LM5085 Datasheet, PDF (4/23 Pages) National Semiconductor (TI) – 75V Constant On-Time PFET Buck Switching Controller

Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the Texas Instruments Sales Office/
Distributors for availability and specifications.
VIN to VCC, VIN to PGATE
ESD Rating (Note 2)
Human Body Model
Storage Temperature Range
-0.3V to 10V
2kV
-65°C to +150°C
VIN to GND
ISEN to GND
ADJ to GND
RT, FB to GND
-0.3V to 76V
-0.3V to V_IN + 0.3V
-0.3V to V_IN + 0.3V
-0.3V to 7V
Operating Ratings (Note 1)
VIN Voltage
Junction Temperature
4.5V to 75V
−40°C to + 125°C
Electrical Characteristics Limits in standard type are for T_J = 25°C only; limits in boldface type apply over the
junction temperature (T_J) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical
correlation. Typical values represent the most likely parametric norm at T_J = 25°C, and are provided for reference purposes only.
Unless otherwise stated the following conditions apply: VIN = 48V, R_T = 100kΩ.
Symbol Parameter
Conditions
Min Typ Max Units
VIN Pin
I_IN
Operating Current
I_Q
Shutdown Current
VCC Regulator (Note 3)
Non-Switching, FB = 1.4V (Note 6)
RT = 0V (Note 6)
1.3 1.8 mA
200 345 µA
V_CC(reg)
VIN - VCC
Vin = 9V, FB = 1.4V, ICC = 0mA
Vin = 9V, FB = 1.4V, ICC = 20mA
6.9
7.7 8.5
V
7.7
V
Vin = 75V, FB = 1.4V, ICC = 0mA
7.7
V
UVLO_Vcc
V_CC(CL)
PGATE Pin
VCC Under-Voltage Lock-out Threshold
UVLO_Vcc Hysteresis
VCC Current Limit
V_CC Increasing
V_CC Decreasing
FB = 1.4V
3.8
V
260
mV
20
40
mA
V_PGATE(HI)
V_PGATE(LO)
PGATE High Voltage
PGATE Low Voltage
PGATE Pin = Open
PGATE Pin = Open
V_IN -0.1 V_IN
V
V_CC
V_CC
V
+0.1
V_PGATE(HI)4.5
V_PGATE(LO)4.5
PGATE High Voltage at Vin = 4.5V
PGATE Low Voltage at Vin = 4.5V
PGATE Pin = Open
PGATE Pin = Open
V_IN -0.1 V_IN
V
V_CC
V_CC
V
+0.1
I_PGATE
Driver Output Source Current
Driver Output Sink Current
VIN = 12V, PGATE = VIN - 3.5V
VIN = 12V, PGATE = VIN - 3.5V
1.75
A
1.5
A
R_PGATE
Driver Output Resistance
Source Current = 500mA
Sink Current = 500mA
2.3
Ω
2.3
Ω
Current Limit Detection
I_ADJ
V_{CL OFFSET}
RT Pin
ADJUST Pin Current Source
Current Limit Comparator Offset
V_ADJ = 46.5V
V_ADJ = 46.5V, V_ADJ - V_ISEN
32
40 48 µA
-9
0
9
mV
RT_SD
RT_HYS
On-Time
Shutdown Threshold
Shutdown Threshold Hysteresis
RT Pin Voltage Rising
0.73
V
50
mV
t_{ON – 1}
t_{ON – 2}
t_{ON - 3}
t_{ON - 4}
On-Time
VIN = 4.5V, R_T = 100kΩ
3.5
5 7.15 µs
VIN = 48V, R_T = 100kΩ
276 360 435 ns
VIN = 75V, R_T = 100kΩ
177 235 285 ns
Minimum On-Time in Current Limit (Note VIN = 48V, 25mV Overdrive at ISEN 55 140 235 ns
7)
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