LT4423A

Part: LT4423A (LT4423AV#TRPBF) — Analog Devices (Linear Technology)

Type: Ideal Diode and Load Switch (integrated P-channel MOSFETs)

Description: 1.9–28 V, 2 A ideal diode and load switch with 200 mΩ typical internal power path, 15 mV forward voltage regulation and 10 μA typical quiescent current.

Operating Conditions:

• Supply voltage (IN): 1.9–28 V (−40°C ≤ TJ ≤ 125°C)
• Operating junction temperature: −40 to 125 °C
• Typical RON (200 mΩ) achieved when IN ≥ 4 V; RON rises below 4 V

Absolute Maximum Ratings:

• IN supply voltage: −0.3 V to 30 V
• OUT supply voltage: −30 V to 30 V
• |IN − OUT|: 30 V
• SHDN input voltage: −30 V to 30 V
• STATUS output voltage: −0.3 V to 30 V
• Input current IN: 3 A
• Output current OUT: −3 A
• Operating junction temperature (LT4423A): −40 to 125 °C
• Storage temperature: −65 to 150 °C

Key Specs:

• Forward regulation voltage (IN − OUT): 15 mV typ (5–25 mV), IOUT = −10 mA
• Internal path on-resistance: 200 mΩ typ (115–400 mΩ), IOUT = −1 A
• Quiescent current in forward regulation: 10 μA typ, 18 μA max (IOUT = −10 mA)
• Quiescent current in shutdown: 0.1 μA typ, 2 μA max
• Reverse leakage current to IN: 0.1 μA typ, 0.5 μA max (IN = GND, OUT = 28 V, SHDN = GND)
• Reverse turn-off time: 15 μs typ, 25 μs max
• Response time to load step (−10 mA to −1 A): 3 μs typ, 7 μs max
• SHDN rising threshold: 1.3 V typ (1–1.6 V); SHDN hysteresis 130 mV typ
• Thermal shutdown: 160 °C typ (power path restored at about 145 °C)

Features:

• Internal 200 mΩ power path
• Reverse current protection
• Load switch capability
• Smooth switchover in diode-OR applications
• Blocks up to 28 V in either direction or polarity when not enabled
• Open-drain STATUS output indicating shutdown, reverse bias or thermal protection
• Integrated thermal protection

Applications:

• Schottky diode replacement
• Battery and wall adapter diode ORing
• Backup battery diode ORing
• Industrial and consumer hand-held applications

Package:

• 10-lead LDFN (3 mm × 2 mm × 0.75 mm)

• Internal 200mΩ Power Path
• Wide Operating Voltage Range: 1.9V to 28V
• Reverse Current Protection
• Load Switch Capability
• Low 10μA Quiescent Current
• Fast 3μs Response to Load Steps
• Low 500nA Off State Current
• Smooth Switchover in Diode-OR Applications
• Integrated Thermal Protection
• 10-Lead (3mm x 2mm x 0.75mm) LDFN Package

• Schottky Diode Replacement
• Battery and Wall Adapter Diode ORing
• Backup Battery Diode ORing
• Industrial and Consumer Hand-Held Applications

Figure 3. Pin Configurations

(Specifications are at TA = 25°C, IN = SHDN = 8.4V, unless otherwise noted.)

TA = 25°C 5 , unless otherwise specified.

Table 2. Absolute Maximum Ratings

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1 All currents into pins are positive; all voltages are referenced to GND unless otherwise noted.

• 2 The LT4423 is tested under pulsed load conditions such that T J ≈ T A . The junction temperature (T J in °C) is calculated from the ambient temperature (T A in °C) and power dissipation (P D in Watts) according to the formula: T J = T A + (P D · θ JA ).
• 3 The LT4423 includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 150°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability.
• 4 Determined by design, not tested in production.
• 5 Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability.

The following advice should be considered when laying out a printed circuit board for the LT4423. First, connect the exposed pad (also connected to IN) to a sufficiently large copper plane for thermal relief. Use Figure 16 to find the minimum copper area (connected to IN) required to limit junction temperature for a given load current and ambient temperature.

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Figure 16. Minimum Thermal Copper vs Load Current and Ambient Temperature

PCB traces to the IN and OUT pins should be wide and short to minimize series resistance and inductance. Figure 17 demonstrates a copper layout strategy for effective thermal and electrical performance.

Figure 17. PCB Layout Strategy for Thermal Management

Figure 1. USB PD 3.0 and Back-Up Battery Supply

Figure 2. LT4423 I-V CURVE

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