Linear Technology DC875 Quick Start Manual page 2

Table 1. Performance Summary (T
PARAMETER
Minimum Input Voltage
Maximum Input Voltage
Maximum (Guaranteed) Output Voltage
Output Current I – small footprint solution
OUT
Output Current I – high current solution
OUT
Maximum Output Voltage
Typical Output Ripple V
Typical Output Regulation
Nominal Switching Frequency
Efficiency
QUICK START PROCEDURE
Demonstration circuit 875 is easy to set up to evaluate
the performance of the LTC3454EDD. Refer to Figure 1
for proper measurement equipment setup and follow
the procedure below:
Preset a DC source capable of 5.5V at 2.5A to 4V.
1.
With power off, connect the input power supply to
2.
'VIN' and 'GND' of the circuit solution of interest.
Turn on the power at the input. The input voltage
3.
may be varied between 2.7V and 5.5VDC.
Make sure that the input voltage does not ex-
NOTE:
ceed 5.5V.
SMALL FOOTPRINT SOLUTION:
If the state-indicator LED is not blipping green,
4.
press the 'ON/OFF' button to turn on the circuit.
Press 'FLASH' to observe a 300ms, 350mA camera
5.
flash.
Press 'TORCH' to observe a constant 150mA LED
6.
light for recording video.
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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 875
= 25°C)
A
CONDITION
I
L
V
IN
V
IN
V
OUT IN
Line
V
IN
V
IN
HIGH EFFICIENCY BUCK-BOOST FLASH LED DRIVER
= 1A
= 2.7V to 5.5V
= 2.7V to 5.5V
= 4.2V, I = 1.0A (20MHz BW)
OUT
= 4.2V, I = 150mA
OUT
= 4.2V, I = 1000mA
OUT
Press 'TORCH' to turn off the 150mA video mode.
7.
Press 'ON/OFF' to turn off the circuit or let the cir-
8.
cuit turn off by not pressing any buttons for ap-
proximately 10 seconds.
Alternatively, the torch and flash modes can be
9.
enabled by connecting 'EN1' (torch), or 'EN1' and
'EN2' (flash) to 'VIN', as indicated in the table.
WARNING- The small footprint solution LED can be
permanently damaged if the flash mode is engaged
for more than a few seconds.
HIGH CURRENT SOLUTION:
Press 'EN1' to observe a 400mA LED illumination.
10.
Press 'EN2' to observe a 600mA LED illumination.
11.
Press 'EN1' and 'EN2' to observe a 1000mA LED
12.
illumination.
As an alternative to pressing 'EN1' and/or 'EN2', the
13.
corresponding terminals may be connected to 'VIN'.
VALUE
2.7V
5.5V
4.95V
150 / 200 / 350mA
400 / 600 / 1000mA
4.9V
10mV
P–P
±0.5%
1.0MHz
92% Typical
86% Typical
2