Datasheet LT1300 - 4
| Description | Micropower High Efficiency 3.3/5V Step-Up DC/DC Converter |
| Pages / Page | 8 / 4 — PIN FUNCTIONS. GND (Pin 1):. VIN (Pin 6):. Sel (Pin 2):. SW (Pin 7):. … |
| File Format / Size | PDF / 230 Kb |
| Document Language | English |
PIN FUNCTIONS. GND (Pin 1):. VIN (Pin 6):. Sel (Pin 2):. SW (Pin 7):. SHDN (Pin 3):. PGND (Pin 8):. Sense (Pin 4):. ILIM (Pin 5):
Text Version of Document
LT1300
U U U PIN FUNCTIONS GND (Pin 1):
Signal Ground.
VIN (Pin 6):
Supply Pin. Must be bypassed with a large value electrolytic to ground. A 0.1µF ceramic capacitor
Sel (Pin 2):
Output Select. When tied to VIN or VOUT close to the pin may be needed in some cases. converter regulates at 5V. When grounded converter regulates at 3.3V.
SW (Pin 7):
Switch Pin. Connect inductor and diode here. Keep layout short and direct to minimize electronic radia-
SHDN (Pin 3):
Shutdown. Pull high to effect shutdown. Tie tion. to ground for normal operation.
PGND (Pin 8):
Power Ground. Tie to signal ground (pin 1)
Sense (Pin 4):
“Output” Pin. under the package. Bypass capacitor from VIN should be
ILIM (Pin 5):
Float for 1A switch current limit. Tie to ground tied directly to the pin. for approximately 400mA. A resistor between ILIM and ground sets peak current to some intermediate value (see Figure 5).
W BLOCK DIAGRAM
VIN L1 D1 VOUT + + C1 C2 SENSE VIN SW 4 2 7 18mV A2 CURRENT R1 COMPARATOR + 3Ω R2 500k 730Ω – A1 OFF COMPARATOR + 1.25V ENABLE OSCILLATOR REFERENCE A3 DRIVER 155kHZ Q2 Q1 144k – 1x 160x 161k BIAS Q3 8.5k GND SELECT SHUTDOWN I PGND LIM 1 2 3 5 8 LT1300 F1
Figure 1.
4
U U U PIN FUNCTIONS GND (Pin 1):
Signal Ground.
VIN (Pin 6):
Supply Pin. Must be bypassed with a large value electrolytic to ground. A 0.1µF ceramic capacitor
Sel (Pin 2):
Output Select. When tied to VIN or VOUT close to the pin may be needed in some cases. converter regulates at 5V. When grounded converter regulates at 3.3V.
SW (Pin 7):
Switch Pin. Connect inductor and diode here. Keep layout short and direct to minimize electronic radia-
SHDN (Pin 3):
Shutdown. Pull high to effect shutdown. Tie tion. to ground for normal operation.
PGND (Pin 8):
Power Ground. Tie to signal ground (pin 1)
Sense (Pin 4):
“Output” Pin. under the package. Bypass capacitor from VIN should be
ILIM (Pin 5):
Float for 1A switch current limit. Tie to ground tied directly to the pin. for approximately 400mA. A resistor between ILIM and ground sets peak current to some intermediate value (see Figure 5).
W BLOCK DIAGRAM
VIN L1 D1 VOUT + + C1 C2 SENSE VIN SW 4 2 7 18mV A2 CURRENT R1 COMPARATOR + 3Ω R2 500k 730Ω – A1 OFF COMPARATOR + 1.25V ENABLE OSCILLATOR REFERENCE A3 DRIVER 155kHZ Q2 Q1 144k – 1x 160x 161k BIAS Q3 8.5k GND SELECT SHUTDOWN I PGND LIM 1 2 3 5 8 LT1300 F1
Figure 1.
4
