Datasheet LTC7812 (Analog Devices) - 5
| Manufacturer | Analog Devices |
| Description | Low IQ, 38V Synchronous Boost+Buck Controller |
| Pages / Page | 44 / 5 — ELECTRICAL. CHARACTERISTICS The. denotes the specifications which apply … |
| File Format / Size | PDF / 2.3 Mb |
| Document Language | English |
ELECTRICAL. CHARACTERISTICS The. denotes the specifications which apply over the specified operating
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LTC7812
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. VBIAS = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
High Fixed Frequency VFREQ = INTVCC; PLLIN/MODE = DC Voltage 485 535 585 kHz Synchronizable Frequency PLLIN/MODE = External Clock l 75 850 kHz
PGOOD1 Output
PGOOD1 Voltage Low IPGOOD1 = 2mA 0.2 0.4 V PGOOD1 Leakage Current VPGOOD1 = 5V ±1 µA PGOOD1 Trip Level VFB1 with Respect to Set Regulated Voltage VFB1 Ramping Negative –13 –10 –7 % Hysteresis 2.5 % VFB1 Ramping Positive 7 10 13 % Hysteresis 2.5 % Delay For Reporting a Fault 40 µs
OV2 Boost Overvoltage Indicator Output
OV2 Voltage Low IOV2 = 2mA 0.2 0.4 V OV2 Leakage Current VOV2 = 5V ±1 µA OV2 Trip Level VFB2 Ramping Positive with Respect to Set 6 10 13 % Regulated Voltage Hysteresis 1.5 %
BOOST2 Charge Pump
BOOST2 Charge Pump Available Output VBOOST2 = 16V; VSW2 = 12V; 65 µA Current Forced Continuous Mode
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The LTC7812 is tested in a feedback loop that servos VITH1,2 to may cause permanent damage to the device. Exposure to any Absolute a specified voltage and measures the resultant VFB. The specification at Maximum Rating condition for extended periods may affect device 85°C is not tested in production and is assured by design, characterization reliability and lifetime. and correlation to production testing at other temperatures (125°C for
Note 2:
The LTC7812 is tested under pulsed load conditions such that the LTC7812E/LTC7812I, 150°C for the LTC7812H). For the LTC7812I T and LTC7812H, the specification at 0°C is not tested in production and is J ≈ TA. The LTC7812E is guaranteed to meet performance specifications from 0°C to 85°C. Specifications over the –40°C to 125°C operating assured by design, characterization and correlation to production testing junction temperature range are assured by design, characterization and at –40°C. correlation with statistical process controls. The LTC7812I is guaranteed
Note 5:
Dynamic supply current is higher due to the gate charge being over the –40°C to 125°C operating junction temperature range and the delivered at the switching frequency. See the Applications Information LTC7812H is guaranteed over the –40°C to 150°C operating junction section. temperature range. High junction temperatures degrade operating
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay lifetimes; operating lifetime is derated for junction temperatures greater times are measured using 50% levels. than 125°C. Note that the maximum ambient temperature consistent with
Note 7:
The minimum on-time condition is specified for an inductor these specifications is determined by specific operating conditions in peak-to-peak ripple current ≥ 40% of I conjunction with board layout, the rated package thermal impedance and MAX (See the Minimum On-Time Considerations in the Applications Information section). other environmental factors. TJ is calculated from the ambient temperature T
Note 8:
Do not apply a voltage or current source to these pins. They must A and power dissipation PD according to the following formula: TJ = TA + (P be connected to capacitive loads only, otherwise permanent damage may D • qJA), where qJA = 44°C/W. occur.
Note 3:
This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. The maximum rated junction temperature will be exceeded when this protection is active. Continuous operation above the specified absolute maximum operating junction temperature may impair device reliability or permanently damage the device. 7812fc For more information www.linear.com/LTC7812 5 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Typical Application Related Parts
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. VBIAS = 12V, VRUN1,2 = 5V, EXTVCC = 0V unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
High Fixed Frequency VFREQ = INTVCC; PLLIN/MODE = DC Voltage 485 535 585 kHz Synchronizable Frequency PLLIN/MODE = External Clock l 75 850 kHz
PGOOD1 Output
PGOOD1 Voltage Low IPGOOD1 = 2mA 0.2 0.4 V PGOOD1 Leakage Current VPGOOD1 = 5V ±1 µA PGOOD1 Trip Level VFB1 with Respect to Set Regulated Voltage VFB1 Ramping Negative –13 –10 –7 % Hysteresis 2.5 % VFB1 Ramping Positive 7 10 13 % Hysteresis 2.5 % Delay For Reporting a Fault 40 µs
OV2 Boost Overvoltage Indicator Output
OV2 Voltage Low IOV2 = 2mA 0.2 0.4 V OV2 Leakage Current VOV2 = 5V ±1 µA OV2 Trip Level VFB2 Ramping Positive with Respect to Set 6 10 13 % Regulated Voltage Hysteresis 1.5 %
BOOST2 Charge Pump
BOOST2 Charge Pump Available Output VBOOST2 = 16V; VSW2 = 12V; 65 µA Current Forced Continuous Mode
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The LTC7812 is tested in a feedback loop that servos VITH1,2 to may cause permanent damage to the device. Exposure to any Absolute a specified voltage and measures the resultant VFB. The specification at Maximum Rating condition for extended periods may affect device 85°C is not tested in production and is assured by design, characterization reliability and lifetime. and correlation to production testing at other temperatures (125°C for
Note 2:
The LTC7812 is tested under pulsed load conditions such that the LTC7812E/LTC7812I, 150°C for the LTC7812H). For the LTC7812I T and LTC7812H, the specification at 0°C is not tested in production and is J ≈ TA. The LTC7812E is guaranteed to meet performance specifications from 0°C to 85°C. Specifications over the –40°C to 125°C operating assured by design, characterization and correlation to production testing junction temperature range are assured by design, characterization and at –40°C. correlation with statistical process controls. The LTC7812I is guaranteed
Note 5:
Dynamic supply current is higher due to the gate charge being over the –40°C to 125°C operating junction temperature range and the delivered at the switching frequency. See the Applications Information LTC7812H is guaranteed over the –40°C to 150°C operating junction section. temperature range. High junction temperatures degrade operating
Note 6:
Rise and fall times are measured using 10% and 90% levels. Delay lifetimes; operating lifetime is derated for junction temperatures greater times are measured using 50% levels. than 125°C. Note that the maximum ambient temperature consistent with
Note 7:
The minimum on-time condition is specified for an inductor these specifications is determined by specific operating conditions in peak-to-peak ripple current ≥ 40% of I conjunction with board layout, the rated package thermal impedance and MAX (See the Minimum On-Time Considerations in the Applications Information section). other environmental factors. TJ is calculated from the ambient temperature T
Note 8:
Do not apply a voltage or current source to these pins. They must A and power dissipation PD according to the following formula: TJ = TA + (P be connected to capacitive loads only, otherwise permanent damage may D • qJA), where qJA = 44°C/W. occur.
Note 3:
This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. The maximum rated junction temperature will be exceeded when this protection is active. Continuous operation above the specified absolute maximum operating junction temperature may impair device reliability or permanently damage the device. 7812fc For more information www.linear.com/LTC7812 5 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Typical Application Related Parts
