Owner manual

MAX8728
Low-Cost, Multiple-Output
Power Supply for LCD Monitors/TVs
4 _______________________________________________________________________________________
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
Current-Sense Transresistance
0.6 1.2 1.8 V/A
LX2 On-Resistance 0.5 1.0 Ω
Soft-Start Period 3ms
POSITIVE CHARGE-PUMP REGULATOR
FBP Regulation Voltage 1.98 2.00 2.02 V
FBP Line Regulation Error V
IN
= V
SUPP
= 10.8V to 13.2V 6 mV
FBP Input Bias Current V
FBP
= 2.1V -50 +50 nA
DRVP p-Channel MOSFET
On-Resistance
4 Ω
DRVP n-Channel MOSFET
On-Resistance
1 Ω
FBP Fault Trip Level Falling edge 1.536
1.600
1.664 V
Positive Charge-Pump Soft-Start
Period
3ms
NEGATIVE CHARGE-PUMP REGULATOR
FBN Regulation Voltage V
REF
- V
FBN
1.727
1.750
1.773 V
FBN Input Bias Current V
FBN
= 250mV -50 +50 nA
FBN Line Regulation V
IN
= 10.8V to 13.2V 6 mV
DRVN p-Channel MOSFET
On-Resistance
4 Ω
DRVN n-Channel MOSFET
On-Resistance
1 Ω
FBN Fault Trip Level Rising edge 600 mV
Negative Charge-Pump
Soft-Start Period
3ms
SEQUENCE CONTROL
SHDN Input Low Voltage 0.4 V
SHDN Input High Voltage 2 V
SHDN Input Current 1µA
EN Charge Current During startup, V
EN
= 1.0V 456µA
EN Turn-On Threshold 0.95 1.00 1.05 V
DEL Capacitor Charge Current During startup, V
DEL
= 1.0V 456µA
DEL Turn-On Threshold 0.95 1.00 1.05 V
GATE Output Sink Current EN = high, GATE = IN 8 11 14 µA
GATE On Voltage EN = high V
IN
- 6
V
IN
- 5
V
IN
- 4 V
GATE Done Threshold EN = high, V
GATE
_
DONE
- V
GATE
_
ON
01 V
GATE Pullup Resistance EN = low, V
GATE
= V
IN
- 5V 1 kΩ