Owner manual

MAX1864/MAX1865
xDSL/Cable Modem Triple/Quintuple Output
Power Supplies
4 _______________________________________________________________________________________
PARAMETER SYMBOL CONDITIONS MIN MAX UNITS
GENERAL
Operating Input Voltage Range
(Note 1)
V
IN
4.5 28 V
MAX1864 2
Quiescent Supply Current I
IN
V
FB
= 0, V
OUT
= 4V, V
FB2
= V
FB3
= V
FB4
= 1.5V,
V
FB5
= -0.1V
MAX1865 3
mA
VL REGULATOR
Output Voltage VL 6V < V
IN
< 28V, 0.1mA < I
LOAD
<20mA 4.75 5.25 V
Power-Supply Rejection PSRR V
IN
= 6V to 28V 3 %
Undervoltage Lockout Trip Level V
UVLO
VL rising, 3% hysteresis (typ) 3 4 V
DC-DC CONTROLLER
Output Voltage (Preset Mode) V
OUT
FB = GND 3.247 3.380 V
Feedback Set Voltage
(Adjustable Mode)
V
SET
FB = COMP 1.211 1.261 V
Current-Sense Amplifier Voltage
Gain
A
LIM
V
IN
- V
LX
= 250mV 4.12 5.68 V/V
Current-Limit Threshold
(Internal Mode)
V
VALLEY
V
ILIM
= 5V 150 350 mV
Current-Limit Threshold
(External Mode)
V
VALLEY
V
ILIM
= 2.5V 400 660 mV
MAX186_T 160 240
Switching Frequency f
OSC
MAX186_U 80 120
kHz
Maximum Duty Cycle D
MAX
74 90 %
POSITIVE ANALOG GAIN BLOCKS
FB2, FB3, FB4 Regulation
Voltage
V
B2
= V
B3
= V
B4
= 5V, I
B2
= I
B3
= I
B4
=
1mA (sink)
1.215 1.265 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)
-2.25 %
NEGATIVE ANALOG GAIN BLOCK
FB5 Regulation Voltage
V
B5
= V
OUT
- 2V, V
OUT
= 3.5V, I
B5
= 1mA
(source)
-25 +10 mV
FB5 to B5 Transconductance ∆ V
FB5
V
B5
= 0, I
B5
= 0.5mA to 5mA (source) -30 mV
ELECTRICAL CHARACTERISTICS
(V
IN
= 12V, ILIM = FB = GND, V
BST
- V
LX
= 5V, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 4)