unformed) leads. (ie. imp18xx-x/s) ** add /t to part number for t ape and reel. (ie. imp18xx-x/t) y r a m m u s e c i v e d g n i k r a m e g a k c a p * * t r a p r e b m u n t e s e r t u p t u o e g a t l o v ) v ( t e s e r e c n a r e l o t ) % ( t e s e r e m i t ) s m ( l l u p - h s u p t u p t u o e g a t s * 2 9 - o t e g a k c a p 3 2 - t o s e g a k c a p t e s e r y t i r a l o p a b c d % 5 = a % 0 1 = b % 0 2 = d 5 - 5 1 8 1 p m i 6 0 . 3 5 0 5 1 x x w o l 0 1 - 5 1 8 1 p m i 8 8 . 2 0 1 0 5 1 x x w o l 0 2 - 5 1 8 1 p m i 5 5 . 2 0 2 0 5 1 x x w o l 5 - r 5 1 8 1 p m i 6 0 . 3 5 0 5 1 x x w o l 8 1 5 a 0 1 - r 5 1 8 1 p m i 8 8 . 2 0 1 0 5 1 x x w o l 8 1 5 b 0 2 - r 5 1 8 1 p m i 5 5 . 2 0 2 0 5 1 x x w o l 8 1 5 d s p e . 3 t _ 5 1 8 1
1999 imp , inc. 408-432-9100/www .impweb.com 3 imp1 imp1 8 8 1 1 5 5 absolute maximum ratings electrical characteristics v oltage on v cc . . . . . . . . . . . . . . . . . . . . . . . . 0.5v to 7v v oltage on reset . . . . . . . . . . . . . . . . . . . . . 0.5v to v cc + 0.5v operating t emperatur e range . . . . . . . . . . . 40 c to 85 c soldering t emperatur e . . . . . . . . . . . . . . . . . . 260 c for 10 seconds storage t emperatur e . . . . . . . . . . . . . . . . . . . 55 c to 125 c v oltages measur ed with r espect to gr ound. these ar e str ess ratings only and functional operation is not implied. p ar amet er symbol conditions min t yp max u nits supply v oltage v cc 1.2 5.5 v output v oltage v oh i out < 500 m a v cc ?0.5v v cc ?0.1v v output current i oh output = 2.4v , v cc 3 2.7v 350 m a output current i ol output = 0.4v , v cc 3 2.7v +10 ma operating current i cc v cc < 5.5v , reset output open 8 20 m a operating current i cc v cc 3.6v , reset output open 6 15 m a v cc t rip point (imp1815-5) v cctp 2.98 3.06 3.15 v v cc t rip point (imp1815-10) v cctp 2.80 2.88 2.97 v v cc t rip point (imp1815-20) v cctp 2.47 2.55 2.64 v output capacitance c out 10 pf v cc detect to reset t rpd 2 5 m s v cc slew rate t f note 1 300 m s ( v cctp (max) to v cctp (min)) v cc slew rate t r 0 ns ( v cctp (min) to v cctp (max)) v cc detect to reset t rpu t r = 5 m s 100 150 250 ms unless otherwise noted, v cc = 1.2v to 5.5v and specifications ar e over the operating temperatur e range of 40 c to +85 c. all voltages ar e r efer enced to gr ound. notes 1. the t f value is for r efer ence in defining values for t rpd and should not be consider ed a r equir ement for pr oper operation or use.
4 408-432-9100/www.impweb.com 1999 imp, inc. imp1 imp1 8 8 1 1 5 5 application information operation ?power monitor the imp1815 detects out-of-tolerance power supply conditions. it resets a processor during power-up, power-down and issues a reset to the system processor when the monitored power supply voltage is below the reset threshold. when an out-of-tolerance v cc voltage is detected, the reset signal is asserted. on power-up, reset is kept active (low) for approximately 150ms after the power supply voltage has reached the selected tolerance. this allows the power supply and microprocessor to stabilize before reset is released. output conditions the imp1815 active low reset signal is valid as long as v cc remains above 1.2v. the reset output on the imp1815 uses a push-pull drive stage that can maintain a valid output below 1.2v. to sink current with v cc below 1.2v, a resistor can be connected from the reset pin (reset) to ground (see figure 1). this configuration will give a valid value on the reset output with v cc approaching 0v. during both power up and down, this con- figuration will draw current when reset is in the high state. a value of 100k w should be adequate to maintain a valid condition. imp1815 microprocessor reset 100k reset 1815_06.eps figure 1. reset valid to 0v v cc figure 2. timing diagram: power-up figure 3. timing diagram: power-down v cctp (max) v cctp v cctp (min) v cc reset t r t rpu v oh 1815_07.eps v cctp (max) v cctp v cctp (min) v cc reset t f v ol t rpd 1815_08.eps
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