LM3743_08 Datasheet, PDF (3/28 Pages) National Semiconductor (TI) – High-Performance Synchronous Buck Controller with Comprehensive Fault Protection Features

Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
V_CC
SW to GND
Boot to GND
Boot to SW
SS/TRACK, ILIM, COMP/EN,FB
to GND
Junction Temperature
Storage Temperature
-0.3V to 6V
-0.3V to 6V
-0.3V to 12V
-0.3V to 6V
-0.3V to V_CC
150°C
−65°C to 150°C
Soldering Information
 
Lead Temperature (soldering, 10sec)
 
Infrared or Convection (20sec)
ESD Rating (Note 3)
260°C
235°C
+ / – 2 kV
Operating Ratings
Supply Voltage Range, V_CC (Note 2)
Junction Temperature Range (T_J)
3.0V to 5.5V
−40°C to +125°C
Electrical Characteristics V_CC = 3.3V, COMP/EN floating unless otherwise indicated in the conditions column.
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.
Symbol
Parameter
Conditions
Min Typ Max Units
SYSTEM PARAMETERS
V_FB
V_UVLO
FB pin voltage in regulation
UVLO thresholds
3.0V ≤ V_CC ≤ 5.5V
Input voltage rising
Input voltage falling
0.786 0.8 0.814 V
2.84 3.0
V
2.45 2.66
I_VCC
Operating V_CC current
Operating V_CC current
Shutdown V_CC current
I_SS/TRACK SS/TRACK pin source current
I_ILIM
ILIM pin source current
V_ILIM Current Limit Trip Level
I_COMP/EN COMP/EN pin pull-up current
V_HS-CLIM High-side current limit threshold
ERROR AMPLIFER
f_SW = 300 kHz, LM3743-300
f_SW = 1 MHz, LM3743-1000
COMP/EN = 0V
1.5 2.5 mA
1.8 3.0 mA
6
50
µA
V_SS/TRACK = 0V
V_ILIM = 0V
8
10.2 12.5 µA
42.5
50 57.5 µA
–25
0
25 mV
V_COMP/EN = 0V
4
µA
Measured at V_CC pin with respect to SW
500
mV
GBW Error Amplifier Unity Gain Bandwidth
30
MHz
G
Error Amplifier DC Gain
90
dB
SR Error Amplifier Slew Rate
C_COMPENSATION = 2.2 nF, I_EAO = 1 mA
I_FB
FB pin Bias Current
I_EAO
EAO pin sourcing/sinking current capability V_COMP/EN = 1.5, V_FB = 0.75V
V_COMP/EN = 1.5, V_FB = 0.85V
GATE DRIVE
0.5
V/µs
10 200 nA
1.7
mA
-1
I_SHDN-BOOT
R_HG-UP
BOOT Pin Shutdown Current
High Side MOSFET Driver Pull-up ON
resistance
V_BOOT-V_SW = 3.3V, V_COMP/EN = 0V
V_BOOT-V_SW = 3.3V, I_HGATE = 350mA
(sourcing)
25
50
µA
1.6
Ω
R_HG-DN
High Side MOSFET Driver Pull-down ON V_BOOT-V_SW = 3.3V, I_HGATE = 350mA
resistance
(sinking)
1
Ω
R_LG-UP Low Side MOSFET Driver Pull-up ON
V_CC = 3.3V, I_LGATE = 350mA (sourcing)
1.6
Ω
resistance
R_LG-DN Low Side MOSFET Driver Pull-down ON V_CC = 3.3V, I_LGATE = 350mA (sinking)
1
Ω
resistance
OSCILLATOR
f_SW
Oscillator Frequency
D_MAX Max Duty Cycle
3.0V ≤ V_CC ≤ 5.5V, LM3743-300
3.0V ≤ V_CC ≤ 5.5V, LM3743-1000
f_SW = 300 kHz, LM3743-300
f_SW = 1 MHz, LM3743-1000
255
300 345
kHz
850 1000 1150
85
91
%
69
76
3
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