Datasheet LTM8045 (Analog Devices) - 9
| Fabricante | Analog Devices |
| Descripción | Inverting or SEPIC μModule (Power Module) DC/DC Converter with Up to 700mA Output Current |
| Páginas / Página | 22 / 9 — pin FuncTions V. OUT (Bank 1):. SYNC (Pin E1):. OUT (Bank 2):. SS (Pin … |
| Formato / tamaño de archivo | PDF / 361 Kb |
| Idioma del documento | Inglés |
pin FuncTions V. OUT (Bank 1):. SYNC (Pin E1):. OUT (Bank 2):. SS (Pin F1):. GND (Bank 3):. RT (Pin G1):. RUN (Pin G3):. VIN (Bank 4):
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LTM8045
pin FuncTions V –
–
OUT (Bank 1):
VOUT is the negative output of the
SYNC (Pin E1):
To synchronize the switching frequency LTM8045. Apply an external capacitor between V + OUT and to an outside clock, simply drive this pin with a clock. The V – OUT . Tie this net to GND to configure the LTM8045 as high voltage level of the clock needs to exceed 1.3V, and a positive output SEPIC regulator. the low level should be less than 0.4V. Drive this pin to
V +
+ less than 0.4V to revert to the internal free running clock.
OUT (Bank 2):
VOUT is the positive output of the LTM8045. Apply an external capacitor between V + Ground this pin if the SYNC function is not used. See the OUT and V – Applications Information section for more information. OUT . Tie this net to GND to configure the LTM8045 as a negative output inverting regulator.
SS (Pin F1):
Place a soft-start capacitor here. Upon start-up,
GND (Bank 3):
Tie these GND pins to a local ground plane the SS pin will be charged by a (nominally) 275k resistor below the LTM8045 and the circuit components. GND to about 2.2V. MUST BE CONNECTED EITHER TO V + – OUT OR VOUT FOR
RT (Pin G1):
The RT pin is used to program the switching PROPER OPERATION. In most applications, the bulk of frequency of the LTM8045 by connecting a resistor from the heat flow out of the LTM8045 is through these pads, this pin to ground. The necessary resistor value for the so the printed circuit design has a large impact on the LTM8045 is determined by the equation RT = (91.9/fOSC) – 1, thermal performance of the part. See the PCB Layout and where fOSC is the typical switching frequency in MHz and Thermal Considerations sections for more details. Return RT is in kΩ. Do not leave this pin open. the feedback divider (RFB) to this net.
RUN (Pin G3):
This pin is used to enable/disable the chip
VIN (Bank 4):
The VIN pin supplies current to the LTM8045’s and restart the soft-start sequence. Drive below 1.235V internal regulator and to the internal power switch. This to disable the chip. Drive above 1.385V to activate chip pin must be locally bypassed with an external, low ESR and restart the soft-start sequence. Do not float this pin. capacitor.
FB (Pin A3):
If configured as a SEPIC, the LTM8045 regulates its FB pin to 1.215V. Apply a resistor between FB and V + OUT . Its value should be RFB = [(VOUT – 1.215)/ 0.0833]kΩ. If the LTM8045 is configured as an inverting converter, the LTM8045 regulates the FB pin to 5mV. Apply a resistor between FB and V – OUT of value RFB = [(|VOUT| + 0.005)/0.0833]kΩ. 8045fc For more information www.linear.com/LTM8045 9 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Photo Package Description Revision History Typical Application Related Parts
pin FuncTions V –
–
OUT (Bank 1):
VOUT is the negative output of the
SYNC (Pin E1):
To synchronize the switching frequency LTM8045. Apply an external capacitor between V + OUT and to an outside clock, simply drive this pin with a clock. The V – OUT . Tie this net to GND to configure the LTM8045 as high voltage level of the clock needs to exceed 1.3V, and a positive output SEPIC regulator. the low level should be less than 0.4V. Drive this pin to
V +
+ less than 0.4V to revert to the internal free running clock.
OUT (Bank 2):
VOUT is the positive output of the LTM8045. Apply an external capacitor between V + Ground this pin if the SYNC function is not used. See the OUT and V – Applications Information section for more information. OUT . Tie this net to GND to configure the LTM8045 as a negative output inverting regulator.
SS (Pin F1):
Place a soft-start capacitor here. Upon start-up,
GND (Bank 3):
Tie these GND pins to a local ground plane the SS pin will be charged by a (nominally) 275k resistor below the LTM8045 and the circuit components. GND to about 2.2V. MUST BE CONNECTED EITHER TO V + – OUT OR VOUT FOR
RT (Pin G1):
The RT pin is used to program the switching PROPER OPERATION. In most applications, the bulk of frequency of the LTM8045 by connecting a resistor from the heat flow out of the LTM8045 is through these pads, this pin to ground. The necessary resistor value for the so the printed circuit design has a large impact on the LTM8045 is determined by the equation RT = (91.9/fOSC) – 1, thermal performance of the part. See the PCB Layout and where fOSC is the typical switching frequency in MHz and Thermal Considerations sections for more details. Return RT is in kΩ. Do not leave this pin open. the feedback divider (RFB) to this net.
RUN (Pin G3):
This pin is used to enable/disable the chip
VIN (Bank 4):
The VIN pin supplies current to the LTM8045’s and restart the soft-start sequence. Drive below 1.235V internal regulator and to the internal power switch. This to disable the chip. Drive above 1.385V to activate chip pin must be locally bypassed with an external, low ESR and restart the soft-start sequence. Do not float this pin. capacitor.
FB (Pin A3):
If configured as a SEPIC, the LTM8045 regulates its FB pin to 1.215V. Apply a resistor between FB and V + OUT . Its value should be RFB = [(VOUT – 1.215)/ 0.0833]kΩ. If the LTM8045 is configured as an inverting converter, the LTM8045 regulates the FB pin to 5mV. Apply a resistor between FB and V – OUT of value RFB = [(|VOUT| + 0.005)/0.0833]kΩ. 8045fc For more information www.linear.com/LTM8045 9 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Photo Package Description Revision History Typical Application Related Parts