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.com 1 Contents STM6315 Contents 1 Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Reset output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Manual reset input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 Negative-going VCC transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4 Valid RST output down to VCC = 0V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5 DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7 Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2/21 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 SOT143-4 – 4-lead small outline transistor package mechanical data. . . . . . . . . . . . . . . . 17 Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3/21 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Hardware hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Reset timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Manual reset timing diagram, switch bounce/debounce . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Supply current vs. supply voltage, VRST = 2.63V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Supply current vs. temperature (no load), VRST = 2.63V . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 RST output voltage vs. output current, VCC = 4.25V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Normalized reset time-out period vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Normalized reset threshold vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Max. transient duration not causing reset pulse vs. reset threshold Overdrive . . . . . . . . . 11 AC testing input/output waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 SOT143-4 – 4-lead small outline transistor package outline . . . . . . . . . . . . . . . . . . . . . . . 17 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). The open drain RST output can be pulled up to a voltage higher than VCC, but less than 6V. The STM6315 comes with standard factory-trimmed reset thresholds of 2.63V, 2.93V, 3.08V, 4.38V, and 4.63V. The STM6315 is available in the SOT143-4 package. Figure 1. Logic diagram VCC STM6315 MR RST VSS Table 1. Signal names Symbol Figure 2. AI11162 Description VCC Supply voltage MR Manual reset input RST Active-low open drain reset output VSS Ground SOT143-4 connections (top view) VSS 1 4 VCC RST 2 3 MR AI11163 5/21 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. 6/21 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. A 10k pull-up is sufficient in most applications. The STM6315 asserts a reset signal to the MCU whenever VCC goes below the reset threshold (VRST), or when the manual reset input (MR) is taken low (see Figure 5 and Figure 6 on page 8). RST is guaranteed valid down to VCC = 1.0V. 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. Each time RST is asserted, it stays low for at least the reset time-out period. Any time VCC goes below the reset threshold, the internal timer clears. The reset timer starts when VCC returns above the reset threshold. 2.2 Manual reset input A logic low on MR asserts RST. RST remains asserted while MR is low, and for trec after it returns high. The MR input has an internal pull-up resistor 63kΩ (typ), allowing it to be left open if not used. This input can be driven with TTL/CMOS-logic levels or with open drain/collector outputs. Connect a standard open push-button switch from MR to VSS to create a manual reset function (see Figure 4 on page 6); external debounce circuitry is not required. If the device is used in a noisy environment, connect a 0.1µF capacitor from MR to VSS to provide additional noise immunity. 2.3 Negative-going VCC transients The STM6315 is relatively immune to negative-going VCC transients (glitches). Figure 12 on page 11 shows typical transient duration versus reset comparator overdrive (for which the STM6315 will NOT generate a reset pulse). The graph was generated using a negative pulse applied to VCC, starting at 0.5V above the actual reset threshold and ending below it by the magnitude indicated (Reset Threshold Overdrive). The graph indicates the maximum pulse width a negative VCC transient can have without causing a reset pulse. As the magnitude of the transient increases (further below the threshold), the maximum allowable pulse width decreases. Any combination of duration and overdrive which lies under the curve will NOT generate a reset signal (see Figure 12). A 0.1µF bypass capacitor mounted as close as possible to the VCC pin provides additional transient immunity. 7/21 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. Figure 5. Reset timing diagram VCC VRST VCC (min) RST trec AI11166 Figure 6. Manual reset timing diagram, switch bounce/debounce MR Glitch Rejection MR MR Input Pulse Width RST trec MR-to-RST Delay 8/21 AI11167b 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 0.75 VCC = 4V 0.50 VCC = 5V 0.25 0.00 –40 –20 0 20 40 60 Temperature, TA (°C) 80 100 120 AI11872c 9/21 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 0.98 –40 10/21 –20 0 20 40 60 Temperature, TA (°C) 80 100 120 AI11875b 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. 11/21 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. Refer also to the STMicroelectronics SURE Program and other relevant quality documents. Table 2. Absolute maximum ratings Symbol TSTG TSLD (1) Parameter Storage temperature (VCC Off) Lead solder temperature for 10 seconds Value Unit –55 to 150 °C 260 °C –0.3 to VCC + 0.3 V VIO Input or output voltage VCC Supply voltage –0.3 to 7.0 V IO Output current 20 mA PD Power dissipation 320 mW 1. Reflow at peak temperature of 260°C (total thermal budget not to exceed 245°C for greater than 30 seconds). 12/21 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. Operating and AC measurement conditions Parameter STM6315 Unit 1.0 to 5.5 V –40 to +125 °C ~5 ns Input Pulse Voltages 0.2 to 0.8VCC V Input and Output Timing Reference Voltages 0.3 to 0.7VCC V VCC Supply Voltage Ambient Operating Temperature (TA) Input Rise and Fall Times Figure 13. AC testing input/output waveforms 0.8VCC 0.2VCC 0.7VCC 0.3VCC AI02568 13/21 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 = 5.5V, no load TA = –40 to +85°C ICC VOL VCC supply current RST output voltage RST output open drain Leakage Current Typ 2.0 VCC = 5.5V, no load TA = –40 to +125°C VCC = 3.6V, no load TA = –40 to +85°C 1.5 Reset Thresholds Reset threshold (2) VRST (see Table 6 on page 18 for detailed listing) tRD VCC-to-RST delay STM6315xAxxxx STM6315xBxxxx trec RST pulse width (2) STM6315xDxxxx STM6315xGxxxx Reset threshold temperature coefficient 14/21 VCC falling; TA = 25°C VCC falling; TA = –40 to 85°C VRST – 1.8% VCC falling; TA = –40 to 125°C VRST – 3.5% VCC falling from (VRST + 100mV) to (VRST – 200mV) at 1mV/µs VRST + 3.5% 35 TA = –40 to +85°C 1 TA = –40 to +125°C 0.8 TA = –40 to +85°C 20 TA = –40 to +125°C 16 TA = –40 to +85°C 140 TA = –40 to +125°C 112 TA = –40 to +85°C 1120 TA = –40 to +125°C 896 V µs 2 ms 2.4 ms 40 ms 48 ms 280 ms 336 ms 2240 ms 2688 ms 1.5 30 210 1680 60 ppm/°C 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 5.5V (except where noted). 2. Other VRST thresholds and trec timings are offered. Minimum order quantities may apply. Contact local sales office for availability. 15/21 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. ECOPACK specifications are available at: www.st.com. 16/21 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 – 0.37 0.51 – 0.015 0.020 b2 – 0.76 0.94 – 0.030 0.037 C – 0.09 0.18 – 0.004 0.007 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 1.92 – – 0.076 – – e1 0.20 – – 0.008 – – L 0.55 – – 0.022 – – L1 – 0.40 0.60 – 0.016 0.024 Θ 0° 10° 0° 10° N 4 4 17/21 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. Minimum order quantities may apply. Contact local sales office for availability. Note: 18/21 For other options, or for more information on any aspect of this device, please contact the ST Sales Office nearest you. 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. Minimum order quantities may apply. Contact local sales office for availability. 2. Where "x" = Assembly Work Week (A to Z), such that "A" = WW01-02, "B" = WW03-04, and so forth. 19/21 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. STM6315 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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