STM1001 Reset circuit Features ■ Precision monitoring of 3 V, 3.3 V, and 5 V supply voltages ■ Open drain RST output ■ 30 ms or 140 ms reset pulse width (min) ■ Low supply current - 6 µA (typ) ■ Guaranteed RST assertion down to VCC= 1.0 V ■ Operating temperature: – –40 °C to 85 °C (industrial grade) ■ Lead-free, small SOT23 package February 2010 Doc ID 10373 Rev 6 SOT23-3 (WX) 1/18 www.st.
Contents STM1001 Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Reset output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Negative-going VCC transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
STM1001 List of tables List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of figures STM1001 List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. 4/18 Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . .
STM1001 1 Description Description The STM1001 microprocessor reset circuit is a low-power supervisory device used to monitor power supplies. It performs a single function: asserting a reset signal whenever the VCC supply voltage drops below a preset value and keeping it asserted until VCC has risen above the preset threshold for a minimum period of time (trec). Figure 1. Logic diagram VCC STM1001 RST VSS Table 1.
Description STM1001 Figure 3. Block diagram VCC VRST COMPARE trec Generator RST (1) AI09118 1. Open drain Figure 4. Hardware hookup VCC VCC (1) STM1001 RST(1) VSS VCC MCU RESET Input VSS AI09119 1. RST output requires pull-up resistor.
STM1001 Operation 2 Operation 2.1 Reset output The STM1001 microprocessor reset circuit asserts a reset signal to the MCU whenever VCC goes below the reset threshold (VRST). RST is guaranteed valid down to VCC = 1 V (0° to 70 °C). During power-up, once VCC exceeds the reset threshold an internal timer keeps RST low for the reset time-out period, trec. After this interval, RST returns high. If VCC drops below the reset threshold, RST goes low.
Typical operating characteristics STM1001 3 Typical operating characteristics Note: Typical values are at TA = 25 °C, VCC = 5 V for L/M versions, VCC = 3.3 V for T/S versions, and VCC = 3.0 V for R versions. Figure 5. Supply current vs. temperature, L/M/R/S/T (no load) 8.0 Supply Current (µA) 6.0 1V 3V 3.6V 5.5V 4.0 2.0 0.0 –40 –20 0 20 40 60 80 Temperature (°C) AI07879 Figure 6. Power-down reset delay vs. temperature - VOD = VTH – VCC (L/M) 140.00 Power-Down Reset Delay (µs) 120.
STM1001 Typical operating characteristics Figure 7. Power-down reset delay vs. temperature - VOD = VTH – VCC (R/S/T) Power-Down Reset Delay (µs) 100.00 80.00 60.00 VOD = 20mV VOD = 125mV VOD = 200mV 40.00 20.00 0.00 –40 –20 0 20 40 60 80 Temperature (°C) Figure 8. AI07878 Power-up trec vs. temperature 250.00 Power-up trec (ms) 240.00 230.00 L/M R/S/T 220.00 210.00 200.00 –40 Note: –20 0 20 Temperature (°C) 40 60 80 AI07881 Valid for trec = 210 ms (typ).
Typical operating characteristics Figure 9. STM1001 Normalized reset threshold vs. temperature 1.003 1.002 1.001 Normalized Treshold 1.000 0.999 0.998 L/M R/S/T 0.997 0.996 0.995 0.994 0.993 –40 –20 0 20 40 60 80 Temperature (°C) AI07882 Figure 10. Max transient duration not causing reset pulse vs. reset comparator overdrive 700.00 Maximum Transient Duration (µs) 600.00 500.00 400.00 R/S/T L/M 300.00 200.00 100.00 0.
STM1001 4 Maximum ratings Maximum ratings Stressing the device above the rating listed in the absolute maximum ratings table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the operating sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC and AC parameters 5 STM1001 DC and AC parameters This section summarizes the operating measurement conditions, and the DC and AC characteristics of the device. The parameters in the DC and AC characteristics tables that follow, are derived from tests performed under the measurement conditions summarized in Table 3: Operating and AC measurement conditions. Designers should check that the operating conditions in their circuit match the operating conditions when relying on the quoted parameters. Table 3.
STM1001 Table 4. DC and AC parameters DC and AC characteristics Sym Description VCC Operating voltage ICC VCC supply current ILO Open drain reset output leakage current VOL VOL RST output low voltage RST output low voltage Test condition(1) Min TA = –40 to +85 °C 1.2 TA = 0 to +70 °C 1.0 Typ Max Unit 5.5 V 5.5 V VCC < 3.6 V 5.5 10 µA VCC < 5.5 V 7 15 µA +1 µA STM1001R/S/T only, IOL = 1.2 mA VCC = VRST (min) 0.3 V STM1001L/M only, IOL = 3.2 mA VCC = VRST (min) 0.
Package mechanical data 6 STM1001 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Figure 12. SOT23-3 – 3-lead small outline transistor package outline E E1 0.15 B M CAB A1 1 e e1 D 0.20 M 3X CAB 0.
STM1001 7 Part numbering Part numbering Table 6. Ordering information scheme Example: STM1001 S B WX 6 F Device type STM1001 Reset threshold voltage L = VRST = 4.50 V to 4.75 V M = VRST = 4.25 V to 4.50 V T = VRST = 3.00 V to 3.15 V S = VRST = 2.85 V to 3.00 V R = VRST = 2.55 V to 2.
Part numbering STM1001 Table 7. Marking description Part number Reset threshold Output Topside marking(1) STM1001LWX6F 4.63 V Open drain RST 8BAx STM1001MWX6F 4.38 V Open drain RST 8BBx STM1001TWX6F 3.08 V Open drain RST 8BCx STM1001SWX6F 2.93 V Open drain RST 8BDx STM1001RWX6F 2.63 V Open drain RST 8BEx STM1001SBWX6F 2.93 V Open drain RST 8BMx 1. Lowercase “x” indicates date code.
STM1001 8 Revision history Revision history Table 8. Document revision history Date Revision 09-Dec-2003 1 Changes First edition 19-Feb-2004 2 22-Mar-2004 2.1 Part number changed from STM6301 09-Apr-2004 3 Device promoted; reformatted; marking updated (Table 7) 19-Nov-2004 4 Update dimensions (Table 5). 19-Sep-2005 5 Remove “Valid RST Output Down to VCC...
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