LM3488は、スイッチング・レギュレータ用のローサイド、NチャネルFET、高性能コントローラで、さまざまな用途に使用できます。このデバイスは昇圧、フライバック、SEPICなど、ローサイドFETを必要とするトポロジに適しています。さらに、LM3488は非常に高いスイッチング周波数で動作可能なため、ソリューション全体を小型化できます。LM3488のスイッチング周波数は、1個の外部抵抗を使用するか、または外部クロックと同期させることで、100kHz~1MHzの任意の値に設定できます。電流モード制御により、帯域幅と過渡応答が優れており、サイクル単位の電流制限機能もあります。出力電流は、単一の外付け抵抗によりプログラム可能です。
LM3488にはサーマル・シャットダウン、短絡保護、過電圧保護などの機能が組み込まれています。省電力シャットダウン・モードにより、合計消費電流は5μAに低減され、電源シーケンシングを実行できます。内部的なソフトスタートにより、スタートアップ時の突入電流が制限されます。
型番 | パッケージ | 本体サイズ(公称) |
---|---|---|
LM3488 | VSSOP (8) | 3.00mm×3.00mm |
LM3488-Q1 |
Changes from N Revision (December 2014) to O Revision
Changes from M Revision (March 2013) to N Revision
Changes from L Revision (March 2013) to M Revision
PIN | TYPE | DESCRIPTION | |
---|---|---|---|
NAME | NO. | ||
ISEN | 1 | I | Current sense input pin. Voltage generated across an external sense resistor is fed into this pin. |
COMP | 2 | A | Compensation pin. A resistor, capacitor combination connected to this pin provides compensation for the control loop. |
FB | 3 | I | Feedback pin. The output voltage should be adjusted using a resistor divider to provide 1.26 V at this pin. |
AGND | 4 | P | Analog ground pin. |
PGND | 5 | P | Power ground pin. |
DR | 6 | O | Drive pin of the IC. The gate of the external MOSFET should be connected to this pin. |
FA/SYNC/SD | 7 | A | Frequency adjust, synchronization, and Shutdown pin. A resistor connected to this pin sets the oscillator frequency. An external clock signal at this pin will synchronize the controller to the frequency of the clock. A high level on this pin for ≥ 30 µs will turn the device off. The device will then draw less than 10µA from the supply. |
VIN | 8 | P | Power supply input pin. |
MIN | MAX | UNIT | ||
---|---|---|---|---|
Input voltage | 45 | V | ||
FB pin voltage | –0.4 < VFB | VFB < 7 | V | |
FA/SYNC/SD pin voltage | –0.4 < VFA/SYNC/SD | VFA/SYNC/SD < 7 | V | |
Peak driver output current (< 10 µs) | 1 | A | ||
Power dissipation | Internally Limited | |||
Junction temperature | 150 | °C | ||
Lead temperature | Vapor Phase (60 s) | 215 | °C | |
Infared (15 s) | 260 | °C | ||
DR pin voltage | −0.4 ≤ VDR | VDR ≤ 8 | V | |
ILIM pin voltage | 600 | mV |
MIN | MAX | UNIT | |||
---|---|---|---|---|---|
V(ESD) | Electrostatic discharge | Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins(1) | –2000 | 2000 | V |
Charged device model (CDM), per JEDEC specification JESD22-C101, all pins(2) | –750 | 750 |
MIN | MAX | UNIT | ||||
---|---|---|---|---|---|---|
V(ESD) | Electrostatic discharge | Human body model (HBM), per AEC Q100-002(1) | –2000 | 2000 | V | |
Charged device model (CDM), per AEC Q100-011 | Corner pins (1, 4, 5, and 8) | –750 | 750 | |||
Other pins | –750 | 750 |
MIN | MAX | UNIT | |
---|---|---|---|
Supply Voltage | 2.97 ≤ VIN | VIN ≤ 40 | V |
Junction Temperature Range | −40 ≤ TJ | TJ ≤ 125 | °C |
Switching Frequency | 100 ≤ FSW | FSW ≤ 1 | kHz/MHz |
THERMAL METRIC(1) | LM3488, LM3488-Q1 |
UNIT | |
---|---|---|---|
DGK | |||
8 PINS | |||
RθJA | Junction-to-ambient thermal resistance | 160 | °C/W |
RθJC(top) | Junction-to-case (top) thermal resistance | 50 | |
RθJB | Junction-to-board thermal resistance | 77 | |
ψJT | Junction-to-top characterization parameter | 4.7 | |
ψJB | Junction-to-board characterization parameter | 76 |
PARAMETER | TEST CONDITIONS | MIN | TYP | MAX | UNIT | |
---|---|---|---|---|---|---|
VFB | Feedback Voltage | VCOMP = 1.4 V, 2.97 ≤ VIN ≤ 40 V | 1.2507 | 1.26 | 1.2753 | V |
VCOMP = 1.4 V, 2.97 ≤ VIN ≤ 40 V, −40°C ≤ TJ ≤ 125°C | 1.24 | 1.28 | ||||
ΔVLINE | Feedback Voltage Line Regulation | 2.97 ≤ VIN ≤ 40 V | 0.001 | %/V | ||
ΔVLOAD | Output Voltage Load Regulation | IEAO Source/Sink | ±0.5 | %/V (max) | ||
VUVLO | Input Undervoltage Lock-out | 2.85 | V | |||
−40°C ≤ TJ ≤ 125°C | 2.97 | |||||
VUV(HYS) | Input Undervoltage Lock-out Hysteresis | 170 | mV | |||
−40°C ≤ TJ ≤ 125°C | 130 | 210 | ||||
Fnom | Nominal Switching Frequency | RFA = 40 KΩ | 400 | kHz | ||
RFA = 40 KΩ, −40°C ≤ TJ ≤ 125°C | 360 | 430 | ||||
RDS1 (ON) | Driver Switch On Resistance (top) | IDR = 0.2A, VIN= 5 V | 16 | Ω | ||
RDS2 (ON) | Driver Switch On Resistance (bottom) | IDR = 0.2A | 4.5 | Ω | ||
VDR (max) | Maximum Drive Voltage Swing(3) | VIN < 7.2 V | VIN | V | ||
VIN ≥ 7.2 V | 7.2 | |||||
Dmax | Maximum Duty Cycle(4) | 100% | ||||
Tmin (on) | Minimum On Time | 325 | nsec | |||
−40°C ≤ TJ ≤ 125°C | 230 | 550 | ||||
ISUPPLY | Supply Current (switching) | See (6) | 2.7 | mA | ||
See (6), −40°C ≤ TJ ≤ 125°C | 3.0 | |||||
IQ | Quiescent Current in Shutdown Mode | VFA/SYNC/SD = 5 V(7), VIN = 5 V | 5 | µA | ||
VFA/SYNC/SD = 5 V(7), VIN = 5 V, −40°C ≤ TJ ≤ 125°C | 7 | |||||
VSENSE | Current Sense Threshold Voltage | VIN = 5 V | 135 | 156 | 180 | mV |
VIN = 5 V, −40°C ≤ TJ ≤ 125°C | 125 | 190 | ||||
VSC | Short-Circuit Current Limit Sense Voltage | VIN = 5 V | 343 | mV | ||
VIN = 5 V, −40°C ≤ TJ ≤ 125°C | 250 | 415 | ||||
VSL | Internal Compensation Ramp Voltage | VIN = 5 V | 92 | mV | ||
VIN = 5 V, −40°C ≤ TJ ≤ 125°C | 52 | 132 | ||||
VSL ratio | VSL/VSENSE | 0.30 | 0.49 | 0.70 | ||
VOVP | Output Overvoltage Protection (with respect to feedback voltage) (5) | VCOMP = 1.4 V | 32 | 50 | 78 | mV |
VCOMP = 1.4 V, −40°C ≤ TJ ≤ 125°C | 25 | 85 | ||||
VOVP(HYS) | Output Over-Voltage Protection Hysteresis(5) | VCOMP = 1.4 V | 60 | mV | ||
VCOMP = 1.4 V, −40°C ≤ TJ ≤ 125°C | 20 | 110 | ||||
Gm | Error Ampifier Transconductance | VCOMP = 1.4 V, IEAO = 100 µA (Source/Sink) | 600 | 800 | 1000 | µmho |
VCOMP = 1.4 V, IEAO = 100 µA (Source/Sink), −40°C ≤ TJ ≤ 125°C | 365 | 1265 | ||||
AVOL | Error Amplifier Voltage Gain | VCOMP = 1.4 V, IEAO = 100 µA (Source/Sink) | 38 | V/V | ||
VCOMP = 1.4 V, IEAO = 100 µA (Source/Sink), −40°C ≤ TJ ≤ 125°C | 26 | 44 | ||||
IEAO | Error Amplifier Output Current (Source/ Sink) | Source, VCOMP = 1.4 V, VFB = 0 V | 80 | 110 | 140 | µA |
Source, VCOMP = 1.4 V, VFB = 0 V, −40°C ≤ TJ ≤ 125°C | 50 | 180 | ||||
Sink, VCOMP = 1.4 V, VFB = 1.4 V | −100 | −140 | −180 | µA | ||
Sink, VCOMP = 1.4 V, VFB = 1.4 V, −40°C ≤ TJ ≤ 125°C | −85 | −185 | ||||
VEAO | Error Amplifier Output Voltage Swing | Upper Limit: VFB = 0 V, COMP Pin = Floating | 2.2 | V | ||
Upper Limit: VFB = 0 V, COMP Pin = Floating, −40°C ≤ TJ ≤ 125°C | 1.8 | 2.4 | ||||
Lower Limit: VFB = 1.4 V | 0.56 | V | ||||
Lower Limit: VFB = 1.4 V, −40°C ≤ TJ ≤ 125°C | 0.2 | 1.0 | ||||
TSS | Internal Soft-Start Delay | VFB = 1.2 V, VCOMP = Floating | 4 | ms | ||
Tr | Drive Pin Rise Time | Cgs = 3000 pf, VDR = 0 to 3 V | 25 | ns | ||
Tf | Drive Pin Fall Time | Cgs = 3000 pf, VDR = 0 to 3 V | 25 | ns | ||
VSD | Shutdown and Synchronization signal threshold (2) | Output = High | 1.27 | V | ||
Output = High, −40°C ≤ TJ ≤ 125°C | 1.4 | |||||
Output = Low | 0.65 | V | ||||
Output = Low, −40°C ≤ TJ ≤ 125°C | 0.3 | |||||
ISD | Shutdown Pin Current | VSD = 5 V | −1 | µA | ||
VSD = 0 V | +1 | |||||
IFB | Feedback Pin Current | 15 | nA | |||
TSD | Thermal Shutdown | 165 | °C | |||
Tsh | Thermal Shutdown Hysteresis | 10 | °C |