Datasheet LMX331, LMX393, LMX339 (Maxim) - 7

General-Purpose, Low-Voltage, Single/Dual/Quad, Tiny-Pack Comparators LMX331/LMX393/LMX339 Pin Description PIN NAME FUNCTION LMX331 LMX393 LMX339
1 — — IN+ Noninverting Input 2 4 12 VSS Negative Supply (Connect to GND) 3 — — IN- Inverting Input 4 — — OUT Comparator Output (Open-Drain) 5 8 3 VDD Positive Supply — 1 2 OUTA Comparator A Output (Open-Drain) — 7 1 OUTB Comparator B Output (Open-Drain) — 2 4 INA- Comparator A Inverting Input — 3 5 INA+ Comparator A Noninverting Input — 5 7 INB+ Comparator B Noninverting Input — 6 6 INB- Comparator B Inverting Input — — 8 INC- Comparator C Inverting Input — — 9 INC+ Comparator C Noninverting Input — — 10 IND- Comparator D Inverting Input — — 11 IND+ Comparator D Noninverting Input — — 13 OUTD Comparator D Output (Open-Drain) — — 14 OUTC Comparator C Output (Open-Drain)
Detailed Description
input voltage (Figure 1). The difference between the trip points is the hysteresis. When the comparator's input The LMX331/LMX393/LMX339 are single/dual/quad, voltages are equal, the hysteresis effectively causes low-cost, general-purpose comparators. They have a one comparator input to move quickly past the other, single-supply operating voltage of 1.8V to 5V. The com- thus taking the input out of the region where oscillation mon-mode input range extends from -0.1V below the occurs. This provides clean output transitions for noisy, negative supply to within 0.7V of the positive supply. slow-moving input signals. They require approximately 60µA per comparator with a 5V supply and 40µA with a 2.7V supply. Additional hysteresis can be generated with two resis- tors, using positive feedback (Figure 2). Use the follow- The LMX331H/LMX393H/LMX339H have 2mV of hys- ing procedure to calculate resistor values: teresis for noise immunity. This significantly reduces the chance of output oscillations even with slow-moving input signals. The LMX331/LMX393/LMX339 and THRESHOLDS LMX331H/LMX393H/LMX339H are ideal for automotive IN+ applications because they operate from -40°C to +125°C (see Typical Operating Characteristics). HYSTERESIS VTH
Applications Information
IN- BAND VHYST VTL
Hysteresis
Many comparators oscillate in the linear region of oper- ation because of noise or undesired parasitic feed- back. This tends to occur when the voltage on one input is equal or very close to the voltage on the other OUT input. The LMX331H/LMX393H/LMX339H have internal hysteresis to counter parasitic effects and noise. The hysteresis in a comparator creates two trip points: Figure 1. Threshold Hysteresis Band (Not to Scale) one for the rising input voltage and one for the falling
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