LT5581 PIN FUNCTIONSVCC (Pin 1): Power Supply, 2.7V to 5.25V. VCC CSQ (Pin 8): Optional Low Frequency Range Extension should be bypassed with a 0.1µF ceramic capacitor. Capacitor. This pin is for frequencies below 250MHz. Use EN (Pin 2): Chip Enable. A logic low or no-connect on the 0.01µF from pin to ground for 10MHz operation. enable pin shuts down the part. A logic high enables the Exposed Pad (Pin 9): Ground. The Exposed Pad must part. An internal 500k pull-down resistor ensures the part be soldered to the PCB. For high frequency operation, is off when the enable driver is in a three-state condition. the backside ground connection should have a low V inductance connection to the PCB ground, using many OUT (Pin 3): Detector Output. through-hole vias. See the layout information in the GND (Pins 4, 5, 6): Ground. Applications Information section. RFIN (Pin 7): RF Input. Should be DC-blocked with coupling capacitor; 1000pF recommended. This pin has an internal 200Ω termination. BLOCK DIAGRAM 9 LT5581 EXPOSED PAD OUTPUT BUFFER 150kHz LPF RF 300Ω IN V RMS OUT 7 3 DETECTOR BIAS GND CSQ EN VCC 8 2 1 4 5 6 5581 BD 5581fb For more information www.linear.com/LT5581 9 Document Outline Description Typical Application Absolute Maximum Ratings Pin Configuration Typical Performance Characteristics Pin Functions Package Description