PTB48510_14 Datasheet, PDF (6/18 Pages) Texas Instruments – DUAL COMPLEMENTARY-OUTPUT DC/DC CONVERTER FOR DSL

Not Recommended for New Designs
PTB48510
PTB48511
SLTS219F – FEBRUARY 2004 – REVISED MARCH 2007
DEVICE INFORMATION
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TERMINAL
NAME
NO.
+V_I ⁽¹⁾
1
Sync In
2
Enable ⁽²⁾
3
-V_I
4
V_O1
5
V_O2
8
COM
6
V_OAdj
7
TERMINAL FUNCTIONS
DESCRIPTION
The positive input supply for the module with respect to V_I (or ground return). When powering the module from
a –48 V telecom central office supply, this input is connected to the primary system ground.
This pin is used when the PTB4851x and PTB4850x DC/DC converter modules are used together. Connecting
this pin to the Sync Out of the PTB4850x module allows the PTB4851x to be synchronized to the same switch
conversion frequency as the PTB4850x.
This is an open-collector (open-drain) negative logic input that enables the module output. This pin is
referenced to –V_I . A logic 0 at this pin enables the module's outputs, and a high impedance disables the
outputs. If this feature is not used the pin should be connected to –V_I .
Note: Connecting this input directly to the EN Out pin of the PTB4850x enables the output voltages from both
converters (PTB4850x and PTB4851x) to power up in sequence.
The negative input supply for the module, and the 0 VDC reference for the Enable, and Sync In signals. When
the module is powered from a +48-V supply, this input is connected to the 48-V Return.
The positive output supply voltage, which is referenced to the COM node. The voltage at V_O1 has the same
magnitude, but is the complement to that at V_O2 .
The negative output supply voltage, which is referenced to the COM node. The voltage at V_O2 has the same
magnitude, but is the complement to that at V_O1 .
The secondary return reference for the module's regulated output voltages. This node is dc isolated from the
input supply pins.
Using a single resistor, this pin allows the magnitude of both V_O1 and V_O2 to be adjusted together, either higher
or lower than their preset value. If not used, this pin should be left open circuit.
(1) Shaded functions indicate signals that are referenced to -V_I
(2) Denotes negative logic: Open = Output Off, –V_I = Normal operation.
6
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