LM34922 Datasheet, PDF (4/17 Pages) Texas Instruments – 28V, 2A Constant On-Time Switching Regulator with Adjustable Current Limit

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 SGND (T_J = 25°C)
BST to SGND
SW to SGND (Steady State)
BST to SW
CS to CSG
CSG to SGND
PGD to SGND
SS to SGND
30V
37V
-1.5V to 30V
-0.3V to 7V
-0.3V to 0.3V
-0.3V to 0.3V
-0.3V to 7V
-0.3V to 3V
RT to SGND
-0.3V to 1V
FB to SGND
-0.3V to 7V
ESD Rating (Note 2)
Human Body Model
2kV
Storage Temperature Range
-65°C to +150°C
For soldering specs see: http://www.ti.com/lit/an/snoa549/
snoa549.pdf
Junction Temperature
150°C
Operating Ratings (Note 1)
VIN Voltage
Junction Temperature
6.0V to 28V
–40°C to +125°C
Electrical Charateristics Specifications with standard type are for T_J = 25°C only; limits in boldface type apply
over the full Operating Junction Temperature (T_J) range. 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_T = 50kΩ.
Symbol
Parameter
Conditions
Min Typ Max Units
Input (VIN Pin)
I_IN
UVLO_VIN
Input operating current
VIN under-voltage lock-out threshold
VIN under-voltage lock-out threshold
hysteresis
Non-switching, FB = 3V
VIN Increasing
1200 1600 µA
4.6 5.3 5.9
V
200
mV
Switch Characteristics
R_DS(ON)
UVLO_GD
Buck Switch R_DS(ON)
Gate Drive UVLO
UVLO_GD Hysteresis
Pre-charge switch voltage
Pre-charge switch on-time
I_TEST = 200mA
BST-SW
I_TEST = 10mA into SW pin
0.3 0.6
Ω
2.4 3.4 4.4
V
350
mV
1.4
V
120
ns
Soft-Start Pin
V_SS
I_SS
V_SS-SH
Current Limit
Pull-up voltage
Internal current source
Shutdown Threshold
2.51
V
10
µA
70 140
mV
V_ILIM
Threshold voltage at CS
CS bias current
FB = 3V
-146 -130 -115 mV
-120
µA
CSG bias current
FB = 3V
-35
µA
On Timer, RT Pin
t_ON - 1
t_ON - 2
t_ON - 3
t_ON - 4
t_ON - 5
t_ON - 6
Off Timer
On-time
On-time (current limit)
On-time
On-time
On-time
On-time
V_IN = 12V, R_T = 50kΩ
V_IN = 12V, R_T = 50kΩ
V_IN = 12V, R_T = 301kΩ
V_IN = 9V, R_T = 30.9kΩ
V_IN = 12V, R_T = 30.9kΩ
V_IN = 16V, R_T = 30.9kΩ
150 200 250 ns
100
ns
1020
ns
130 171 215 ns
105 137 170 ns
79 109 142 ns
t_OFF
Minimum Off-time (LM34922)
Regulation Comparator (FB Pin)
90 150 208 ns
V_REF
FB regulation threshold
FB bias current
SS pin = steady state
FB = 3V
2.46 2.51 2.56 V
100
nA
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