MAX1739/MAX1839
†
Wide Brightness Range
CCFL Backlight Controllers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 8.2V, V
SH
/SUS = V
SH
= 5.5V, MINDAC = GND, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER CONDITIONS MIN TYP MAX UNITS
DAC AND ERROR AMPLIFIER
DAC Resolution Guaranteed monotonic 5 Bits
MINDAC Input Voltage Range 0 2 V
MINDAC Input Bias Current 0 < V
MINDAC
< 2V -1 1 µA
MINDAC Digital PWM Disable
Threshold
MINDAC = VL 2.4 2.9 4 V
CSAV Input Voltage Range 0 0.8 V
V
MINDAC
= 0, DAC code = 11111 binary 188 194 200
V
MINDAC
= 0, DAC code = 00001 binary 2 6.25 16
CSAV Regulation Point
V
MINDAC
= 1V, DAC code = 00000 binary 93 100 110
mV
CSAV Input Bias Current -1 1 µA
CSAV to CCI Transconductance 1V < V
CCI
< 2.7V 100 µmho
CTFB Input Voltage Range 0 2 V
CTFB Input Bias Current -1 1 µA
CTFB Regulation Point 570 600 630 mV
CTFB to CCV Transconductance 1V < V
CCV
< 2.7V 30 40 50 µmho
TIMERS AND FAULT DETECTION
Chopping Oscillator Frequency No AC signal on MODE, not synchronized 24 28 32 kHz
No AC signal on MODE 205 220 235
32kHz AC signal on MODE 250
Digital PWM Chop-Mode Frequency
100kHz AC signal on MODE 781
Hz
MODE to DPWM Sync Ratio F
MODE
/ F
DPWM
128
No AC signal on MODE 2.06 2.33 2.73
32kHz AC signal on MODE 2.05
Lamp-Out Detection Timeout Timer
(Center-Tap Voltage Stuck at
Maximum) (Note 1)
V
CSAV
< CSAV
lamp-out
threshold
100kHz AC signal on MODE 0.66
s
CSAV Lamp-Out Threshold 50 75 100 mV
Fault-Detection Threshold on CCV (Note 2) 0.4 1 V
No AC signal on MODE 332 291 259
32kHz AC signal on MODE 256
Shorted Buck-Switch Detection
Timeout Timer (UL1950 Protection)
(Note 3)
V
CCV
< fault-
detection
threshold on CCV
100kHz AC signal on MODE 82
ms
Lamp Turn-On Delay After SH/SUS or SH forces device on or SH rises 4 ms
MODE Operating Voltage Range -5.5 11 V
MODE = GND Threshold
(min Brightness = 0)
To sync DPWM oscillator, not in shutdown
(Note 4)
0.6 V
MODE = REF Threshold
(max Brightness = 0)
To sync DPWM oscillator, not in shutdown
(Note 4)
1.4 2.6 V
MODE = V
L
Threshold
(MAX1739 SMB Interface Mode)
To sync DPWM oscillator, not in shutdown
(Note 4)
VL - 0.6 V
MODE AC Signal Amplitude Peak to peak (Note 5) 2 V
MODE AC Signal Synchronization
Range
Chopping oscillator synchronized to MODE AC
signal
32 100 kHz
(18 Seiten)
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