DATASHEET
ISL6423B
FN6412
Rev 1.00
Apr 10, 2007
Single Output LNB Supply and Control Voltage Regulator with I2C Interface for
Advanced Satellite Set-Top Box Designs
The ISL6423B is a highly integrated voltage regulator and
interface IC, specifically designed for supplying power and
control signals from advanced satellite set-top box (STB)
modules to the low noise blocks (LNBs) of singe antenna
ports. The device consists of a current-mode boost PWM
and a low-noise linear regulator along with the circuitry
required for 22kHz tone generation, modulation and I2C
device interface. The device makes the total LNB supply
design simple, efficient and compact with low external
component count.
Features
The current-mode boost converters provides the linear
regulator with input voltage that is set to the final output
voltages, plus typically 0.8V to insure minimum power
dissipation across each linear regulator. This maintains
constant voltage drop across the linear pass element while
permitting adequate voltage range for tone injection.
• Output Back Bias Capability of 28V
The final regulated output voltage is available at output
terminals to support the operation of an antenna port for
single tuners. The outputs for each PWM can be controlled
in two ways, full control from I2C using the VTOP and VBOT
bits or set the I2C to the lower range i.e., 13V/14V, and
switch to higher range i.e., 18V/19V, with the SELVTOP pin.
All the functions on this IC are controlled via the I2C bus by
writing 8 bits words onto the System Registers (SR). The
same register can be read back, and five I2C bits will report
the diagnostic status. Separate enable command sent on the
I2C bus provides for standby mode control for the PWM and
linear combination, disabling the output and forcing a shutdown
mode. The output channel is capable of providing 750mA of
continuous current. The overcurrent limit can be digitally
programmed to four levels.
The External modulation input EXTM can accept a
modulated Diseqc command and transfer it symmetrically to
the output. Alternatively the EXTM pin can be used to
modulate the continuos internal tone.
The FLT pin serves as an interrupt for the processor when
any condition turns OFF the LNB controller (Over
Temperature, Overcurrent, Disabled). The nature of the
Disable can be read of the I2C registers.
• Single Chip Power solution
- Operation for 1-Tuner/1-Dish Applications
- Integrated DC/DC Converter and I2C Interface
• Switch-Mode Power Converter for Lowest Dissipation
- Boost PWMs with >92% Efficiency
- Selectable 13.3V or 18.3V Outputs
- Digital Cable Length Compensation (1V)
- I2C and Pin Controllable Output
• I2C Compatible Interface for Remote Device Control
• Registered Slave Address 0001 00XX
• 2.5V, 3.3V, 5V Logic Compatible
• External Pin to Toggle Between V and H Polarization
• Built-In Tone Oscillator Factory Trimmed to 22kHz
- Facilitates DiSEqC (EUTELSAT) Encoding
- External Modulation Input
• Internal Over-Temperature Protection and Diagnostics
• Internal OV, UV, Overload and Overtemp Flags
(Visible on I2C)
• FLT signal
• LNB Short-Circuit Protection and Diagnostics
• QFN, EPTSSOP Packages
• Pb-Free Available (RoHS Compliant)
Applications
• LNB Power Supply and Control for Satellite Set-Top Box
Ordering Information
PART
NUMBER*
ISL6423BERZ
(Note)
PART
MARKING
6423BERZ
TEMP.
(°C)
PKG.
DWG. #
PACKAGE
-20 to +85 24 Ld 4x4 QFN
(Pb-free)
L24.4x4D
ISL6423BEVEZ ISL6423BEVEZ -20 to +85 28 Ld EPTSSOP M28.173B
(Pb-free)
(Note)
NOTE: Intersil Pb-free plus anneal products employ special Pb-free
material sets; molding compounds/die attach materials and 100% matte
tin plate termination finish, which are RoHS compliant and compatible
with both SnPb and Pb-free soldering operations. Intersil Pb-free
products are MSL classified at Pb-free peak reflow temperatures that
meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
Add “-T” suffix for tape and reel.
FN6412 Rev 1.00
Apr 10, 2007
Page 1 of 16
ISL6423B
Pinouts
ISL6423B
(28 LD EPTSSOP)
TOP VIEW
28 CPSWIN
VCC 1
27 CPSWOUT
NC 2
FLT 3
26 CPVOUT
SGND 4
25 EXTM
SGND 5
24 SDA
TCAP 6
23 SCL
ADDR0 7
22 TDOUT
ADDR1 8
21 TDIN
BYPASS 9
20 VO
PGND 10
19 NC
GATE 11
18 NC
17 AGND
VSW 12
NC 13
16 SELVTOP
CS 14
15 TXT
FN6412 Rev 1.00
Apr 10, 2007
SGND
FLT
VCC
CPSWIN
CPSWOUT
CPVOUT
ISL6423B
(24 LD QFN)
TOP VIEW
24
23
22
21
20
19
17
SDA
ADDR0
3
16
SCL
ADDR1
4
15
TDOUT
BYPASS
5
14
TDIN
PGND
6
13
VO
7
8
9
10
11
12
AGND
2
SELVTOP
TCAP
TXT
EXTM
CS
18
VSW
1
GATE
SGND
Page 2 of 16
11
17
16
23
4
3
7
Q
OC1
OUVF
ADDR0
ADDR1
SDA SCL
ISELL&H
PGND
ILIM1
CS
AMP
-
+
CS
I2 C
INTERFACE
CLK1
TDOUT
13
12
TTH
TTH
+
BGV
DIV &
WAVE SHAPING
REF
VOLTAGE
ADJ1
VREF1
INT
TONE
TONE
INJ
CKT
VSW
VO
+
-
AGND
OSC.
MSEL1
8
TDIN
TXT
-
TONE
DECODER
14
BAND GAP
REF VOLTAGE
THERMAL
SHUTDOWN
DCL
VTOP VBOT
SLOPE
COMPENSATION
15
OTF
OLF/BCF
EN
ENT
9
FLT
CLK1
S
6
ADDR1
ADDR0
SCL
OUVF
PWM
LOGIC
GATE
SELVTOP
DCL
SDA
OLF/BCF
OVERCURRENT
PROTECTION
LOGIC SCHEME 1
COUNTER
EXT TONE CKT
UVLO
POR
SOFT-START
NOTE:
5
1. Pinouts shown are for the QFN package.
EN1/EN2
10
2
18
20
CPSWIN
INT 5V
SOFT-START
CPSWOUT
ENT1
EXTM
Page 3 of 16
BYPASS
24
SGND
ON CHIP
LINEAR
TCAP
1
SGND
TXT
22
VCC
CHARGE PUMP
CPVOUT
21
19
ISL6423B
FN6412 Rev 1.00
Apr 10, 2007
Block Diagram
VIN
RTN
0
FLT BAR
EXTM
C23
56µF
C26
0
R10
18
0.22µF
1µF
0
SGND
EXTM
TCAP
SDA
ADDR0
U2
SCL
ADDR1 ISL6423ER TDOUT
BYPASS
TDIN
PGND
VO
TPC6002
Q2
100
C28
0.1µF
18
17
16
15
14
13
SDA
SCL
L4 220µH
C15
R7
2
0.22µF
15
VLNB
R23
10k
M6
NDS356AP
D8
1.5KE24
R24
4.7k
R13 4.7k
C16
10n
7
8
9
10
11
12
2
R12
D6
CMS06
1
2
3
0
100
1
GATE
VSW
CS
TXT
SELVTOP
AGND
C27
1
2
3
4
5
6
0
R11
24
23
22
21
20
19
0
C25 47n
SGND
FLT
VCC
CPSWIN
CPSWOUT
CPVOUT
C24
1µF
C29
1n
Q4
2N2222A
RTN
R22
47k
R9
470
L5
15µH
TXT
R8
0.1
6
5
4
1
TDOUT
C21
100pF
SELVTOP
0
D5
0
L6 4.7µH
1
CMS06
D7
Page 4 of 16
C22
56µF
0
C18
10µF
0
CMS06
NOTE : SDA and SCL require pull up to the required logic level.
2
C19
10µF
0
C20
10µF
0
ISL6423B
FN6412 Rev 1.00
Apr 10, 2007
Typical Application Schematic QFN
ISL6423B
Absolute Maximum Ratings
Thermal Information
Supply Voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0V to 18.0V
Logic Input Voltage Range
(SDA, SCL, ENT, DSQIN 1 and 2, SEL18V 1 and 2) . -0.5V to 7V
Thermal Resistance (Typical, Notes 2, 3)
JA (°C/W)
JC (°C/W)
QFN Package (Notes 2, 3) . . . . . . . . . .
38
4.5
EPTSSOP Package (Notes 2, 3) . . . . .
35
2.5
Maximum Junction Temperature (Note 4) . . . . . . . . . . . . . . . +150°C
Maximum Storage Temperature Range . . . . . . . . . . -40°C to +150°C
Operating Temperature Range . . . . . . . . . . . . . . . . . -20°C to +85°C
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTES:
2. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See
Tech Brief TB379.
3. For JC, the "case temp" location is the center of the exposed metal pad on the package underside.
4. +150°C max junction temperature is intended for short periods of time to prevent shortening the lifetime. Operation close to +150°C junction may
trigger the shutdown of the device even before +150°C, since this number is specified as typical.
Electrical Specifications
VCC = 12V, TA = -20°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C. EN = H, VTOP
VBOT = L, ENT = L, DCL = L, IOUT = 12mA, unless otherwise noted. See software description section for I2C
access to the system.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
8
12
14
V
EN = L
-
1.5
3.0
mA
EN = VTOP = VBOT = ENT = H, No Load
-
4.0
8.0
mA
Start Threshold
7.5
-
7.95
V
Stop Threshold
7.0
-
7.55
V
Start to Stop Hysteresis
350
400
500
mV
-
8196
-
Cycles
Operating Supply Voltage Range
Standby Supply Current
Supply Current
IIN
UNDERVOLTAGE LOCKOUT
SOFT-START
COMP Rise Time (Note 5)
Output Voltage (Note 5)
Line Regulation
Load Regulation
Dynamic Output Current Limiting
(Note 5)
VO1
(Refer to Table 1)
13.04
13.3
13.56
V
VO1
(Refer to Table 1)
14.02
14.3
14.58
V
VO1
(Refer to Table 1)
17.94
18.3
18.66
V
VO1
(Refer to Table 1)
19.00
19.3
19.68
V
DVO1,
DVO2
VIN = 8V to 14V; VO = 13.3V
-
4.0
40.0
mV
VIN = 8V to 14V; VO = 18.3V
-
4.0
60.0
mV
DVO1,
DVO2
IO = 0mA to 350mA
-
50
80
mV
IO = 0mA to 750mA
-
100
200
mV
IMAX
DCL = 0, ISEL H = 0, ISEL L = 0 (Note 8)
275
305
345
mA
DCL = 0, ISEL H = 0, ISEL L = 1 (Note 8)
515
570
630
mA
DCL = 0, ISEL H = 1, ISEL L = 0 (Note 8)
635
705
775
mA
DCL = 0, ISEL H = 1, ISEL L = 1 (Note 8)
800
890
980
mA
-
900
-
ms
-
51
-
ms
Dynamic Overload Protection Off Time
TOFF
Dynamic Overload Protection On Time
TON
Static Output Current Limiting
IMAX
DCL = 1 (Note 8)
-
1000
-
mA
Cable Fault CABF Threshold
ICAB
EN = 1, VO = 19V, No Tone.
2
10
20
mA
FN6412 Rev 1.00
Apr 10, 2007
DCL = 0, Output Shorted (Note 8)
Page 5 of 16
ISL6423B
Electrical Specifications
VCC = 12V, TA = -20°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C. EN = H, VTOP
VBOT = L, ENT = L, DCL = L, IOUT = 12mA, unless otherwise noted. See software description section for I2C
access to the system. (Continued)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
TONE OSCILLATOR
Tone Frequency
ftone
ENT = H
20.0
22.0
24.0
kHz
Tone Amplitude
Vtone
ENT = H, IO = 5mA
500
680
800
mV
Tone Duty Cycle
dctone
ENT = H,
40
50
60
%
Tone Rise or Fall Time
Tr, Tf
ENT = H,
5
10
14
s
TONE DECODER
Input Amplitude
Vtdin
200
-
1000
mV
Frequency Capture Range
Ftdin
17.5
-
26.5
kHz
Input Impedance
Zdet
-
8.6
-
k
Detector Output Voltage
Vtdout_L
Tone Present, ILOAD = 3mA
-
-
0.4
V
Detector Output Leakage
Itdout_H
Tone absent, VO = 6V
-
-
10
A
Tone Decoder Rx Threshold
VRXth
TXT = L and TTH = 0 (Note 9)
100
150
200
mV
Tone Decoder Tx Threshold
VTXth
TXT = H and TTH = 0 (Note 9)
400
450
500
mV
IOUT = 750mA
-
0.8
1.05
V
LINEAR REGULATOR
Drop-out Voltage
Output Backward Leakage Current
IBKLK
EN = 0; VOBK = 27V
-
2.0
3.0
mA
Output Backward Leakage Current
IBKLK
EN = 0; VOBK = 28V
-
3.0
17
mA
Output Backward Current Threshold
IBKTH
EN = 1; VOFAULT = 19V (Note 7)
-
140
-
mA
Output Backward Current Limit
IBKLM
EN = 1; VOFAULT = 19V (Note 7)
-
350
-
mA
Output Backward Voltage
VOBK
EN = 0
-
-
27
V
Output Under Voltage
(Asserted high during soft-start)
OUVF bit is asserted high, Measured from
the typ. output set value
-6
-
-2
%
Output Over Voltage
(Asserted high during soft-start)
OUVF bit is asserted high, Measured from
the typ. output set value
+2
-
+6
%
Asserted LOW
-
-
0.8
V
Asserted HIGH
1.7
-
-
V
-
25
-
A
-
700
-
nA
325
450
500
mV
TXT, EXTM, SELVTOP AND ADDR 0/1 INPUT PINs (Note 8)
Input Current
CURRENT SENSE (CS pin)
Input Bias Current
IBIAS
Overcurrent Threshold
VCS
Static current mode, DCL = H
ERROR AMPLIFIER
Open Loop Voltage Gain
AOL
-
93
-
dB
Gain Bandwidth Product
GBP
-
14
-
MHz
Maximum Duty Cycle
90
93
-
%
Minimum Pulse Width
-
20
-
ns
PWM
FN6412 Rev 1.00
Apr 10, 2007
Page 6 of 16
ISL6423B
Electrical Specifications
VCC = 12V, TA = -20°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C. EN = H, VTOP
VBOT = L, ENT = L, DCL = L, IOUT = 12mA, unless otherwise noted. See software description section for I2C
access to the system. (Continued)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
396
440
484
kHz
Temperature Shutdown Threshold
-
150
-
°C
Temperature Shutdown Hysteresis
-
20
-
°C
OSCILLATOR
Oscillator Frequency
fo
Fixed at (20)(ftone)
Thermal Shutdown
OTFI
FLT (released)
VO = 6V
-
-
10
A
FLT (asserted)
ISINK = 3.2mA
-
-
0.4
V
NOTES:
5. Internal digital soft-start
6. EXTM, TXT and SELVTOP and addr 0/1 pins have 200k internal pulldown resistors.
7. On exceeding this backward current limit threshold for a period of 2ms, the device enters the Backward dynamic current limit mode (350mA typ)
and the BCF I2C bit is set. The dynamic current limit duty ratio during a back current fault is ON = 2ms/OFF = 50ms. The output will remain
clamped to the fault output voltage till released. On removal of the fault condition the device returns to normal operation
8. In the Dynamic current limit mode the output is ON for 51ms and OFF for 900ms. But remains continuously ON in the Static mode. When tone
is ON the minimum current limit is 50mA lower the values indicated in the table.
Tone Waveform
ENT
I2C
MSEL
I2C
EXTM
PIN
VOUT
PIN
22kHz
22kHz
22kHz
22kHz
22kHz
22kHz
INTERNAL TONE
INTERNAL TONE
Tr = 10µs TYP
EXTERNAL TONE
Tr = 10µs TYP
RETURNS TO NOMINAL VOUT ~1 PERIOD
AFTER THE LAST EXTM RISING EDGE
T > 55µs;
NOTES:
9. The signal pin TXT changes the decoder threshold during tone transmit and receive. TTH allows threshold control through I2C.
10. The tone rise and fall times are not shown due to resolution of graphics. It is 10µs typ for 22kHz.
11. The EXTM pins have input thresholds of Vil(max) = 0.8V and Vih(min) = 1.7V
FIGURE 1. TONE WAVEFORM
FN6412 Rev 1.00
Apr 10, 2007
Page 7 of 16
ISL6423B
Typical Performance Curves
0.80
0.80
0.70
0.70
0.60
IOUT_max
0.50
IOUT (A)
IOUT (A)
0.60
0.40
0.30
0.40
0.30
0.20
0.20
0.10
0.10
0.00
0
20
40
60
80
IOUT_max
0.50
0.00
0
20
TEMPERATURE (°C)
FIGURE 2. OUTPUT CURRENT DERATING (EPTSSOP)
40
60
80
TEMPERATURE (°C)
FIGURE 3. OUTPUT CURRENT DERATING (4x4 QFN)
Functional Pin Description
SYMBOL
FUNCTION
SDA
Bidirectional data from/to I2C bus.
SCL
Clock from I2C bus.
VSW
Input of the linear post-regulator.
PGND
CS
Dedicated ground for the output gate driver of respective PWM.
Current sense input; connect the sense resistor Rsc at this pin for desired peak overcurrent value for the boost FET. The
set peak limit is effective in the static mode current limit only i.e., DCL = HIGH.
SGND
Small signal ground for the IC.
TCAP
Capacitor for setting rise and fall time of the output voltage. Typical value is 0.1µF.
BYPASS
Bypass capacitor for internal 5V.
TXT
TXT is the Tone Transmit signal input used to change the Tone Decoder Threshold from TXT = 0, 200mV max during
Receive to TXT = 1, 400mV min during Transmit.
VCC
Main power supply to the chip.
GATE
This output drives the boost FET gate. The output is held low when VCC is below the UVLO threshold.
VO
ADDR0 & ADDR1
Output voltage for the LNB is available at VO pin.
Logic combination at the ADDR0 & 1 can select four different chip select addresses.
EXTM
This pin can be used in two ways:
1) As an input for externally modulated Diseqc tone signal which is transferred to the symmetrically onto VOUT
2) Alternatively apply a Diseqc modulation envelope which modulates an internal tone and then transfers it symmetrically
onto VOUT
FLT
This is an Open Drain output from the controller. When the FLT goes low it indicates that an Over Temperature, Over load
fault, UVLO, or an I2C reset condition has occurred. The processor should then look at the I2C register to get the actual
cause of the error. A high on the FLT indicates that the device is functioning normally.
CPVOUT, CPSWIN
CPSWOUT
A 47n charge pump decoupling capacitor is to be connected to CPVOUT. Connect a 1.5n capacitor between CPSWIN and
CPSWOUT
SELVTOP
When this pin is low the VOUT is in the 13V, 14V range selected by the I2C bit VBOT.
When this pin is high the 18V, 19V range selected by the I2C bit VTOP. The Voltage select pin enable VSPEN I2C bit must
be set low for the SELVTOP pins to be active. Setting VSPEN high disables this pins and voltage selection will be done
using the I2C bits VBOT and VTOP only.
TDIN, TDOUT
FN6412 Rev 1.00
Apr 10, 2007
TDIN is the tone decoder input and TDOUT is the tone detector output. TDOUT is an open drain output
Page 8 of 16
ISL6423B
Functional Description
Linear Regulator
The ISL6423B single output voltage regulator makes an
ideal choice for advanced satellite set-top box and personal
video recorder applications. The device utilizes built-in
DC/DC step up converters that, operates from a single
supply source ranging from 8V to 14V, and generates the
voltage needed to enable the linear post-regulator to work
with a minimum of dissipated power. An undervoltage
lockout circuit disables the device when VCC drops below a
fixed threshold (7.5V typ).
The output linear regulator will sink and source current. This
feature allows full modulation capability into capacitive loads
as high as 0.75F. In order to minimize the power
dissipation, the output voltage of the internal step-up
converter is adjusted to allow the linear regulator to work at
minimum dropout.
DiSEqC Encoding
The internal oscillator is factory-trimmed to provide a tone of
22kHz in accordance with DiSEqC (EUTELSAT) standards.
No further adjustment is required. The tone oscillator can be
controlled either by the I2C interface (ENT bit) or by a
dedicated pin (EXTM) that allows immediate DiSEqC data
encoding separately for each LNB. All the functions of this IC
are controlled via the I2C bus by writing to the system
registers. The same registers can be read back, and four bits
will report the diagnostic status. The internal oscillator
operates the converters at twenty times the 22k tone
frequency. The device offers full I2C compatibility, and
supports 2.5V, 3.3V or 5V logic, up to an operational speed of
400kHz.
If the Tone Enable (ENT) bit is set LOW and the MSEL bits
set LOW through I2C, then the EXTM terminal activates the
internal tone signal, modulating the DC output with a
680mVPP typical symmetrical tone waveform. The presence
of this signal usually provides the LNB with information
about the band to be received.
Burst coding of the tone can be accomplished due to the fast
response of the EXTM input and rapid tone response. This
allows implementation of the DiSEqC (EUTELSAT)
protocols.
When the ENT bit is set HIGH, a continuous 22kHz tone is
generated regardless of the EXTM pin logic status for the
regulator channel LNB-A. The ENT bit must be set LOW
when the EXTM pin is used for DiSEqC encoding.
The EXTM accepts an externally modulated tone command
when the MSEL I2C bit is set HIGH and ENT is set LOW.
DiSEqC Decoder
TDIN is the input to the tone decoder. It accepts and the tone
signal derived from the VOUT thru the 10nF decoupling
capacitor. The detector threshold can be set to 200mV max
in the Receive mode and to 400mV min in the Transmit
mode by means of the logic presented to the TXT pin. If tone
is detected the open drain pin TDOUT is asserted low. This
enables the tone diagnostics to be performed, apart from the
normal tone detection function.
FN6412 Rev 1.00
Apr 10, 2007
When the device is put in the shutdown mode (EN = LOW),
the PWM power block is disabled. When the regulator blocks
are active (EN = HIGH and VSPEN = LOW), the output can
be controlled via I2C logic to be 13V/14V or 18V/19V
(typical) by means of the VTOP and VBOT bits (Voltage
Select) for remote controlling of non-DiSEqC LNBs.
When the regulator blocks are active (EN = HIGH and
VSPEN = HIGH), the VBOT and SELVTOP pin will control
the output between 13V and 14V and the VTOP and
SELVTOP pin will control the output between 18V and 19V.
Output Timing
The output voltage rise and fall times can be set by an the
external capacitor on the TCAP pin. The output rise and fall
times is given by the equation:
327.6T
C = ------------------V
(EQ. 1)
Where C is the TCAP value in nF, T is the required transition
time in ms and V is the differential transition voltage from
low output voltage range to the high output range in Volts.
The maximum recommended value for TCAP is 0.15µF. Too
large a value of TCAP prevents the output from rising to the
nominal value, within the soft-start time when the error
amplifier is released. Too small a value of the TCAP can cause
high peak currents in the boost circuit. For example, a 10V/ms
slew on a 80µF VSW capacitor with an inductor of 15µH can
cause a peak inductor current of approximately 2.3A.
Current Limiting
Dynamic current limiting block has four thresholds that can
be selected by the ISEL H and ISEL L bits of the SR. Refer
to Table 8 and Table 9 for threshold selection using these
bits. The DCL bit has to be set to low for this mode of
operation. In the dynamic overcurrent mode a fault
exceeding the selected overcurrent threshold for a period
greater than 51ms, will shutdown the output for 900ms,
during which the I2C bit OLF is set high. At the end of 900ms
the OLF bit is returned to the low state, a soft-start cycle
(~20ms long) is initiated to ramp VSW and VOUT back up. If
the fault is still present the overcurrent will be reached early
in the soft-start cycle and the 51ms shutdown timer will be
started again. If the fault is still present at the end of the
51ms, the OLF bit is again set high and the device once
again enters the 900ms OFF time. This dynamic operation
greatly reduces the power dissipation in a short circuit
condition, while still ensuring excellent power-on start-up in
most conditions.
Page 9 of 16
ISL6423B
However, there could be some cases in which a highly
capacitive load on the output may cause a difficult start-up
when the dynamic protection is selected. This can be solved
by initiating any power start-up in static mode (DCL = HIGH)
and then switching to the dynamic mode (DCL = LOW) after
a predetermined interval. When in static mode, the OLF bit
goes HIGH when the current clamp limit is reached and
returns LOW at the end of initial power-on soft-start. In the
Static mode the output current through the linears is limited to
a 990mA typ.
When a 19.3V line is connected onto a VOUT1 or 2 that has
been set to 13.3V the linear will then enter a back current
limited state. When a back current of greater than 140mA
typical is sensed at the lower FET of the linear for a period
greater that 2ms the output is disabled for a period of 50ms
and the BCF bit is set. If the 19.3V remains connected, the
output will cycle through the ON = 2ms/OFF = 50ms. The
output will return to the setpoint when the fault is removed.
BCF bit is set high during the 50ms OFF period.
Thermal Protection
This IC is protected against overheating. When the junction
temperature exceeds +150°C (typical), the step-up converter
and the linear regulator are shut off and the OTF bit of the
SR is set HIGH. When the junction is cooled down to +130°C
(typical), normal operation is resumed and the OTF bit is
reset LOW. If a part is repeatedly driven to the overtemp
shutdown temperature the chip is latched off after the fourth
occurrence and the I2C OTF bit is latched high and FLT_bar
low. This OTF counter and FLT_bar can be reset and the
chip restarted by either a power down/up and reload the I2C
or power can be left on and the reset accomplished by
toggling the I2C bit EN low then back high.
I2C Bus Interface for ISL6423B
(Refer to Philips I2C Specification, Rev. 2.1)
Data transmission from main microprocessor to the ISL6423B
and vice versa takes place through the two wire I2C bus
interface, consisting of the two lines SDA and SCL. Both SDA
and SCL are bidirectional lines, connected to a positive supply
voltage via a pull up resistor. (Pull up resistors to positive supply
voltage must be externally connected). When the bus is free,
both lines are HIGH. The output stages of ISL6423B will have
an open drain/open collector in order to perform the wired-AND
function. Data on the I2C bus can be transferred up to 100Kbps
in the standard-mode or up to 400Kbps in the fast-mode. The
level of logic “0” and logic “1” is dependent of associated value
of VDD as per electrical specification table. One clock pulse is
generated for each data bit transferred.
Data Validity
The data on the SDA line must be stable during the HIGH
period of the clock. The HIGH or LOW state of the data line
can only change when the clock signal on the SCL line is
LOW. Refer to Figure 4.
SDA
SCL
DATA LINE CHANGE
STABLE
OF DATA
DATA VALID ALLOWED
FIGURE 4. DATA VALIDITY
START and STOP Conditions
External Output Voltage Selection
When the I2C bit VSPEN is set high the output voltage can
be selected by the I2C bus. Additionally, the package offers
the pin SELVTOP for independent 13 thru 19V output
voltage selection., when the VSPEN bit is set low. A
summary of the voltage control is given in Table 1. For
further details refer to the individual registers SR1 and SR3
As shown in Figure 5, START condition is a HIGH to LOW
transition of the SDA line while SCL is HIGH.
The STOP condition is a LOW to HIGH transition on the SDA
line while SCL is HIGH. A STOP condition must be sent
before each START condition.
TABLE 1.
VSPEN
VTOP
VBOT
SELVTOP
VOUT
0
x
0
0
13.3V
0
x
1
0
14.3V
0
0
x
1
18.3V
0
1
x
1
19.3V
1
0
0
x
13.3V
1
0
1
x
14.3V
1
1
0
x
18.3V
1
1
1
x
19.3V
FN6412 Rev 1.00
Apr 10, 2007
SDA
SCL
S
P
START
CONDITION
STOP
CONDITION
FIGURE 5. START AND STOP WAVEFORMS
Page 10 of 16
ISL6423B
ISL6423B Software Description
Byte Format
Every byte put on the SDA line must be eight bits long. The
number of bytes that can be transmitted per transfer is
unrestricted. Each byte has to be followed by an
acknowledge bit. Data is transferred with the most significant
bit first (MSB).
Acknowledge
The master (microprocessor) puts a resistive HIGH level on
the SDA line during the acknowledge clock pulse (Figure 6).
The peripheral that acknowledges has to pull down (LOW)
the SDA line during the acknowledge clock pulse, so that the
SDA line is stable LOW during this clock pulse. (Of course,
set-up and hold times must also be taken into account.)
The peripheral which has been addressed has to generate
an acknowledge after the reception of each byte, otherwise
the SDA line remains at the HIGH level during the ninth
clock pulse time. In this case, the master transmitter can
generate the STOP information in order to abort the transfer.
The ISL6423B will not generate the acknowledge if the
POWER OK signal from the UVLO is LOW.
Interface Protocol
The interface protocol is comprised of the following, as
shown below in Table 2:
• A start condition (S)
• A chip address byte (MSB on left; the LSB bit determines
read (1) or write (0) transmission) (the assigned I2C slave
address for the ISL6423B is 0001 0XXX)
• A sequence of data (1 byte + Acknowledge)
• A stop condition (P)
TABLE 2. INTERFACE PROTOCOL
S 0
0
0
1
0
A1
A0 R/W ACK
Data (8 bits)
ACK P
System Register Format
• R, W = Read and Write bit
• R = Read-only bit
All bits reset to 0 at Power-On
TABLE 3. STATUS REGISTER (SR1)
SCL
1
2
8
9
R, W
R, W
R, W
R
R
R
R
R
SR1H
SR1M
SR1L
OTF
CABF
OUVF
OLF
BCF
SDA
TABLE 4. TONE REGISTER (SR2)
MSB
START
ACKNOWLEDGE
FROM SLAVE
R, W
R, W
R, W
R, W
R, W
R, W
R, W
R, W
SR2H
SR2M
SR2L
ENT
MSEL
TTH
X
X
FIGURE 6. ACKNOWLEDGE ON THE I2C BUS
TABLE 5. COMMAND REGISTER (SR3)
R, W
R, W
R, W
R, W
Avoiding detection of the acknowledgement, the
microprocessor can use a simpler transmission; it waits one
clock without checking the slave acknowledging, and sends
the new data.
SR3H SR3M SR3L
DCL
VSPEN
X
This approach, though, is less protected from error and
decreases the noise immunity.
SR4H SR4M SR4L
Transmission Without Acknowledge
R, W
R, W
R, W
R, W
ISELH ISELL
TABLE 6. CONTROL REGISTER (SR4)
R, W
R, W
R, W
R, W
EN
R, W
R, W
R, W
R, W
VTOP
VBOT
Transmitted Data (I2C bus WRITE mode)
When the R/W bit in the chip is set to 0, the main
microprocessor can write on the system registers (SR2 thru
SR4) of the ISL6423B via I2C bus. These will be written by
the microprocessor as shown below. The spare bits of
registers can be used for other functions.
FN6412 Rev 1.00
Apr 10, 2007
Page 11 of 16
ISL6423B
TABLE 7. STATUS REGISTER SR1 CONFIGURATION
SR1H
SR1M
SR1L
OTF
CABF
OUVF
OLF
BCF
FUNCTION
0
0
0
X
X
X
X
X
SR1 is selected
0
0
0
X
X
X
0
X
IOUT set limit, Normal Operation
0
0
0
X
X
X
1
X
IOUT > Static/Dynamic Limiting Mode/Power blocks disabled
0
0
0
X
X
X
X
0
Iobck set limit, Normal Operation
0
0
0
X
X
X
X
1
Iobck > Dynamic Limiting Mode / Power blocks disabled
0
0
0
X
X
0
X
X
VIN/VOUT within specified range
0
0
0
X
X
1
X
X
VIN/VOUT is not within specified range
0
0
0
X
0
X
X
X
Cable is connected, Io is >20mA
0
0
0
X
1
X
X
X
Cable is open, Io 150°C, Power blocks disabled
TABLE 8. TONE REGISTER SR2 CONFIGURATION
SR2H
SR2M
SR2L
ENT
MSEL
TTH
X
X
FUNCTION
0
0
1
X
X
X
X
X
SR2 is selected
0
0
1
0
0
X
X
X
Int Tone = 22kHz, modulated by EXTM, Tr, Tf = 10µs typ
0
0
1
0
1
X
X
X
Ext 22k modulated input, Tr, Tf = 10µs typ
0
0
1
1
0
X
X
X
Int Tone = 22kHz, modulated by ENT bit, Tr, Tf = 10µs typ
0
0
1
X
X
0
X
X
TXT = 0; Decoder Rx threshold is set at 200mV max
0
0
1
X
X
1
X
X
TXT = 0; Decoder Tx threshold is set at 400mV min
NOTE: X indicates “Read Only” and is a “Don’t Care” for the Write mode.
TABLE 9. COMMAND REGISTER SR3 CONFIGURATION
SR3H
SR3M
SR3L
DCL
VSPEN
X
ISELH
ISELL
FUNCTION
0
1
0
X
X
X
X
X
SR3 is selected
0
1
0
0
X
X
0
0
IOUT limit threshold = 305mA typ.
0
1
0
0
X
X
0
1
IOUT limit threshold = 570mA typ.
0
1
0
0
X
X
1
0
IOUT limit threshold = 705mA typ.
0
1
0
0
X
X
1
1
IOUT limit threshold = 890mA typ.
0
1
0
1
X
X
X
X
Dynamic current limit NOT selected
0
1
0
0
X
X
X
0
1
0
X
0
X
X
X
SELVTOP H/W pin Enabled
0
1
0
X
1
X
X
X
SELVTOP H/W pin Disabled
Dynamic current limit selected
NOTE: X indicates “Read Only” and is a “Don’t Care” for the Write mode.
FN6412 Rev 1.00
Apr 10, 2007
Page 12 of 16
ISL6423B
TABLE 10. CONTROL REGISTER SR4 CONFIGURATION
SR4H
SR4M
SR4L
EN
X
X
VTOP
VBOT
FUNCTION
0
1
1
1
X
X
0
0
SR4 is selected
0
1
1
1
X
X
0
0
VSPEN = SELVTOP = 0, VOUT = 13V, VBOOST = 13V + VDROP
0
1
1
1
X
X
0
1
VSPEN = SELVTOP = 0, VOUT = 14V, VBOOST = 14V + VDROP
0
1
1
1
X
X
1
0
VSPEN = SELVTOP = 0, VOUT = 13V, VBOOST = 13V + VDROP
0
1
1
1
X
X
1
1
VSPEN = SELVTOP = 0, VOUT = 14V, VBOOST = 14V + VDROP
0
1
1
1
X
X
0
0
VSPEN = 0,SELVTOP = 1, VOUT = 18V, VBOOST = 18V + VDROP
0
1
1
1
X
X
0
1
VSPEN = 0,SELVTOP = 1, VOUT = 18V, VBOOST = 18V + VDROP
0
1
1
1
X
X
1
0
VSPEN = 0,SELVTOP = 1, VOUT = 19V, VBOOST = 19V + VDROP
0
1
1
1
X
X
1
1
VSPEN = 0,SELVTOP = 1, VOUT = 19V, VBOOST = 19V + VDROP
0
1
1
1
X
X
0
0
VSPEN = 1,SELVTOP = X VOUT = 13V, VBOOST = 13V + VDROP
0
1
1
1
X
X
0
1
VSPEN = 1,SELVTOP = X VOUT = 14V, VBOOST = 14V + VDROP
0
1
1
1
X
X
1
0
VSPEN = 1,SELVTOP = X VOUT = 18V, VBOOST = 18V + VDROP
0
1
1
1
X
X
1
1
VSPEN = 1,SELVTOP = X VOUT = 19V, VBOOST = 19V + VDROP
0
1
1
0
X
X
X
X
PWM and Linear for channel 1 disabled
NOTE: X indicates “Read Only” and is a “Don’t Care” for the Write mode.
Received Data (I2C bus READ MODE)
ADDR0 and ADDR1 Pins
The ISL6423B can provide to the master a copy of the
system register information via the I2C bus in read mode.
The read mode is Master activated by sending the chip
address with R/W bit set to 1. At the following Master
generated clock bits, the ISL6423B issues a byte on the
SDA data bus line (MSB transmitted first).
Connecting these pin to GND the chip I2C interface address
is 0001000, but, it is possible to choose between four
different addresses by setting these pins to the logic levels
indicated in Table 11.
At the ninth clock bit the MCU master can:
• Acknowledge the reception, starting in this way the
transmission of another byte from the ISL6423B.
• Not acknowledge, stopping the read mode
communication.
The read only bits of the register SR1 convey diagnostic
information about the ISL6423B, as indicated in the Table 7.
TABLE 11. ADDRESS PIN CHARACTERISTICS
VADDR
ADDR1
ADDR0
VADDR-1 “0001000”
0
0
VADDR-2 “0001001”
0
1
VADDR-3 “0001010”
1
0
VADDR-4 “0001011”
1
1
Power–On I2C Interface Reset
The I2C interface built into the ISL6423B is automatically reset
at power-on. The I2C interface block will receive a Power OK
logic signal from the UVLO circuit. This signal will go HIGH
when chip power is OK. As long as this signal is LOW, the
interface will not respond to any I2C commands and the
system register SR1 thru SR4 are all initialized to all zero,
thus keeping the power blocks disabled. Once the VCC rises
above UVLO, the POWER OK signal to the I2C is asserted
high, and the I2C interface becomes operative and the SR’s
can be configured by the main microprocessor. About 400mV
of hysteresis is provided in the UVLO threshold to avoid false
triggering of the Power-On reset circuit. (I2C comes up with
EN = 0; EN goes HIGH at the same time as (or later than) all
other I2C data for that PWM becomes valid).
FN6412 Rev 1.00
Apr 10, 2007
Page 13 of 16
ISL6423B
I2C Bit Description
I2C Electrical Characteristics
TABLE 12.
BIT
NAME
DESCRIPTION
EN
ENable Output for channels 1 and 2
VTOP
Voltage TOP select i.e. 18V, 19V for channels 1 and 2
VBOT
Voltage BOTtom select i.e. 13V, 14V for channels 1 and 2
ENT
ENable Tone
MSEL
Modulation SELect
DCL
Dynamic Current Limit select
VSPEN
Voltage Select Pin ENable
PARAMETER
TEST
CONDITION
MIN
TYP
MAX
Input Logic
High, VIH
SDA, SCL
2.0V
Input Logic
Low, VIL
SDA, SCL
0.8V
Input Logic
Current, IIL
SDA, SCL;
0.4V < VDD< 3.3V
10A
Input Logic
Current IOL
VOL = 0.4V
ISELH
Current limit “I” SELect High and Low bit
and ISELL
Input
Hysteresis
SDA, SCL
OTF
Over Temperature Fault bit
CABF
CABle Fault or open status bit
SCL Clock
Frequency
OUVF
Over and Under Voltage Fault status bit
OLF
Over Load Fault status bit
BCF
Backward Current Fault bit
TTH
Tone THreshold is the OR of the signal pin TXT
3mA
165mV
200mV
235mV
0
100kHz
400kHz
Input Filter
Spike reject
50ns
© Copyright Intersil Americas LLC 2006-2007. All Rights Reserved.
All trademarks and registered trademarks are the property of their respective owners.
For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil may modify the circuit design and/or specifications of products at any time without notice, provided that such
modification does not, in Intersil's sole judgment, affect the form, fit or function of the product. Accordingly, the reader is cautioned to verify that datasheets are
current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its
subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
FN6412 Rev 1.00
Apr 10, 2007
Page 14 of 16
ISL6423B
Package Outline Drawing
L24.4x4D
24 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE
Rev 2, 10/06
4.00
4X 2.5
A
20X 0.50
B
PIN 1
INDEX AREA
PIN #1 CORNER
(C 0 . 25)
24
19
1
18
4.00
2 . 50 ± 0 . 15
13
0.15
(4X)
12
7
0.10 M C A B
0 . 07
24X 0 . 23 +- 0
. 05 4
24X 0 . 4 ± 0 . 1
TOP VIEW
BOTTOM VIEW
SEE DETAIL "X"
0.10 C
C
0 . 90 ± 0 . 1
BASE PLANE
( 3 . 8 TYP )
SEATING PLANE
0.08 C
SIDE VIEW
(
2 . 50 )
( 20X 0 . 5 )
C
0 . 2 REF
5
( 24X 0 . 25 )
0 . 00 MIN.
0 . 05 MAX.
( 24X 0 . 6 )
DETAIL "X"
TYPICAL RECOMMENDED LAND PATTERN
NOTES:
1. Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3. Unless otherwise specified, tolerance : Decimal ± 0.05
4. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
5. Tiebar shown (if present) is a non-functional feature.
6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 indentifier may be
either a mold or mark feature.
FN6412 Rev 1.00
Apr 10, 2007
Page 15 of 16
ISL6423B
Thin Shrink Small Outline Exposed Pad Plastic Packages (EPTSSOP)
M28.173B
N
INDEX
AREA
E
0.25(0.010) M
28 LEAD THIN SHRINK SMALL OUTLINE PLASTIC PACKAGE
B M
INCHES
E1
GAUGE
PLANE
-B-
SYMBOL
A
1
2
3
TOP VIEW
0.05(0.002)
-A-
SEATING PLANE
-C-
e
2
0.10(0.004)
C A M
3
B S
A2
MILLIMETERS
MAX
-
MIN
MAX
NOTES
0.047
-
1.20
-
A1
0.002
0.006
0.05
0.15
-
A2
0.031
0.051
0.80
1.05
-
b
0.0075
0.0118
0.19
0.30
9
c
0.0035
0.0079
0.09
0.20
-
D
0.378
0.386
9.60
9.80
3
E1
0.169
0.177
4.30
4.50
4
e
c
A1
b
1
L
A
D
0.10(0.004) M
0.25
0.010
MIN
0.026 BSC
0.65 BSC
-
E
0.246
0.256
6.25
6.50
-
L
0.0177
0.0295
0.45
0.75
6
N
28
28
7
0°
8°
0°
8°
-
P
-
0.138
-
5.50
11
P1
-
0.118
-
3.0
11
Rev. 0 6/05
P1
N
P
BOTTOM VIEW
FN6412 Rev 1.00
Apr 10, 2007
NOTES:
1. These package dimensions are within allowable dimensions of
JEDEC MO-153-AET, Issue E.
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate
burrs. Mold flash, protrusion and gate burrs shall not exceed
0.15mm (0.006 inch) per side.
4. Dimension “E1” does not include interlead flash or protrusions.
Interlead flash and protrusions shall not exceed 0.15mm (0.006
inch) per side.
5. The chamfer on the body is optional. If it is not present, a visual
index feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. Dimension “b” does not include dambar protrusion. Allowable
dambar protrusion shall be 0.08mm (0.003 inch) total in excess
of “b” dimension at maximum material condition. Minimum space
between protrusion and adjacent lead is 0.07mm (0.0027 inch).
10. Controlling dimension: MILLIMETER. Converted inch dimensions are not necessarily exact. (Angles in degrees)
11. Dimensions “P” and “P1” are thermal and/or electrical enhanced
variations. Values shown are maximum size of exposed pad
within lead count and body size.
Page 16 of 16
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