LM34917A Datasheet, PDF (3/16 Pages) National Semiconductor (TI) – Ultra Small 33V, 1.25A Constant On-Time Buck Switching Regulator with Intelligent Current Limit

Absolute Maximum Ratings (Note 1)
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VIN to RTN
BST to RTN
SW to RTN (Steady State)
BST to VCC
VIN to SW
BST to SW
VCC to RTN
SGND to RTN
50V
64V
-1.5V
50V
50V
14V
14V
-0.3V to +0.3V
Current out of ISEN
SS to RTN
All Other Inputs to RTN
ESD Rating (Note 2)
Human Body Model
Storage Temperature Range
Junction Temperature
See text
-0.3V to 4V
-0.3 to 7V
2kV
-65°C to +150°C
150°C
Operating Ratings (Note 1)
V_IN Voltage
Junction Temperature
8.0V to 33V
−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: V_IN = 12V, R_ON = 200kΩ. See (Note 4) and (Note 5).
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Start-Up Regulator, V_CC
V_CCReg V_CC regulated output
Vin > 9V
6.6
7.0
7.4
V
V_IN-V_CC dropout voltage
I_CC = 0 mA,
1.3
V
V_CC = UVLO_VCC + 250 mV
V_CC output impedance
V_IN = 8V
150
Ω
(0 mA ≤ I_CC ≤ 5 mA)
V_IN = 12V
0.75
V_CC current limit (Note 3)
V_CC = 0V
11
mA
UVLO_VCC
V_CC under-voltage lockout
threshold
V_CC increasing
5.45
V
UVLO_VCC hysteresis
UVLO_VCC filter delay
I_IN operating current
I_IN shutdown current
Switch Characteristics
V_CC decreasing
100 mV overdrive
Non-switching, FB = 3V
RON/SD = 0V
145
mV
3
µs
0.68
0.95
mA
85
160
µA
Rds(on)
UVLO_GD
Softstart Pin
Buck Switch Rds(on)
Gate Drive UVLO
UVLO_GD hysteresis
I_TEST = 200 mA
V_BST - V_SW Increasing
0.33
0.7
Ω
2.65
4
4.62
V
450
mV
V_SS
I_SS
V_RES
Pull-up voltage
Internal current source
Restart threshold after OVP
shutdown
2.5
V
11.6
µA
0.18
V
Current Limit
I_LIM
Threshold
Response time
V_IN = 8V, V_FB = 2.4V
V_IN = 30V, V_FB = 2.4V
V_IN = 30V, V_FB = 1.0V
1.15
1.35
1.55
A
1.05
1.2
1.45
0.95
1.15
1.35
150
ns
3
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