Datasheet LT8301 (Analog Devices) - 6

HerstellerAnalog Devices
Beschreibung42VIN Micropower No-Opto Isolated Flyback Converter with 65V/1.2A Switch
Seiten / Seite24 / 6 — PIN FUNCTIONS. EN/UVLO (Pin 1):. SW (Pin 4):. GND (Pin 2):. IN (Pin 5):. …
RevisionB
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DokumentenspracheEnglisch

PIN FUNCTIONS. EN/UVLO (Pin 1):. SW (Pin 4):. GND (Pin 2):. IN (Pin 5):. RFB (Pin 3):. BLOCK DIAGRAM

PIN FUNCTIONS EN/UVLO (Pin 1): SW (Pin 4): GND (Pin 2): IN (Pin 5): RFB (Pin 3): BLOCK DIAGRAM

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LT8301
PIN FUNCTIONS EN/UVLO (Pin 1):
Enable/Undervoltage Lockout. The SW pin. The ratio of the RFB resistor to an internal 10k EN/UVLO pin is used to enable the LT8301. Pull the pin resistor, times a trimmed 1.0V reference voltage, deter- below 0.2V to shut down the LT8301. This pin has an mines the output voltage (plus the effect of any non-unity accurate 1.228V threshold and can be used to program a transformer turns ratio). Minimize trace area at this pin. VIN undervoltage lockout (UVLO) threshold using a resis-
SW (Pin 4):
Drain of the 65V Internal DMOS Power tor divider from VIN to ground. A 2.5µA current hysteresis Switch. Minimize trace area at this pin to reduce EMI and al ows the programming of VIN UVLO hysteresis. If neither voltage spikes. function is used, tie this pin directly to VIN.
V GND (Pin 2):
Ground. Tie this pin directly to local ground
IN (Pin 5):
Input Supply. The VIN pin supplies current to internal circuitry and serves as a reference voltage for plane. the feedback circuitry connected to the RFB pin. Locally
RFB (Pin 3):
Input Pin for External Feedback Resistor. bypass this pin to ground with a capacitor. Connect a resistor from this pin to the transformer primary
BLOCK DIAGRAM
T1 DOUT VIN NPS:1 V + OUT • CIN LPRI LSEC COUT • RFB V – OUT 5 3 4 VIN RFB SW BOUNDARY DETECTOR 1:4 M3 M2 OSCILLATOR – – gm 25µA RREF + S 10kΩ 1.0V A3 R Q DRIVER M1 + R1 EN/UVLO – + 1 A2 RSENSE 2.5µA A1 R2 + – 1.228V VIN GND 2 M4 REFERENCE REGULATORS 8301 BD Rev. B 6 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts