Fairchild SLTS218B Data Handbook
Summary
These TI DC/DC converters are high-performance, isolated power solutions designed specifically for mission-critical xDSL broadband applications in central office environments. The PTB4850x series supports powering up to 64 DSL ports with adjustable current capacities (up to 21A) and incorporates comprehensive safety features like Over-Current and Over-Temperature protection. This manual provides detailed model comparisons, pin configurations, operational guidelines, and compliance details for variant models (PTB48500 through PTB48502). They are essential components for telecom engineers requiring stable, reliable power delivery for ADSL chipset arrays.
Page 1 Text Content
查询PT78ST114供应商 PTB48500, PTB48501, PTB48502
Dual-Output, 48-V Input Isolated
SLTS218B - SEPTEMBER 2003 - REVISED NOVEMBER 2004
DC/DC Converter for x DSL
Features Dual Outputs Fixed Frequency Operation (Independently Regulated) Temp Range: –40 to 100 °C Input Voltage Range: Industry Standard Outline 36 V to 75 V Operates with PTB4851x for Power-up/Down Sequencing Complete AC7 Power Solution 1500 VDC Isolation Powers up to 64 DSL Ports Over-Current Protection Safety Approvals: Over-Temperature Shutdown UL/c UL 60950 Under-Voltage Lockout EN 60950
Description Pin Configuration The PTB4850x power modules are a output current limit, over-temperature Pin Function
dual-output isolated DC/DC converter, protection, input under-voltage lockout +VI designed to provide the logic supply volt- Sync Out
(UVLO). The PTB48500 and PTB48501
Enable #
ages for AC-7 based x DSL applications. also incorporates a power-up reset (POR)
EN Out
The PTB48500 is rated for 13 A of total output.
output current, making it suitable for The modules are designed to operate
+VO 2
32-channel x DSL applications. The with one of the PTB4851x DC/DC con-
PTB48501 and PTB48502 provide output verter modules. The combination of a
POR* / COM †
current for powering up to 64 x DSL chan- PTB4850x and PTB4851x converter
Vo2 Adjust
nels. The PTB48501 is rated for 16.5 A provides the complete the power supply +VO 1 total output current, and the PTB48502, for an AC7 chipset. The “EN Out” and
Shaded functions indicate signals
21 A. The PTB48502 incorporates 10 W “Sync Out” pins provide compatible out-
that are referenced to –VI.
of additional capacity for powering periph- put signals for controlling both the power
Denotes positive logic:
eral circuitry. Any of these converters can up sequence and switching frequency of Open = Normal operation
be used for other applications with simi- –VI = Outputs Off
the PTB48510.
lar power requirements. Denotes negative logic:
The PTB4850x modules employ
High = Normal operation
The modules operate from a standard double-sided surface mount construction,
Low = Reset
telecom (-48 V) central office (CO) supply and are an industry standard size.
This pin is COM on the PTB48502
and include an “on/off” enable control,
Stand-Alone Application
Sync Out
+VI EN Out
* Pin 8 is ‘COM’ on PTB48502
PTB4850x
(8) * POR
Vo2 Adj
Enable
COM 7, (8) *
For technical support and further information visit http://power.ti.com
Page Summary Contents For Fairchild SLTS218B Data Handbook
Manual Details
| Brand | Fairchild |
|---|---|
| Pages | 15 |
| File Size | 433.86 KB |
| Published | July 07, 2026 |
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Frequently Asked Questions
What is the input voltage range for this DC/DC converter?
The system operates with an industry standard outline of 36 V to 75 V.
How do I connect the EN Out pin when using a –48V telecom supply?
If powering from a –48V telecom supply, connect the EN Out input to the primary line where the power-up sequence must be precisely controlled.
What is the maximum total output current for each model?
The PTB4850x modules offer 13 A (PTB48500), 16.5 A (PTB48501), or 21 A (PTB48502) of total output current.
Does this converter provide protection against voltage fluctuations?
Yes, it includes Over-Current Protection and Under-Voltage Lockout (UVLO).
What is the purpose of the Sync Out pin?
The 'Sync Out' signal is designed to synchronize two PTB4851x modules using a common reference point.