Diodes ZXLD1356/ ZXLD1356Q - Manual (Page 5)

ZXLD1356/ ZXLD1356Q
Document number: DS33470 Rev. 4 - 2
5 of 29
www.diodes.com
October 2012
© Diodes Incorporated
ZXLD1356/ ZXLD1356Q
A Product Line of
Diodes Incorporated
Electrical Characteristics
(V
IN
= 24V, @T
AMB
= +25°C, unless otherwise specified.)
Symbol Parameter Condition Min Typ Max Unit
V
SU
Internal regulator start-up threshold 4.85 5.2 V
V
SD
Internal regulator shutdown threshold 4.40 4.75 V
I
INQoff
Quiescent supply current with output off ADJ pin grounded 65 108 µA
I
INQon
Quiescent supply current with output switching
(Note 6) ADJ pin floating, L = 68mH,
3 LEDsf = 360kHz
1.6 mA
V SENSE
Mean current sense threshold voltage
(Defines LED current setting accuracy) Measured on I SENSE pin with respect
to V
IN
V
ADJ
= 1.25V; V
IN
= 18V
195 200 205 mV
V SENSEHYS
Sense threshold hysteresis ±15 %
I SENSE I SENSE pin input current V SENSE = V IN -0.2 4 10 µA
V
REF
Internal reference voltage
Measured on ADJ pin with pin
floating
1.25 V
ΔV
REF
/ ΔT Temperature coefficient of V
REF
50 ppm/°C
V
ADJ
External control voltage range on ADJ pin for
DC brightness control (Note 7)
0.3 2.5 V
V
ADJoff
DC voltage on ADJ pin to switch device from
active (on) state to quiescent (off) state
V
ADJ
falling 0.15 0.20 0.27 V
V
ADJon
DC voltage on ADJ pin to switch device from
quiescent (off) state to active (on) state
V
ADJ
rising 0.2 0.25 0.3 V
R ADJ Resistance between ADJ pin and V REF 0< V ADJ < V REF , V ADJ > V REF +100mV
30
10.4
50
14.2
65
18.0
k Ω
I
LXmean
Continuous LX switch current 0.55 A
R
LX
LX switch ‘On’ resistance @ I
LX
= 0.55A 0.5 0.75 Ω
I
LX(leak)
LX switch leakage current 5 µA
D
PWM(LF)
Duty cycle range of PWM signal applied to ADJ
pin during low frequency PWM dimming mode
PWM frequency <300Hz PWM
amplitude = V
REF
Measured on ADJ pin
0.001 1
Brightness control range 1000:1
DC ADJ
(*) DC Brightness control range Note 8 5:1
t
SS
Start up time
(See graphs for more details)
Time taken for output current to reach
90% of final value after voltage on
ADJ pin has risen above 0.3V.
Requires external capacitor 22nF.
2 ms
f
LX
Operating frequency
(See graphs for more details)
ADJ pin floating L= 68mH (0.36V)
I
OUT
= 0.55A @ V
LED
= 3.6V
Driving 3 LEDs
360 kHz
f
LXmax
Recommended maximum operating frequency 500 kHz
Notes: 6. Static current of device is approximately 700 µA, see Graph, Page 17.
7. 100% brightness corresponds to V ADJ = V ADJ(nom) = V REF . Driving the ADJ pin above V REF will increase the V SENSE . threshold and output current
proportionally.
8. Ratio of maximum brightness to minimum brightness before shutdown V REF =1.25/0.25. V REF externally driven to 2.5V, ratio 10.1.