Datasheet LT1300 - 7
| Description | Micropower High Efficiency 3.3/5V Step-Up DC/DC Converter |
| Pages / Page | 8 / 7 — APPLICATIONS INFORMATION. Table 1. Recommended Inductors. EFFICIENCY … |
| File Format / Size | PDF / 230 Kb |
| Document Language | English |
APPLICATIONS INFORMATION. Table 1. Recommended Inductors. EFFICIENCY 2.5VIN, 5VOUT. COMPONENT. PART NUMBER. VENDOR. L (. DCR (
Text Version of Document
LT1300
U U W U APPLICATIONS INFORMATION Table 1. Recommended Inductors EFFICIENCY 2.5VIN, 5VOUT COMPONENT PART NUMBER VENDOR L (
µ
H) DCR (
Ω
) ILIM PIN 50mA LOAD 200mA LOAD HEIGHT (mm) PHONE NUMBER
DO1608-103 Coilcraft 10 0.11 Float 83 83 3.5 (708) 639–6400 DO3316-223 Coilcraft 22 0.050 Float 85 85 5.5 DO1608-223 Coilcraft 22 0.31 Ground 85 — 3.5 CTX10-1 Coiltronics 10 0.038 Float 85 85 4.2 (407) 241–7876 CTX20-1 Coiltronics 20 0.175 Ground 86 — 4.2 LQH3C2204K0M00 Murata-Frie 22 0.7 Ground 81 — 2.0 (404) 436–1300 CD54-100M Sumida 10 0.11 Float 85 85 4.5 (708) 956–0666 CDRH62-220M Sumida 22 0.38 Ground 84 — 3.0 CDRH62-100M Sumida 10 0.17 Float 81 82 3.0 GA10-102K Gowanda 10 0.038 Float 85 86 6.6 Through-Hole (716) 532–2234
Inductor Selection Table 2. Recommended Capacitors
For full output power, the inductor should have a satura-
VENDOR SERIES TYPE PHONE#
tion current rating of 1.25A for worst-case current limit, AVX TPS Surface Mount (803)448–9411 although it is acceptable to bias an inductor 20% or more Sanyo OS-CON Through-Hole (619) 661–6835 into saturation. Smaller inductors can be used in conjunc- Panasonic HFQ Through-Hole (201) 348–5200 tion with the ILIM pin. Efficiency is significantly affected by inductor DCR. For best efficiency limit the DCR to 0.03Ω
Diode Selection
or less. Toroidal types are preferred in some cases due to Best performance is obtained with a Schottky rectifier their closed design and inherent EMI/RFI superiority. diode such as the 1N5817. Phillips Components makes Recommended inductors are listed in Table 1. this in surface mount as the PRLL5817. Motorola makes the MBRS130LT3 which is slightly better and also in
Capacitor Selection
surface mount. For lower output power a 1N4148 can be Low ESR capacitors are required for both input and output used although efficiency will suffer substantially. of the LT1300. ESR directly affects ripple voltage and efficiency. For surface mount applications AVX TPS series
Layout Considerations
tantalum capacitors are recommended. These have been The LT1300 is a high speed, high current device. The input specially designed for SMPS and have low ESR along with capacitor must be no more than 0.2" from VIN (pin 6) and high surge current ratings. For through-hole application ground. Connect the PGND and GND (pins 8 and 1) Sanyo OS-CON capacitors offer extremely low ESR in a together under the package. Place the inductor adjacent to small size. Again, if peak switch current is reduced using SW (pin 7) and make the switch pin trace as short as the ILIM pin, capacitor requirements can be relaxed and possible. This keeps radiated noise to a minimum. smaller, higher ESR units can be used. Low frequency output ripple can be reduced by adding multiple output capacitors. If capacitance is reduced, output ripple will increase. Suggested capacitor sources are listed in Table 2. Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 7
U U W U APPLICATIONS INFORMATION Table 1. Recommended Inductors EFFICIENCY 2.5VIN, 5VOUT COMPONENT PART NUMBER VENDOR L (
µ
H) DCR (
Ω
) ILIM PIN 50mA LOAD 200mA LOAD HEIGHT (mm) PHONE NUMBER
DO1608-103 Coilcraft 10 0.11 Float 83 83 3.5 (708) 639–6400 DO3316-223 Coilcraft 22 0.050 Float 85 85 5.5 DO1608-223 Coilcraft 22 0.31 Ground 85 — 3.5 CTX10-1 Coiltronics 10 0.038 Float 85 85 4.2 (407) 241–7876 CTX20-1 Coiltronics 20 0.175 Ground 86 — 4.2 LQH3C2204K0M00 Murata-Frie 22 0.7 Ground 81 — 2.0 (404) 436–1300 CD54-100M Sumida 10 0.11 Float 85 85 4.5 (708) 956–0666 CDRH62-220M Sumida 22 0.38 Ground 84 — 3.0 CDRH62-100M Sumida 10 0.17 Float 81 82 3.0 GA10-102K Gowanda 10 0.038 Float 85 86 6.6 Through-Hole (716) 532–2234
Inductor Selection Table 2. Recommended Capacitors
For full output power, the inductor should have a satura-
VENDOR SERIES TYPE PHONE#
tion current rating of 1.25A for worst-case current limit, AVX TPS Surface Mount (803)448–9411 although it is acceptable to bias an inductor 20% or more Sanyo OS-CON Through-Hole (619) 661–6835 into saturation. Smaller inductors can be used in conjunc- Panasonic HFQ Through-Hole (201) 348–5200 tion with the ILIM pin. Efficiency is significantly affected by inductor DCR. For best efficiency limit the DCR to 0.03Ω
Diode Selection
or less. Toroidal types are preferred in some cases due to Best performance is obtained with a Schottky rectifier their closed design and inherent EMI/RFI superiority. diode such as the 1N5817. Phillips Components makes Recommended inductors are listed in Table 1. this in surface mount as the PRLL5817. Motorola makes the MBRS130LT3 which is slightly better and also in
Capacitor Selection
surface mount. For lower output power a 1N4148 can be Low ESR capacitors are required for both input and output used although efficiency will suffer substantially. of the LT1300. ESR directly affects ripple voltage and efficiency. For surface mount applications AVX TPS series
Layout Considerations
tantalum capacitors are recommended. These have been The LT1300 is a high speed, high current device. The input specially designed for SMPS and have low ESR along with capacitor must be no more than 0.2" from VIN (pin 6) and high surge current ratings. For through-hole application ground. Connect the PGND and GND (pins 8 and 1) Sanyo OS-CON capacitors offer extremely low ESR in a together under the package. Place the inductor adjacent to small size. Again, if peak switch current is reduced using SW (pin 7) and make the switch pin trace as short as the ILIM pin, capacitor requirements can be relaxed and possible. This keeps radiated noise to a minimum. smaller, higher ESR units can be used. Low frequency output ripple can be reduced by adding multiple output capacitors. If capacitance is reduced, output ripple will increase. Suggested capacitor sources are listed in Table 2. Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 7
