For technical support and further information visit http://power.ti.com
85 W Dual Complementary-Output
DC/DC Converter for DSL
Specifications (Unless otherwise stated, T
A =25°C, VI =48 V, CI =0 F, ±CO =0 F, |+IO | = |–IO |, and |±IO | =0.5 |±IO |max)
PTB48600A
Characteristic
Symbol
Conditions
Min
Typ
Max
Units
Output Power
PO
Total output power from ±VO
0—
85 (1)
W
Output Current
|±I
O |
Over V
I range, |+IO | – |–IO | ≤ 0.1 A
0
—
8.5 (2)
A
Output Load Imbalance
|+I
O | – |–IO ||+IO | ≥0.1 A, |–IO | ≥ 0.1 A
0
—
1
(3)
A
Output Voltage
|±V
O |
Inlcudes set-point, line,
|+I
O | – |–IO | ≤ 0.1 A
4.75 (2)
5
5.25 (2)
V
–40
≤T
A ≤+85°C
Temperature Variation
Reg
TEMP
–40
≤T
A ≤ +85°C, |±IO| =0.1 A
+VO
—±1
—
%Vo
–VO
—±1
—
Line Regulation
Reg
LINE
Over VI range, balanced load
±VO
—
±0.1
±0.4
%Vo
Load Regulation
Reg
LOAD
Over ±IO range, balanced load
±VO
—
±0.2
±0.4
%Vo
Efficiency
η
—85
—
%
Vo Ripple (pk-pk)
±VR
20 MHz bandwidth,
—
20
30 (4)
mVpp
C
O =10 F tantalum capacitor
Transient Response
tTR
0.1 A/s load step, 50% to 75% ±IOmax
—
30
—
s
V
TR
|±V
O | over/undershoot
—
±1
—
%V
o
Over Current Threshold
|±IO|trip
VI =36 V, |+IO| = |–IO|,
9
1012A
reset followed by auto-recovery
Short Circuit Current
Continuous over-current trip,
|±I
O |PK
—16
—
A
|+I
O | = |–IO |
Duty
—
10
—
%
Output Voltage Adjust Range
|±V
O | adj
|+V
O | and |–VO | adjust simulataneously
3.31
—
6
V
Switching Frequency
S
Over VI and IO ranges
440
470 (5)
500
kHz
Under-Voltage Lockout
V
I on
V
I increasing
—
33
—
V
VIoff
VI decreasing
—
32
—
On/Off Enable (pin 3)
Referenced to –VI (pin 4)
Input High Voltage
V
IH
+3.6
—
+75 (6)
V
Input Low Voltage
V
IL
–0.2
—
+0.8
Input Low Current
IIL
——–1
mA
Standby Input Current
II standby
pin 3 open circuit
—
2
—
mA
Start-up Time
tON
|±I
O | =1 A, |±VO | rising 0 to 0.95 |±VO | typ
6
1022ms
Internal Input Capacitance
CI
—3
—F
External Output Capacitance
±CO
Capacitance from either output to COM
0
—
5,000 (7)
F
Reliability
MTBF
Per Telcordia SR-332
2.8
—
106 Hrs
50% stress, TA =40°C, gnd benign
Notes:
(1) See Safe Operating Area curves or contact the factory for the appropriate derating.
(2) Under balanced load conditions, load current flowing out of +VO is balanced to within ±0.1 A of that flowing into –VO.
(3) A load imbalance is the difference in current flowing from +VO to –VO. The module can operate with a higher imbalance but with reduced specifications.
(4) Output voltage ripple is measured with a 10 F tantalum capacitor connected from +V
O (pin 5) or –VO (pin 8), to COM (pin 6).
(5) This is the free-running frequency. The module can be made to synchronize with the PTB48500 when both modules are used together in a system.
(6) The On/Off Enable (pin 3) has an internal pull-up and may be controlled with an open-collector (or open-drain) transistor. The input is diode protected
and may be connected to +VI. The open-circuit voltage is 5 V max. If it is left open circuit the converter will operate when input power is applied.
(7) Electrolytic capacitors with very low equivalent series resistance (ESR) may induce instability when used on the output. Consult the factory before using
capacitors with organic, or polymer-aluminum type electrolytes.
SLTS239 JANUARY 2005
PTB48600 —48-V Input