LM5155DSSR - 2.2MHz Wide Vin 1.5A Boost/SEPIC/Flyback Controller | Texas Instruments
N.º de pieza: LM5155DSSR ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $1.85 | $1,85 |
| 10 | $1.65 | $16,50 |
| 100 | $1.42 | $142,00 |
| 500 | $1.18 | $590,00 |
| 1.000 | $0.96 | $960,00 |
| 3.000 | $0.8 | $2.400,00 |
LM5155DSSR Descripción general
What is a boost controller? A boost (step-up) controller is a type of switching DC-DC controller that maintains a constant output voltage higher than its input voltage by cycling an external power MOSFET through an inductor-capacitor energy-transfer network. The LM5155 family belongs to the broader hierarchy: boost controller -> DC-DC switching controller -> power management IC -> semiconductor. Its peak-current-mode control simplifies loop compensation and provides cycle-by-cycle current limiting, making it preferable to voltage-mode control for low-ESR ceramic output caps.
Key features include a 1.5-A peak gate-drive output capable of driving large high-side MOSFETs at high dV/dt, an ultra-wide input range from 2.97 V (cold-crank survival) up to 45 V, programmable peak current limit, internal 3-ms soft start, PGOOD output for sequencing, and selectable spread-spectrum or external synchronization. The 12-pin WSON-EP provides low profile and excellent thermal performance.
The LM5155 uses peak current mode control with internal slope compensation to support both boost and SEPIC topologies across the full duty-cycle range. Its 1.5-A gate driver enables operation at up to 2.2 MHz with minimal switching-node transition losses, which is essential for compact designs using small L-C filtering. An external VCC LDO output powers the gate driver from the boosted output, reducing input-current draw at high duty cycles.
Typical applications include automotive pre-boost supplies for audio amplifiers running through cold-crank transients, industrial 24-V to 48-V boost converters, SEPIC-isolated supplies for RS-485/RS-232 transceivers, and flyback auxiliary rails in multi-output SMPS designs. The wide input range suits battery-powered systems that experience large voltage transients.
When designing with the LM5155, ensure the BIAS pin is supplied by at least 3 V for startup from a 1-cell battery. Choose an RT resistor carefully to avoid subharmonic instability; the RT resistor also sets the maximum duty-cycle clamp. Use a Schottky rectifier in continuous-conduction boost topology to maximize efficiency.
Alternativas directas para LM5155DSSR — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
LM5155DSSR
✅ Sustitución directa✓ En stock
$0.8 / unidad
Ver hoja de datos →LM5155DSST
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
LM5155QDSSTQ1
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
LM51551DSST
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
LM5155DSSR Valores máximos y características eléctricas
| Topología | Boost, SEPIC, Flyback (non-synchronous) |
| Rango de tensión de entrada | 1.5 V to 45 V (with BIAS); 2.97 V to 45 V (self-bootstrapping) |
| Rango de tensión de salida | Up to 50 V |
| Frecuencia de conmutación | 100 kHz to 2.2 MHz (programmable) |
| Peak Gate Drive Current | 1.5 A |
| Control Method | Peak Current Mode PWM |
| Duty Cycle Range | Up to 93% (typical) |
| Arranque suave | Internal 3 ms (programmable via SS pin) |
| Rango de temperatura de funcionamiento | -40 C to +125 C |
| Encapsulado | 12-WSON (DSS) 3x2 mm with exposed pad |
| Recuento de pines | 12 |
| Tipo de montaje | Surface Mount |
| Estado RoHS | Compliant |
| PGOOD Output | Yes (open-drain) |
| External Sync Input | Yes (RT/SYNC pin) |
| Slope Compensation | Internal (adaptive) |
| AEC-Q100 Qualified | No (LM5155QDSSTQ1 is automotive grade) |
Configuración de pines de LM5155DSSR
| Pin 1 | VIN — Input supply voltage |
| Pin 2 | EN — Enable input (active high) |
| Pin 3 | RT/SYNC — Resistor timing / external sync input |
| Pin 4 | SS — Soft-start programming |
| Pin 5 | FB — Feedback voltage input |
| Pin 6 | COMP — Compensation network node |
| Pin 7 | PGOOD — Power-good indicator (open-drain) |
| Pin 8 | BIAS — Auxiliary supply input for VCC LDO |
| Pin 9 | VCC — Internal LDO output (gate driver supply) |
| Pin 10 | SW — Switch node (external MOSFET drain connection) |
| Pin 11 | BST — Bootstrap for high-side gate drive |
| Pin 12 | PGND — Power ground (with exposed thermal pad) |
Aplicaciones típicas
LM5155DSSR es adecuado para 6 aplicacións: Automotive Pre-Boost for Audio Amplifiers, Industrial 24V to 48V Boost Converter, SEPIC Isolated Supply for RS-485 Transceivers, Flyback Auxiliary Rail in Multi-Output SMPS, Battery-Powered Boost for Portable Equipment, LED Driver Boost for Display Backlight.
Automotive Pre-Boost for Audio Amplifiers
The LM5155DSSR's 1.5-V to 45-V wide Vin range and 2.97-V minimum cold-start capability make it ideal for automotive audio amplifier pre-boost supplies that must survive cold-crank transients on a 12-V battery. The 1.5-A gate driver easily switches large high-side MOSFETs at 1-2 MHz for compact Class-D amplifier rails. According to TI automotive reference designs, a boost converter built on LM5155DSSR delivers stable 18-20 V rails from a fluctuating 6-16 V automotive battery, with the PGOOD output providing sequencing to downstream amplifiers.
Recomendado
Industrial 24V to 48V Boost Converter
The LM5155DSSR's 45-V abs-max input rating and 50-V output capability suit industrial 24-V bus to 48-V step-up converters used in telecom auxiliary rails, PLC systems, and PoE midspan power systems. The 2.2-MHz switching frequency enables small L-C filtering for compact DIN-rail designs. According to TI application notes, the LM5155 in boost topology delivers up to 95% efficiency at moderate loads with proper MOSFET and Schottky selection.
Recomendado
SEPIC Isolated Supply for RS-485 Transceivers
The LM5155DSSR's SEPIC topology support enables isolated supply rails for RS-485 transceivers operating in industrial environments with ground potential differences. The built-in transformer isolation of SEPIC topology eliminates the need for a separate digital isolator on the power path. The 1.5-A gate driver and 2.2-MHz capability minimize transformer footprint, while the FT-PCB layout keeps EMI within CISPR 22 limits with proper shielding.
Recomendado
Flyback Auxiliary Rail in Multi-Output SMPS
The LM5155DSSR's flyback topology support and wide Vin range make it ideal for auxiliary rails in multi-output SMPS designs, including standby supplies, fan supplies, and gate-drive bias rails in primary-side-control architectures. According to TI datasheet, flyback topology supports output voltages both above and below the input rail with simple transformer isolation. The internal slope compensation handles continuous-conduction flyback operation without subharmonic oscillations.
Recomendado
Battery-Powered Boost for Portable Equipment
The LM5155DSSR's 1.5-V minimum input (when BIAS pin is supplied) enables boost conversion from a single-cell Li-ion or alkaline battery pack for portable equipment. The 1.5-A gate driver and high-frequency capability enable compact designs where PCB area is at a premium. The internal 3-ms soft start prevents inrush currents that could trigger battery protection circuits, while the PGOOD output enables proper power-sequencing for downstream MCUs.
Recomendado
LED Driver Boost for Display Backlight
The LM5155DSSR's 50-V output capability and high-frequency switching support multi-string LED backlight boost converters for industrial displays, automotive clusters, and signage. According to TI application notes, the LM5155 in boost topology drives 6-12 series LED strings at 100-200 mA each from a 12-V or 24-V supply. The PGOOD output can be used for fault indication, while the SS pin enables programmable startup timing for inrush control.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para LM5155DSSR — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | LM5155DSST | LM5155QDSSTQ1 | LM51551DSST |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | WSON-12 (DSS) | WSON-12 (DSS) - same | WSON-12 (DSS) - same | WSON-12 (DSS) - same |
| Input Voltage Range | 1.5 V to 45 V | 1.5 V to 45 V | 1.5 V to 45 V | 1.5 V to 45 V |
| Output Voltage | Up to 50 V | Up to 50 V | Up to 50 V | Up to 65 V |
| Switching Frequency | 100 kHz to 2.2 MHz | 100 kHz to 2.2 MHz | 100 kHz to 2.2 MHz | 100 kHz to 2.2 MHz |
| Peak Gate Drive Current | 1.5 A | 1.5 A | 1.5 A | 1.5 A |
| Topology | Boost, SEPIC, Flyback | Boost, SEPIC, Flyback | Boost, SEPIC, Flyback | Boost, SEPIC, Flyback |
| AEC-Q100 Qualified | No | No | Yes | No |
| Operating Temperature | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C (AEC-Q100) | -40 C to +125 C |
| Price (1000 pcs) | $0.96 | $0.96 | $1.40 | $1.10 |
Diferenciadores clave
- Ultra-wide Vin range from 1.5 V to 45 V (frente a LM5155QDSSTQ1)
- Higher output voltage capability (frente a LM51551DSST)
- 1.5-A peak gate drive for high-speed switching (frente a LM5155DSST (tape/reel variant))
Notas de diseño
The WSON-12 (DSS) package has an exposed thermal pad on the bottom that MUST be soldered to a PCB ground plane with thermal vias for heat dissipation. According to TI datasheet, the thermal pad connects to PGND and should have at least 6 thermal vias (0.3 mm drill) connecting to an inner ground plane. For continuous 1.5-A gate-drive operation at 2.2 MHz, adequate thermal management via 1-oz copper pours of 1 square inch is required to keep Tj below 125 C.
Place input capacitors as close to the VIN and PGND pins as possible to minimize high-frequency switching noise. Use a 100-nF ceramic capacitor in parallel with a 4.7-uF to 10-uF bulk capacitor on VIN. According to TI datasheet layout guidelines, the BST capacitor should be placed close to the BST and SW pins, with trace length minimized to avoid gate-drive ringing. Keep the feedback trace away from the SW node to avoid noise injection.
Do not operate the LM5155DSSR without a valid RT resistor on the RT/SYNC pin - the device will not switch and may have undefined behavior. Ensure the BIAS pin voltage is at least 3 V for low-Vin startup; if BIAS is supplied from the output rail, the output must be below the BIAS abs-max rating. Do not exceed the SW pin abs-max voltage of 50 V; in flyback topology with high turns ratios, the leakage-inductance spike may exceed this - add a snubber or RCD clamp.
The high-side gate-drive loop (BST capacitor, internal gate driver, SW node, PGND) carries high di/dt pulses that can disrupt analog signal integrity. Minimize this loop area by placing the BST capacitor directly between BST and SW pins. Keep the SW node copper area small to minimize EMI radiation. According to TI application notes, a shielded inductor or pot-core inductor can further reduce EMI in sensitive applications.
Información de cumplimiento
RoHS compliant per TI product page. The LM5155DSSR is NOT AEC-Q100 qualified - choose LM5155QDSSTQ1 for automotive applications requiring AEC-Q100.
