SC644 SEMTECH [Semtech Corporation], SC644 Datasheet - Page 10

• Manufacturer Part Number: SC644
• Manufacturer: SEMTECH [Semtech Corporation]

Pin Descriptions
Pin #
0

2
3
4
5
6
7
8
9
20

2
3
4
5
6
7
8
9
T
THERMAL PAD
Pin Name
PGND
AGND
LDO4
LDO3
LDO2
LDO
OUT
SPIF
C2+
C+
BL3
BL2
BL
BL4
BL5
BL6
BYP
C-
C2-
IN
Pin Function
Battery voltage input
Ground pin for high current charge pump
Current sink output for backlight LED 3 — leave this pin open if unused
Current sink output for backlight LED 2 — leave this pin open if unused
Current sink output for backlight LED  — leave this pin open if unused
Current sink output for backlight LED 4 — leave this pin open if unused
Current sink output for backlight LED 5 — leave this pin open if unused
Current sink output for backlight LED 6 — leave this pin open if unused
Analog ground pin — connect to ground and separate from PGND current
Output of LDO4
Output of LDO3
SemPulse single wire interface pin — used to enable/disable the device and to configure all regis-
ters (refer to Register Map and SemPulse Interface sections)
Bypass pin for LDO reference — connect a 22nF ceramic capacitor to AGND
Output of LDO2
Output of LDO
Charge pump output — all LED anode pins should be connected to this pin
Positive connection to bucket capacitor 2
Positive connection to bucket capacitor 
Negative connection to bucket capacitor 
Negative connection to bucket capacitor 2
Thermal pad for heatsinking purposes — connect to ground plane using multiple vias — not con-
nected internally
SC644
0