Datasheet LTC1265, LTC1265-3.3, LTC1265-5 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | 1.2A, High Efficiency Step-Down DC/DC Converter |
| Pages / Page | 16 / 4 — TYPICAL PERFOR A CE CHARACTERISTICS. DC Supply Current. Supply Current in … |
| File Format / Size | PDF / 244 Kb |
| Document Language | English |
TYPICAL PERFOR A CE CHARACTERISTICS. DC Supply Current. Supply Current in Shutdown. Gate Charge Losses. PI FU CTIO S
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Text Version of Document
LTC1265/LTC1265-3.3/LTC1265-5
W U TYPICAL PERFOR A CE CHARACTERISTICS DC Supply Current Supply Current in Shutdown Gate Charge Losses
2.1 8 5.5 DOES NOT INCLUDE SHUTDOWN = 3V GATE CHARGE 5.0 T 1.8 7 A = 25C V 4.5 IN = 12V 1.5 ACTIVE MODE µA) 6 4.0 5 3.5 1.2 VIN = 9V 3.0 4 0.9 2.5 3 2.0 VIN = 6V 0.6 SUPPLY CURRENT (mA) SUPPLY CURRENT ( 1.5 2 SWITCHING CURRENT (mA) 1.0 0.3 SLEEP MODE 1 0.5 0 0 0 0 2 4 6 8 10 12 14 3 4 5 6 7 8 9 10 11 12 13 0 200 400 600 800 1000 INPUT VOLTAGE (V) INPUT VOLTAGE (V) FREQUENCY (kHz) 1265 G07 1265 G08 1265 G09
U U U PI FU CTIO S PWR VIN (Pins 1, 13):
Supply for the Power MOSFET and
SENSE+ (Pin 8):
The (+) Pin to the Current Comparator. A its Driver. Must decouple this pin properly to ground. Must built-in offset between Pins 7 and 8 in conjunction with always tie Pins 1 and 13 together. RSENSE sets the current trip threshold.
VIN (Pin 2):
Main Supply for All the Control Circuitry in the
N/C,VFB (Pin 9):
For the LTC1265 adjustable version, this LTC1265. pin serves as the feedback pin from an external resistive divider used to set the output voltage. On the LTC1265-3.3
LBOUT (Pin 3):
Open-Drain Output of the Low-Battery and LTC1265-5 versions, this pin is not used. Comparator. This pin will sink current when Pin 4 (LBIN) goes below 1.25V. During shutdown, this pin is high
SHDN (Pin 10):
Pulling this pin HIGH keeps the internal impedance. switch off and puts the LTC1265 in micropower shut- down. Do not float this pin.
LBIN (Pin 4):
The (–) Input of the Low-Battery Comparator. The (+) input is connected to a reference voltage of 1.25V.
SGND (Pin 11):
Small-Signal Ground. Must be routed separately from other grounds to the (–) terminal of C
C
OUT.
T (Pin 5):
External capacitor CT from Pin 5 to ground sets the switch off time. The operating frequency is dependent
PGND (Pin 12):
Switch Driver Ground. Connects to the on the input voltage and CT. (–) terminal of CIN. Anode of the Schottky diode must be connected close to this pin.
ITH (Pin 6):
Feedback Amplifier Decoupling Point. The current comparator threshold is proportional to Pin 6
SW (Pin 14):
Drain of the P-Channel MOSFET Switch. voltage. Cathode of the Schottky diode must be connected close to this pin.
SENSE – (Pin 7):
Connect to the (–) input of the current comparator. For LTC1265-3.3 and LTC1265-5, it also connects to an internal resistive divider which sets the output voltage. 4
W U TYPICAL PERFOR A CE CHARACTERISTICS DC Supply Current Supply Current in Shutdown Gate Charge Losses
2.1 8 5.5 DOES NOT INCLUDE SHUTDOWN = 3V GATE CHARGE 5.0 T 1.8 7 A = 25C V 4.5 IN = 12V 1.5 ACTIVE MODE µA) 6 4.0 5 3.5 1.2 VIN = 9V 3.0 4 0.9 2.5 3 2.0 VIN = 6V 0.6 SUPPLY CURRENT (mA) SUPPLY CURRENT ( 1.5 2 SWITCHING CURRENT (mA) 1.0 0.3 SLEEP MODE 1 0.5 0 0 0 0 2 4 6 8 10 12 14 3 4 5 6 7 8 9 10 11 12 13 0 200 400 600 800 1000 INPUT VOLTAGE (V) INPUT VOLTAGE (V) FREQUENCY (kHz) 1265 G07 1265 G08 1265 G09
U U U PI FU CTIO S PWR VIN (Pins 1, 13):
Supply for the Power MOSFET and
SENSE+ (Pin 8):
The (+) Pin to the Current Comparator. A its Driver. Must decouple this pin properly to ground. Must built-in offset between Pins 7 and 8 in conjunction with always tie Pins 1 and 13 together. RSENSE sets the current trip threshold.
VIN (Pin 2):
Main Supply for All the Control Circuitry in the
N/C,VFB (Pin 9):
For the LTC1265 adjustable version, this LTC1265. pin serves as the feedback pin from an external resistive divider used to set the output voltage. On the LTC1265-3.3
LBOUT (Pin 3):
Open-Drain Output of the Low-Battery and LTC1265-5 versions, this pin is not used. Comparator. This pin will sink current when Pin 4 (LBIN) goes below 1.25V. During shutdown, this pin is high
SHDN (Pin 10):
Pulling this pin HIGH keeps the internal impedance. switch off and puts the LTC1265 in micropower shut- down. Do not float this pin.
LBIN (Pin 4):
The (–) Input of the Low-Battery Comparator. The (+) input is connected to a reference voltage of 1.25V.
SGND (Pin 11):
Small-Signal Ground. Must be routed separately from other grounds to the (–) terminal of C
C
OUT.
T (Pin 5):
External capacitor CT from Pin 5 to ground sets the switch off time. The operating frequency is dependent
PGND (Pin 12):
Switch Driver Ground. Connects to the on the input voltage and CT. (–) terminal of CIN. Anode of the Schottky diode must be connected close to this pin.
ITH (Pin 6):
Feedback Amplifier Decoupling Point. The current comparator threshold is proportional to Pin 6
SW (Pin 14):
Drain of the P-Channel MOSFET Switch. voltage. Cathode of the Schottky diode must be connected close to this pin.
SENSE – (Pin 7):
Connect to the (–) input of the current comparator. For LTC1265-3.3 and LTC1265-5, it also connects to an internal resistive divider which sets the output voltage. 4
