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SC621 Datasheet, PDF (5/23 Pages) Semtech Corporation – LED Light Management Unit Charge Pump, 4 LEDs, 400mA Flash LED, Dual LDOs, and SemWireTM Interface
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SC621
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min Typ Max Units
LDO Electrical Specifications (continued)
Load Regulation
ΔV
LOAD
V = 3.3V, V = 3.7V,
LDO1
IN
I = 1mA to 100 mA
LDO1
V = 1.8V, V = 3.7V,
LDO2
IN
I = 1mA to 100 mA
LDO2
Dropout Voltage(5)
V
I = 100mA
100
D
LDO1
Current Limit
Power Supply
Rejection Ratio
Output Voltage Noise
Minimum Output Capacitor
I
200
LIM
PSRR
2.5V < VLDO1 < 3V, f < 1kHz, CBYP = 22nF, ILDO1 = 50mA,
50
LDO1
V = 3.7V with 0.5V ripple
IN
P-P
PSRR
f < 1kHz, CBYP = 22nF, ILDO2 = 50mA,
60
LDO2
V = 3.7V with 0.5V ripple
IN
P-P
e
LDO1, 10Hz < f < 100kHz, CBYP = 22nF, CLDO = 1μF,
100
n-LDO1
I = 50 mA, V = 3.7V, 2.5V < V < 3V
LDO1
IN
LDO1
LDO2, 10Hz < f < 100kHz, C = 22nF, C = 1μF,
e
BYP
LDO
50
n-LDO2
I = 50 mA, V = 3.7V
LDO2
IN
C
1
LDO(MIN)
Digital I/O Electrical Specifications (FLEN, SWIF)
25
mV
20
150
mV
mA
dB
μV
RMS
μF
Input High Threshold
V
IH
V = 5.5V
1.6
V
IN
Input Low Threshold
V
IL
V = 3.0V
IN
0.4
V
Input High Current
I
IH
V = 5.5V
IN
-1
+1
μA
Input Low Current
I
IL
V = 5.5V
IN
-1
+1
μA
SemWire Bit Rate
f
SWIF
10
75 kbit/s
SemWire Start-up Time(6)
tEN
1
ms
SemWire Disable Time(7)
t
DIS
10
ms
SemWire Data Latch Delay(8)
D
DL
5
bit
Notes:
(1) ΔV is the voltage difference between any two LEDs.
F
(2) Once tripped, flash output will remain disabled until FLEN pin is cycled or reset via serial interface.
(3) Current matching equals ± [I - I ] / [I + I ].
BL(MAX) BL(MIN
BL(MAX) BL(MIN)
(4) Test voltage is VOUT = 4.0V — a relatively extreme LED voltage — to force a transition during test. Typically VOUT = 3.2V for white LEDs.
(5) Dropout is defined as (V -V ) whenV drops 100mV from nominal. Dropout does not apply to LDO2 since it has a maximum output voltage
IN LDO1
LDO1
of 1.8V.
(6) The SemWire start-up time is the minimum period that the SWIF pin must be held high to enable the part before commencing
communication.
(7) The SemWire disable time is the minimum period that the SWIF pin must be pulled low to shut the part down.
(8) The SemWire data latch delay is the maximum duration after communication has ended before the register is updated.
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