ISL78171 Datasheet, PDF (4/29 Pages) Intersil Corporation – 6-Channel, 50mA Automotive LED Driver with Ultra-high Dimming Ratio and Phase Shift Control

Pin Configuration
ISL78171
ISL78171
(20 LD QFN)
TOP VIEW
FAULT 1
VIN 2
EN 3
VDC 4
PWM 5
SMBDAT/SDA 6
20 19 ₁₈ 17
EPAD
7 8 9 10
16 OVP
15 CH5
14 ^CH4
13 CH3
12 CH2
11 ^CH1
Pin Descriptions (I = Input, O = Output, S = Supply, X = Don’t Care)
PIN NAME
FAULT
VIN
EN
VDC
PWM
SMBDAT/SDA
SMBCLK/SCL
FPWM
AGND
CH0, CH1
CH2, CH3
CH4, CH5
OVP
RSET
COMP
PGND
LX
EPAD
PIN # TYPE
DESCRIPTION
1
O This signal is the Fault disconnect switch gate control.
2
S This is the input voltage for the device and LED power.
3
I This is the Enable input. The device needs 4ms for initial power-up enable. It will be disabled if it is not biased for
longer than 30.5ms.
4
S This is the internal LDO output for the purpose of filtering. Connect a 1uF X7R decoupling capacitor to ground.
5
I This is the PWM brightness control pin or DPST control input. The pin has an internal pull down of 2M so can be
left floating when not used.
6
I/O This is the SMBus/I²C serial data input and output. When pins 6 and 7 are grounded or in logic 0’s for longer than
60ms, the drivers will be controlled by external PWM signal.
7
I This is the SMBus/I²C serial clock input. When pins 6 and 7 are grounded or in logic 0’s for longer than 60ms, the
drivers will be controlled by external PWM signal.
8
I This pin sets the PWM dimming frequency, by connecting a resistor between this pin and ground. When FPWM is
tied to VDC and SMBCLK/SMBDAT is tied to ground, the device will be in Direct PWM Dimming where the output
follows the input frequency and duty cycle without any digitization.
9
S This pin is the Analog Ground for precision circuits.
10, 11,
12, 13,
14, 15
I These pins are the constant current sink and channel monitoring input for the LED string channels 0 through 5.
16
I This is the Over voltage protection input.
17
I A resistor connected between this pin and GND sets the max usable LED current, (see Equation 1 for calculating
the I_LED(peak)). The value in the DC register 0x07 should be set to FF while setting the max LED current.
18
O This is the Boost converter feedback compensation pin.
19
S This pin is the Power ground pin.
20
O This pin is the Boost converter switch node.
This pad is not an electrical connection but should be used to connect PGND and AGND. For example use top plane
as PGND and bottom plane as AGND with vias on EPAD to allow heat dissipation and minimum noise coupling from
PGND to AGND operation.
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FN8602.0
June 15, 2015