Quick Start Procedure - Analog Devices Linear ADI Power LTC3310-1 Manual

QUICK START PROCEDURE

Demonstration circuit 3043A is easy to set up and evaluate
the performance of the LTC3310-1. Refer to Figure 1 for
proper measurement equipment setup and follow the pro-
cedure below:
NOTE: For accurate V , V
IN
ments, measure V at the VIN SNSE and GND SNSE tur-
IN
rets and V at the VOUT SNSE and GND SNSE turrets as
OUT
illustrated as VM1 and VM2 in Figure 1. When measuring
the input or output voltage ripple, care must be taken
to avoid a long ground lead on the oscilloscope probe.
Measure the output voltage ripple by touching the probe
tip directly across the output turrets or to TP1 as shown
in Figure 2.
1. Set the JP1 Jumper to the HI position.
2. With power off, connect the input power supply to VIN
and GND. If the input EMI filter is desired, connect the
input power supply to VIN EMI and GND. Connect LD1
with the load set to 0A.
3. Slowly increase PS1 to 1V. If AM1 reads less than
20mA, increase PS1 to 3.3V. Verify that VM1 reads
3.3V and VM2 reads 1.2V. Record VM1, VM2, VM3
AM1 and AM2. Connect an oscilloscope voltage probe
as shown in Figure 2. Set Channel to AC-coupled, volt-
age scale to 20mV and time base to 10µs. Record V
ripple voltage. Verify that PGOOD voltage is above 3V.
Calculate Die temperature using formula below:
V
SSTT
T (°C) = – 273
J
4mV
4. Increase the load by 1A intervals up to 10A and observe
the voltage output regulation, ripple voltage, and the
voltage on the SSTT turret.
5. If Pulse Skip Mode is desired, set PS1 to 0V. Install a
0Ω in the R5 location or short the MODE/SYNC turret
to VIN. Repeat steps 1 through 4. In step 4 observe
that the switching waveform is now operating in Pulse
Skip Mode at low currents.
and efficiency measure-
OUT
DEMO MANUAL DC3043A
6. To change the frequency, remove R4 and install the
desired RT resistor in the R6 location. Note, the MODE/
SYNC pin is an output when R6 is installed and the
MODE/SYNC pin should have high impedance to GND
and VIN. Size the inductor, output capacitors and com-
pensation components to provide the desired inductor
ripple and a stable output.
7. To test the transient response with a base load, add the
desired resistor to produce a minimum load between
VOUT and I_STEP turrets (RL shown on Figure 1).
Note that the total load resistance will be RL plus R10
(50mΩ). Adjust a signal generator with a 10ms period,
10% duty cycle and an amplitude from 1V to 2V to start.
8. Measure the I_STEP voltage to observe the current,
V /50mΩ. Adjust the amplitude of the pulse to
I_STEP
provide the desired transient. Adjust the rising and
falling edge of the pulse to provide the desired ramp
rate. The Load Transient Response Measurement plot
shows a load step from 1.5A (RL = 0.62Ω) to 7.5A.
V
I_STEP
I =
OUT
50mΩ
V = V
GS SG_INPUT
9. When done, turn off SG1, PS1 and Load. Remove all
OUT
connections to demo board.
Load Transient Response Measurement
V
SG_INPUT
2V/DIV
V
I_STEP
100mV/DIV
V
OUT
20mV/DIV
LTC3310-1
3.3V
IN
LOADSTEP 1.5A TO 7.5A 6A/µs
– V
I_STEP
dc3043a QSP01
10µs/DIV
TO 1V
OUT
Rev. 0
3