STM1810 STM1811 STM1812 STM1813 STM1815 STM1816 STM1817 STM1818 Low power reset circuit Features ■ Precision monitoring of 3 V, 3.3 V, and 5 V supply voltages ■ Four output configurations: – Push-pull, active-high (STM1812,1817) – Push-pull, active-low (STM1810,1815) – Open-drain, active-low (STM1811,1816) – Open-drain, active-low with push-button detect (STM1813,1818) ■ Reset pulse width - 100 ms (min.) ■ Low supply current - 4 µA (typ.) ■ Guaranteed assertion down to VCC = 1.
Contents STM1810/1811/1812/1813/1815/1816/1817/1818 Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1 Functional block diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2.1 Active-low RST output (push-pull) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2.
STM1810/1811/1812/1813/1815/1816/1817/1818 List of tables List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. Table 13. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STM1810/STM1815 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of figures STM1810/1811/1812/1813/1815/1816/1817/1818 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. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. 4/25 Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 SOT23-3 connections . . . . . . . . . . . . . . . . . . . . . . . . .
STM1810/1811/1812/1813/1815/1816/1817/1818 1 Description Description STM181x devices are low power reset devices used to monitor power supplies for microcontrollers. They perform a single function: asserting a reset signal whenever 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). They provide excellent circuit reliability without additional external components when used with +3.0 V / +3.
Description STM1810/1811/1812/1813/1815/1816/1817/1818 Table 2. Signal names Symbol Description VSS Ground RST Active-low reset output RST(1) Active-high reset output VCC Supply voltage and input for reset threshold monitor 1. For STM1812, STM1817. Figure 2. SOT23-3 connections 234 234 6## 633 !) 2. RST for STM1812 and STM1817. Figure 3. Hardware hookup 6## 6## 6## 34- X -#5 2ESET )NPUT 234 0USH BUTTON RESET 633 633 !) A 1.
STM1810/1811/1812/1813/1815/1816/1817/1818 1.1 Description Functional block diagrams Figure 4. 6## Push-pull active-low output (STM1810/1812/1815/1817) 6234 TREC GENERATOR #/-0!2% 234 !) A 1. RST for STM1812 and STM1817. Figure 5. Open-drain, active-low output (STM1811/1816) 6## 6234 #/-0!2% TREC GENERATOR 234 !) 1. 5.5 kΩ internal pull-up resistor. Figure 6.
Description 1.2.3 STM1810/1811/1812/1813/1815/1816/1817/1818 Active-high RST output (push-pull) Pulses high when VCC drops below VRST, and stays high as long as VCC is below the reset threshold. It remains high for trec after VCC rises above the reset threshold. 1.2.4 Active-low RST output (open-drain with internal 5.5 kΩ pull-up) with manual reset detect Pulses low when VCC drops below VRST, or RST is externally pulled low for at least 1.5 µs.
STM1810/1811/1812/1813/1815/1816/1817/1818 2 Operation 2.1 Reset output Operation The STM181x asserts a reset signal to the microcontroller (MCU) whenever VCC goes below the reset threshold (VRST), and is guaranteed valid down to VCC = 1.0 V (0 °C to 105 °C). A microcontroller’s (MCU) reset input starts the MCU in a known state.
Operation 2.5 STM1810/1811/1812/1813/1815/1816/1817/1818 Valid RST output down to VCC = 0 V When VCC falls below 1 V, the RST output no longer sinks current, but becomes an open circuit. In most systems this is not a problem, as most MCUs do not operate below 1 V. However, in applications where RST output must be valid down to 0 V, a pull-down resistor may be added to hold the RST output low (see Figure 11).
STM1810/1811/1812/1813/1815/1816/1817/1818 Figure 9. Operation Manual reset timing diagram, switch bounce/debounce (STM1813/1818) 6## /PEN %XTERNAL PUSH BUTTON T0"234 T0"234 3WITCH BOUNCE #LOSED 234 !) Figure 10. Interfacing MCUs with bidirectional reset pins (RST, open-drain, STM1811/1816) 6## 34- 34- 6## 6## -#5 234 INPUT 234 633 633 !) Figure 11.
Operation STM1810/1811/1812/1813/1815/1816/1817/1818 Figure 12. Valid reset (RST) output down to VCC = 0 V (push-pull) 6## 6## 34- 34- 6## 20 -#5 234 633 234 )NPUT 633 !) 1. ~100 kΩ resistor recommended.
STM1810/1811/1812/1813/1815/1816/1817/1818 Typical operating characteristics Typical values are at TA = 25 °C. Figure 13. Supply current vs. temperature (no load) 3UPPLY CURRENT ! 6## 6 6## 6 n n 4EMPERATURE # !) B Figure 14. Normalized reset time-out period (trec) vs. temperature - VOD = VTH – VCC .
Typical operating characteristics STM1810/1811/1812/1813/1815/1816/1817/1818 Figure 15. VCC-to-reset output delay vs. temperature - VOD = VTH – VCC n n 4EMPERATURE # !) B Figure 16. Voltage output low vs.
STM1810/1811/1812/1813/1815/1816/1817/1818 Typical operating characteristics Figure 17. Voltage output high vs. ISOURCE 6## 6/54 6 6## 6 /UTPUT CURRENT M! !) B Figure 18. Normalized reset threshold vs. temperature .
Typical operating characteristics STM1810/1811/1812/1813/1815/1816/1817/1818 Figure 19. Max. transient duration NOT causing reset pulse vs. reset threshold overdrive 2ESET THRESHOLD OVERDRIVE M6 !) B 1. Reset occurs above the line.
STM1810/1811/1812/1813/1815/1816/1817/1818 4 Maximum rating Maximum rating Stressing the device above the rating listed in Table 7 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 STM1810/1811/1812/1813/1815/1816/1817/1818 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 8. Designers should check that the operating conditions in their circuit match the operating conditions when relying on the quoted parameters. Table 8.
STM1810/1811/1812/1813/1815/1816/1817/1818 Table 9. Sym. DC and AC parameters DC and AC characteristics Alternative Description VCC Operating voltage ICC VCC supply current Test condition(1) Min. Typ. Max. Unit TA = 0 to +105 °C 1.0 5.5 V TA = –40 to +105 °C 1.2 5.5 V 4 10 µA 9 16 µA VCC = 3.6 V, no load VCC = 5.5 V, no load VIH Input high voltage STM1813/1818 only VIL Input low voltage STM1813/1818 only VOH Output high voltage 0 < IOH < 500 µA 0.7 VCC V 0.4 VCC – 0.
Package mechanical STM1810/1811/1812/1813/1815/1816/1817/1818 6 Package mechanical 6.1 ECOPACK® 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 21.
STM1810/1811/1812/1813/1815/1816/1817/1818 Table 10. Package mechanical SOT23-3 – 3-lead small outline transistor package mechanical data mm inches Symbol Typ. Min. Max. A 0.89 A1 Min. Max. 1.12 0.035 0.044 0.01 0.10 0.001 0.004 A2 0.88 1.02 0.035 0.042 b 0.30 0.50 0.012 0.020 C 0.08 0.20 0.003 0.008 D 2.80 3.04 0.110 0.120 E 2.10 2.64 0.083 0.104 E1 1.20 1.40 0.047 0.055 e 0.89 1.03 0.035 0.041 e1 1.78 2.05 0.070 0.081 L 0.54 Typ. 0.021 L1 0.
Part numbering 7 STM1810/1811/1812/1813/1815/1816/1817/1818 Part numbering Table 11. Ordering information scheme Example STM1810 L WX 7 F Device type STM181x Reset threshold voltage STM1810 - 1813 L = VRST = 4.50 V to 4.75 V (4.62 V typ.) M = VRST = 4.25 V to 4.49 V (4.37 V typ.) STM1815 - 1818 T = VRST = 2.98 V to 3.15 V (3.06 V typ.) S = VRST = 2.80 V to 2.97 V (2.88 V typ.) R = VRST = 2.47 V to 2.64 V (2.55 V typ.
STM1810/1811/1812/1813/1815/1816/1817/1818 Table 12. Part numbering Marking description Part number Reset threshold Output Topside marking(1) STM1810L 4.62 V Push-pull RST 9AAx STM1810M 4.37 V Push-pull RST 9ABx STM1811L 4.62 V Open-drain RST 9AHx STM1811M 4.37 V Open-drain RST 9AJx STM1812L 4.62 V Push-pull RST 9AQx STM1812M 4.37 V Push-pull RST 9ARx STM1813L 4.62 V Open-drain RST 9AXx STM1813M 4.37 V Open-drain RST 9AYx STM1815T 3.
Revision history 8 Revision history Table 13. 24/25 STM1810/1811/1812/1813/1815/1816/1817/1818 Document revision history Date Revision Changes 26-Aug-04 1.0 First Issue. 05-Oct-04 2.0 Update reset characteristics, add typical graphs, remove SC70 references (Figure , 1, 3, 6, 10, 11, 13, 14, 15, 16, 17, 18, 19; and 20, Table 9, 11, and 12). 19-Nov-04 3.0 Update dimensions (Table 10). 07-Dec-04 4.0 Remove some voltage options (Table 1, 10, 11, and 12). 29-Jun-05 5.
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