Datasheet LT1375, LT1376 (Analog Devices) - 6
| Hersteller | Analog Devices |
| Beschreibung | 1.5A, 500kHz Step-Down Switching Regulators |
| Seiten / Seite | 28 / 6 — TYPICAL PERFORMANCE CHARACTERISTICS. Maximum Load Current. at VOUT = 10V. … |
| Dateiformat / Größe | PDF / 518 Kb |
| Dokumentensprache | Englisch |
TYPICAL PERFORMANCE CHARACTERISTICS. Maximum Load Current. at VOUT = 10V. at VOUT = 3.3V. at VOUT = 5V. BOOST Pin Current
Modelllinie für dieses Datenblatt
- LT1375CN8#PBF LT1375CN8-5#PBF LT1375CS8#PBF LT1375CS8#TRPBF LT1375CS8-5#PBF LT1375CS8-5#TRPBF LT1375HVCS8#PBF LT1375HVCS8#TRPBF LT1375HVIS8#PBF LT1375HVIS8#TRPBF LT1375IN8#PBF LT1375IN8-5#PBF LT1375IS8#PBF LT1375IS8#TRPBF LT1375IS8-5#PBF LT1375IS8-5#TRPBF
- LT1376CN8#PBF LT1376CN8-5#PBF LT1376CS#PBF LT1376CS#TRPBF LT1376CS8#PBF LT1376CS8#TRPBF LT1376CS8-5#PBF LT1376CS8-5#TRPBF LT1376HVCS#PBF LT1376HVCS#TRPBF LT1376HVCS8#PBF LT1376HVCS8#TRPBF LT1376HVIS#PBF LT1376HVIS#TRPBF LT1376HVIS8#PBF LT1376HVIS8#TRPBF LT1376IN8#PBF LT1376IN8-5#PBF LT1376IS#PBF LT1376IS#TRPBF LT1376IS8#PBF LT1376IS8#TRPBF LT1376IS8-5#PBF LT1376IS8-5#TRPBF
Textversion des Dokuments
LT1375/LT1376
W U TYPICAL PERFORMANCE CHARACTERISTICS Maximum Load Current Maximum Load Current Maximum Load Current at VOUT = 10V at VOUT = 3.3V at VOUT = 5V
1.50 1.50 1.50 VOUT = 10V L = 20µH L = 20µH L = 20µH 1.25 1.25 L = 10µH 1.25 L = 10µH L = 10µH 1.00 1.00 1.00 L = 5µH L = 5µH 0.75 0.75 0.75 L = 5µH CURRENT (A) CURRENT (A) CURRENT (A) 0.50 0.50 0.50 0.25 0.25 0.25 VOUT = 3.3V VOUT = 5V 0 0 0 0 5 10 15 20 25 0 5 10 15 20 25 0 5 10 15 20 25 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1375/76 G13 1375/76 G14 1375/76 G15
BOOST Pin Current VC Pin Shutdown Threshold Switch Voltage Drop
12 1.4 0.8 T SHUTDOWN J = 25°C TJ = 25°C 10 1.2 0.6 8 1.0 6 0.4 0.8 4 SWITCH VOLTAGE (V) BOOST PIN CURRENT (mA) THRESHOLD VOLTAGE (V) 0.2 0.6 2 0 0.4 0 0 0.25 0.50 0.75 1.00 1.25 –50 –25 0 25 50 75 100 125 0 0.25 0.50 0.75 1.00 1.25 1.50 SWITCH CURRENT (A) JUNCTION TEMPERATURE (°C) SWITCH CURRENT (A) 1375/76 G16 1375/76 G11 1375/76 G18
U U U PIN FUNCTIONS BOOST:
The BOOST pin is used to provide a drive voltage, with the external catch diode. Maximum negative switch higher than the input voltage, to the internal bipolar NPN voltage allowed is – 0.8V. power switch. Without this added voltage, the typical
SHDN:
The shutdown pin is used to turn off the regulator switch voltage loss would be about 1.5V. The additional and to reduce input drain current to a few microamperes. boost voltage allows the switch to saturate and voltage Actually, this pin has two separate thresholds, one at loss approximates that of a 0.3Ω FET structure, but with 2.38V to disable switching, and a second at 0.4V to force much smaller die area. Efficiency improves from 75% for complete micropower shutdown. The 2.38V threshold conventional bipolar designs to > 87% for these new parts. functions as an accurate undervoltage lockout (UVLO).
VSW:
The switch pin is the emitter of the on-chip power This is sometimes used to prevent the regulator from NPN switch. It is driven up to the input pin voltage during operating until the input voltage has reached a predeter- switch on time. Inductor current drives the switch pin mined level. negative during switch off time. Negative voltage is clamped 13756fd 6
W U TYPICAL PERFORMANCE CHARACTERISTICS Maximum Load Current Maximum Load Current Maximum Load Current at VOUT = 10V at VOUT = 3.3V at VOUT = 5V
1.50 1.50 1.50 VOUT = 10V L = 20µH L = 20µH L = 20µH 1.25 1.25 L = 10µH 1.25 L = 10µH L = 10µH 1.00 1.00 1.00 L = 5µH L = 5µH 0.75 0.75 0.75 L = 5µH CURRENT (A) CURRENT (A) CURRENT (A) 0.50 0.50 0.50 0.25 0.25 0.25 VOUT = 3.3V VOUT = 5V 0 0 0 0 5 10 15 20 25 0 5 10 15 20 25 0 5 10 15 20 25 INPUT VOLTAGE (V) INPUT VOLTAGE (V) INPUT VOLTAGE (V) 1375/76 G13 1375/76 G14 1375/76 G15
BOOST Pin Current VC Pin Shutdown Threshold Switch Voltage Drop
12 1.4 0.8 T SHUTDOWN J = 25°C TJ = 25°C 10 1.2 0.6 8 1.0 6 0.4 0.8 4 SWITCH VOLTAGE (V) BOOST PIN CURRENT (mA) THRESHOLD VOLTAGE (V) 0.2 0.6 2 0 0.4 0 0 0.25 0.50 0.75 1.00 1.25 –50 –25 0 25 50 75 100 125 0 0.25 0.50 0.75 1.00 1.25 1.50 SWITCH CURRENT (A) JUNCTION TEMPERATURE (°C) SWITCH CURRENT (A) 1375/76 G16 1375/76 G11 1375/76 G18
U U U PIN FUNCTIONS BOOST:
The BOOST pin is used to provide a drive voltage, with the external catch diode. Maximum negative switch higher than the input voltage, to the internal bipolar NPN voltage allowed is – 0.8V. power switch. Without this added voltage, the typical
SHDN:
The shutdown pin is used to turn off the regulator switch voltage loss would be about 1.5V. The additional and to reduce input drain current to a few microamperes. boost voltage allows the switch to saturate and voltage Actually, this pin has two separate thresholds, one at loss approximates that of a 0.3Ω FET structure, but with 2.38V to disable switching, and a second at 0.4V to force much smaller die area. Efficiency improves from 75% for complete micropower shutdown. The 2.38V threshold conventional bipolar designs to > 87% for these new parts. functions as an accurate undervoltage lockout (UVLO).
VSW:
The switch pin is the emitter of the on-chip power This is sometimes used to prevent the regulator from NPN switch. It is driven up to the input pin voltage during operating until the input voltage has reached a predeter- switch on time. Inductor current drives the switch pin mined level. negative during switch off time. Negative voltage is clamped 13756fd 6