Datasheet LTC3852 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Low Input Voltage, Synchronous Step-Down DC/DC Controller |
| Pages / Page | 32 / 4 — ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply … |
| File Format / Size | PDF / 429 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifi cations which apply over the full operating
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LTC3852
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C (Note 2), VIN1 = 3.3V, VIN2 = 15V, VRUN = 3.3V, SHDN = 0V, MODE/PLLIN = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Oscillator and Phase-Locked Loop (Step-Down Regulator)
fNOM1 Nominal Frequency RFREQ = 60k 460 500 540 kHz fLOW1 Lowest Frequency RFREQ = 160k 205 235 265 kHz fHIGH1 Highest Frequency RFREQ = 36k 690 750 810 kHz fNOM2 Nominal Frequency RFREQ = 60k (Note 7) 460 500 540 kHz fLOW2 Lowest Frequency RFREQ = 160k (Note 7) 205 235 265 kHz fHIGH2 Highest Frequency RFREQ = 36k (Note 7) 690 750 810 kHz fMODE MODE/PLLIN Minimum Input Frequency MODE/PLLIN = External Clock 250 kHz MODE/PLLIN Maximum Input Frequency 750 kHz RMODE/PLLIN MODE/PLLIN Input Resistance 100 kΩ IFREQ Phase Detector Output Current Sinking Capability fMODE > fOSC –90 μA Sourcing Capability fMODE < fOSC 75 μA
PGOOD Output
VPGL PGOOD Voltage Low IPGOOD = 2mA 0.1 0.3 V IPGOOD PGOOD Leakage Current VPGOOD = 5V ±1 μA VPG PGOOD Trip Level VFB with Respect to Regulated Voltage VFB Ramping Negative –12 –10 –8 % VFB Ramping Positive 8 10 12 %
VPUMP Charge Pump Supply (VIN1 = 3.3V; VSHDN = 3.3V, VRUN = 0); CVIN1 = 4.7μF, CFLY = 2.2μF, CVPUMP = 4.7μF
VIN1 Input Voltage Range 2.7 5.5 V VPUMP Charge Pump Doubler Output Voltage CFLY = 2.2μF 2.7V < VIN1 < 5.5V; IVPUMP = 1mA l 4.8 5.05 5.3 V ISHDN Shutdown Pin Current SHDN = 0V; VPUMP = 0V 1 μA VRIPPLE Output Ripple at VPUMP IVPUMP = 50mA (Note 10) 20 mVP-P fPUMP Charge Pump Frequency 0.6 1.2 1.8 MHz VIH SHDN Input Threshold l 1.3 V VIL SHDN Input Threshold l 0.4 V IIH SHDN Input Current –1 1 μA IIL SHDN Input Current –1 1 μA ROL Effective Open-Loop Output Resistance VIN1 = 2.7V, VPUMP = 4.5V 6 Ω (Note 8)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings may
Note 5:
Rise and fall times are measured using 10% and 90% levels. Delay cause permanent damage to the device. Exposure to any Absolute Maximum times are measured using 50% levels. Rise and fall times are assured by Rating condition for extended periods may affect device reliability and lifetime. design, characterization and correlation with statistical process controls.
Note 2:
The LTC3852 is tested under pulsed load conditions such that
Note 6:
The minimum on-time condition is specifi ed for an inductor TJ ≈ TA. The LTC3852E is guaranteed to meet specifi cations from peak-to-peak ripple current equal to 40% of IMAX (see Minimum On-Time 0°C to 85°C junction temperature. Specifi cations over the –40°C to Considerations in the Applications Information Section). 125°C operating junction temperature range are assured by design,
Note 7:
VIN1 = 3.3V; Connect VPUMP, VIN2 and INTVCC together. characterization and correlation with statistical process controls. The
Note 8:
ROL = (2VIN - VOUT)/IOUT LTC3852I is guaranteed over the –40°C to 125°C operating junction
Note 9:
V temperature range. T IN2 swept while not connected to VPUMP or INTVCC. J is calculated from the ambient temperature, TA and power dissipation P
Note 10:
Guaranteed by design, not tested in production. D according to the following formula: TJ = TA + (PD • 38°C/W)
Note 3:
The LTC3852 is tested in a feedback loop that servos VITH to a specifi ed voltage and measures the resultant VFB.
Note 4:
Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. See Applications information. 3852f 4
ELECTRICAL CHARACTERISTICS The
l
denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C (Note 2), VIN1 = 3.3V, VIN2 = 15V, VRUN = 3.3V, SHDN = 0V, MODE/PLLIN = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Oscillator and Phase-Locked Loop (Step-Down Regulator)
fNOM1 Nominal Frequency RFREQ = 60k 460 500 540 kHz fLOW1 Lowest Frequency RFREQ = 160k 205 235 265 kHz fHIGH1 Highest Frequency RFREQ = 36k 690 750 810 kHz fNOM2 Nominal Frequency RFREQ = 60k (Note 7) 460 500 540 kHz fLOW2 Lowest Frequency RFREQ = 160k (Note 7) 205 235 265 kHz fHIGH2 Highest Frequency RFREQ = 36k (Note 7) 690 750 810 kHz fMODE MODE/PLLIN Minimum Input Frequency MODE/PLLIN = External Clock 250 kHz MODE/PLLIN Maximum Input Frequency 750 kHz RMODE/PLLIN MODE/PLLIN Input Resistance 100 kΩ IFREQ Phase Detector Output Current Sinking Capability fMODE > fOSC –90 μA Sourcing Capability fMODE < fOSC 75 μA
PGOOD Output
VPGL PGOOD Voltage Low IPGOOD = 2mA 0.1 0.3 V IPGOOD PGOOD Leakage Current VPGOOD = 5V ±1 μA VPG PGOOD Trip Level VFB with Respect to Regulated Voltage VFB Ramping Negative –12 –10 –8 % VFB Ramping Positive 8 10 12 %
VPUMP Charge Pump Supply (VIN1 = 3.3V; VSHDN = 3.3V, VRUN = 0); CVIN1 = 4.7μF, CFLY = 2.2μF, CVPUMP = 4.7μF
VIN1 Input Voltage Range 2.7 5.5 V VPUMP Charge Pump Doubler Output Voltage CFLY = 2.2μF 2.7V < VIN1 < 5.5V; IVPUMP = 1mA l 4.8 5.05 5.3 V ISHDN Shutdown Pin Current SHDN = 0V; VPUMP = 0V 1 μA VRIPPLE Output Ripple at VPUMP IVPUMP = 50mA (Note 10) 20 mVP-P fPUMP Charge Pump Frequency 0.6 1.2 1.8 MHz VIH SHDN Input Threshold l 1.3 V VIL SHDN Input Threshold l 0.4 V IIH SHDN Input Current –1 1 μA IIL SHDN Input Current –1 1 μA ROL Effective Open-Loop Output Resistance VIN1 = 2.7V, VPUMP = 4.5V 6 Ω (Note 8)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings may
Note 5:
Rise and fall times are measured using 10% and 90% levels. Delay cause permanent damage to the device. Exposure to any Absolute Maximum times are measured using 50% levels. Rise and fall times are assured by Rating condition for extended periods may affect device reliability and lifetime. design, characterization and correlation with statistical process controls.
Note 2:
The LTC3852 is tested under pulsed load conditions such that
Note 6:
The minimum on-time condition is specifi ed for an inductor TJ ≈ TA. The LTC3852E is guaranteed to meet specifi cations from peak-to-peak ripple current equal to 40% of IMAX (see Minimum On-Time 0°C to 85°C junction temperature. Specifi cations over the –40°C to Considerations in the Applications Information Section). 125°C operating junction temperature range are assured by design,
Note 7:
VIN1 = 3.3V; Connect VPUMP, VIN2 and INTVCC together. characterization and correlation with statistical process controls. The
Note 8:
ROL = (2VIN - VOUT)/IOUT LTC3852I is guaranteed over the –40°C to 125°C operating junction
Note 9:
V temperature range. T IN2 swept while not connected to VPUMP or INTVCC. J is calculated from the ambient temperature, TA and power dissipation P
Note 10:
Guaranteed by design, not tested in production. D according to the following formula: TJ = TA + (PD • 38°C/W)
Note 3:
The LTC3852 is tested in a feedback loop that servos VITH to a specifi ed voltage and measures the resultant VFB.
Note 4:
Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. See Applications information. 3852f 4
