Datasheet LTC3315A (Analog Devices) - 9
| Hersteller | Analog Devices |
| Beschreibung | Dual 5V, 2A Synchronous Step-Down DC/DCs in 2mm × 2mm LQFN |
| Seiten / Seite | 22 / 9 — PIN FUNCTIONS EN1 (Pin 1):. SW2 (Pin 6):. IN (Pin 7, Pin 10):. FB1 (Pin … |
| Dateiformat / Größe | PDF / 1.6 Mb |
| Dokumentensprache | Englisch |
PIN FUNCTIONS EN1 (Pin 1):. SW2 (Pin 6):. IN (Pin 7, Pin 10):. FB1 (Pin 2):. GND (Pin 8, Pin 9, Exposed Pad Pin 13):
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LTC3315A
PIN FUNCTIONS EN1 (Pin 1):
Enable Input for Buck Regulator 1. Active
SW2 (Pin 6):
Switch Node for Buck Regulator 2. Connect high. The EN1 pin has a precision threshold and an an inductor to this pin with a short, wide trace. optional external resistor divider from VIN or another
V
supply programs when Buck Regulator 1 is enabled. If
IN (Pin 7, Pin 10):
Input Supply Pins. The VIN pins sup- ply current to internal circuitry and to each buck’s PMOS the precision threshold is not required, drive EN1 to VIN power switch. Connect both V to enable. Do not float. IN pins together with a short, wide trace and bypass to GND with low ESR capacitors
FB1 (Pin 2):
Feedback Input for Buck Regulator 1. located as close as possible to the pins. Program the output voltage and close the control loop
GND (Pin 8, Pin 9, Exposed Pad Pin 13):
Ground. by connecting this pin to the middle node of a resistor Connect the exposed pad to a continuous ground plane divider between the output and ground. The LTC3315A on the printed circuit board directly under the LTC3315A regulates FB1 to 500mV (typical). A phase lead capaci- for electrical contact and rated thermal performance. tor connected between VOUT1 and FB1 may be used to Additionally, Pin 8 and Pin 9 should be shorted to the optimize transient response. exposed pad with a wide trace.
FB2 (Pin 3):
Feedback Input for Buck Regulator 2.
SW1 (Pin 11):
Switch Node for Buck Regulator 1. Connect Program the output voltage and close the control loop an inductor to this pin with a short, wide trace. by connecting this pin to the middle node of a resistor divider between the output and ground. The LTC3315A
MODE/SYNC (Pin 12):
Mode Selection and External Clock regulates FB2 to 500mV (typical). A phase lead capaci- Synchronization Input. Ground this pin to enable pulse- tor connected between VOUT2 and FB2 may be used to skipping mode. For higher efficiency at light loads, tie optimize transient response. this pin to VIN to enable Burst Mode. For fast transient response and constant frequency operation over a wide
EN2 (Pin 4):
Enable Input for Buck Regulator 2. Active load range, float this pin to enable forced continuous high. The EN2 pin has a precision threshold and an mode. Drive MODE/SYNC with an external clock to syn- optional external resistor divider from VIN or another chronize both buck converters to the applied frequency. supply programs when Buck Regulator 2 is enabled. If When syncing, the operating mode is forced continuous. the precision threshold is not required, drive EN2 to VIN The slope compensation is automatically adapted to the to enable. Do not float. external clock frequency. In the absence of an external
PGOOD (Pin 5):
Power Good Output. Open drain out- clock both buck converters will switch at the default put. When the regulated output voltage of either enabled switching frequency. switching regulator falls below its PGOOD threshold or rises above its overvoltage threshold, this pin is driven low. When both buck regulators are disabled PGOOD is driven low. Rev. 0 For more information www.analog.com 9 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts
PIN FUNCTIONS EN1 (Pin 1):
Enable Input for Buck Regulator 1. Active
SW2 (Pin 6):
Switch Node for Buck Regulator 2. Connect high. The EN1 pin has a precision threshold and an an inductor to this pin with a short, wide trace. optional external resistor divider from VIN or another
V
supply programs when Buck Regulator 1 is enabled. If
IN (Pin 7, Pin 10):
Input Supply Pins. The VIN pins sup- ply current to internal circuitry and to each buck’s PMOS the precision threshold is not required, drive EN1 to VIN power switch. Connect both V to enable. Do not float. IN pins together with a short, wide trace and bypass to GND with low ESR capacitors
FB1 (Pin 2):
Feedback Input for Buck Regulator 1. located as close as possible to the pins. Program the output voltage and close the control loop
GND (Pin 8, Pin 9, Exposed Pad Pin 13):
Ground. by connecting this pin to the middle node of a resistor Connect the exposed pad to a continuous ground plane divider between the output and ground. The LTC3315A on the printed circuit board directly under the LTC3315A regulates FB1 to 500mV (typical). A phase lead capaci- for electrical contact and rated thermal performance. tor connected between VOUT1 and FB1 may be used to Additionally, Pin 8 and Pin 9 should be shorted to the optimize transient response. exposed pad with a wide trace.
FB2 (Pin 3):
Feedback Input for Buck Regulator 2.
SW1 (Pin 11):
Switch Node for Buck Regulator 1. Connect Program the output voltage and close the control loop an inductor to this pin with a short, wide trace. by connecting this pin to the middle node of a resistor divider between the output and ground. The LTC3315A
MODE/SYNC (Pin 12):
Mode Selection and External Clock regulates FB2 to 500mV (typical). A phase lead capaci- Synchronization Input. Ground this pin to enable pulse- tor connected between VOUT2 and FB2 may be used to skipping mode. For higher efficiency at light loads, tie optimize transient response. this pin to VIN to enable Burst Mode. For fast transient response and constant frequency operation over a wide
EN2 (Pin 4):
Enable Input for Buck Regulator 2. Active load range, float this pin to enable forced continuous high. The EN2 pin has a precision threshold and an mode. Drive MODE/SYNC with an external clock to syn- optional external resistor divider from VIN or another chronize both buck converters to the applied frequency. supply programs when Buck Regulator 2 is enabled. If When syncing, the operating mode is forced continuous. the precision threshold is not required, drive EN2 to VIN The slope compensation is automatically adapted to the to enable. Do not float. external clock frequency. In the absence of an external
PGOOD (Pin 5):
Power Good Output. Open drain out- clock both buck converters will switch at the default put. When the regulated output voltage of either enabled switching frequency. switching regulator falls below its PGOOD threshold or rises above its overvoltage threshold, this pin is driven low. When both buck regulators are disabled PGOOD is driven low. Rev. 0 For more information www.analog.com 9 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Typical Application Related Parts