STM6315 Open drain microprocessor reset Features ■ Low supply current of 1.5µA (typ) ■ ±1.8% reset threshold accuracy (25°C) ■ Guaranteed RST assertion down to VCC = 1.0V ■ Open drain RST output can exceed VCC ■ Power supply transient immunity ■ Operating temperature: –40 to +125°C ■ Available in SOT143-4 package. March 2007 SOT143-4 (W1) Rev 5 1/21 www.st.
Contents STM6315 Contents 1 Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Reset output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Manual reset input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.
STM6315 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of figures STM6315 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. 4/21 Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 SOT143-4 connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Block diagram . . . . . . . . . . . . . . . . . . . . . . .
STM6315 1 Summary description Summary description The STM6315 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). It also provides a manual reset input (MR).
Summary description Figure 3. STM6315 Block diagram VCC COMPARE VRST trec Generator RST DEBOUNCE MR AI11164 Figure 4. Hardware hookup VCC VCC VCC 10k STM6315 MR Manual Reset RST(1) VSS MCU RESET Input VSS AI11165 1. Open drain RST output requires external pull-up resistor.
STM6315 Operation 2 Operation 2.1 Reset output The STM6315 Microprocessor Reset Circuit has an active-low, open drain reset output. This output structure will sink current when RST is asserted. Connect a pull-up resistor from RST to any supply voltage up to 6V (see Figure 4 on page 6). Select a resistor value large enough to register a logic low, and small enough to register a logic high while supplying all input current and leakage paths connected to the reset output line.
Operation 2.4 STM6315 Valid RST output down to VCC = 0V When VCC falls below 1V, 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 1V. However, in applications where RST output must be valid down to 0V, a pull-down resistor may be added to hold the RST output low. This resistor must be large enough to not load the RST output, and still be small enough to pull the output to Ground. A 100KΩ resistor is recommended.
STM6315 Typical operating characteristics 3 Typical operating characteristics Note: Typical values are at TA = 25°C. Figure 7. Supply current vs. supply voltage, VRST = 2.63V 3.00 2.75 Supply Current, ICC (µA) 2.50 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 0.00 0.0 Figure 8. 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Supply Voltage, VCC (V) 4.0 4.5 5.0 5.5 AI11871c Supply current vs. temperature (no load), VRST = 2.63V 2.25 Supply Current, ICC (µA) 2.00 1.75 1.50 1.25 1.00 VCC = 2V VCC = 3V 0.
Typical operating characteristics Figure 9. STM6315 RST output voltage vs. output current, VCC = 4.25V 0.20 Output Voltage (V) 0.16 0.12 0.08 0.04 0 0 3 6 Output Current (mA) 9 12 AI11873c Figure 10. Normalized reset time-out period vs. temperature Normalized Reset Time-out Period, trec/trec (typ) (–) 1.14 1.12 1.10 1.08 1.06 1.04 1.02 1.00 0.
STM6315 Typical operating characteristics Normalized Reset Threshold, VRST/VRST-typ (–) Figure 11. Normalized reset threshold vs. temperature 1.01 1.005 1 0.995 0.99 –40 –20 0 20 40 60 Temperature, TA (°C) 80 100 120 AI11876c Figure 12. Max. transient duration not causing reset pulse vs. reset threshold Overdrive 100 Transient Duration (µs) 90 80 70 60 50 40 30 20 10 0 1 Note: 10 100 Reset Threshold Overdrive (mV) 1000 AI11877 Reset occurs above the curve.
Maximum rating 4 STM6315 Maximum rating Stressing the device above the rating listed in the Table 2: Absolute maximum ratings 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.
STM6315 5 DC and AC parameters 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.
DC and AC parameters Table 4. Sym VCC STM6315 DC and AC characteristics Description Test Condition (1) Max Unit 5.5 V 12 µA 15 µA 10 µA VCC = 3.6V, no load TA = –40 to +125°C 12 µA VCC > 4.25V, ISINK = 3.2mA 0.4 V VCC > 2.5V, ISINK = 1.2mA 0.3 V VCC > 1.0V, ISINK = 80µA 0.3 V VCC > VRST, RST not asserted 1 µA VRST + 1.8% V VRST – 2.5% VRST VRST + 2.5% V Operating voltage Min 1.0 VCC = 5.
STM6315 Table 4. Sym DC and AC parameters DC and AC characteristics (continued) Description Test Condition (1) Min VRST > 4.0V 0.8 V VRST < 4.0V 0.3VCC V Typ Max Unit Manual Reset Input VIL MR low input threshold VIH MR low input threshold MR input pulse width VRST > 4.0V 2.4 V VRST < 4.0V 0.7VCC V 1 µs MR glitch rejection 100 ns MR-to-RST delay 500 ns MR pull-up resistance 32 63 100 kΩ 1. Valid for ambient operating temperature: TA = –40 to 125°C; VCC = 2.5 to 5.
Package mechanical data 6 STM6315 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a Lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark.
STM6315 Package mechanical data Figure 14. SOT143-4 – 4-lead small outline transistor package outline E E1 0.15 B M CAB A1 1 e/2 e1 e D 0.15 M CAB b2 0.20 M 4X CAB 3X b A2 C 0.10 A C A C θ L1 C L SOT143-4 Note: Drawing is not to scale. Table 5. SOT143-4 – 4-lead small outline transistor package mechanical data mm inches Symbol Typ Min Max Typ Min Max A – 0.89 1.12 – 0.035 0.044 A1 – 0.01 0.10 – 0.001 0.004 A2 – 0.88 1.02 – 0.035 0.042 b – 0.
Part numbering 7 STM6315 Part numbering Table 6. Ordering information scheme Example: STM6315 R D W1 3 F Device Type STM6315 Reset Threshold Voltage (1) L = VRST = 4.63V M = VRST = 4.38V S = VRST = 2.93V R = VRST = 2.63V RST Pulse Width (1) A = trec = 1.5ms B = trec = 30ms D = trec = 210ms G = trec = 1680ms Package W1 = SOT143-4 Temperature Range 3 = –40 to 125°C Shipping Method F = ECOPACK Package, Tape & Reel 1. Other VRST thresholds and trec timings are offered.
STM6315 Part numbering Table 7. Marking description Part Number Reset Threshold (1) (V) RST Pulse Width (1) (ms) Output Topside Marking (2) STM6315LB 4.63 30 Open drain RST 9LBx STM6315MD 4.38 210 Open drain RST 9MDx STM6315SD 2.93 210 Open drain RST 9SDx STM6315RA 2.63 1.5 Open drain RST 9RAx STM6315RB 2.63 30 Open drain RST 9RBx STM6315RD 2.63 210 Open drain RST 9RDx STM6315RG 2.63 1680 Open drain RST 9RGx 1. Other VRST thresholds and trec timings are offered.
Revision history 8 STM6315 Revision history Table 8. 20/21 Document revision history Date Revision Changes 14-Nov-2005 1.0 First edition. 08-Feb-2006 2.0 Update template, characteristics, marking (Figure 7, 8, 9, 10, and 11; Table 4, 6, and 7). 12-Apr-2006 3 Updated characteristics (Figure 7, 8, and 11; Table 4, 6, and 7). 27-Jul-2006 4 Updated Table 3, 5 and 6. 21-Mar-2007 5 Updated Table 2, 6, and 7.
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