Datasheet MAX917, MAX918, MAX919, MAX920 (Maxim) - 12
| Manufacturer | Maxim |
| Description | SOT23, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference |
| Pages / Page | 15 / 12 — SOT23, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without … |
| Revision | 2 |
| File Format / Size | PDF / 226 Kb |
| Document Language | English |
SOT23, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference. Zero-Crossing Detector. Logic-Level Translator
Model Line for this Datasheet
Text Version of Document
SOT23, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference
6) Verify the trip voltages and hysteresis as follows:
Zero-Crossing Detector
Figure 5 shows a zero-crossing detector application. ⎛ 1 1 1 ⎞ V rising : V = V × R1 + + The MAX919’s inverting input is connected to ground, IN THR REF ⎝⎜ R1 R2 R3⎠⎟ and its noninverting input is connected to a 100mVP-P V falling : V = signal source. As the signal at the noninverting input IN THF crosses 0V, the comparator’s output changes state. ⎛ 1 1 1 ⎞ R1 = V × R1 + + × V REF CC
Logic-Level Translator
⎝⎜ R1 R2 R3 + R4⎠⎟ − R3 + R4 The Typical Application Circuit shows an application Hysteresis = VTHR - VTHF that converts 5V logic to 3V logic levels. The MAX920 is powered by the +5V supply voltage, and the pullup
Board Layout and Bypassing
resistor for the MAX920’s open-drain output is connect- Power-supply bypass capacitors are not typically ed to the +3V supply voltage. This configuration allows needed, but use 100nF bypass capacitors close to the the full 5V logic swing without creating overvoltage on device’s supply pins when supply impedance is high, the 3V logic inputs. For 3V to 5V logic-level translations, supply leads are long, or excessive noise is expected simply connect the +3V supply voltage to VCC and the
MAX917–MAX920
on the supply lines. Minimize signal trace lengths to +5V supply voltage to the pullup resistor. reduce stray capacitance. A ground plane and sur- VCC face-mount components are recommended. V V CC CC 100mVP-P R3 IN+ OUT R1 R4 VIN IN- VCC OUT R2 MAX919 VEE VEE MAX918 V MAX920 REF Figure 5. Zero-Crossing Detector
Typical Application Circuit
Figure 4. MAX918/MAX920 Additional Hysteresis +5V (+3V)
Pin Configurations (continued)
+3V (+5V) TOP VIEW 100kΩ VCC RPULLUP IN- N.C. 1 8 N.C. OUT 3V (5V) IN- (REF) 2 7 V MAX917 CC 100kΩ LOGIC OUT MAX918 IN+ IN+ 3 MAX919 6 OUT MAX920 MAX920 VEE 4 5 N.C. VEE
SO
5V (3V) LOGIC IN LOGIC-LEVEL ( ) ARE FOR MAX917/MAX918. TRANSLATOR
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6) Verify the trip voltages and hysteresis as follows:
Zero-Crossing Detector
Figure 5 shows a zero-crossing detector application. ⎛ 1 1 1 ⎞ V rising : V = V × R1 + + The MAX919’s inverting input is connected to ground, IN THR REF ⎝⎜ R1 R2 R3⎠⎟ and its noninverting input is connected to a 100mVP-P V falling : V = signal source. As the signal at the noninverting input IN THF crosses 0V, the comparator’s output changes state. ⎛ 1 1 1 ⎞ R1 = V × R1 + + × V REF CC
Logic-Level Translator
⎝⎜ R1 R2 R3 + R4⎠⎟ − R3 + R4 The Typical Application Circuit shows an application Hysteresis = VTHR - VTHF that converts 5V logic to 3V logic levels. The MAX920 is powered by the +5V supply voltage, and the pullup
Board Layout and Bypassing
resistor for the MAX920’s open-drain output is connect- Power-supply bypass capacitors are not typically ed to the +3V supply voltage. This configuration allows needed, but use 100nF bypass capacitors close to the the full 5V logic swing without creating overvoltage on device’s supply pins when supply impedance is high, the 3V logic inputs. For 3V to 5V logic-level translations, supply leads are long, or excessive noise is expected simply connect the +3V supply voltage to VCC and the
MAX917–MAX920
on the supply lines. Minimize signal trace lengths to +5V supply voltage to the pullup resistor. reduce stray capacitance. A ground plane and sur- VCC face-mount components are recommended. V V CC CC 100mVP-P R3 IN+ OUT R1 R4 VIN IN- VCC OUT R2 MAX919 VEE VEE MAX918 V MAX920 REF Figure 5. Zero-Crossing Detector
Typical Application Circuit
Figure 4. MAX918/MAX920 Additional Hysteresis +5V (+3V)
Pin Configurations (continued)
+3V (+5V) TOP VIEW 100kΩ VCC RPULLUP IN- N.C. 1 8 N.C. OUT 3V (5V) IN- (REF) 2 7 V MAX917 CC 100kΩ LOGIC OUT MAX918 IN+ IN+ 3 MAX919 6 OUT MAX920 MAX920 VEE 4 5 N.C. VEE
SO
5V (3V) LOGIC IN LOGIC-LEVEL ( ) ARE FOR MAX917/MAX918. TRANSLATOR
12 ______________________________________________________________________________________
