Owner manual

MAX1864/MAX1865
xDSL/Cable Modem Triple/Quintuple Output
Power Supplies
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PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX186_T 160 200 240
Switching Frequency f
OSC
MAX186_U 80 100 120
kHz
Maximum Duty Cycle D
MAX
77 82 90 %
Soft-Start Period t
SOFT
1024 1/f
OSC
Soft-Start Steps V
REF
/64 V
DH Output Low Voltage I
SINK
= 10mA, measured from DH to LX 0.1 V
DH Output High Voltage I
SOURCE
= 10mA, measured from BST to DH 0.1 V
DL Output Low Voltage I
SINK
= 10mA, measured from DL to GND 0.1 V
DL Output High Voltage I
SOURCE
= 10mA, measured from DL to GND V
L
- 0.1 V
DH, DL On-Resistance 310Ω
Output Drive Current Sourcing or sinking, V
DH
or V
DL
= VL/2 0.5 A
LX, BST Leakage Current V
BST
= V
LX
= V
IN
= 28V, V
FB
= 1.5V 0.03 20 µA
POSITIVE ANALOG GAIN BLOCKS
FB2, FB3, FB4 Regulation
Voltage
V
B2
= V
B3
= V
B4
= 5V,
I
B2
= I
B3
= I
B4
= 1mA (sink)
1.226 1.240 1.257 V
FB2, FB3, FB4 to B_
Transconductance
∆V
FB
_
V
B2
= V
B3
= V
B4
= 5V, I
B2
= I
B3
= I
B4
=
0.5mA to 5mA (sink)
-1 -1.75 %
Feedback Input Leakage
Current
I
FB
_V
FB2
= V
FB3
= V
FB4
= 1.5V 0.01 100 nA
V
B2
= V
B3
= V
B4
= 2.5V 10 23
Driver Sink Current I
B
_
V
FB2
= V
FB3
=
V
FB4
= 1.188V
V
B2
= V
B3
= V
B4
= 4.0V 26
mA
NEGATIVE ANALOG GAIN BLOCK
FB5 Regulation Voltage
V
B5
= V
OUT
- 2V, V
OUT
= 3.5V, I
B5
= 1mA
(source)
-20 -5 +10 mV
FB5 to B5 Transconductance ∆V
FB5
V
B5
= 0, I
B5
= 0.5mA to 5mA (source) -13 -20 mV
Feedback Input Leakage
Current
I
FB5
V
FB5
= -100mV 0.01 100 nA
Driver Source Current I
B5
V
FB5
= 200mV, V
B5
= V
OUT
- 2.0V, V
OUT
=
3.5V
10 25 mA
POWER GOOD (POK)
OUT Trip Level (Preset Mode) FB = GND, falling edge, 1% hysteresis (typ) 2.88 3 3.12 V
FB Trip Level (Adjustable Mode) Falling edge, 1% hysteresis (typ) 1.070 1.114 1.159 V
FB2, FB3, FB4 Trip Level Falling edge, 1% hysteresis (typ) 1.070 1.114 1.159 V
FB5 Trip Level Rising edge, 35mV hysteresis (typ) 368 500 632 mV
POK Output Low Level I
SINK
= 1mA 0.4 V
POK Output High Leakage V
POK
= 5V 1 µA
THERMAL PROTECTION (Note 3)
Thermal Shutdown Rising temperature 160 °C
Thermal Shutdown Hysteresis 15 °C
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 12V, ILIM = FB = GND, V
BST
- V
LX
= 5V, T
A
= 0°C to +85°C. Typical values are at T
A
= +25°C, unless otherwise noted.)