Owner manual
MAX8728
Low-Cost, Multiple-Output
Power Supply for LCD Monitors/TVs
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
IN
= V
INL
= V
SUPP
= 12V, V
OUT1
= +3.3V, V
SRC
= 28V, GND1 = GND2 = GNDP = GND = 0, I
REF
= 0, T
A
= 0°C
to +85°C. Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER CONDITIONS MIN TYP MAX
UNITS
DEL, EN Discharge Switch
On-Resistance
SHDN = low or fault tripped 20 Ω
FBN Discharge Switch
On-Resistance
EN = low or fault tripped 5 kΩ
POSITIVE GATE-DRIVER TIMING AND CONTROL SWITCHES
CTL Input Low Voltage 0.6 V
CTL Input High Voltage 2.0 V
CTL Input Leakage Current -1 +1 µA
CTL-to-GON Rising Propagation
Delay
1kΩ from DRN to GND, 1.5nF from GON to
GND
100 ns
CTL-to-GON Falling Propagation
Delay
1kΩ from DRN to GND, 1.5nF from GON to
GND
250 ns
SRC Input Voltage Range 38 V
V
MODE
= V
REF
, V
DEL
= V
CTL
= 3V 1.5 2.0
SRC Input Current
V
MODE
= V
REF
, V
DEL
= 3V, V
CTL
= 0 0.14 0.20
mA
DRN Input Current
V
MODE
= V
REF
, V
DRN
= 8V, V
DEL
= 3V,
V
GON
> V
DRN
, V
CTL
= 0
01µA
SRC Switch On-Resistance V
MODE
= V
REF
, V
DEL
= V
CTL
= 3V 15 30 Ω
SRC Switch Saturation Current
V
MODE
= V
REF
, V
DEL
= V
CTL
= 3V,
V
SRC
- V
GON
> 5V
260 mA
DRN Switch
On-Resistance
V
MODE
= V
REF
, V
DEL
= 3V, V
CTL
= 0, V
GON
= 28V, V
THR
= 1.4V
25 50 Ω
DRN Switch Saturation Current
V
MODE
= V
REF
, V
DEL
= 3V, V
CTL
= 0, V
GON
= 28V, V
THR
= 1.4V, V
GON
- V
DRN
> 5V
100 mA
MODE Switch On-Resistance SHDN = GND 1 kΩ
MODE Current-Source Stop
Voltage Threshold
MODE rising 1.2 1.4 1.6 V
MODE Charge Current Operating mode 2, V
MODE
= 0.7V 40 50 60 µA
MODE Voltage Threshold Enabling DRN switch control in mode 2 0.8 1.0 1.2 V
THR to GON Voltage Gain 9.4 10.0 10.6 V/V
FAULT DETECTION
Duration to Trigger Fault 50 ms
Thermal Shutdown Threshold 15°C typical hysteresis +160 °C
SWITCHING-FREQUENCY SELECTION
FSEL = V
CC
(1MHz)
V
CC
- 0.4
FSEL = REF (0.5MHz) 1.65 2.35FSEL Input Levels
FSEL = GND (1.5MHz) 0.5
V
FSEL Input Current Forced to V
CC
10 µA