MAX1574ETB-T Maxim Integrated Products, MAX1574ETB-T Datasheet - Page 7

• Manufacturer Part Number: MAX1574ETB-T
• Description: LED Drivers High Efficiency 180m A, 1x-2x, White LED
• Manufacturer: Maxim Integrated Products

Specifications of MAX1574ETB-T

• Number Of Segments: 3
• Low Level Output Current: 60000 uA (Typ)
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Supply Current: 2 uA (Typ)
• Maximum Power Dissipation: 1454 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TDFN EP
• Minimum Operating Temperature: - 40 C

Table 1. Recommended Components
When driving fewer than three LEDs, connect any unused
LED_ directly to IN (Figure 3). When connected in this
manner, the corresponding LED driver is disabled.
The MAX1574’s 180mA output capability makes it suit-
able for driving white LED camera strobes/flashes. For
example, the typical operating circuit drives a 3-LED
flash module with up to 60mA/LED. To ensure 180mA
total drive capability at low input voltages, increase C1
to 0.47µF.
To drive fewer or more LEDs with regulated total cur-
rent up to 180mA or to reduce the number of connect-
ing wires, short LED1, LED2, and LED3 together. When
connected this way, some LED modules have good
LED-to-LED forward-voltage matching, while others
may require individual ballast resistors. It is a good
idea to keep the ballast resistance as low as practical
for reasonable matching because high-ballast resis-
tance reduces the output drive capability due to the
higher V
DESIGNATION
COMPONENT
D1, D2, D3
C
IN
R
, C
C1
SET
OUT
OUT
requirement.
Driving Camera Strobes/Flashes
Driving Fewer than Three LEDs
Applications Information
As Required
_______________________________________________________________________________________
VALUE
0.22µF
0.47µF
180mA, 1x/2x, White LED Charge Pump
1µF
—
MANUFACTURER
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
Panasonic
Kamaya
Citizen
Nichia
TDK
TDK
TDK
C1005X5R0J105M 1µF ±20%, 6.3V X5R ceramic capacitors (0402)
C1005X5R0J224K
C1005X5R0J474K
JMK107BJ105KA
JMK105BJ224KV
JMK105BJ474KV
PART NUMBER
NSCW215T
CL-470S
—
For LED drivers, input ripple is more important than out-
put ripple. Input ripple depends on the source supply’s
impedance. Adding a lowpass filter to the input further
reduces input ripple. Alternatively, increasing C
2.2µF cuts input ripple in half with only a small increase in
footprint. The 1x mode always has very low input ripple.
Use only ceramic capacitors with an X5R, X7R, or better
dielectric. See Table 1 for a list of recommended parts.
The MAX1574 is a high-frequency switched-capacitor
voltage regulator. For best circuit performance, use a
solid ground plane and place C
close to the MAX1574 as possible. Refer to the
MAX1574 evaluation kit for an example.
in 3mm x 3mm TDFN
White LED flash module
1% resistor
1µF ±10%, 6.3V X5R ceramic capacitors (0603)
0.22µF ±10%, 6.3V X5R ceramic capacitor (0402)
0.22µF ±10%, 6.3V X5R ceramic capacitor (0402)
0.47µF ±10%, 6.3V X5R ceramic capacitor (0402)
0.47µF ±10%, 6.3V X5R ceramic capacitor (0402)
White LEDs
PC Board Layout and Routing
DESCRIPTION
Component Selection
IN
, C
OUT
Input Ripple
, and C1 as
IN
to
7