PIN CONNECTIONS
STATIC AND DYNAMIC ELECTRICAL CHARACTERISTICS
PIN CONNECTIONS
VOUT
VDC2
VDC1
20
GND
TRANSPARENT
TOP VIEW
VIN
PGNDB
SWB
SWA
PGNDA
EN
1
2
3
24
23
22
21
19
18 WAKE
17 COMP
16 PWM
EP GND
4
5
6
7
CH1
8
CH2
9
CH3
10
CH4
11
CH5
12
CH6
15 ISET
14 FAIL
13 GND
Figure 3. 34845 Pin Connections
Table 4. 34845 Pin Definitions
Pin Number
1
2
3
4
5
6
7 - 12
13, 19, 21
14
Pin Name
VIN
PGNDB
SWB
SWA
PGNDA
EN
CH1 - CH6
GND
FAIL
Definition
Main voltage supply Input. IC Power input supply voltage, is used internally to produce internal voltage regulation
for logic functioning, and also as an input voltage for the boost regulator.
Power ground. This is the ground terminal for the internal Boost FET.
Boost switch node connection B. Switching node of boost converter.
Boost switch node connection A. Switching node of boost converter.
Power ground. This is the ground terminal for the internal Boost FET.
Enable pin (active high, internal pull-down).
LED string connections 1 to 6. LED current drivers. Each line has the capability of driving up to 30 mA.
Ground Reference for all internal circuits other than the Boost FET. The Exposed Pad (EP) should be used for
thermal heat dissipation.
Fault detected pin (open drain):
No Failure = Low-impedance pull-down
Failure = High-impedance
When a fault situation is detected, this pin goes into high impedance.
15
16
17
18
20
22
ISET
PWM
COMP
WAKE
VDC1
OVP
LED current setting. The maximum current is set using a resistor from this pin to GND.
External PWM control signal.
Boost compensation component connection. This passive terminal is used to compensate the boost converter.
Add a capacitor and a resistor in series to GND to stabilize the system as well as a shunt capacitor.
Low power consumption mode for single wire control. This is achieved by connecting the WAKE and PWM pins
together and grounding the ENABLE (EN) pin.
2.5 V internal voltage decoupling. This pin is for internal use only, and not to be used for other purposes. A
capacitor of 2.2
μF
should be connected between this pin and ground.
External boost over-voltage setting. Requires a resistor divider from VOUT to GND. If no external OVP setting
is desired, this pin should be grounded.
34845
GND
OVP
8
Analog Integrated Circuit Device Data
Freescale Semiconductor
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
