Datasheet
LM3549
SNVS640A –AUGUST 2010–REVISED MAY 2013
www.ti.com
Electrical Characteristics
(1) (2)
(continued)
Limits in standard type face are for T
A
= 25°C. Limits in boldface type apply over the full operating ambient temperature
range (−30°C ≤ T
A
≤ +85°C). Unless otherwise noted, specifications apply to Figure 1 with: V
IN
= 3.6V, C
IN
= 10 µF, C
OUT
=
4.7µF and L1 = 2.2 µH.
(3)
Parameter Test Conditions Min Typ Max Units
Drivers (R_OUT, G_OUT, B_OUT)
I
OUT MIN
Minimum output current 97 107 118 mA
I
OUT MAX
Maximum output current 690 705 720 mA
I
LIM
Current limit 15 %
R
OUT
Driver on resistance I
OUT
= 500 mA 0.2 Ω
Driver System Characteristics
I
OUT
Current accuracy After settling, 500 mA (ISET = 276h) −6 ±1 +6 %
t
r
Current rise time 50 µs
t
f
Current fall time 50 µs
I
STEP
Current step 0.64 mA
Buck or Boost Converter
Positive current limit range Programmable 500 2000 mA
Positive current limit accuracy Set to 1000 mA -20 +20 %
Negative current limit range Programmable 550 2200 mA
Negative current limit Set to 550 mA -20 +20 %
accuracy
V
OUT MAX
Maximum output voltage 4.6 V
f
SW
Switching frequency 2.25 2.4 2.55 MHz
r
DSON P1S
P1 on resistance in buck 100 mΩ
mode (small)
r
DSON P1L
P1 on resistance in boost 55 mΩ
mode (large)
r
DSON N1
N1 on resistance 160 mΩ
r
DSON N3
N3 on resistance in buck VOUT = 0.8V 70 mΩ
mode
r
DSON P2
P2 on resistance in boost VOUT = 3.6V 65 mΩ
mode
r
DSON N2
N2 on resistance 150 mΩ
PWM Input (Global brightness control)
f
PWM
PWM frequency 7-bit resolution 4 20 kHz
8-bit resolution 4 10
9-bit resolution 4 5
t
TO
Timeout For PWM zero 260 300 340 µs
t
ON
Minimum on time 1 µs
t
OFF
Minimum off time 1 µs
Logic Input EN
VIL Logic input low level 0.5 V
VIH Logic input high level 1.2 V
Logic Inputs SDA, SCL, R_EN, G_EN, B_EN, PWM
VIL Logic input low level VEN = 1.65 to VDD 0.2* VEN V
VIH Logic input high level VEN = 1.65 to VDD 0.8* VEN V
Logic Outputs SDA, FAULT
VOL Output low level I
OUT
= 3 mA 0.5 V
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