Diodes ZXLD1374 - Manual (Page 7)

ZXLD1374
Document number: DS35032 Rev. 3 - 2
7 of 39
www.diodes.com
September 2012
© Diodes Incorporated
ZXLD1374
A Product Line of
Diodes Incorporated
Electrical Characteristics
(cont.) (V
IN
= V
AUX
= 12V, @T
A
= +25°C, unless otherwise specified.)
Symbol Parameter Conditions Min Typ Max Units
Output Parameters
V
FLAGL
FLAG Pin Low Level Output Voltage Output sinking 1mA 0.5 V
I
FLAGOFF
FLAG Pin Open-Drain Leakage Current V
FLAG
= 40V 1 µA
V
STATUS
STATUS Flag No-Load Output Voltage
(Note 13)
Normal operation 4.2 4.5 4.8
V
Out of regulation (V
SHP
out of range)
(Note 12)
3.3 3.6 3.9
V
IN
under-voltage (V
IN
< 5.6V) 3.3 3.6 3.9
Switch stalled (t
ON
or t
OFF
> 100µs) 3.3 3.6 3.9
LX over-voltage state (V
LX
> 60V) 2.4 2.7 3.0
Over-temperature (T
J
> 125°C) 1.5 1.8 2.1
Excess sense resistor current
(V
SENSE
> 0.375V)
0.6 0.9 1.2
Excessive switch current (I
SW
>1.5A) 0.6 0.9 1.2
R
STATUS
Output Impedance of STATUS Output Normal operation 10 kΩ
Low Side Switch Output (LX pins tied together)
I
LX-LG
Low Side Switch Leakage Current
Output stage off, V
LX
= 60V
(Note 14)
60 µA
R
DS(ON)
LX Pin MOSFET on Resistance I
LX
= 1.5A (t
ON
< 100µs) 0.5 0.8 Ω
t
PDHL
Propagation Delay High-Low
V
SENSE
= 225mV ± 30%, C
L
= 680pF,
R
L
= 120 Ω
86 ns
t
PDLH
Propagation Delay Low-High 131 ns
t
LXR
LX Output Rise Time 208 ns
t
LXF
LX Output Fall Time 12 ns
t
STALL
Time to assert ‘STALL’ flag and
warning on STATUS output
(Note 15)
LX low or high 100 170 µs
LED Thermal control circuit (TADJ) parameters
V
TADJH
Upper Threshold Voltage
Onset of output current reduction (V
TADJ
falling)
560 625 690 mV
V
TADJL
Lower Threshold Voltage
Output current reduced to <10% of set value
(V
TADJ
falling)
380 440 500 mV
I
TADJ
TADJ Pin Input Current V
TADJ
= 1.25V 1 µA
Notes: 12. Flag is asserted if V
SHP
<2.5V or V
SHP
>3.5V
13. In the event of more than one fault/warning condition occurring, the higher priority condition will take precedence. E.g. ‘Excessive coil current’
and ‘Out of regulation’ occurring together will produce an output of 0.9V on the STATUS pin. The voltage levels on the STATUS output assume
the Internal regulator to be in regulation and V
ADJ
<=V
REF
. A reduction of the voltage on the STATUS pin will occur when the voltage on V
IN
is near –
this is due to the feedback loop increasing the sense voltage.
14. With the device still in switching mode the LX pin has an over-voltage detection circuit connected to it with a resistance of approximately 1M Ω.
15. If t
ON
exceeds t
STALL
, LX turns off and then an initiate a restart cycle occurs. During this phase, ADJ is grounded internally and the SHP pin is
switched to its nominal operating voltage, before operation is allowed to resume. Restart cycles will be repeated automatically until the operating
conditions are such that normal operation can be sustained. If t
OFF
exceeds t
STALL
, the switch will remain off until normal operation is possible.