LTC3207/LTC3207-1
PIN FUNCTIONS
CAMHL (Pin 8):
Selects CAM high register when asserted
high and CAM low register when low. The high to low
transition automatically resets the charge pump mode to
1x. The logic level for CAMHL is referenced to DV
CC
. If
unused, the pin should be connected to ground.
DV
CC
(Pin 9):
Supply Voltage for All Digital I/O Lines. This
pin sets the logic reference level of the device. DV
CC
will
reset the data registers when set below the undervoltage
lockout threshold which is the recommended method for
resetting the part after power up. A 0.1µF X5R or X7R
ceramic capacitor should be connected to ground.
SCL (Pin 10):
I
2
C Clock Input. The logic-level for SCL is
referenced to DV
CC
.
SDA (Pin 11):
Input Data for the Serial Port. Serial data
is shifted in one bit per clock to control the device. The
logic-level is referenced to DV
CC
.
C1P C2P C1M, C2M (Pin 24, 23, 20, 19):
Charge Pump
,
,
Flying Capacitor Pins. A 2.2µF X7R or X5R ceramic ca-
pacitor should be connected from C1P to C1M and C2P
to C2M.
V
BAT
(Pin 21):
Supply Voltage for the Entire Device. This
pin must be bypassed with a single 2.2µF low ESR ceramic
capacitor.
ENU (Pin 22):
Input. Used to enable or disable the prese-
lected ULED outputs. When the pin is toggled from low
(disable) to high (enable), the device illuminates the prese-
lected LEDs. When ENU is controlling selected outputs and
other outputs have been enabled the charge pump mode
will be reset to 1x on the falling edge of ENU. When ENU
is controlling selected outputs and no other outputs are
active the part will go from enabled to shutdown. The ENU
logic-level is referenced to DV
CC
. This pin is connected to
ground if unused.
Exposed Pad (Pin 25):
Ground. The Exposed Pad must
be soldered to PCB ground.
BLOCK DIAGRAM
19
C2M
850kHz
OSCILLATOR
21
V
BAT
20
C1M
23
C2P
24
C1P
GND
CPO
CHARGE PUMP
25
1
9
22
8
DV
CC
ENU
CAMHL
11
10
SDA
SCL
SHIFT REGISTER
2 SECOND
SAFETY TIMER
+
–
–
+
12
12 UNIVERSAL
CURRENT SOURCES
AND DACS
1.22V
CONTROL
LOGIC
MASTER/SLAVE
REG
CAM CURRENT
SOURCE
CAM
7
ULED12
18
ULED11
17
ULED10
16
ULED9
15
ULED1
ULED2
ULED3
ULED4
ULED5
ULED6
ULED7
ULED8
2
3
4
5
6
12
13
14
3207 BD
3207fc
7
LINER [ LINEAR TECHNOLOGY ]
