PIN CONNECTIONS
PIN CONNECTIONS
COMP
VOUT
VDC2
VDC1
PWM
25
24 CK
23 VDC3
TRANSPARENT
TOP VIEW
QFN - EP
5MM X 5MM
32 LEAD
EP GND
22 SLOPE
21 NIN
20 PIN
19 ISET
18 FAIL
17 I9
9
I1
10
I2
11
I3
12
I4
13
I5
14
I6
15
I7
16
I8
M/~S
SCK
27
SDA
26
32
VIN 1
PGNDB 2
SWB 3
SWA 4
PGNDA 5
A0/SEN 6
EN 7
IO 8
31
30
29
28
EP = Exposed Pad
Figure 3. 34844 Pin Connections
Table 1. 34844 Pin Definitions
A functional description of each pin can be found in the Functional Pin Description section beginning on
Pin Number
1
2
3
4
5
6
7
8 - 17
18
Pin Name
VIN
PGNDB
SWB
SWA
PGNDA
A0/SEN
EN
I0-I9
FAIL
Pin Function
Power
Power
Input
Input
Power
Input
Input
Input
Open Drain
Formal Name
Input voltage
Power Ground
Switch node B
Switch node A
Power Ground
Device Select
Enable
LED Channel
Fault detection
Input supply
Power ground
Boost switch connection B
Boost switch connection A
Power ground
Address select, device select pin or OVP HW control
Enable pin (active high, internal pull-up)
LED string connections
Fault detected pin (open drain):
No Failure = Low impedance
Failure = High Impedance
LED current setting resistor
Positive input analog current control
Definition
19
20
21
22
23
24
25
ISET
PIN
NIN
SLOPE
VDC3
CK
PWM
Passive
Input
Input
Passive
Output
Input/Output
Input
Current set
Positive current scale
Negative current scale Negative input analog current control
Boost Slope
Internal Regulator 3
Clock signal
External PWM
Boost slope compensation Setting resistor
Decoupling capacitor for internal phase locked loop power
Clock synchronization pin (input for M/~S = low - internal pull-up, output
for M/~S = high)
External PWM input (internal pull-down)
34844
Analog Integrated Circuit Device Data
Freescale Semiconductor
3
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
