Datasheet LT3473, LT3473A (Analog Devices) - 8
| 制造商 | Analog Devices |
| 描述 | Micropower 1A Boost Converter with Schottky and Output Disconnect |
| 页数 / 页 | 12 / 8 — APPLICATIO S I FOR ATIO. Figure 3. Efficiency Comparison of Different … |
| 文件格式/大小 | PDF / 276 Kb |
| 文件语言 | 英语 |
APPLICATIO S I FOR ATIO. Figure 3. Efficiency Comparison of Different Inductors. Capacitor Selection. Inductor Selection
该数据表的模型线
文件文字版本
LT3473/LT3473A
U U W U APPLICATIO S I FOR ATIO
resulting sum is fed into the positive terminal of the PWM 80 VIN = 3.6V comparator A2. When this voltage exceeds the level of the VOUT = 20V 75 error signal VC, the SR latch is reset, turning off the power switch Q1. The error amplifier sets the peak current level 70 to keep the output in regulation. If the error amplifier’s output increases, more current is delivered to the output; 65 EFFICIENCY (%) if it decreases, less current is delivered. TOKO A915AY-6R8M SUMIDA CDRH4D28-6R8 60 The LT3473 includes an internal power Schottky diode and SUMIDA CDRH5D18-6R2 COILCRAFT ME3220-682 a PNP transistor, Q2, for output disconnect. Q2 discon- COILCRAFT MSS5131-682 55 nects the load from the input during shutdown. The part 0 20 40 60 80 100 LEAD CURRENT lO (mA) 3473 F03 also has a power good indication pin, PGOOD. When the FB voltage reaches within 100mV of the reference voltage,
Figure 3. Efficiency Comparison of Different Inductors
the comparator A4 turns on Q5, sinking current from
Capacitor Selection
PGOOD pin. The small package of ceramic capacitors makes them The LT3473 has thermal shutdown feature with threshold suitable for LT3473 applications. X5R and X7R types of at about 145°C. ceramic capacitors are recommended because they retain their capacitance over wider voltage and temperature
Inductor Selection
ranges than other types such as Y5V or Z5U. A 4.7µF input A 6.8µH inductor is recommended for the LT3473. The capacitor, a 0.47µF output capacitor and a 2.2µF capacitor minimum inductor size that may be used in a given appli- bypassing output disconnect PNP are sufficient for most cation depends on required efficiency and output current. LT3473 applications. Inductors with low core losses and small DCR (copper
Table 2. Recommended Ceramic Capacitor Manufacturers
wire resistance) at 1.2MHz are good choices for LT3473
MANUFACTURER TELEPHONE URL
applications. Some inductors in this category with small Taiyo Yuden 408-573-4150 www.t-yuden.com size are listed in Table 1. The efficiency comparison of AVX 843-448-9411 www.avxcorp.com different inductors is shown in Figure 3. Murata 814-237-1431 www.murata.com Kemet 408-986-0424 www.kemet.com
Table 1. Recommended Inductors DCR CURRENT DIMENSION PART (m
Ω
) RATING (A) (mm) MANUFACTURER
DO1605T-682 200 1.1 5.4 × 4.2 × 1.8 Coilcraft ME3220-682 270 1.0 3.2 × 2.5 × 2.0 800-322-2645 MSS6122-682 100 1.45 6.1 × 6.1 × 2.2 www.coilcraft.com MSS5131-682 60 1.05 5.1 × 5.1 × 3.1 LQH55DN6R8 74 2.0 5.7 × 5.0 × 4.7 Murata 814-237-1431 www.murata.com CDRH5D18-6R2 71 1.4 5.7 × 5.7 × 2.0 Sumida CDRH4D28-6R8 81 1.12 4.7 × 4.7 × 3.0 847-956-0666 CDRH5D28-6R2 33 1.8 5.7 × 5.7 × 3.0 www.sumida.com CRD53-4R7 74 1.68 6.0 × 5.2 × 3.2 A918CY-6R2M 62 1.49 6.0 × 6.0 × 2.0 Toko (TYPE D62LCB) 408-432-8281 A915AY-6R8M 68 1.51 5.0 × 5.0 × 3.0 www.tokoam.com (TYPE D53LC) 3473f 8
U U W U APPLICATIO S I FOR ATIO
resulting sum is fed into the positive terminal of the PWM 80 VIN = 3.6V comparator A2. When this voltage exceeds the level of the VOUT = 20V 75 error signal VC, the SR latch is reset, turning off the power switch Q1. The error amplifier sets the peak current level 70 to keep the output in regulation. If the error amplifier’s output increases, more current is delivered to the output; 65 EFFICIENCY (%) if it decreases, less current is delivered. TOKO A915AY-6R8M SUMIDA CDRH4D28-6R8 60 The LT3473 includes an internal power Schottky diode and SUMIDA CDRH5D18-6R2 COILCRAFT ME3220-682 a PNP transistor, Q2, for output disconnect. Q2 discon- COILCRAFT MSS5131-682 55 nects the load from the input during shutdown. The part 0 20 40 60 80 100 LEAD CURRENT lO (mA) 3473 F03 also has a power good indication pin, PGOOD. When the FB voltage reaches within 100mV of the reference voltage,
Figure 3. Efficiency Comparison of Different Inductors
the comparator A4 turns on Q5, sinking current from
Capacitor Selection
PGOOD pin. The small package of ceramic capacitors makes them The LT3473 has thermal shutdown feature with threshold suitable for LT3473 applications. X5R and X7R types of at about 145°C. ceramic capacitors are recommended because they retain their capacitance over wider voltage and temperature
Inductor Selection
ranges than other types such as Y5V or Z5U. A 4.7µF input A 6.8µH inductor is recommended for the LT3473. The capacitor, a 0.47µF output capacitor and a 2.2µF capacitor minimum inductor size that may be used in a given appli- bypassing output disconnect PNP are sufficient for most cation depends on required efficiency and output current. LT3473 applications. Inductors with low core losses and small DCR (copper
Table 2. Recommended Ceramic Capacitor Manufacturers
wire resistance) at 1.2MHz are good choices for LT3473
MANUFACTURER TELEPHONE URL
applications. Some inductors in this category with small Taiyo Yuden 408-573-4150 www.t-yuden.com size are listed in Table 1. The efficiency comparison of AVX 843-448-9411 www.avxcorp.com different inductors is shown in Figure 3. Murata 814-237-1431 www.murata.com Kemet 408-986-0424 www.kemet.com
Table 1. Recommended Inductors DCR CURRENT DIMENSION PART (m
Ω
) RATING (A) (mm) MANUFACTURER
DO1605T-682 200 1.1 5.4 × 4.2 × 1.8 Coilcraft ME3220-682 270 1.0 3.2 × 2.5 × 2.0 800-322-2645 MSS6122-682 100 1.45 6.1 × 6.1 × 2.2 www.coilcraft.com MSS5131-682 60 1.05 5.1 × 5.1 × 3.1 LQH55DN6R8 74 2.0 5.7 × 5.0 × 4.7 Murata 814-237-1431 www.murata.com CDRH5D18-6R2 71 1.4 5.7 × 5.7 × 2.0 Sumida CDRH4D28-6R8 81 1.12 4.7 × 4.7 × 3.0 847-956-0666 CDRH5D28-6R2 33 1.8 5.7 × 5.7 × 3.0 www.sumida.com CRD53-4R7 74 1.68 6.0 × 5.2 × 3.2 A918CY-6R2M 62 1.49 6.0 × 6.0 × 2.0 Toko (TYPE D62LCB) 408-432-8281 A915AY-6R8M 68 1.51 5.0 × 5.0 × 3.0 www.tokoam.com (TYPE D53LC) 3473f 8