SGM802 Low-Power, SC70/SOT µp Reset Circuit with Capacitor-Adjustable Reset Timeout Delay

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Low-Power, SC70/SOT µp Reset Circuit with GENERAL DESCRIPTION The low-power micro-processor supervisor circuit monitors system voltages from 1.6V to 5V.

1 Low-Power, SC70/SOT µp Reset Circuit with GENERAL DESCRIPTION The low-power micro-processor supervisor circuit monitors system voltages from 1.6V to 5V. This device performs a single function: it asserts a reset signal whenever the supply voltage falls below its reset threshold. The reset output remains asserted for the reset timeout period after rises above the reset threshold. The reset timeout is externally set by a capacitor to provide more flexibility. FEATURES Monitor System Voltages from 1.6V to 5V Capacitor-Adjustable Reset Timeout Period Low Quiescent Current (3µA TYP) Push-Pull Output Option Guaranteed Valid to = 1V Immune to Short Transients Available in Green SC70-4 (R) and SOT-143 Packages The has an active-high, push-pull reset output. It is available in Green SC70-4 (R) and SOT-143 packages. The is specified over an ambient temperature range of -40 to +85. TYPICAL APPLICATION APPLICATIONS Portable Equipment Battery-Powered Computers/Controllers Automotive Medical Equipment Intelligent Instruments Embedded Controllers Critical µp Monitoring Set-Top Boxes Computers C SRT SRT GND MICROPROCESSOR SYSTEM GND REV. A. 2

2 PACKAGE/ORDERING INFORMATION MODEL PIN-PACKAGE SOT-143 SC70-4 (R) THRESHOLD (TYP) ORDERING NUMBER PACKAGE MARKING PACKING OPTION 1.63V -1.63YKA4G/TR S78XX Tape and Reel, V -2.32YKA4G/TR S79XX Tape and Reel, V -2.63YKA4G/TR S7AXX Tape and Reel, V -2.93YKA4G/TR S7BXX Tape and Reel, V -1.63YC4G/TR S7DXX Tape and Reel, V -2.32YC4G/TR S7EXX Tape and Reel, V -2.63YC4G/TR S7FXX Tape and Reel, V -2.93YC4G/TR S80XX Tape and Reel, 3000 NOTE: XX = Date Code. Green (RoHS & HSF): defines "Green" to mean Pb-Free (RoHS compatible) and free of halogen substances. If you have additional comments or questions, please contact your SGMICRO representative directly. MARKING INFORMATION SYY X X Date code - Month ("A" = Jan. "B" = Feb. "L" = Dec.) Date code - Year ("A" = 2010, "B" = 2011 ) Chip I.D. For example: S78BA (2011, January) ABSOLUTE MAXIMUM RATINGS All Voltages Referenced to GND V to 6V SRT, (Push-Pull) V to ( + 0.3V) Input Current (All Pins)...20mA Output Current ()...20mA Operating Temperature Range to +85 Storage Temperature Range to +150 Junction Temperature Lead Temperature (Soldering, 10s) ESD Susceptibility HBM V MM...300V NOTE: 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. CAUTION This integrated circuit can be damaged by ESD if you don t pay attention to ESD protection. SGMICRO recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. SGMICRO reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. Please contact SGMICRO sales office to get the latest datasheet. 2

3 Low-Power, SC70/SOT µp Reset Circuit with PIN CONFIGURATIONS (TOP VIEW) GND SRT GND 2 3 SRT SOT-143 SC70-4 (R) PIN DESCRIPTION SOT-143 PIN SC70-4 (R) NAME FUNCTION 1 2 GND Ground. 2 1 Supply Voltage and Reset Threshold Monitor Input. 3 3 SRT 4 4 Set Reset Timeout Input. Connect a capacitor between SRT and ground to set the timeout period. Determine the period as follows: t RP = C SRT with t RP in seconds and C SRT in farads. changes from low to high whenever drops below the selected reset threshold voltage. remains high for the reset timeout period after exceeds the reset threshold. 3

4 ELECTRICAL CHARACTERISTICS ( = 1V to 5.5V, T A = -40 to +85, typical values are at = 5V and T A = +25, unless otherwise specified.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage Range V 5.0V Supply Current Reset Threshold Accuracy I CC V TH 3.3V μa 2.0V T A = +25 V TH - 2.5% V TH + 2.5% V T A = -40 to +85 V TH - 3.5% V TH + 3.5% Hysteresis V HYST 4 V TH mv to Reset Delay t RD falling at 1mV/µs 80 µs Reset Timeout Period t RP C SRT = 1500pF ms C SRT = V SRT Ramp Current I RAMP V SRT = 0 to 0.65V, = 1.6V to 5V 210 na V SRT Ramp Threshold V TH-RAMP = 1.6V to 5V (V RAMP rising) 0.6 V 1.0V, I SOURCE = 1µA 0.8 Output Voltage High Output Voltage Low V OH V OL 1.8V, I SOURCE = 150µA 0.8 V 2.7V, I SOURCE = 500µA V, I SOURCE = 800µA V, I SINK = 500µA V, I SINK = 1.2mA 0.3 V 4.5V, I SINK = 3.2mA 0.4 4

5 TYPICAL PERFORMANCE CHARACTERISTICS = 5V, C SRT = 1500pF, T A = +25, unless otherwise noted. 6 Supply Current vs. Supply Voltage Reset Timeout Period vs. C SRT Supply Current (μa) V TH = 1.63V Supply Voltage (V) Reset Timeout Period (ms) C SRT (nf) Reset Timeout Period (μs) Reset Timeout Period vs. Temperature C SRT = 0 Reset Timeout Period (ms) Reset Timeout Period vs. Temperature C SRT = 1500pF Temperature ( ) Temperature ( ) Normalized Reset Threshold Normalized Reset Threshold vs. Temperature Transient Duration (µs) Maximum Transient Duration vs. Reset Threshold Overdrive V TH = 2.93V Temperature ( ) Reset Threshold Overdrive (mv) 5

6 TYPICAL PERFORMANCE CHARACTERISTICS = 5V, C SRT = 1500pF, T A = +25, unless otherwise noted. 6

7 DETAILED DESCRIPTION Reset Output The reset output is typically connected to the reset input of a µp. A µp s reset input starts or restarts the µp in a known state. The µp supervisory circuit provides the reset logic to prevent code-execution errors during power-up, power-down, and brownout conditions. changes from low to high whenever drops below the threshold voltage. Once exceeds the threshold voltage, remains high for the capacitoradjustable reset timeout period. This device output is guaranteed valid for > 1V. Operating as a Voltage Detector The can be operated in a voltage detector mode by floating the SRT pin. The reset delay times for rising above or falling below the threshold are not significantly different. The reset output is deasserted smoothly without false pulses. Low-Power, SC70/SOT µp Reset Circuit with Selecting a Reset Capacitor The reset timeout period is adjustable to accommodate a variety of µp applications. Adjust the reset timeout period (t RP ) by connecting a capacitor (C SRT ) between SRT and ground. Calculate the reset timeout capacitor as follows: C SRT = (t RP )/( ) where t RP is in seconds and C SRT is in farads. The reset delay time is set by a current/capacitorcontrolled ramp compared to an internal 0.6V reference. An internal 210nA ramp current source charges the external capacitor. The charge to the capacitor is cleared when a reset condition is detected. Once the reset condition is removed, the voltage on the capacitor ramps according to the formula: dv/dt = I/C. The C SRT capacitor must ramp to 0.6V to deassert the reset. C SRT must be a low-leakage (<10nA) type capacitor; ceramic is recommended. + - V REF μp SRT TIMEOUT C SRT GND Figure 1. Typical Operating Circuit 7

8 APPLICATION INFORMATION Negative-Going Transients In addition to issuing a reset to the µp during power-up, power-down, and brownout conditions, this supervisor is relatively immune to short-duration negative-going transients (glitches). The graph Maximum Transient Duration vs. Reset Threshold Overdrive in the Typical Performance Characteristics shows this relationship. The area below the curve of the graph is the region in which these devices typically do not generate a reset pulse. This graph was generated using a negative-going pulse applied to, starting above the actual reset threshold (V TH ) and ending below it by the magnitude indicated (reset-threshold overdrive). As the magnitude of the transient decreases (further below the reset threshold), the maximum allowable pulse widthdecreases. Typically, a transient that goes 100mV below the reset threshold and lasts 50µs or less does not cause a reset pulse to be issued. Ensuring a Valid Down to = 0 When falls below 1V, current-sinking (sourcing) capabilities decline drastically. For applications using the, a 100kΩ pull up resistor between and holds high when falls below 1V (Figure 2). Low-Power, SC70/SOT µp Reset Circuit with GND 100kΩ Figure 2. Ensuring Valid to = 0 Layout Consideration SRT is a precise current source. When developing the layout for the application, be careful to minimize board capacitance and leakage currents around this pin. Traces connected to SRT should be kept as short as possible. Traces carrying high-speed digital signals and traces with large voltage potentials should be routed as far from SRT as possible. Leakage current and stray capacitance (e.g., a scope probe) at this pin could cause errors in the reset timeout period. When evaluating these parts, use clean prototype boards to ensure accurate reset periods. 8

9 PACKAGE OUTLINE DIMENSIONS SC70-4 (R) D e1 e 0.65 E1 E b d b RECOMMENDED LAND PATTERN (Unit: mm) L L1 A A1 A2 θ 0.20 c Dimensions In Millimeters Dimensions In Inches Symbol MIN MAX MIN MAX A A A b b c d 0.050TYP 0.002TYP D E E e 0.65 TYP TYP e L REF REF L θ

10 PACKAGE OUTLINE DIMENSIONS SOT-143 D 1.90 e e E1 E 2.2 d b1 b RECOMMENDED LAND PATTERN (Unit: mm) L L1 A A1 A2 θ c Symbol Dimensions In Millimeters Dimensions In Inches MIN MAX MIN MAX A A A b b c D d TYP TYP E E e 0.95 TYP TYP e L 0.55 REF REF L θ

11 TAPE AND REEL INFORMATION REEL DIMENSIONS TAPE DIMENSIONS P2 P0 W Q1 Q2 Q1 Q2 Q1 Q2 B0 Q3 Q4 Q3 Q4 Q3 Q4 Reel Diameter P1 A0 K0 Reel Width (W1) DIRECTION OF FEED NOTE: The picture is only for reference. Please make the object as the standard. KEY PARAMETER LIST OF TAPE AND REEL Package Type Reel Diameter Reel Width W1 A0 B0 K0 P0 P1 P2 W Pin1 Quadrant SC70-4 (R) Q3 SOT Q3 11

12 Low-Power, SC70/SOT µp Reset Circuit with CARTON BOX DIMENSIONS NOTE: The picture is only for reference. Please make the object as the standard. KEY PARAMETER LIST OF CARTON BOX Reel Type Length Width Height Pizza/Carton 7 (Option)

SGM800 Low-Power, SOT µp Reset Circuit with Capacitor-Adjustable Reset Timeout Delay

SGM800 Low-Power, SOT µp Reset Circuit with Capacitor-Adjustable Reset Timeout Delay GENERAL DESCRIPTION The low-power micro-processor supervisor circuit monitors system voltages from 1.6V to 5V. This device performs a single function: it asserts a reset signal whenever the V CC supply