Datasheet LTC3802 (Analog Devices) - 8
| Hersteller | Analog Devices |
| Beschreibung | Dual 550kHz Synchronous 2-Phase DC/DC Controller with Programmable Up/Down Tracking |
| Seiten / Seite | 28 / 8 — TYPICAL PERFOR A CE CHARACTERISTICS. Supply Current vs Temperature. … |
| Dateiformat / Größe | PDF / 359 Kb |
| Dokumentensprache | Englisch |
TYPICAL PERFOR A CE CHARACTERISTICS. Supply Current vs Temperature. Supply Current vs Supply Voltage
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LTC3802
W U TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Temperature Supply Current vs Supply Voltage
10 10 TA = 25°C IVCC IPVCC IVCC (NO LOAD) IPVCC (NO LOAD) 1 1 IBOOST1 IBOOST1, IBOOST2 IBOOST2 (NO LOAD) (NO LOAD) 0.1 0.1 IVCC I SUPPLY CURRENT (mA) VCC SHUTDOWN SHUTDOWN SUPPLY CURRENT (mA) VCC = VPVCC = VBOOST – VSW = 5V 0.01 0.01 –50 –25 0 25 50 75 100 125 3 3.5 4 4.5 5 5.5 6 SUPPLY VOLTAGE (V) TEMPERATURE (°C) 3802 G26 3802 G27
U U U PI FU CTIO S (28-Pin SSOP/32-Pin QFN Package) PVCC (Pin 1/Pin 29):
Driver Power Supply Input. PVCC
SW1 (Pin 5/Pin 1):
Channel 1 Controller Switching Node. provides power to the two BG drivers and must be con- Connect SW1 to the switching node of the channel 1 nected to an external voltage high enough to fully turn on converter. When the bottom MOSFET QB1 turns on, the the external MOSFETs, QB1 and QB2. PVCC requires at current limit comparator and the burst comparator least a 10µF bypass capacitor directly to PGND. monitor the voltage at SW1. If the voltage drop across MOSFET QB1 is too large, the controller enters current
BG1 (Pin 2/Pin 30):
Channel 1 Controller Bottom Gate limit; if it is too small, the switcher enters Burst Mode Drive. The BG1 pin drives the gate of the bottom N-channel operation. See Current Limit and Burst Mode Applica- synchronous switch MOSFET, QB1. BG1 is designed to tions Information. drive typically up to 10,000pF of gate capacitance.
PGND (Pin 6/Pins 2, 3, 23, 24):
Power Ground. The BG
BOOST1 (Pin 3/Pin 31):
Channel 1 Controller Top Gate drivers return to this pin. Connect PGND to a high current Driver Supply. BOOST1 should be bootstrapped to SW1 ground node in close proximity to the sources of external with a 0.1µF capacitor. An external Schottky diode from MOSFETs QB1 and QB2 and the V PV IN, PVCC and VOUT CC to BOOST1 creates a complete floating charge- bypass capacitors. pumped supply at BOOST1. No other external supplies are required.
IMAX1 (Pin 7/Pin 4):
Channel 1 Controller Current Limit Set. The I
TG1 (Pin 4/Pin 32):
Channel 1 Controller Top Gate Drive. MAX1 pin has an internal 10µA current source pull-up, allowing the current limit and burst comparator The TG1 pin drives the top N-channel MOSFET with a threshold to be programmed by a single external resistor voltage swing equal to PVCC superimposed on the switch to SGND. See Current Limit and Burst Mode Applications node voltage SW1. TG1 is designed to drive typically up to Information. 6000pF of gate capacitance. 3802f 8
W U TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Temperature Supply Current vs Supply Voltage
10 10 TA = 25°C IVCC IPVCC IVCC (NO LOAD) IPVCC (NO LOAD) 1 1 IBOOST1 IBOOST1, IBOOST2 IBOOST2 (NO LOAD) (NO LOAD) 0.1 0.1 IVCC I SUPPLY CURRENT (mA) VCC SHUTDOWN SHUTDOWN SUPPLY CURRENT (mA) VCC = VPVCC = VBOOST – VSW = 5V 0.01 0.01 –50 –25 0 25 50 75 100 125 3 3.5 4 4.5 5 5.5 6 SUPPLY VOLTAGE (V) TEMPERATURE (°C) 3802 G26 3802 G27
U U U PI FU CTIO S (28-Pin SSOP/32-Pin QFN Package) PVCC (Pin 1/Pin 29):
Driver Power Supply Input. PVCC
SW1 (Pin 5/Pin 1):
Channel 1 Controller Switching Node. provides power to the two BG drivers and must be con- Connect SW1 to the switching node of the channel 1 nected to an external voltage high enough to fully turn on converter. When the bottom MOSFET QB1 turns on, the the external MOSFETs, QB1 and QB2. PVCC requires at current limit comparator and the burst comparator least a 10µF bypass capacitor directly to PGND. monitor the voltage at SW1. If the voltage drop across MOSFET QB1 is too large, the controller enters current
BG1 (Pin 2/Pin 30):
Channel 1 Controller Bottom Gate limit; if it is too small, the switcher enters Burst Mode Drive. The BG1 pin drives the gate of the bottom N-channel operation. See Current Limit and Burst Mode Applica- synchronous switch MOSFET, QB1. BG1 is designed to tions Information. drive typically up to 10,000pF of gate capacitance.
PGND (Pin 6/Pins 2, 3, 23, 24):
Power Ground. The BG
BOOST1 (Pin 3/Pin 31):
Channel 1 Controller Top Gate drivers return to this pin. Connect PGND to a high current Driver Supply. BOOST1 should be bootstrapped to SW1 ground node in close proximity to the sources of external with a 0.1µF capacitor. An external Schottky diode from MOSFETs QB1 and QB2 and the V PV IN, PVCC and VOUT CC to BOOST1 creates a complete floating charge- bypass capacitors. pumped supply at BOOST1. No other external supplies are required.
IMAX1 (Pin 7/Pin 4):
Channel 1 Controller Current Limit Set. The I
TG1 (Pin 4/Pin 32):
Channel 1 Controller Top Gate Drive. MAX1 pin has an internal 10µA current source pull-up, allowing the current limit and burst comparator The TG1 pin drives the top N-channel MOSFET with a threshold to be programmed by a single external resistor voltage swing equal to PVCC superimposed on the switch to SGND. See Current Limit and Burst Mode Applications node voltage SW1. TG1 is designed to drive typically up to Information. 6000pF of gate capacitance. 3802f 8