Advanced Monolithic Systems AMS23 ADJUSTABLE VOLTAGE MONITOR RoHS compliant FEATURES APPLICATIONS • ±2% Voltage Threshold Accuracy • Operating Voltage 1.4V to 15V • Open collector output • Low supply current – 0.9µA (typ) • Guaranteed out assertion down to VCC = 0.7V • Power Supply Transient Immunity • Adjustable threshold voltage from 1.25V to 12V • CPU and Logic Circuit Reset • Portable and Battery Powered Equipment • Memory Battery Back-Up Circuit • Window Comparator • Cellular Phones • Pagers GENERAL DESCRIPTION The AMS23 low power voltage detector provides monitoring of battery, power-supply, and regulated system voltages. A precision voltage reference and comparator monitors the VCC input and compares it with a specified voltage threshold condition. When VCC falls below a specified trip point threshold, the output (OUT) is forced low and remains asserted as long as the VCC input remains below VTH- + hysteresis (VHYST). The AMS23 device is guaranteed to output the correct logic state for VCC down to 0.7V. They are also designed to ignore fast transients on VCC. This small, low power device is ideal for portable applications and is available in space-saving SOT23-5 package. ORDERING INFORMATION OUTPUT PIN CONNECTIONS PACKAGE OPERATING TEMPERATURE RANGE TYPE 5L SOT-23 (M) NC 1 5 VCC GND 2 TYPE OPEN COLLECTOR 5 LEAD SOT-23 AMS23M1 ADJ 3 4 V OUT -40 to +85° C Top View Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS23 ABSOLUTE MAXIMUM RATINGS Supply Voltage Output Current Input or Output Voltage 0.7 to 15 20mA -0.3 to VCC +0.3 Storage Temperature Lead Solder Temperature for 25 secs. Power Dissipation -55ºC to 150ºC 265ºC 320mW DC AND AC ELECTRICAL CHARACTERISTICS Electrical Characteristics at TA=25°C and VCC= 3.3V, unless otherwise noted. PARAMETER (Note 2) Operating Voltage VCC Supply Current Output Current, NPN Collector AMS23 Typ. CONDITIONS Min. 1.25 Units Max. 15 VCC = 3.0V, No load 0.9 3.0 VCC= 5.5V, No load 1.1 3.6 V µA VCC = 1.5V 1.0 3 mA VCC =2.5V 3.0 14 mA Detect Voltage Release Voltage VTH -2% VTHVTH- +VHYST VTH- +2% V V Threshold Hysteresis 0.2VTH- 0.05VTH- 0.08VTH- V Voltage Thresholds VCC to OUT Detect Delay VCC falling from (VTH- + 100mV) to 2 µs ±100 ppm/ºC (VTH- - 100mV) at 10mV/µs Threshold Temperature Coefficient Note 1: Valid for Ambient Operating Temperature: TA= 25ºC. BLOCK DIAGRAM Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS23 PIN DESCRIPITIONS AMS23 PIN NUMBERS NAME DESCRIPTION 1 NC Not Connect 2 GND Ground is the reference for the power supply. It must be connected to the system ground. 3 ADJ Adjustable input pin. Using two resistor dividers the voltage threshold could be set between 1.25V to 12V. 4 V OUT Open Collector. This is the open collector output. It goes low when VCC drops below VTHand remains low as long as VCC is below VTH- + VHYST. 5 VCC This is the Supply Voltage for the Voltage Detector. OPERATION OUTPUT The AMS23 Voltage Detector monitors system voltage from 1.25V to 12V. The detector is designed to ignore fast transients on VCC and has a voltage hysteresis (VHYST). The AMS23 asserts an output signal (OUT) whenever VDETECT goes below the Voltage Detect Threshold (VTH-). The output signal (OUT) stays asserted until VDETECT goes above the Voltage Detect Release (VTH+). Output voltage (VOUT) is guaranteed valid down to VCC = 0.7V at 25ºC. The AMS23 has an Open Collector active-low output which will sink current when output is asserted. Connect a pull-up resistor from OUT to any supply voltage up to 15V. Select a resistor value large enough to register logic low, and small enough to register logic high while all of the input current and leakage paths connected to the reset output line are being supplied. A 10k pull-up is sufficient in most applications. The advantages of Open Collector Output is the ability to connect more open drain outputs in parallel (wired OR connections) as well as connect the output to a power supply voltage different from VCC. Negative-Going VCC Transients and Undershoot The AMS23 device is relatively immune to negative-going VCC transients (glitches). 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. Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS23 PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted. 5 LEAD SOT-23 PLASTIC PACKAGE (M1) 0.110-0.120 (2.794-3.048) 0.102-0.118 (2.60-3.00) 0.059-0.070 (1.50-1.75) 0.014-0.020 (0.350-0.50) 0.037 (0.95) TYP 0.018-0.024 (0.457-0.610) 10° NOM 0.036-0.051 (0.090-1.30) 0.0035-0.0080 (0.090-0.20) 0.003 (0.150) MAX Advanced Monolithic Systems, Inc. 0.075 (1.90) TYP www.advanced-monolithic.com 10° NOM 0.018-0.024 (0.457-0.610) (SOT-23-5 ) AMS DRW# 051001 Phone (925) 443-0722 Fax (925) 443-0723