Datasheet LT1777 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | Low Noise Step-Down Switching Regulator |
| Seiten / Seite | 24 / 1 — FEATURES. DESCRIPTIO. Programmable dI/dt Limit. Internally Limited dV/dt. … |
| Dateiformat / Größe | PDF / 286 Kb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTIO. Programmable dI/dt Limit. Internally Limited dV/dt. APPLICATIO S. TYPICAL APPLICATIO
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LT1777 Low Noise Step-Down Switching Regulator
U FEATURES DESCRIPTIO
■
Programmable dI/dt Limit
The LT®1777 is a Buck (step-down) regulator designed for ■
Internally Limited dV/dt
noise sensitive applications. It contains a dI/dt limiting ■ High Input Voltage: 48V Max circuit programmed via a small external inductor in the ■ 700mA Peak Switch Rating switching path. Internal circuitry also generates controlled ■ True Current Mode Control dV/dt ramp rates. ■ 100kHz Fixed Operating Frequency The monolithic die includes all oscillator, control and ■ Synchronizable to 250kHz protection circuitry. The part can accept operating input ■ Low Supply Current in Shutdown: 30µA voltages as high as 48V, and contains an output switch ■ Low Thermal Resistance 16-Pin SO Package rated at 700mA peak current. Current mode control offers excellent dynamic input supply rejection and short-circuit
U
protection. The internal control circuitry is normally pow-
APPLICATIO S
ered via the VCC pin, thereby minimizing power drawn ■ Automotive Cellular and GPS Receivers directly from the VIN supply (see Applications Informa- ■ Telecom Power Supplies tion). The fused-lead SO16 package and 100kHz switch- ■ Industrial Instrument Power Supplies ing frequency allow for minimal PC board area requirements. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO Low Noise 5V Step-Down Supply VSW Switching Waveforms
VIN 24V 10 + 39µF VIN 63V 3 4 SHDN VCC 100pF V 1 SW LT1777 µH* 220µH VOUT VOLTAGE 12 6 SYNC VSW 5V 10V/DIV 14 5 400mA V V + C D 100µF 36.5k 13 FB MBRS1100 10V 1% 100pF 12k SGND V 2200pF SW 7 CURRENT 12.1k 200mA/DIV 1% *PROGRAMS dI/dT 1777 TA01 1777 TA02 500ns/DIV 1
U FEATURES DESCRIPTIO
■
Programmable dI/dt Limit
The LT®1777 is a Buck (step-down) regulator designed for ■
Internally Limited dV/dt
noise sensitive applications. It contains a dI/dt limiting ■ High Input Voltage: 48V Max circuit programmed via a small external inductor in the ■ 700mA Peak Switch Rating switching path. Internal circuitry also generates controlled ■ True Current Mode Control dV/dt ramp rates. ■ 100kHz Fixed Operating Frequency The monolithic die includes all oscillator, control and ■ Synchronizable to 250kHz protection circuitry. The part can accept operating input ■ Low Supply Current in Shutdown: 30µA voltages as high as 48V, and contains an output switch ■ Low Thermal Resistance 16-Pin SO Package rated at 700mA peak current. Current mode control offers excellent dynamic input supply rejection and short-circuit
U
protection. The internal control circuitry is normally pow-
APPLICATIO S
ered via the VCC pin, thereby minimizing power drawn ■ Automotive Cellular and GPS Receivers directly from the VIN supply (see Applications Informa- ■ Telecom Power Supplies tion). The fused-lead SO16 package and 100kHz switch- ■ Industrial Instrument Power Supplies ing frequency allow for minimal PC board area requirements. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO Low Noise 5V Step-Down Supply VSW Switching Waveforms
VIN 24V 10 + 39µF VIN 63V 3 4 SHDN VCC 100pF V 1 SW LT1777 µH* 220µH VOUT VOLTAGE 12 6 SYNC VSW 5V 10V/DIV 14 5 400mA V V + C D 100µF 36.5k 13 FB MBRS1100 10V 1% 100pF 12k SGND V 2200pF SW 7 CURRENT 12.1k 200mA/DIV 1% *PROGRAMS dI/dT 1777 TA01 1777 TA02 500ns/DIV 1