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dc1029bf
DEMO MANUAL DC1029B
QUICK START PROCEDURE
For fast evaluationof LTC2928performance,theboard con-
tains four low drop out regulators (LDO): LT1761ES-2.5,
LT1761ES-1.5,LT1761ES-1.8, LT1761ES-3.3, and a push
button with control circuitry for ON control signal genera-
tion. LDO outputs are +2.5V, +1.5V, 1.8V, and +3.3V. Each
LDO has an enable input, and works as a power supply.
Demonstration circuit 1029B is easy to set up to evaluate
the performance of the LTC2928 with the on-board sup-
plies. Refer to Figure 1 for the proper circuit connection.
For the load resistors R1, R2, R3, and R4 use 51Ω 1W
resistors. Connect four scope probes to the load resistors
R1, R2, R3, and R4.
Place jumpers in the following positions:
JP1 (OPERATION) LAST
JP2 (ON) INT_ON
JP3 (V1) INT
JP4 (V3) INT
JP5 (V2) INT
JP6 (V4) INT
JP7 (SQT1) GND
JP8 (VSEL) ALL POSITIVE
JP9 (RT1 Control) TIME POSITION
JP10 (SQT2) GND
JP11 (V1 POLARITY) V1_POS
JP12 (MS1) GND
JP13 (RT2 Control) TIME POSITION
JP14 (OVA CONFIG) 32%
JP15 (MS2) GND
JP16 (RT3 Control) TIME POSITION
JP17 (VCC Select) LOW VCC
JP18 (RDIS) OPEN
JP19 (RT4 Control) TIME POSITION
1. With the +5V power supply off, connect the supply to
the 5V_AUX and GND turrets.
2. Turn the +5V supply on and after that switch the ONcon-
trol signal from low to high by pressing the buttonS1.
3. The power-up output voltages should correlate with the
transient shown in Figure 3 (power-up phase). Accept-
able tolerance in the sequence timing is ±20%.
4. Press the button PB (S1) to change the ON signal
from high to low and observe the output voltages. The
power-down output voltages should correlate with the
transient shown in Figure 3. (power-down phase). Ac-
ceptable tolerance in the sequence timing is ±20%.
5. Turn the +5V power supply off and connect four ex-
ternal power supply terminals with DC1029 as shown
in Figure 2. Use external power supplies with output
voltages +2.5V, +1.5V, +1.8V, and +3.3V. Leave output
loads as in previous experiments or replace them with
3W resistors 2.5Ω, 1.5Ω, 2Ω, and 3Ω accordingly to
have current in each rail around 1A.
6. Change jumpers V1 (JP1), V2 (JP2), V3 (JP3), and V4
(JP4) positions from INT to EXT.
7. Turn-on all five power supplies. Pushing the button
PB (S1) changes the ON signal from low to high and
after the power-up transient completes, press PB (S1)
a second time to initiate the power-down. The output
voltage sequence timing should be similar to the timing
with the internal power supplies.
8. The DC1029B could be used for the original customer
design. Based on the sequence timing and threshold
parameters define all the optional components’values,
replace them on the board and verify design perfor-
mance. Contact LTC Field Applications Engineers to
get help in the designing or verifying your circuit with
a special tool.
