Datasheet

LM3488
LM3488-Q1
www.ti.com SNVS089M –JULY 2000–REVISED MARCH 2013
Operating Ratings
(1)
Supply Voltage 2.97V ≤ V
IN
≤ 40V
Junction Temperature Range −40°C ≤ T
J
≤ +125°C
Switching Frequency 100kHz ≤ F
SW
≤ 1MHz
(1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which
operation of the device is intended to be functional. For specifications and test conditions, see the Electrical Characteristics.
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 Unit
V
FB
Feedback Voltage V
COMP
= 1.4V, 1.26 V
2.97 ≤ V
IN
≤ 40V 1.2507/1.24 V(min)
1.2753/1.28 V(max)
ΔV
LINE
Feedback Voltage Line Regulation 2.97 ≤ V
IN
≤ 40V 0.001 %/V
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
360 kHz(min)
430 kHz(max)
R
DS1 (ON)
Driver Switch On Resistance (top) I
DR
= 0.2A, V
IN
= 5V 16 Ω
R
DS2 (ON)
Driver Switch On Resistance (bottom) I
DR
= 0.2A 4.5 Ω
V
DR (max)
Maximum Drive Voltage Swing
(1)
V
IN
< 7.2V V
IN
V
V
IN
≥ 7.2V 7.2
D
max
Maximum Duty Cycle
(2)
100 %
T
min
(on) Minimum On Time 325 nsec
230 nsec(min)
550 nsec(max)
I
SUPPLY
Supply Current (switching)
(3)
2.7 mA
3.0 mA (max)
I
Q
Quiescent Current in Shutdown Mode V
FA/SYNC/SD
= 5V
(4)
, V
IN
= 5V 5 µA
7 µA (max)
V
SENSE
Current Sense Threshold Voltage V
IN
= 5V 156 mV
135/ 125 mV (min)
180/ 190 mV (max)
V
SC
Short-Circuit Current Limit Sense V
IN
= 5V 343 mV
Voltage 250 mV (min)
415 mV (max)
V
SL
Internal Compensation Ramp Voltage V
IN
= 5V 92 mV
52 mV(min)
132 mV(max)
V
SL
ratio V
SL
/V
SENSE
0.49 0.30 (min)
0.70 (max)
V
OVP
Output Over-voltage Protection (with V
COMP
= 1.4V 50 mV
respect to feedback voltage)
(5)
32/ 25 mV(min)
78/ 85 mV(max)
(1) The voltage on the drive pin, V
DR
is equal to the input voltage when input voltage is less than 7.2V. V
DR
is equal to 7.2V when the input
voltage is greater than or equal to 7.2V.
(2) The limits for the maximum duty cycle can not be specified since the part does not permit less than 100% maximum duty cycle
operation.
(3) For this test, the FA/SYNC/SD Pin is pulled to ground using a 40K resistor .
(4) For this test, the FA/SYNC/SD Pin is pulled to 5V using a 40K resistor.
(5) The over-voltage protection is specified with respect to the feedback voltage. This is because the over-voltage protection tracks the
feedback voltage. The over-voltage thresold can be calculated by adding the feedback voltage, V
FB
to the over-voltage protection
specification.
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