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Pin Function
1+Vin
2–Vin
3
EN 1
4
EN 2
5
TEMP
6
Pin Not Present
7
Do Not Connect
8Vo1 Adjust
9+Vo1
PT4850 Series
25-A Triple Output Isolated DC/DC
Converter For Logic Applications
Pin Function
10
+Vo1
11
+Vo1
12
COM
13
COM
14
COM
15
+Vo2
16
+Vo2
17
Vo2 Adjust
18
COM
On/Off Enable Logic
Pin Configuration
Pin Descriptions
Pin 3
Pin 4
Output Status
1×
Off
01
On
×0
Off
Notes:
Logic 1 =Open circuit
Logic 0 = –Vin (pin 2) potential
For positive Enable function, connect pin 3
to pin 2 and use pin 4.
For negative Enable function, leave pin 4
open and use pin 3.
+Vin:
The positive input supply for the module with
respect to –Vin. When powering the module from a
–48V telecom central office supply, this input is
connected to the primary system ground.
–Vin:
The negative input supply for the module, and
the 0VDC reference for the EN 1, and EN 2 inputs.
When powering the module from a +48V supply,
this input is connected to the 48V(Return).
EN 1:
The negative logic input that activates the
module output. This pin must be connected to –Vin
to enable the module’s outputs. A high impedance
disables the module’s outputs.
EN 2:
The positive logic input that activates the
module output. If not used, this pin should be left
open circuit. Connecting this input to –Vin disables
the module’s outputs.
TEMP:
This pin produces an output signal that tracks
a temperature that is approximately the module’s
metal case. The output voltage is referenced to –Vin
and rises approximately 10mV/°C from an intital
value of 0.1VDC at –40°C. The signal is available
whenever the module is supplied with a valid input
voltage, and is independant of the enable logic status.
(Note: A load impedance of less than 1M
will adversly
affect the module’s over-temperature shutdown threshold.
Use a high-impedance input when monitoring this signal.)
Vo 1:
The highest regulated output voltage, which is
referenced to the COM node.
Vo 2:
The regulated output that is designed to power
logic circuitry. It is referenced to the COM node.
Vo 3:
The low-voltage regulated output that provides
power for a -processor or DSP core, and is refer-
enced to the COM node.
COM:
The secondary return reference for the module’s
three regulated output voltages. It is DC isolated from
the input supply pins.
Vo(n) Adjust: Using a single resistor, this pin allows the
associated output Vo(n) to be adjusted higher or lower
than the preset value. If not used, this pin should be
left open circuit.
Vo(n) Rem Sense: An external remote sense input is
provided for the two lowest voltage outputs, +Vo2
and +Vo3. Connecting the remote sense pins im-
proves the load regulation of the applicable output
by allowing the regulation circuit to compensate for
voltage drop between the converter and load. If
desired these inputs may be left disconnected.
Note: Shaded functions indicate those pins that are at primary-side potential.
Pin Function
19
COM
20
COM
21
Vo3 Adjust
22
+Vo3
23
+Vo3
24
Vo3 Rem Sense
25
Vo2 Rem Sense
26
Do Not Connect
SLTS166C - FEBRUARY 2002 - REVISED MARCH 2003
Environmental Specifications
Characteristics
Symbols
Conditions
Min
Typ
Max
Units
Operating Temperature Range
Ta
Over Vin Range
–40
—
+85 (i)
°C
Case Temperature
Tc
—
105
°C
Storage Temperature
Ts
—
–40
—
+125
°C
Over Temperature Protection
OTP
Case temperature
—
110
125
°C
Mechanical Shock
Per Mil-STD-883D, Method 2002.3
—
500
—
G’s
1 msec, Sine, mounted
Mechanical Vibration
Mil-STD-883D, Method 2007.2
Suffix N
—
10 (ii)
—
G’s
20-2000 Hz
Suffix A, C
—
20 (ii)
—
Weight
—
Vertical/Horizontal
—
90
—
grams
Flammability
—
Meets UL 94V-O
Notes:
(i) See SOA curves or consult factory for appropriate derating.
(ii) The case pins on through-hole pin configurations (N & A) must be soldered. For more information see the applicable package outline drawing.