ADP1650 Analog Devices, ADP1650 Datasheet - Page 26

• Manufacturer Part Number: ADP1650
• Description: 1.5 A LED Flash Driver with I2C-Compatible Interface
• Manufacturer: Analog Devices

Specifications of ADP1650

• Product Description: 1.5 A LED Flash Driver with I2C-Compatible Interface
• Led #: 1
• Led Configuration: Serial
• Topology: Inductive
• Application: Flash
• I2c Support: Yes
• Max Iout (ma): 1500mA
• Brightness Control: I2C
• Peak Efficiency (%): 90%
• Switching Frequency: 3MHz
• Over Volt Protection (v): 5.5V
• Vin Min (v): 2.7V
• Vout (v): 4.575 to 5.425
• Synchronous: Yes
• Package: 12-Bump WLCSP

ADP1650
APPLICATIONS INFORMATION
EXTERNAL COMPONENT SELECTION
Selecting the Inductor
The ADP1650 boost converter increases the battery voltage
to allow driving of one LED, whose voltage drop is higher than
the battery voltage plus the current source headroom voltage.
This allows the converter to regulate the LED current over the
entire battery voltage range and with a wide variation of LED
forward voltage.
The inductor saturation current should be greater than the sum
of the dc input current and half the inductor ripple current. A
reduction in the effective inductance due to saturation increases
the inductor current ripple. Table 18 provides a list of recom-
mended inductors.
Selecting the Input Capacitor
The ADP1650 requires an input bypass capacitor to supply
transient currents while maintaining constant input and output
voltages. The input capacitor carries the input ripple current,
allowing the input power source to supply only the dc current.
Increased input capacitance reduces the amplitude of the
switching frequency ripple on the battery. Due to the dc bias
characteristics of ceramic capacitors, a 0603, 6.3 V, X5R/X7R,
10 μF ceramic capacitor is preferable.
Higher value input capacitors help to reduce the input voltage
ripple and improve transient response.
To minimize supply noise, place the input capacitor as close to
the VIN pin of the ADP1650 as possible. As with the output
Table 18. Suggested Inductors
Vendor
Toko
Toko
Coilcraft
Murata
FDK
Table 19. Suggested Input Capacitors
Vendor
Murata
TDK
Taiyo Yuden
Table 20. Suggested Output Capacitors
Vendor
Murata
TDK
Taiyo Yuden
Value
10 μF, 6.3 V
10 μF, 6.3 V
10 μF, 6.3 V
Value
10 μF, 6.3 V
10 μF, 6.3 V
10 μF, 6.3 V
Value (μH)
1.0
1.0
1.0
1.0
1.0
Part No.
FDSD0312
DFE2520
XFL3010
LQM32P_G0
MIPS3226D
Part No.
GRM188R60J106ME47
C1608JB0J106K
JMK107BJ106MA
Part No.
GRM188R60J106ME47
C1608JB0J106K
JMK107BJ106MA
Rev. C | Page 26 of 32
DCR (mΩ)
41.5
50
43
60
40
capacitor, a low ESR capacitor is required. Table 19 provides a
list of suggested input capacitors.
Selecting the Output Capacitor
The output capacitor maintains the output voltage and supplies
the LED current during the NFET power switch on period. It also
stabilizes the loop. The recommended capacitor is a 10 μF, 6.3 V,
X5R/X7R ceramic capacitor.
Note that dc bias characterization data is available from capa-
citor manufacturers and should be taken into account when
selecting input and output capacitors. The 6.3 V capacitors are
best for most designs. Table 20 provides a list of recommended
output capacitors.
Higher output capacitor values reduce the output voltage ripple
and improve load transient response. When choosing this value,
it is also important to account for the loss of capacitance due to
output voltage dc bias.
Ceramic capacitors have a variety of dielectrics, each with different
behavior over temperature and applied voltage. Capacitors must
have a dielectric that ensures the minimum capacitance over the
necessary temperature range and dc bias conditions. X5R or X7R
dielectrics with a voltage rating of 6.3 V or 10 V are recommended
for best performance. Y5V and Z5U dielectrics are not recom-
mended for use with any dc-to-dc converter because of their
poor temperature and dc bias characteristics.
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
Dimensions L × W × H (mm)
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
Dimensions L × W × H (mm)
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
ISAT (A)
4.5
3.4
2.4
3
3
Dimensions L × W × H (mm)
3.0 × 3.0 × 1.2
2.5 × 2.0 × 1.2
3.0 × 3.0 × 1.0
3.2 × 2.5 × 1.0
2.5 × 2.0 × 1.2