LT3495, LT3495B, LT3
495
-
1, AND LT3495B
-
1
1
DESCRIPTION
Dem onstration circuits 1219A-A, -B, -C and -D are
M icropow er Low Noise Boost Converters W ith Output
Disconnect featuring the four different Lt3495 versions:
LT3495, LT3495B, LT3495-1, and LT3495B-1.
All ver-
sions
convert a 3V-6V source to 15V. The –A and -B ver-
sions supply 75m A at 3Vin w hile the -C and -D supply
36m A. The –A and –C versions feature the LT3495EDDB
and the LT3495EDDB-1 respectively, w hich have non-
audible sw itching frequency over the entire load range.
All LT3495 versions feature a low noise control schem e,
integrated output disconnect function, dim m ing control,
and single output sense resistor. These circuits are in-
tended for space-conscious applications such as OLED
pow er, M P3 Players, and Low Noise Bias Supplies.
The LT3495 datasheet gives a com plete description of
the parts, operation and application inform ation. The
datasheet m ust be read in conjunction w ith this quick
start guide for w orking on or m odifying the dem o circuit
1219.
Design files for this circuit board are available. Call
the LTC factory.
L
, LTC, LTM , LT are registered tradem arks of Linear Technology Corporation.
PERF ORM A NCE SU M M A RY F OR DC1 2 1 9 A -A /L T3 4 9 5 A ND
DC1 2 1 9 A -B /L T3 4 9 5 B
Specifications are at TA = 25°C
SYM BOL PARAM ETER CONDITIONS M IN TYP M AX UNITS
V
IN
Input Supply Range
3 6
V
V
OUT
Output Voltage Range V
IN
= 3.6V, I
LOAD
= 75m A
14.6 15 15.4
V
V
OUT
Output Voltage Range V
IN
= 6V, I
LOAD
= 75m A
14.6 15 15.4
V
RIPPLE
V
IN
= 3.6V, I
LOAD
= 75m A 10
EFFICIENCY
Load at Vout V
IN
= 3.6V, I
LOAD
= 75m A
80.5 %
EFFICIENCY
Load at Vout V
IN
= 6V, I
LOAD
= 75m A
83.5 %
PERF ORM A NCE SU M M A RY F OR DC1 2 1 9 A -C/L T3 4 9 5 -1 A ND
DC1 2 1 9 A -D/L T3 4 9 5 B -1
Specifications are at TA = 25°C
SYM BOL PARAM ETER CONDITIONS M IN TYP M AX UNITS
V
IN
Input Supply Range
3 6
V
V
OUT
Output Voltage Range V
IN
= 3.6V, I
LOAD
= 36m A
14.6 15 15.4
V
V
OUT
Output Voltage Range V
IN
= 6V, I
LOAD
= 36m A
14.6 15 15.4
V
RIPPLE
V
IN
= 3.6V, I
LOAD
= 36m A 10
EFFICIENCY
Load at Vout V
IN
= 3.6V, I
LOAD
= 36m A
82.5 %
EFFICIENCY
Load at Vout V
IN
= 6V, I
LOAD
= 36m A
84.5 %
DEMO
C IR C U IT
12 19
Q U IC K S TA R T G U IDE
L T 3 4 9 5 , L T 3 4 9 5 B , L T 3 4 9 5 -
1, a n d
L T 3 4 9 5 B -
1
Mic ro p o w e r L o w N o ise B o o st C o n v e rte rs W ith Ou tp u t
Disc o n n e c t
LT3495, LT3495B, LT3
495
-
1, AND LT3495B
-
1
2
Q U ICK STA RT PROCEDU RE
Dem onstration circuit 1219 is easy to set up to evaluate
the perform ance of the LT3495, LT3495B, LT3495-1, and
LT3495B-1. Refer to Figure 1 for proper m easurem ent
equipm ent setup and follow the procedure below :
NOTE.
W hen m easuring the input or output voltage ripple, care m ust be
taken to avoid a long ground lead on the oscilloscope probe. M easure the
input or output voltage ripple by touching the probe tip directly across the
Vin or Vout and GN D term inals. See
Error! Reference source not found.
for
proper scope probe technique.
1.
Place jum pers in the follow ing positions:
JP1 - Run
2.
W ith pow er off, connect the input pow er supply to
Vin and GND.
3.
Turn on the pow er at the input.
Check for the proper output voltages. Vout = 14.6V to 15.4V.
NOTE.
If there is no output, tem porarily disconnect the load to m ake sure
that the load is not set too high.
4.
Once the proper output voltage is established, ad-
just the load w ithin the operating range and ob-
serve the output voltage regulation, ripple voltage,
efficiency and other param eters.
Figure 1.
Proper M easurem ent Equipm ent Setup
VIN
GND
Figure 2.
M easuring Input or output Ripple
LT3495, LT3495B, LT3
495
-
1, AND LT3495B
-
1
3