LTC3890EUH

Part: LTC3890 — Analog Devices / Linear Technology

Type: Dual Synchronous Step-Down DC/DC Controller

Description: 4 V to 60 V input, dual-channel 2-phase synchronous step-down controller with 50 µA quiescent current, programmable frequency up to 900 kHz, and output voltages from 0.8 V to 24 V.

Operating Conditions:

• Supply voltage: 4 V to 60 V
• Operating temperature: -40 °C to 125 °C (grade-dependent, up to -55 °C to 150 °C for MP-grade)
• Output voltage range: 0.8 V to 24 V
• Synchronizable frequency range: 75 kHz to 850 kHz

Absolute Maximum Ratings:

• Max junction/storage temperature: 150 °C (storage -65 °C to 150 °C)

Key Specs:

• Regulated feedback voltage: 0.800 V ±1% (0.792 V to 0.808 V, -40 °C to 85 °C)
• Quiescent current (one channel in sleep mode): 50 µA typ, 75 µA max (no load)
• Shutdown current: 14 µA typ, 25 µA max (RUN1,2 = 0 V)
• Undervoltage lockout threshold (INTV CC ramping up): 3.92 V typ (3.6 V min, 4.2 V max)
• Maximum current sense threshold (I LIM = FLOAT): 75 mV typ (64 mV min, 85 mV max)
• Minimum on-time: 95 ns typ
• INTV CC regulated output voltage: 5.1 V typ (4.85 V min, 5.35 V max, 6 V < V IN < 60 V)
• Gate driver transition times: TG rise/fall time 25 ns / 16 ns typ, BG rise/fall time 28 ns / 13 ns typ (C LOAD = 3300 pF)

Features:

• Wide V IN range from 4 V to 60 V with 65 V absolute maximum rating
• 2-phase out-of-phase controllers reduce input capacitance requirements and power supply noise
• Phase-lockable and programmable fixed frequency from 50 kHz to 900 kHz
• Selectable Continuous, Pulse-Skipping, or low ripple Burst Mode operation at light loads
• Internal LDO powers gate drive from V IN or EXTV CC
• Power Good output voltage monitors and output overvoltage protection
• Very low dropout operation with 99% maximum duty cycle

Applications:

• Automotive Always-On Systems
• Battery Operated Digital Devices
• Distributed DC Power Systems

Package:

• 32-Lead Plastic QFN (5 mm × 5 mm × 0.75 mm)

• n Wide V IN Range: 4V to 60V (65V Abs Max)
• n Low Operating I Q : 50μA (One Channel On)
• n Wide Output Voltage Range: 0.8V ≤ V OUT ≤ 24V
• n RSENSE or DCR Current Sensing
• n Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
• n Phase-Lockable Frequency (75kHz to 850kHz)
• n Programmable Fixed Frequency (50kHz to 900kHz)
• n Selectable Continuous, Pulse-Skipping or Low Ripple Burst Mode ® Operation at Light Loads
• n Selectable Current Limit
• n Very Low Dropout Operation: 99% Duty Cycle
• n Adjustable Output Voltage Soft-Start or T racking
• n Power Good Output Voltage Monitors
• n Output Overvoltage Protection
• n Low Shutdown I Q : < 14μA
• n Internal LDO Powers Gate Drive from V IN or EXTV CC
• n No Current Foldback During Start-Up
• n Small Low Profile (0.75mm) 5mm × 5mm QFN Package
• n AEC-Q100 Qualified for Automotive Applications

• n Automotive Always-On Systems
• n Battery Operated Digital Devices
• n Distributed DC Power Systems

ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at T A = 25°C. V IN = 12V , V RUN1,2 = 5V , EXTV CC = 0V unless otherwise noted. (Note 2)

V

V

V

V

Rev . D

The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at T A = 25°C. V IN = 12V , V RUN1,2 = 5V , EXTV CC = 0V unless otherwise noted. (Note 2)

Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Ratings for extended periods may affect device reliability and lifetime.

Note 2: The LTC3890 is tested under pulsed load conditions such that T J ≈ T A . The L TC3890E is guaranteed to meet performance specifications from 0°C to 85°C. Specifications over the -40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The L TC3890I is guaranteed over the -40°C to 125°C operating junction temperature range, the LTC3890H is guaranteed over the -40°C to 150°C operating junction temperature range and the LTC3890MP is tested and guaranteed over the -55°C to 150°C operating junction temperature range.

High junction temperatures degrade operating lifetimes; operating lifetime is derated for junction temperatures greater than 125°C. Note that the maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board layout, the rated package thermal impedance and other environmental factors.

Note 3: T J is calculated from the ambient temperature T A and power dissipation P D according to the following formula:

$$T_J = T_A + (P_D \bullet 34^\circ\mathrm{C/W})$$

Note 4: The LTC3890 is tested in a feedback loop that servos V ITH1,2 to a specified voltage and measures the resultant V FB . The specification at 85°C is not tested in production and is assured by design, characterization and correlation to production testing at other temperatures (125°C for the LTC3890E/LTC3890I, 150°C for the LTC3890H/LTC3890MP). For the LTC3890MP , the specification at -40°C is not tested in production and is assured by design, characterization and correlation to production testing at -55°C.

Note 5: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. See Applications information.

Note 6: Rise and fall times are measured using 10% and 90% levels. Delay times are measured using 50% levels.

Note 7: The minimum on-time condition is specified for an inductor peak-to-peak ripple current ≥ 40% of I MAX (See Minimum On-Time Considerations in the Applications Information section).

(Note 1)

High Efficiency Dual 8.5V/3.3V Output Step-Down Converter