Rainbow Electronics MAX1865 - Manual (Page 3)

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 3 10 Ω
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.)