MAX6819/MAX6820 19-1951 Rev 3 12/05 SOT23 Power-Supply Sequencers General Description Features The MAX6819/MAX6820 are power-supply sequencers Adjustable Primary Supply Voltage Monitor for dual-voltage microprocessors (Ps) and multivoltage (Monitors Down to 0.62V) systems. These devices monitor a primary supply voltage Internal Charge Pump to Enhance External and enable/disable an external n-channel MOSFET Secondary Supply n-Channel MOSFET Switch switch for a secondary supply voltage. The MAX6819/ Delay from Primary Supply Good to Secondary MAX6820 control local component voltage sequencing when system power-on/power-off characteristics cannot Supply Enabled be guaranteed (supplies come from a multivoltage sys- Factory Fixed 200ms (MAX6819) tem bus, silver box, or must be sequenced in different Capacitor Adjustable (MAX6820) modes for components on the same board). These small Logic Driven ENABLE Input (MAX6819) power-supply sequencers improve system reliability. Immune to Short Voltage Transients The MAX6819/MAX6820 include an internal voltage ref- Few External Components erence/comparator with externally adjustable thresh- olds to monitor the primary power supply. When the -40C to +125C Operating Temperature Range primary supply is below the desired threshold, an exter- Small 6-Pin SOT23 Package nal secondary supply MOSFET switch is disabled. Ordering Information When the primary supply exceeds the threshold, an internal charge pump is activated and the external PIN- TO P MOSFET switch is enabled to connect the secondary PART TEMP RANGE PACKAGE M ARK supply to the load. The charge pump fully enhances the n-channel MOSFET switch to provide a very low R DS- MAX6819UT-T -40C to +125C 6 SOT23-6 AARF voltage drop. The devices can be connected to ON MAX6820UT-T -40C to +125C 6 SOT23-6 AARG support various supply sequencing priorities such as Products must be ordered in 2,500 piece increments. V before V or V before V . I/O CORE CORE I/O Devices are available in both leaded and lead-free packaging. The MAX6819 features a logic-driven EN input to Specify lead-free by replacing -T with +T when ordering. enable/disable the external MOSFET drive and includes an internally fixed 200ms enable timeout period Typical Operating Circuits (V to V ). The PRIMARY GOOD SECONDARY ENABLE PRIMARY SUPPLY MAX6820 allows the enable timeout period to be (3.3V) adjusted with a single external capacitor. Both devices SECONDARY SUPPLY are specified over the automotive temperature range (1.8V) (-40C to +125C) and are available in space-saving V GATE CC2 6-pin SOT23 packages. DUAL-SUPPLY BOARD OR P MAX6819 Applications V GND CC1 Dual-Voltage Microprocessors ON Multivoltage Systems SETV EN OFF Digital Signal Processors Power PC Series Processors Pin Configurations TOP VIEW Pin Configurations and Typical Operating Circuits V16 V CC1 CC2 continued at end of data sheet. MAX6819 GND 2 5 GATE Power PC is a trademark of IBM corp. SETV34 EN SOT23-6 Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.SOT23 Power-Supply Sequencers ABSOLUTE MAXIMUM RATINGS Referenced to GND Continuous Power Dissipation (T = +70C) A V , V , EN .....................................................-0.3V to +6.0V 6-Pin SOT23 (derate 8.7mW/C above +70C)............696mW CC1 CC2 SETV, SETD..................-0.3V to the higher of (V + 0.3V) and Operating Temperature Range .........................-40C to +125C CC1 (V + 0.3V) Junction Temperature......................................................+150C CC2 GATE ...................................................................-0.3V to +12.0V Storage Temperature Range .............................-65C to +150C Input Current/Output Current (all pins) ...............................20mA Lead Temperature (soldering 10s) ..................................+300C 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 (V or V > +2.125V to +5.5V, T = -40C to +125C, unless otherwise specified. Typical values are at T = +25C.) (Note 1) CC1 CC2 A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS V , CC1 Operating Voltage Range (Note 2) 0.9 5.5 V V CC2 V , V Supply Current I V = V = +3.3V 60 120 A CC1 CC2 CC CC1 CC2 20 A V , V D i sabl e Mod e C urr ent V = V = +3.3V, EN = GND C C 1 C C 2 CC1 CC2 MAX6819 6 V , V Slew Rate (Note 3) V/s CC1 CC2 MAX6820 (Note 4) 1.2 / t DELAY 2.0 2.125 V Undervoltage Lockout (UVLO) V 1.875 UVLO 0.618 0.634 V SETV Threshold V V rising, enables GATE 0.602 TH SETV 10 100 nA SETV Input Current (Note 3) -1 % SETV Threshold Hysteresis V falling, disables GATE SETV 200 280 ms SETV to GATE Delay t V > V , V 2V (MAX6819) 140 DELAY SETV TH EN SETD Ramp Current (MAX6820) I V or V > +2.125V 400 500 600 nA SETD CC1 CC2 1.242 1.273 V SETD Voltage (MAX6820) V V or V > +2.125V 1.210 SETD CC1 CC2 SETD Threshold Hysteresis V falling -62 mV SETD (MAX6820) GATE Turn-On Time t C = 1500pF, V = + 3.3V, V = + 7.8V 0.5 1.5 10 ms ON GATE C C 2 GATE 30 s GATE Turn-Off Time t C = 1500pF, V = + 3.3V, V = + 0.5V OFF GATE C C 2 GATE With respect to V (Note 2) CC2 4.5 5.5 6.0 R > 50M to V GATE CC2 GATE Voltage V V GATE With respect to V (Note 2) CC2 4.0 6.0 R > 5M to V GATE CC2 0.4 V IL EN Input Voltage V or V > +2.125V to + 5.5V V CC1 CC2 V 2.0 IH Note 1: 100% production tested at T = +25C. Specifications over temperature limit are guaranteed by design. A Note 2: Either V or V must be > 2.125V. The other supply can go to 0. CC1 CC2 Note 3: Guaranteed by design, not production tested. 6 Note 4: t (s) = 2.48 10 C DELAY SET 2 MAX6819/MAX6820