XRP6840 Datasheet, PDF (6/17 Pages) Exar Corporation – 4.3A Supercapacitor Flash LED Driver with I2C

XRP6840
4.3A Supercapacitor Flash LED Driver with I²C
PIN DESCRIPTION
Name
C_GND
RDY
SCL, SDA
P_GND
RESET_N
LED₁, LED₂, LED₃
(XRP6840A)
LED₁, NC, LED₂
(XRP6840B)
FLASH
NC
GND
CAP
V_OUT
C_2P, C_2N
C_1P, C_2P
V_IN
Thermal Pad
Pin Number
1
2
3, 4
5, 11
6
7, 8, 9
7, 8, 9
10
12
13
14
15
16, 17
18, 19
20
-
Description
Charge pump ground pin.
Active high push-pull output. RDY is high when V_OUT reached to 100mV below its
V_{OUT_LIMIT} voltage. The V_{OUT_LIMIT} for Flash mode is determined by STATUS2 register [B7
B6 B5]. The V_{OUT_LIMIT} for Torch mode is 4.50V.
The SDA and SCL pins connect to the I²C bus. Multiple functions can be programmed
through his interface. They can also be used for read-back.
Power ground pin. The Source of internal NMOS is connected to this pin.
Active Low input pin.
If RESET_N = 0, then XRP6840 is in Shut-down mode
If RESET_N = 0 and STATUS1 register [B5] = 0, then reset all registers to logic low.
If RESET_N = 0 and STATUS1 register [B5] = 1, then all bits of all registers will be
saved.
LED₁, LED₂, LED₃ connect to the drain of the internal NMOS which are current sources
for LED current. These current sources are controlled by LEDFLASH or LEDTORCH
registers which is programmed through I²C to provide the Torch and Flash current for
the LEDs. LED₁, LED₂, LED₃ pins can be connected together to provide higher LED
current. If a pin is not used connect it to V_OUT. The XRP6840 incorporates a short LED
protection circuit which shut-down LED current if LED voltage approaches to V_{OUT_LIMIT}.
Digital Input pin. Active high. If STATUS1 register [B7 B6] = 11 and FLASH = 1 then
LEDs are ON for one Flash timeout duration. Flash Timeout duration is controlled by
STATUS1 register [B1 B0].
No connection. This pin can be connected to P_GND pin for heat sink.
Ground pin. This ground pin doesn’t carry high internal current.
This pin is the output of an internal Op-Amp. This internal Op-Amp is powered by V_OUT.
The output voltage is half of V_OUT, and output resistance is 470Ω. The sink and source
current is limited by 470Ω output resistance. This provides active balancing between
two internal sections of the super capacitor.
Output voltage. Connect positive terminal of SuperCap here. Connect the LEDs
between this pin and the corresponding internal current source. Decouple with 10µF
ceramic capacitor close to the pins of the IC.
Connect C₂ external flying capacitor between these pins.
Connect C₁ external flying capacitor between these pins.
Power supply input. Decouple with 10µF ceramic capacitor close to the pins of the IC.
Connect thermal pad to P_GND pins.
ORDERING INFORMATION
Part Number
Junction
Temperature
Range
Marking Package
XRP6840AILB-F
-40°C≤T_A≤+125°C
6840AI
YYWWX
20-pin TQFN
XRP6840AILBTR-F -40°C≤T_A≤+125°C
6840AI
YYWWX
20-pin TQFN
XRP6840BILB-F
-40°C≤T_A≤+125°C
6840BI
YYWWX
20-pin TQFN
XRP6840BILBTR-F -40°C≤T_A≤+125°C
6840BI
YYWWX
20-pin TQFN
XRP6840EVB
XRP6840 Evaluation Board – XRP6840A based.
Packing
Quantity
Bulk
3K/Tape & Reel
Bulk
3K/Tape & Reel
Note 1
RoHS Compliant/
Halogen Free
RoHS Compliant/
Halogen Free
RoHS Compliant/
Halogen Free
RoHS Compliant/
Halogen Free
“YY” = Year – “WW” = Work Week – “X” = Lot Number
Note 2
3 Channels
3 Channels
2 Channels
2 Channels
© 2009 Exar Corporation
6/17
Rev. 1.0.0