The ICL7665S Ultra CMOS Micropower Over/Under Voltage Detector contains two separate low power programmable voltage detectors. Typically 3µA operating current is required, the device is designed for applications requiring high or low voltage warnings, programmable trip points, or fault monitoring and correction. Trigger point and hysteresis for both voltage detectors through external resistors. An internal bandgap type reference provides accurate threshold voltages simultaneously from any supply in the 1.6V to 16V range. The ICL7665S, the super programmable over/under voltage detector is a drop-in replacement for the industry standard. The ICL7665B offers a wider operating voltage and temperature range, improved threshold accuracy (ICL7665SA) and temperature coefficient, and guaranteed maximum supply current. Highlight all improvements in the Electrical Characteristics section. All key parameters are guaranteed over the entire commercial and industrial temperature range.

feature

Guaranteed maximum quiescent current of 10µA over temperature

Wider operating voltage range guaranteed throughout the entire process operating temperature range

2% Threshold Accuracy (ICL7665SA)

Dual Comparators with Precision Internal Reference

100ppm/°C Threshold Voltage Temperature Coefficient

100% tested at 2V

output current sink capability. up to 20mA

Individually programmable upper and lower trip voltage and hysteresis levels

Lead-free available (RoHS compliant)

application

pocket pager

Portable Instruments

charging system

storage power backup

battery powered system

laptop

Liquid level detector

notes:

1. Add "-T*" suffix to tape and reel. See TB347 for reel specifications.

2. Lead-free PDIPs can only be used for through-hole wave solder processing. They are not suitable for reflow process applications.

3. Intersil lead-free + annealed products feature a special lead-free material set; molding compound/mold connection material and 100% matte tinplate termination finish, RoHS compliant, and compatible with SnPb and lead-free soldering operations. Intersil's lead-free products are MSL classified at lead-free peak reflow temperatures that meet or exceed the lead-free requirements of IPC/JEDEC J STD-020.

Absolute Maximum Ratings Thermal Information

Power supply voltage (Note 5). -0.3 to +18V

Output voltages OUT1 and OUT2. -0.3V to +18V

(About GND) (Note 5)

Output voltages HYST1 and HYST2. -0.3V to +18V

(About V+) (Note 5)

Input voltage setting 1 and setting 2. (Ground -0.3V) to (V+V-+0.3V)

(Note 5)

Maximum receive output output 1 and output 2. 25 mA

Maximum source output current

HYST1 and HYST2. -25mA

operating conditions

temperature range

ICL7665SC. 0°C to +70°C

ICL7665SI. -40°C to +85°C

Thermal Resistance (Typical, Note 4) θJA (Celsius/Watt)

PDIP package*. 115

SOIC package. 160

Maximum Junction Temperature (Plastic). +150 degrees Celsius

Maximum Junction Temperature (CERDIP). +175 degrees Celsius

Maximum storage temperature range. -65°C to +150°C

Maximum lead temperature (10s for soldering). + 300 degrees Celsius

(SOIC - lead only)

Lead-free reflow profile.

Lead-free PDIPs are available for through-hole wave solder processing only. They are not intended for reflow process applications.

NOTE: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to these conditions may affect product reliability and

cause malfunctions not covered by the warranty.

notes:

4. θJA is measured in free air with components mounted on an evaluation PC board.

5. Due to the inherent SCR structure in the CMOS process used to fabricate these devices, connecting any terminal to a voltage greater than (V++0.3V) or less than (GND-0.3V) may cause destructive device latch-up. For these reasons, it is recommended not to apply power from the same power supply to the device from an external input before power is established to the device, and in multiple power supply systems, turn on the power to the ICL7665 first. If this is not possible, the input and/or output current must be limited to ±0.5mA and the voltage range must not exceed the above.

Electrical Specifications The following specifications apply to the ICL7665S and ICL7665SA. V+=5V, TA=+25°C, test circuit diagram 7. unless otherwise specified

Electrical Specifications The following specifications apply to the ICL7665S and ICL7665SA. V+=5V, TA=+25°C, test circuit diagram 7. Unless otherwise specified (continued)

notes:

At 6.4mW/°C, derate when ambient temperature is higher than +25°C.

7. All major improvements compared to industry standard ICL7665 are high strength

Conditions (Note 5)

VSET1>1.3V, OUT1 is turned on, HYST1 is turned on

VSET1<1.3V, OUT1 switch is off, HYST1 switch is off

VSET2>1.3V, OUT2 switch is off, HYST2 switch is on

VSET2<1.3V, OUT2 is on, HYST2 is off

Note:

8. See the electrical specifications for specific thresholds.

Detailed description

As shown in the functional diagram, the ICL7665S includes two comparators comparing the SET1 and SET2 terminals to the internal 1.3V bandgap reference. The outputs of the two comparators drive open-drain N-channel transistors for OUT1 and OUT2, and open-drain P-channel transistor outputs for HYST1 and HYST2. Each section, the undervoltage detector and the overvoltage detector, both use an internal 1.3V reference voltage independently of the other. The offset voltages of the two comparators are usually not equal, so VSET1 will usually not be exactly equal to VSET2. The input impedance of the SET1 and SET2 pins is very high and is ignored for most practical applications. The four outputs are open-drain MOS transistors that, when turned on, behave as low-resistance switches to their respective supply rails. This minimizes setup error hysteresis and maximizes output flexibility. This bandgap reference and each comparator are about 100mA.

Precautions

Junction-isolated CMOS devices like the ICL7665S have an inherent thyristor or 4-layer PNPN structure distributed in the die. In some cases, a potentially damaging high-current mode can be triggered. This bubblegum can be controlled by the input or output relative to the power supply, or by applying excessive power supply voltage. In low current analog circuits, such as the ICL7665S, the SCR can also be triggered very rapidly ("instantly") by applying input power, such as through impedance batteries and short lead switch lengths. The rate of rise of the supply voltage can exceed 100V/µs in this circuit. Low impedance capacitors (eg., 0.05µF disc ceramic) located in the ICL7665S can be used to reduce supply voltages in rate-of-rise battery applications. The growth rate of the inline OS supply is limited by other factors, and is usually not a problem. If the set voltage V+ must be applied before the supply voltage, the input current should be limited to 0.5mA with an appropriate external resistor, usually for the voltage anyway. For if it may be driven by other circuits, the output is out of supply at all times. Also, when the V+ supply is powered up, false transitions on the OUTx outputs may occur even if the threshold voltage set by the resistor is not violated. This occurs with microsecond time constants and V+ transients in the internal bandgap circuit. If this happens, connecting 1µF to the SETx pins will act as additional capacitance to move the external time constant by an amount greater than the internal time constant.

Simple Threshold Detector Figure 9 shows threshold detection. It can be seen from FIG. 9B that at low input voltage, OUT1 is off, or high, and OUT2 is on, or low. When the input rises (eg, when powered up) at VNOM (usually the final operating voltage), the output 2 pass reaches VTR2 height. If the voltage is higher than VNOM as comparable to VTR1, OUT1 goes low. The equations give VSET1 and VSET2 from Figure 9A: Since the trip voltage of each comparator is nominally 1.3V, the value VIN for each trip point can be changed from

Both detectors can be used individually or simultaneously, in any of the circuits shown here. When the VIN is very close to one of the trigger voltages, normal variations and noise can cause it to wander back and forth at this level, resulting in erratic output switching conditions. Adding hysteresis, making the trip point slightly different for rising and falling inputs, will avoid this condition. Hysteresis Threshold Detector Figure 10A shows how this hysteresis can be set, while Figure 10B shows that the hysteresis around each trigger point produces switching action at different points depending on whether the VIN is rising or falling (arrows indicate direction changes. HYST The output is basically a switch that shorts R31 or R32 points when the VIN is higher than the corresponding trip. So if the input voltage rises from a low value, the trip point will be controlled by R1N, R2N and R3N until the trip point is reached. When this value When passed, the detector changes state, R3N is shorted, and the trip point is controlled only by R1N and R2N (the lower value). The input must then be dropped to this new point to restore the initial comparator state, but once that happens, trip this point Will be presented again. An alternative circuit to obtain hysteresis is shown in Figure 11. In this configuration, the HYST pin is connected in parallel with the set resistor on the resistor. The values of the resistor are different in size, but have basically the same effect. The governing equations are shown in the table 1. These ignore the effect of the HYST output resistance, but if the resistance value is higher than about 100kΩ.

application

Single Supply Fault Monitor Figure 12 shows a single supply. The overvoltage trip point is around 5.5V, and the undervoltage trip point is around 4.5V. Both have some hysteresis to prevent unstable output shutdown conditions. These two outputs are wired together or configured with a pull-up resistor to generate a power-good signal.

Multiple Power Failure Monitors

The ICL7665S can monitor multiple power supplies simultaneously when connected as shown in Figure 13. The resistor is chosen to be the sum of the current through R21A, r211b and R31 equal to the current through R11 when the two input voltages are at the desired low voltage detection point. At this time, the current through R11 is equal to 1.3V/R11. The voltage at the VSET input is determined by monitoring the voltages of the two supplies. The trip voltage of one power supply and the other power supply is at rated voltage when both power supplies are below rated voltage. The other side of the ICL7665S can be used to detect that there is no negative supply. The trigger point of OUT1 depends on the negative supply voltage and the actual +5V supply voltage

Combining Low Battery Warning and Low Battery Disconnect is important to prevent excessive battery discharge when using rechargeable batteries in the system. The circuit shown in Figure 14 provides a low battery warning and disconnects the low battery and prevents damage to the battery system. The result is that when used to shut down the ICL7663S, the battery voltage drops to a value that should disconnect the load. As long as VSET1 is greater than 1.3V, OUT1 is low, but when VSET1 drops below 1.3V, OUT1 will turn high to shut down the ICL7663S. OUT2 is used for low battery warning. When VSET2 is greater than 1.3V, OUT2 is high and low battery warning is turned on. When VSET2 is lower than 1.3V, the output 2 battery is low, and the low battery warning goes out. Trip Voltage For low battery warning, can be set higher than the trip off voltage to give early warning of low battery before disconnecting the battery. Power-fail warning and power-on/power-off reset Figure 14 shows a power-fail warning circuit with power-on/power-off reset. When the unregulated DC input is above the trigger point, output 1 is low. When the DC input falls below the trigger point, output 1 turns off and the power failure warning goes high. The 7805's input voltage will continue to provide 5V output at 1A until the VIN is less than 7.3V, this circuit will provide some warning before the 5V output starts to drop. The ICL7665S OUT2 is used to prevent the microprocessor from writing spurious data to the CMOS battery backup memory output that causes OUT2 to go low when the 7805 5V falls below the ICL7665S trigger point.

Simple high and low temperature alarm

Figure 16 shows a simple high/low temperature alarm that uses the ICL7665S with NPN transistors. The voltage at the top of this R1 is determined by the transistor and the wiper arm position of R1. This voltage has a negative temperature coefficient. R1 is adjusted to alarm when the temperature of the NPN transistor reaches the selected high temperature. When this happens, OUT2 goes low. R2 is adjusted so that VSET1 is equal to 1.3V when the temperature of the transistor reaches the selected temperature for low temperature alarm. When the temperature drops below this limit, OUT1 goes low. AC Mains Failure and Outage Detector Figure 17 shows the secondary side by monitoring the transformer. This capacitor C1 charges through R1 when OUT1 is off. At a normal 100 VAC input to the transformer, Output 1 will discharge C1 once per cycle, approximately every 16.7ms. When the AC input voltage drops, OUT1 will remain off, so C1 will not discharge. When the voltage on C1 reaches 1.3V, output 2 turns off, and the power failure warning is excited. The time constant R1C1 is chosen such that charging C1 to 1.3V takes more than 16.7ms.