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Technical content

Features

 Two low power high accuracy comparators  Precise Threshold: ±2%  7.5% Hysteresis to Eliminate the Output Chatter  CMOS Outputs Can Drive LED or MCU Interface  11µA Supply Current @VCC=3.7V  Power Supply Transient Immunity  Operating Temperature Range -40°C to +85°C  Available in SOT23-6  Lead-free, Rohs-compliant and Halogen-free Pin Assignment VCCOUT1 GND CN303 3 4

6 IN2

w w w . c o n s o n a n c e - e l e c . c o m 3 R e v 1 . 0 Block Diagram Figure 3 Block Diagram Pin Description Pin No. Symbol Description 1 IN1 Voltage Detect Input 1. Generally IN1 pin should be tied to an external resistor divider to sense the voltage being monitored.

2 GND Negative Terminal of Power Supply(Ground)

3 OUT1

Voltage Detect Output 1. CMOS output. When the voltage at IN1 pin rises above the internal reference voltage, OUT1 becomes high; When the voltage at IN1 pin falls below the internal reference voltage by 7.5%(typical), OUT1 becomes low. 4 VCC Positive Terminal of Power Supply. This pin is the power supply to internal circuit.

5 OUT2

Voltage Detect Output 2. CMOS output. When the voltage at IN2 pin rises above the internal reference voltage, OUT2 becomes high; When the voltage at IN2 pin falls below the internal reference voltage by 7.5%(typical), OUT2 becomes low. 6 IN2 Voltage Detect Input 2. Generally IN2 pin should be tied to an external resistor divider to sense the voltage being monitored.

w w w . c o n s o n a n c e - e l e c . c o m 4 R e v 1 . 0 ABSOLUTE MAXIMUM RATINGS Terminal Voltage (With respect to GND) Input/Output Current Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond 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=3V , TA= －40℃ to 85 ℃, Typical values are at TA=25℃, unless otherwise noted.) Parameters Symbol Test Conditions M i n T y p M a x U n i t Operating V oltage Range V C C 1 . 9 6 V Operating Current I VCC VCC＝1.9V 5 1 0 1 5 uA VCC＝3.0V 6 1 1 1 6 VCC＝5.0V 7 1 2 1 7 IN1 Rising Threshold V RTH1 IN1 voltage rises 1.187 1.211 1.235 V IN1 Falling Threshold V FTH1 IN1 voltage falls 1.09 1.12 1.15 IN2 Rising Threshold V RTH2 IN2 voltage rises 1.187 1.211 1.235 IN2 Falling Threshold V FTH2 IN2 voltage falls 1.09 1.12 1.15 IN1 Leakage Current I IN1 －100 0 100 nA IN2 Leakage Current I IN2 －100 0 100 nA IN1 to OUT1 Delay t PD1 30mV Overdrive 15 us IN2 to OUT2 Delay t PD2 30mV Overdrive 15 us OUT1 and OUT2 Low V oltage VOL VCC＝2V , ISINK＝1.5mA 0.3 V VCC＝3V , I SINK＝3.2mA 0 . 3 VCC＝5V , I SINK=6mA 0 . 3 OUT1 and OUT2 High V oltage VOH VCC＝2V , ISOURCE=1.5mA VCC－0.4 V VCC＝3V , ISOURCE＝3mA VCC－0.4 VCC＝5V , VLBI＝1.5V ISOURCE＝5mA VCC－0.4 Startup Delay 2.5 ms Note: During power-up, VCC must exceed 1.9V for the startup delay time before the output is in the correct state.

w w w . c o n s o n a n c e - e l e c . c o m 5 R e v 1 . 0 Detailed Description The CN303 is a two-channel voltage detector with 2 low power high accuracy comparators, the device consists of 2 comparators, bandgap reference and hysteresis control circuit etc. If the voltage at IN1(IN2) pin rises above the rising threshold VRTH, OUT1(OUT2) will become high after a short delay(15us typical); If the voltage at IN1(IN2) pin falls below the falling threshold VFTH, OUT1(OUT2) will become low after a delay of 15us typical. The difference between rising threshold and falling threshold is also called hysteresis, which can provide noise immunity and remove the possibility of output chatter due to battery terminal voltage recovery after the load removal. The CN303 offers fixed hysteresis of 7.5%. The CN303 monitors 2 voltage levels or 2 independent voltages, it is specially designed for monitoring single or multi cell lithium, alkaline, NiCd, NiMH and multi-cell lead acid batteries. The common application of the CN303 is to use one output as the early warning signal and the other as a dead-battery indicator. The operation of the device can be best understood by referring to Figure 4. IN1(IN2) VFTH VRTH OUT1(OUT2) Figure 4 Timing waveform Applications Information Resistor Value Selection Choosing the proper external resistors is a balance between accuracy and current consumption. There is a leakage current into IN1(IN2), and the current travels through the resistor divider, which introduces error. If extremely high resistor value are used, this current introduces significant error. With extremely low resistor value, this error becomes negligible, but the resistor divider draws more current from the power supply. Adding External Capacitance to Enhance Noise Immunity If monitoring voltages in a noisy environment, add a bypass capacitor of 0.1μF from battery terminal to GND as close as possible to the device. For systems with large transients, additional capacitance may be required. A small capacitor (<1nF) from IN1 and IN2 pin to GND may provide additional noise immunity. Negative-Going IN1(IN2) Transients In addition to issuing a low output at OUT1(OUT2) pin during power-up, power-down and brownout conditions of the monitored voltage, the CN303 is relatively immune to short-duration negative-going IN1(IN2) transients (glitches). As the magnitude of the transient increases (goes farther below the falling threshold), the maximum allowable pulse width decreases. Typically, a IN1(IN2) transient that goes 20mV

w w w . c o n s o n a n c e - e l e c . c o m 7 R e v 1 . 0 Use two CN303 for 4-Channel Monitoring Outputs 4-channel monitoring outputs can be obtained by using two CN303, as shown in Figure 7. Figure 7 Obtain 4-Channel Monitoring Outputs

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Package Information

Consonance does not assume any responsibility for use of any circuitry described. Consonance reserves the right to change the circuitry and specifications without notice at any time.