Datasheet
LM5045
www.ti.com
SNVS699G –FEBRUARY 2011–REVISED MARCH 2013
Electrical Characteristics (continued)
Limits in standard typeface are for T
J
= 25°C only; limits in boldface type apply the junction temperature range of -40°C to
+125°C. Unless otherwise specified, the following conditions apply: VIN = 48V, RT = 25kΩ, RD1=RD2=20kΩ. No load on
HO1, HO2, LO1, LO2, SR1, SR2, COMP=0V, UVLO=2.5V, OVP=0V, SSOFF=0V.
Symbol Parameter Conditions Min Typ Max Units
Oscillator (RT Pin)
F
SW1
Frequency (LO1, half oscillator R
T
= 25 kΩ 185 200 215 kHz
frequency)
F
SW2
Frequency (LO1, half oscillator R
T
= 10 kΩ 420 480 540 kHz
frequency)
DC level 2.0 V
RT sync threshold 2.8 3 3.3 V
Synchronous Rectifier Timing Control (RD1 & RD2 Pins)
T1 SR trailing edge delay R
D1
=20 kΩ 45 65 90 ns
SR turn-off to HO&LO both on
R
D1
=100 kΩ 232 300 388 ns
T2 SR leading edge R
D2
=20 kΩ 43 65 90 ns
HO or LO turn-off to SR turn-on
R
D2
=100 kΩ 227 300 384 ns
Comp Pin
V
PWM-OS
COMP current to RAMP offset V
RAMP
=0V 680 800 940 µA
V
SS-OS
SS to RAMP offset V
RAMP
=0V 0.78 1.0 1.22 V
COMP current to RAMP gain ΔRAMP/ΔI
COMP
2400 Ω
SS to RAMP gain ΔSS/ΔRAMP 0.5
COMP current for SSSR charge V
SS
> 2V 690 800 915 µA
current enable
COMP to output delay 120 ns
Minimum duty cycle I
COMP
= 1mA 0 %
Slope Compensation (SLOPE Pin)
I
SLOPE
Slope compensation current ramp Peak of RAMP current 100 µA
BOOST (BST Pin)
V
Bst uv
BST under-voltage threshold V
BST
-V
HS
rising 3.8 4.7 5.6 V
Hysteresis 0.5 V
HO1, HO2, LO1, LO2 Gate Drivers
V
OL
Low-state output voltage I
HO/LO
= 100mA 0.16 0.32 V
V
OH
High-state output voltage I
HO/LO
= 100mA 0.27 0.495 V
V
OHL
= V
CC
-V
LO
V
OHH
= V
BST
-V
HO
Rise Time C-load = 1000pF 16 ns
Fall Time C-load = 1000pF 11 ns
I
OHL
Peak Source Current V
HO/LO
= 0V 1.5 - A
I
OLL
Peak Sink Current V
HO/LO
= V
CC
2 - A
SR1, SR2 Gate Drivers
V
OL
Low-state output voltage I
SR1/SR2
= 10mA 0.05 0.1 V
V
OH
High-state output voltage I
SR1/SR2
= 10mA, 0.17 0.28 V
V
OH
= V
REF
-V
SR
Rise Time C-load = 1000pF 60 ns
Fall Time C-load = 1000pF 20 ns
I
OHL
Peak Source Current V
SR
= 0V 0.1 - A
I
OLL
Peak Sink Current V
SR
= V
REF
0.4 - A
Thermal
TSD Thermal Shutdown Temp 160 °C
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