LM3478_09 Datasheet, PDF (3/22 Pages) National Semiconductor (TI) – High Efficiency Low-Side N-Channel Controller for Switching Regulator

Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Input Voltage
FB Pin Voltage
FA/SD Pin Voltage
Peak Driver Output Current (<10µs)
Power Dissipation
Storage Temperature Range
Junction Temperature
ESD Susceptibilty
Human Body Model (Note 2)
45V
-0.4V < V_FB < 7V
-0.4V < V_FA/SD < 7V
1.0A
Internally Limited
−65°C to +150°C
+150°C
2kV
Lead Temperature
MM Package
Vapor Phase (60 sec.)
Infared (15 sec.)
DR Pin Voltage
I_SEN Pin Voltage
215°C
260°C
−0.4V ≤ VDR ≤ 8V
500mV
Operating Ratings (Note 1)
Supply Voltage
Junction Temperature
Range
Switching Frequency
2.97V ≤ V_IN ≤ 40V
−40°C ≤ T_J ≤ +125°C
100kHz ≤ F_SW ≤ 1MHz
Electrical Characteristics
Specifications in Standard type face are for T_J = 25°C, and in bold type face apply over the full Operating Temperature
Range. Unless otherwise specified, V_IN = 12V, R_FA = 40kΩ
Symbol
Parameter
Conditions
Typical
Limit
Units
V_FB
Feedback Voltage
V_COMP = 1.4V,
2.97 ≤ V_IN ≤ 40V
1.26
V
1.2416/1.228
V(min)
1.2843/1.292
V(max)
ΔV_LINE
Feedback Voltage Line
2.97 ≤ V_IN ≤ 40V
0.001
%/V
Regulation
ΔV_LOAD
Output Voltage Load
Regulation
I_EAO Source/Sink
±0.5
%/V (max)
V_UVLO
Input Undervoltage Lock-out
2.85
V
2.97
V(max)
V_UV(HYS)
Input Undervoltage Lock-out
Hysteresis
170
mV
130
mV (min)
210
mV (max)
F_nom
Nominal Switching Frequency R_FA = 40KΩ
400
kHz
350
kHz(min)
440
kHz(max)
R_{DS1 (ON)}
Driver Switch On Resistance I_DR = 0.2A, V_IN= 5V
16
Ω
(top)
R_{DS2 (ON)}
Driver Switch On Resistance I_DR = 0.2A
(bottom)
4.5
Ω
V_{DR (max)}
D_max
T_min (on)
Maximum Drive Voltage
Swing(Note 6)
V_IN < 7.2V
V_IN ≥ 7.2V
Maximum Duty Cycle(Note 7)
Minimum On Time
V_IN
V
7.2
100
%
325
nsec
210
nsec(min)
600
nsec(max)
I_SUPPLY
Supply Current (non-
switching)
(Note 9)
2.7
mA
3.3
mA (max)
I_Q
V_SENSE
Quiescent Current in
Shutdown Mode
Current Sense Threshold
Voltage
V_FA/SD = 5V (Note 10),
V_IN = 5V
V_IN = 5V
5
µA
10
µA (max)
156
mV
135/ 125
mV (min)
180/ 190
mV (max)
V_SC
Short-Circuit Current Limit V_IN = 5V
Sense Voltage
343
mV
250
mV (min)
415
mV (max)
3
www.national.com