PRELIMINARY INFORMATION 1 TCM809 TCM810 3-PIN µP RESET MONITORS 2 FEATURES GENERAL DESCRIPTION ■ The TCM809 and TCM810 are cost-effective system supervisor circuits designed to monitor VCC in digital systems and provide a reset signal to the host processor when necessary. No external components are required. The reset output is driven active within 20msec of VCC falling through the reset voltage threshold. Reset is maintained active for a minimum of 140msec after VCC rises above the reset threshold. The TCM810 has an active-high reset output while the TCM809 has an active-low reset output. The output of the TCM809 is guaranteed valid down to V CC = 1V. Both devices are available in a SOT-23B-3 package. The TCM809/810 are optimized to reject fast transient glitches on the VCC line. Low supply current of 17µA (VCC = 3.3V) makes these devices suitable for battery powered applications. ■ ■ ■ ■ ■ ■ Precision VCC Monitor for 3.0V, 3.3V, 5.0V Nominal System V Supplies 140msec Guaranteed Minimum RESET, RESET Output Duration RESET Output Guaranteed to VCC = 1.0V (TCM809) Low 17µA Supply Current VCC Transient Immunity Small SOT-23B-3 Package No External Components TYPICAL APPLICATIONS ■ ■ ■ ■ Computers Embedded Systems Battery Powered Equipment Critical µP Power Supply Monitoring 3 4 ORDERING INFORMATION TYPICAL OPERATING CIRCUIT VCC VCC PROCESSOR VCC Part No. Package Temp. Range TCM809xENB TCM810xENB SOT-23B-3 SOT-23B-3 – 40°C to +85°C – 40°C to +85°C 5 NOTE: The "X" denotes a suffix for VCC threshold - see table below. RESET INPUT RESET TCM809 GND GND PIN CONFIGURATION Suffix Reset VCC Threshold (V) L M T S R 4.63 4.38 3.08 2.93 2.63 6 *SOT-23B-3 GND 7 1 TCM809xENB TCM810xENB RESET (RESET) 3 VCC 2 8 NOTE: *SOT-23B-3 is equivalent to JEDEC (TO-236) ** () is for TCM810 TCM809/810-04 TELCOM SEMICONDUCTOR, INC. 8/29/96 5-15 3-PIN µP RESET MONITORS PRELIMINARY INFORMATION TCM809 TCM810 ABSOLUTE MAXIMUM RATINGS* Supply Voltage (VCC to GND) ................................ +6.0V RESET, RESET ............................ – 0.3V to (VCC + 0.3V) Input Current, VCC.. ..................................................20mA Output Current, RESET, RESET .............................20mA dV/dt (VCC) .......................................................... 100V/µS Operating Temperature Range ............... – 40°C to +85°C Power Dissipation (TA ≤ 70°C) SOT-23B-3 (derate 4mW/°C above +70°C) ... 230mW Storage Temperature Range ................ – 65°C to +150°C Lead Temperature (Soldering, 10 sec) ................. +260°C *This is a stress rating only and functional operation of the device at these or any other conditions above 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. ELECTRICAL CHARACTERISTICS: Vcc = 5V, TA = Operating Temperature Range unless otherwise noted. Symbol Parameter VCC Range ICC Supply Current VTH Reset Threshold Reset Threshold Tempco VCC to Reset Delay Reset Active Timeout Period RESET Output Voltage Low (TCM809) VOL VOH RESET Output Voltage High (TCM809) RESET Output Voltage Low (TCM810) VOL Test Conditions Min Typ Max Unit TA = 0°C to +70°C TA = – 40°C to +85°C TCM8xxL/M: VCC < 5.5V TCM8xxR/S/T: VCC < 3.6V (Note 2) TCM8xxL: TA = +25°C TA = – 40°C to +85°C TCM8xxM: TA = +25°C TA = – 40°C to +85°C TCM8xxT: TA = +25°C TA = – 40°C to +85°C TCM8xxS: TA = +25°C TA = – 40°C to +85°C TCM8xxR: TA = +25°C TA = – 40°C to +85°C 1.0 1.2 — — — — 24 17 5.5 5.5 60 50 V 4.56 4.50 4.31 4.25 3.04 3.00 2.89 2.85 2.59 2.55 — 4.63 — 4.38 — 3.08 — 2.93 — 2.63 — 30 4.70 4.75 4.45 4.50 3.11 3.15 2.96 3.00 2.66 2.70 — 20 240 — — — — — — — — 560 0.3 0.4 0.3 — — 0.3 0.4 µsec msec V — — V (Note 2) VCC = VTH to (VTH – 100mV) — 140 TCM809R/S/T: VCC = VTH min, ISINK = 1.2mA — TCM809L/M: VCC = VTH min, ISINK = 3.2mA — VCC > 1.0V, ISINK = 50µA — TCM809R/S/T: VCC > VTH max, ISOURCE = 500µA 0.8 VCC TCM809L/M: VCC > VTH max, ISOURCE = 800µA VCC – 1.5 TCM810R/S/T: VCC = VTH max, ISINK = 1.2mA — TCM810L/M: VCC = VTH max, ISINK = 3.2mA — VOH RESET Output Voltage High (TCM810) 1.8 < VCC < VTH min, ISOURCE = 150µA NOTES: 1. Production testing done at TA = +25°C, over temperature limits guaranteed by design. 2. RESET output for TCM809, RESET Output for TCM810. 0.8 VCC µA V ppm/°C V V PIN DESCRIPTION Pin No. (SOT-23B-3) Symbol 1 2 GND RESET (TCM809) 2 RESET (TCM810) 3 VCC 5-16 Description Ground RESET output remains low while VCC is below the reset voltage threshold, and for 240msec (140msec min.) after VCC rises above reset threshold. RESET output remains high while VCC is below the reset voltage threshold, and for 240msec (140msec min.) after VCC rises above reset threshold. Supply voltage (Typ. +3.0V to +5.0V) TELCOM SEMICONDUCTOR, INC. 3-PIN µP RESET MONITORS PRELIMINARY INFORMATION 1 TCM809 TCM810 APPLICATIONS INFORMATION VCC Transient Rejection The TCM809/810 provides accurate VCC monitoring and reset timing during power-up, power-down, and brownout/sag conditions, and rejects negative-going transients (glitches) on the power supply line. Figure 1 shows the maximum transient duration vs. maximum negative excursion (overdrive) for glitch rejection. Any combination of duration and overdrive which lies under the curve will not generate a reset signal. Combinations above the curve are detected as a brownout or power-down. Transient immunity can be improved by adding a capacitor in close proximity to the VCC pin of the TCM809/810. valid to VCC = 0V, a pull-down resistor must be connected from RESET to ground to discharge stray capacitances and hold the output low (Figure 2). This resistor value, though not critical, should be chosen such that it does not appreciably load RESET under normal operation (100kΩ will be suitable for most applications). Similarly, a pull-up resistor to VCC is required for the TCM810 to ensure a valid high RESET for VCC below 1.0V. 3 VCC VCC TCM809 VCC 2 RESET VTH MAXIMUM TRANSIENT DURATION (µsec) Duration 4 R1 100k GND Overdrive Figure 2. Ensuring RESET Valid to VCC = 0V Processors With Bidirectional I/O Pins 400 TA = +25°C 320 240 160 TCM8xxLM 80 Some µP's (such as Motorola 68HC11) have bidirectional reset pins. Depending on the current drive capability of the processor pin, an indeterminate logic level may result if there is a logic conflict. This can be avoided by adding a 4.7k resistor in series with the output of the TCM809/810 (Figure 3). If there are other components in the system which require a reset signal, they should be buffered so as not to load the reset line. If the other components are required to follow the reset I/O of the µP, the buffer should be connected as shown with the solid line. 5 6 TCM8xxR/S/T 0 1 10 1000 100 RESET COMPARATOR OVERDRIVE, (VTH - VCC (mV) Figure 1. Maximum Transient Duration vs. Overdrive for Glitch Rejection at 25°C BUFFER BUFFERED RESET TO OTHER SYSTEM COMPONENTS VCC 7 VCC VCC µP RESET Signal Integrity During Power-Down The TCM809 RESET output is valid to VCC = 1.0V. Below this voltage the output becomes an "open circuit" and does not sink current. This means CMOS logic inputs to the µP will be floating at an undetermined voltage. Most digital systems are completely shutdown well above this voltage. However, in situations where RESET must be maintained TELCOM SEMICONDUCTOR, INC. TCM809 RESET GND 4.7k RESET GND 8 Figure 3. Interfacing to Bidirectional Reset I/O 5-17 3-PIN µP RESET MONITORS PRELIMINARY INFORMATION TCM809 TCM810 TYPICAL CHARACTERISTICS Supply Current vs.Temperature (No Load, TCM8xxR/S/T) 35 Supply Current vs.Temperature (No Load, TCM8xxL/M) 30 VCC = 5V VCC = 5V 25 SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 30 25 20 VCC = 3V 15 10 5 0 –40 0 20 40 60 VCC = 3V 15 10 VCC = 1V 5 VCC = 1V –20 20 0 –40 85 –20 0 VOD = VTH – VCC VOD = 10mV 80 60 VOD = 20mV 40 0 –40 VOD = 100mV VOD = 200mV –20 0 20 40 60 140 VOD = 10mV 100 80 VOD = 20mV 60 40 VOD = 100mV 20 0 –40 85 VOD = 200mV –20 20 40 60 85 Normalized Reset Threshold vs. Temperature 1.003 250 NORMALIZED THRESHOLD POWER-UP RESET TIMEOUT (msec) 0 TEMPERATURE (°C) Power-Up Reset Timeout vs. Temperature 245 TCM8xxL/M 240 TCM8xxR/S/T 235 230 1.002 1.001 1.000 0.999 0.998 0.997 –20 0 20 40 TEMPERATURE (°C) 5-18 85 VOD = VTH – VCC 120 TEMPERATURE (°C) 225 –40 60 Power-Down Reset Delay vs. Temperature (TCM8xxL/M) POWER-DOWN RESET DELAY (µsec) POWER-DOWN RESET DELAY (µsec) Power-Down Reset Delay vs. Temperature (TCM8xxR/S/T) 20 40 TEMPERATURE (°C) TEMPERATURE (°C) 100 20 60 85 –40 –20 0 20 40 60 85 TEMPERATURE (°C) TELCOM SEMICONDUCTOR, INC.