Datasheet LTC7821 (Analog Devices) - 8
| Manufacturer | Analog Devices |
| Description | Hybrid Step-Down Synchronous Controller |
| Pages / Page | 36 / 8 — TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. … |
| Revision | A |
| File Format / Size | PDF / 1.6 Mb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Voltage at Timer Pin to Start and
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Text Version of Document
LTC7821
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Voltage at Timer Pin to Start and Maximum Current Sense Threshold HYS_PRGM Voltage Window Stop Capacitor Balancing vs Common Mode Voltage vs Temperature vs Temperature
55.0 1.5 1.5 1.2 1.3 0.9 52.5 0.6 Stop Balancing 1.1 V 0.3 HYS_PRGM = 1.2V (V) 50.0 - VIN/2 (v) 0.0 0.9 VHYS_PRGM = INTVCC –0.3 V TIMER 0.7 V MID_SNS –0.6 47.5 –0.9 Start Balancing 0.5 CURRENT SENSE THRESHOLD (mV) –1.2 45.0 –1.5 0.3 0 5 10 15 20 25 30 35 40 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 V TEMPERATURE (°C) TEMPERATURE (°C) SENSE COMMON MODE VOLTAGE (V)7821 G19 7821 G20 7821 G21
TEMP Pin Trip Voltage Steady-State Output Voltage vs Temperature Line Transient 10V/ms Ripple of Typical Application
1.30 PULSE- SKIPPING V MODE 1.25 IN 10V/DIV 100mV/DIV RISING AC-COUPLED 1.20 Burst Mode MID OPERATION (V) 10V/DIV 100mV/DIV 1.15 AC-COUPLED FALLING V TEMP VOUT CONTINUOUS 100mV/DIV 1.10 MODE AC-COUPLED 100mV/DIV AC-COUPLED 1.05 1ms/DIV 7821 G23 7821 G24 V 10µs/DIV IN = 48V VOUT = 12V 1.00 ILOAD = 30mA –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) 7821 G22
Load Transient 2A–12A–2A of Typical Application Short-Circuit and Recovery TEMP Fault Characteristic
TEMP 2V/DIV VOUT 10V/DIV SW3 I 20V/DIV L 10A/DIV IL FAULT 20A/DIV 10V/DIV PGOOD VOUT 5V/DIV 500mV/DIV PGOOD AC-COUPLED 5V/DIV VOUT 20V/DIV 50µs/DIV 7821 G25 200ms/DIV 7821 G26 20ms/DIV 7821 G27 VIN = 48V VOUT = 12V fSW = 500kHz Rev A 8 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 Package Description Revision History Related Parts
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, unless otherwise noted. Voltage at Timer Pin to Start and Maximum Current Sense Threshold HYS_PRGM Voltage Window Stop Capacitor Balancing vs Common Mode Voltage vs Temperature vs Temperature
55.0 1.5 1.5 1.2 1.3 0.9 52.5 0.6 Stop Balancing 1.1 V 0.3 HYS_PRGM = 1.2V (V) 50.0 - VIN/2 (v) 0.0 0.9 VHYS_PRGM = INTVCC –0.3 V TIMER 0.7 V MID_SNS –0.6 47.5 –0.9 Start Balancing 0.5 CURRENT SENSE THRESHOLD (mV) –1.2 45.0 –1.5 0.3 0 5 10 15 20 25 30 35 40 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 V TEMPERATURE (°C) TEMPERATURE (°C) SENSE COMMON MODE VOLTAGE (V)7821 G19 7821 G20 7821 G21
TEMP Pin Trip Voltage Steady-State Output Voltage vs Temperature Line Transient 10V/ms Ripple of Typical Application
1.30 PULSE- SKIPPING V MODE 1.25 IN 10V/DIV 100mV/DIV RISING AC-COUPLED 1.20 Burst Mode MID OPERATION (V) 10V/DIV 100mV/DIV 1.15 AC-COUPLED FALLING V TEMP VOUT CONTINUOUS 100mV/DIV 1.10 MODE AC-COUPLED 100mV/DIV AC-COUPLED 1.05 1ms/DIV 7821 G23 7821 G24 V 10µs/DIV IN = 48V VOUT = 12V 1.00 ILOAD = 30mA –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) 7821 G22
Load Transient 2A–12A–2A of Typical Application Short-Circuit and Recovery TEMP Fault Characteristic
TEMP 2V/DIV VOUT 10V/DIV SW3 I 20V/DIV L 10A/DIV IL FAULT 20A/DIV 10V/DIV PGOOD VOUT 5V/DIV 500mV/DIV PGOOD AC-COUPLED 5V/DIV VOUT 20V/DIV 50µs/DIV 7821 G25 200ms/DIV 7821 G26 20ms/DIV 7821 G27 VIN = 48V VOUT = 12V fSW = 500kHz Rev A 8 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 Package Description Revision History Related Parts
