QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1204A
POSITIVE HIGH VOLTAGE IDEAL DIODE-OR
LT
C4358
1
FEATURES
*Operates 9-75V, Up To 5A Load Current per Chan-
nel
*Demo Board Features Two Independent LTC4358
Circuits Sharing a Common Ground
*0.093-inch Turret Holes Accommodate 12 AWG
Wire
APPLICATIONS
*Servers, Routers, Switches, Mass Storage
*Solar Panel Isolation
*Battery Charger Isolation
*Battery Isolation
*Droop Sharing
*N+1 Redundant Supplies
DESCRIPTION
Demonstration Circuit 1204 showcases the
LTC®4358 5A ideal diode. The board includes two
independent LTC4358 ideal diode circuits with a
common ground, operating over a 9-28V range.
L
, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered
trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy
Drive, FilterCAD, Hot Swap, LinearView, µModule, Micropower SwitcherCAD, Multimode
Dimming, No Latency ∆Σ, No Latency Delta-Sigma, No R
SENSE
, Operational Filter, PanelProtect,
PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT,
UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names
may be trademarks of the companies that manufacture the products.
PERFORMANCE SUMMARY
Specifications are at TA = 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Input Operating Range
9 28 V
I
OUT
Maximum Load Current Limited by MOSFET Dissipation
5
A
Board Layout
DC1204A is a 2-layer board. The inputs and outputs
of the two ideal diode circuits are entirely independ-
ent, sharing only a common ground. Banana jacks
are provided for input and output connections; tur-
rets facilitate connection of voltmeters and scope
probes.
Modifying for More Current
You cannot modify DC1204A for higher current lev-
els. If currents greater than 5A are needed, use the
LTC4357 positive high voltage ideal diode controller
featured on DC1203A.
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1204A
POSITIVE HIGH VOLTAGE IDEAL DIODE-OR
LT
C4358
2
Thermals
The LTC4358CDE is designed and tested to handle
up to 5A load current. DC1204A can safely carry 5A
in each channel, simultaneously. Nevertheless, typi-
cal LTC4358s can handle 7A operating at room
temperature with a dissipation of about 1W. Under
these conditions the package temperature rise
measures less than 40 degrees Celsius cooled only
by convection currents, permitting operation of
DC1204A up to about 75 degrees Celsius air ambi-
ent with no air flow. The forward drop at 7A in a 25
degree Celsius air ambient is typically less than
150mV.
Locally Generated Spikes
When bench testing with input short circuits, it is
possible to generate high voltage transients in ex-
cess of the LTC4358's 28V abs/max rating. A 47
microfarad electrolytic capacitor has been included
on the output of each ideal diode to suppress these
spikes.
Pads are included on the bottom of the board for
use of an optional transient voltage suppressor
(TVS or TransZorb) in lieu of a capacitor. The peak
clamping voltage must be less than 28V.
In practical applications the output is most often
bypassed by a large bulk reservoir capacitor. If the
connections to this capacitor are short, no clamp or
other bypassing is necessary to protect against out-
put spikes when the input is short circuited.
Basic Operation
Connect two 9-28V power supplies to the input as
shown in Figure 1, and short VOUT A and VOUT B
together. Connect a load to the combined output. By
adjusting the supplies slightly above and below one
another, the diode behavior is evident from observ-
ing the flow of current in each supply. The higher of
the two supplies will carry the full load current.
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1204A
POSITIVE HIGH VOLTAGE IDEAL DIODE-OR
LT
C4358
3
Figure 1. Proper Measurement Equipment Setup
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1204A
POSITIVE HIGH VOLTAGE IDEAL DIODE-OR
LT
C4358
4
