DCP3603AC

Part: DCP3603BCMR — STMicroelectronics

Type: Synchronous Step-Down (Buck) Converter

Description: 3.3–36 V input, 3 A synchronous step-down converter in SOT23-6L with 1.0 MHz fixed switching frequency, 85 μA typical quiescent current (LCM version) and peak current mode control.

Operating Conditions:

• Supply voltage (VIN): 3.3–36 V
• Operating temperature (junction): -40 to 150 °C
• Output current: 0 to 3 A
• Switching frequency: 1.0 MHz typical (DCP3603Bx variant)

Absolute Maximum Ratings:

• Max supply voltage (VIN): 38 V
• Max junction temperature: 150 °C
• Storage temperature: -55 to 150 °C
• SW and EN pin voltage: up to VIN + 0.3 V
• BOOT-SW differential voltage: 5.5 V

Key Specs:

• Feedback voltage: 0.850 V typ (0.833–0.867 V), VIN = 24 V, TJ = 25 °C
• Quiescent current: 85 μA typ, 120 μA max (LCM, VEN = 3.3 V, no switching); 1.4 mA typ (LNM)
• Shutdown current: 4.5 μA typ, 8 μA max (VEN = 0 V)
• High-side / low-side RDS(on): 0.14 Ω typ (0.21 Ω max) / 0.08 Ω typ (0.14 Ω max) at ISW = 0.1 A
• High-side current limit: 4.0–6.3 A (5.1 A typ); low-side current limit 3.2–4.5 A (3.8 A typ)
• Switching frequency (DCP3603Bx): 0.8–1.2 MHz (1.0 MHz typ)
• Minimum on-time / off-time: 90 ns / 135 ns typ
• UVLO: 2.85–3.2 V rising, 2.6–2.9 V falling
• Soft-start time: 1.3 ms typ
• Thermal shutdown: 175 °C typ, recovery at 155 °C

Features:

• 93% typical efficiency at 1000 mA (VIN = 12 V, VOUT = 5 V)
• Synchronous rectification with internal compensation network
• Peak current mode control
• LCM (high light-load efficiency) and LNM (low noise, forced PWM) versions
• Switching frequency dithering (±50 kHz) for EMI improvement
• Output overvoltage protection (120% of VFB threshold)
• Pulse-by-pulse high-side and low-side overcurrent protection
• Thermal shutdown
• Precision enable
• ESD: HBM ±2000 V, CDM ±500 V

Applications:

• Major appliances
• Smart metering
• Industrial 12/24 V bus conversion

Package:

• SOT23-6L (6 pins), RthJA 117 °C/W

• 89% typical efficiency at 1000 mA load (V IN = 24 V, V OUT = 5 V)
• 93% typical efficiency at 1000 mA load (V IN = 12 V, V OUT = 5 V)
• 3.3 V to 36 V input operating voltage range
• Up to 3 A output current capability
• 85 μA operating quiescent current
• 500 kHz or 1.0 MHz fixed switching frequency
• Synchronous rectification
• Internal compensation network
• Peak current mode control
• Two different versions: LCM for high efficiency at light loads and LNM for noise-sensitive applications
• Output overvoltage protection
• Thermal shutdown
• Precision enable
• Switching frequency dithering
• Available in SOT23-6L package

• Major appliances
• Smart metering
• Industrial 12/24 V bus conversion

TJ = 25 °C, V IN = 24 V, unless otherwise specified.

Table 7. Electrical characteristics

Table 7. Electrical characteristics

Table 3. Absolute maximum ratings

Note: Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not guaranteed.

Table 4. Thermal data

Note: These values were calculated in accordance with JESD specification and simulated on a 4-layer JEDEC board.

Table 5. Recommended operating conditions

Table 6. ESD ratings

Table 6. ESD ratings

The shutdown block disables the switching activity if the junction temperature is higher than a fixed internal threshold (TSH refer to Table 7). The thermal sensing element is close to the power elements, ensuring fast and accurate temperature detection. A hysteresis of approximately 20 °C prevents the device from turning ON and OFF too fast. After a thermal protection event is expired, the DCP3603 restarts with a new soft-start.

Table 1. Typical external components

Table 1. Typical external components

To meet environmental requirements, ST offers these devices in different grades of ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions, and product status are available at: www.st.com. ECOPACK is an ST trademark.