LM34922_15 Datasheet, PDF (4/19 Pages) Texas Instruments – 28V, 2A Constant On-Time Switching Regulator with Adjustable Current Limit

LM34922
SNVS813A – JUNE 2012 – REVISED MARCH 2013
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Electrical Charateristics (continued)
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 specified 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
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
Power Good (PGD pin)
Threshold at FB, with respect to V_REF
Threshold hysteresis
FB increasing
91
95
%
3.3
%
PGD_VOL
PGD_LKG
Thermal Shutdown
Low state voltage
Off state leakage
I_PGD = 1mA, FB = 0V
V_PGD = 7V, FB = 3V
125 180 mV
0.1
µA
T_SD
Thermal shutdown
Thermal shutdown hysteresis
Junction temperature increasing
155
°C
20
°C
Thermal Resistance
θJA
Junction to Ambient, 0 LFPM Air Flow ⁽¹⁾
θJC
Junction to Case,⁽¹⁾
48
°C/W
10
°C/W
(1) JEDEC test board description can be found in JESD 51-5 and JESD 51-7.
4
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