Linear Technology DC1596A, LTC3607EUD Demo Manual
DESCRIPTION
DEMO MANUAL DC1596A
LTC3607EUD
Dual 600mA 15V Monolithic
Synchronous Step-Down Regulator
Demonstration circuit DC1596 is a dual output regulator
consisting of two constant-frequency step-down convert-
®
ers, based on the LTC
3607 monolithic dual channel
synchronous buck regulator. The DC1596 has an input
voltage range of 4.5V to 15V, with each regulator capable of
delivering up to 600mA of output current. The DC1596 can
®
operate in either Burst Mode
operation or pulse-skipping
mode. In shutdown, the DC1596 quiescent current is less
than 1µA. The DC1596 is a very efficient circuit attaining
up to 90%. The DC1596 uses the LTC3607’s16-lead QFN
PERFORMANCE SUMMARY
PARAMETER CONDITIONS VALUE
Minimum Input Voltage 4.5V
Maximum Input Voltage 15V
Run RUN Pin = GND
Output V
Typical Output Ripple V
Output Voltage V
Typical Output Ripple V
Mode Setting Mode Pin Floating
Burst Mode Operation Output Current Thresholds
Pulse-Skipping Operation Output Current
Thresholds
Switching Frequency 2.25MHz ±20%
oltage V
Regulation V
OUT1
OUT1
Regulation V
OUT2
OUT2
RUN Pin = V
IN1
V
IN1
IN2
V
IN2
Mode Pin Grounded
Channel 1: PV
Channel 2: PV
Channel 1: PV
Channel 2: PV
Specifications are at TA = 25°C
IN
= 4.5V to 15V, I
= 12V, I
= 4.5V to 15V, I
= 12V, I
= 600mA (20MHz BW) <20mV
OUT1
= 600mA (20MHz BW) <20mV
OUT2
= 12V, V
IN1
= 12V, V
IN2
= 12V, V
IN1
= 12V, V
IN2
package, which has an exposed pad on the bottom side
of the IC for better thermal performance. These features,
plus a set operating frequency range of 2.25MHz, make
the DC1596 demo board an ideal circuit for industrial or
distributed power applications.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
Shutdown
Operating
= 0A to 600mA 1.2V ±4% (1.152V-1.148V)
OUT1
= 0A to 600mA 2.5V ±4% (2.425V-2.6V)
OUT2
= 1.8V
OUT1
= 3.3V
OUT2
= 1.8V
OUT1
= 3.3V
OUT2
1.5V ±4% (1.44V-1.56V)
1.8V ±4% (1.728V-1.872V)
P-P
3.3V ±4% (3.168V-3.432V)
5V ±4% (4.8V-5.2V)
P-P
Burst Mode Operation
Pulse-Skipping
< 480mA
I
OUT1
I
< 360mA
OUT2
< 330mA
I
OUT1
I
< 240mA
OUT2
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DEMO MANUAL DC1596A
QUICK START PROCEDURE
The DC1596 is easy to set up to evaluate the performance
of the LTC3607. For a proper measurement equipment
configuration, set up the circuit according to the diagram
in Figure 1.
Note: When measuring the input or output voltage ripple,
care must be taken to avoid a long ground lead on the
oscilloscope probe. Measure the input or output voltage
ripple by touching the probe tip directly across the V
or V
technique in Figure 2.
Please follow the procedure outlined below for proper
operation.
1. Connect the input power supply to the PVIN1/PVIN2 and
Before proceeding to operation, insert jumper shunts
2.
3. Turn on VOUT1 and VOUT2 by shifting shunts XJP1
and GND terminals. See the proper scope probe
OUT
GND terminals (V
are connected). Connect the loads between the VOUT
and GND terminals. Refer to Figure 1 for the proper
measurement equipment setup.
XJP1 and XJP2 into the OFF positions of headers JP1
and JP2, shunt XJP3 into the pulse-skip position of
MODE header JP3, and shunt XJP4 into the VOUT1
voltage options of choice of header JP4: 1.2V, 1.5V, or
1.8V, and shunt XJP5 into the VOUT2 voltage options
of choice of header JP5: 2.5V, 3.3V
Apply 5.5V at PVINs 1, 2. Measure both VOUTs; they
should read 0V. If desired, one can measure the shut
down supply current at this point. The supply current
will be less than 1µA in shutdown.
and XJP2 from the OFF positions to the ON positions.
Both output voltages should be within a tolerance of
±2%.
IN1
and V
are separate nodes but
IN2
, or 5V.
IN
-
5. Set the load current of both outputs to 600mA and the
input voltages to 12V, and then measure each output
ripple voltage (refer to Figure 2 for proper measure
ment technique);
20mVAC. Also, observe the voltage waveform at either
switch node (Pin 5 for reg.1 and Pin 8 for reg.2) of each
regulator. The switching frequencies should be about
2.25MHz ±20% (T = 555ns and 370ns). Both switch
node waveforms should be rectangular in shape, and
180° out-of-phase with each other.
6. To operate the ckt.s in Burst Mode operation, change
the shunt position of header JP3
7.
Regulators 1 (PVIN1) and 2 (PVIN2) are completely
separated from each other; thus, they can be powered
from different individual input supplies (if R11 is re
moved), as can the signal input supply, SVIN. However,
must powered for either regulator to function
SVIN
(SVIN is connected to PVIN1 through a filter on the
demo board.).
8. When finished, insert shunts XJP1 and XJP2 to the OFF
position(s) and disconnect the power.
Warning: If the power for the demo board is carried in
long leads, the input voltage at the part could “ring”, which
could affect the operation of the circuit or even exceed the
maximum voltage rating of the IC. To eliminate the ring
ing, a small tantalum capacitor (for instance, AV
TPSY226M035R0200) is inserted on the pads between
the input power and return terminals on the bottom of the
demo board. The (greater) ESR of the tantalum capacitor
will dampen the (possible) ringing voltage caused by the
long input leads. On a normal, typical PCB, with short
traces, this capacitor is not needed.
they should each measure less than
to BURST MODE.
-
-
-
X part #
4. Vary the input voltages from 5.8V (the minimum V
dependent on V
0A to 600mA. Both output voltages should be within
±4% tolerance.
) to 15V, and the load currents from
OUT
2
IN
is
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QUICK START PROCEDURE
DEMO MANUAL DC1596A
Figure 1. Proper Measurement Equipment Setup
VIN GND
Figure 2. Measuring Input or Output Ripple
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