LM3552SDEV National Semiconductor, LM3552SDEV Datasheet - Page 14

• Manufacturer Part Number: LM3552SDEV
• Description: BOARD EVALUATION LM3552SD
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3552SDEV

• Current - Output / Channel: 700mA
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 4 V
• Features: Flash Timeout Protection
• Voltage - Input: 2.7 ~ 5.5V
• Utilized Ic / Part: LM3552
• Core Chip: LM3552
• Topology: Boost
• No. Of Outputs: 1
• Output Current: 1A
• Input Voltage: 2.7V To 5.5V
• Development Tool Type: Hardware - Eval/Demo Board
• Mcu Supported Families: LM3552
• Lead Free Status / RoHS Status: Not applicable / Not applicable

www.national.com
DUAL-MODE CONFIGURATION
Using the Dual-Mode configuration with either the LM3551/2,
a 5V, high current rail (approx. 700mA total) can be created
while still allowing for a high flash with a true load disconnect.
R1 and R2 setup the +5V following the equation:V
× (1 + R1/R2) . When the LM3551/2 is on, and the T/F pin is
low (logic '0'), the part will provide a regulated output voltage
that can be used to provide a voltage rail within a system. By
setting the T/F pin high, the LM3551/2 will allow the current
R
OUT
1
= 29.5kΩ,R
= 1.265
I
FLASH
2
= 500mA
14
= 10kΩ R
to flow through the flash LED while still maintaining the fixed
output voltage rail. The flash current is set by R
equation R
exceed 500mA. The total usable output current is dependent
upon the output voltage selected. If the dual-mode configu-
ration is used, the FTO pin should be grounded to prevent the
voltage rail from being shutdown at an unwanted time.
F
= 3Ω
F
= [(V
OUT
- V
LED
) / I
LED
20151209
] - 0.36Ω , and should not
F
using the