Intersil ISL9209CIRZ Charging system safety circuit Datasheet

ISL9209C
®
Data Sheet
January 16, 2009
FN6489.1
Charging System Safety Circuit
Features
The ISL9209C is an integrated circuit (IC) optimized to
provide a redundant safety protection to a Li-ion battery from
failures of a charging system. The IC monitors the input
voltage, the battery voltage, and the charge current. When
any of the three parameters exceeds its limit, the IC turns off
an internal P-Channel MOSFET to remove the power from
the charging system. In addition to the above protected
parameters, the IC also monitors its own internal
temperature and turns off the P-Channel MOSFET when the
temperature exceeds +140°C. Together with the battery
charger IC and the protection module in a battery pack, the
charging system using the ISL9209C has triple-level
protection and is two-fault tolerant.
• Fully Integrated Protection Circuit for Three Protected
Variables
The IC is designed to turn on the internal PFET slowly to
avoid in-rush current at power-up but will turn off the PFET
quickly when the input is overvoltage in order to remove the
power before any damage occurs. The ISL9209C has a logic
warning output to indicate the fault and an enable input to
allow the system to remove the input power.
• Pb-Free (RoHS Compliant)
• High Accuracy Protection Thresholds
• User Programmable Overcurrent Protection Threshold
• Input Overvoltage Protection in Less Than 1µs
• High Immunity of False Triggering Under Transients
• Warning Output to Indicate the Occurrence of Faults
• Enable Input
• Easy to Use
• Thermal Enhanced TDFN Package
Applications
• Cell Phones
• Digital Still Cameras
• PDAs and Smart Phones
Ordering Information
PART NUMBER
PART
(Note)
MARKING
ISL9209CIRZ*
09CZ
• Portable Instruments
TEMP.
RANGE
(°C)
-40 to +85
PACKAGE
(Pb-free)
PKG.
DWG. #
12 Ld 4x3 TDFN L12.4x3A
*Add “-T” suffix for tape and reel. Please refer to TB347 for details on reel
specifications
NOTE: These Intersil Pb-free plastic packaged products employ special
Pb-free material sets, molding compounds/die attach materials, and
100% matte tin plate plus anneal (e3 termination finish, which is 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.
• Desktop Chargers
Related Literature
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
(SMDs)”
• Technical Brief TB379 “Thermal Characterization of
Packaged Semiconductor Devices”
• Technical Brief TB389 “PCB Land Pattern Design and
Surface Mount Guidelines for QFN Packages”
Pinout
ISL9209C
(12 LD 4x3 TDFN)
TOP VIEW
Typical Application Circuit
INPUT
VIN
OUT
C1
ISL6292
BATTERY
CHARGER
ISL9209C
RVB
EN
RILIM
WRN
GND
1
1
12 NC
VIN
2
11 OUT
GND
3
10 OUT
WRN
4
9
ILIM
NC
5
8
VB
NC
6
7
EN
EPAD
VB
ILIM
VIN
BATTERY
PACK
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2007, 2009. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
ISL9209C
Absolute Maximum Ratings (Reference to GND)
Thermal Information
Supply Voltage (VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 30V
Output and VB Pin (OUT, VB) (Note 1) . . . . . . . . . . . . -0.3V to 7.0V
Other Pins (ILIM, WRN, EN) . . . . . . . . . . . . . . . . . . . . -0.3V to 5.5V
Thermal Resistance (Typical, Notes 2, 3) θJA (°C/W) θJC (°C/W)
4x3 TDFN Package . . . . . . . . . . . . . . .
41
3.5
Maximum Junction Temperature (Plastic Package) . . . . . . . +150°C
Maximum Storage Temperature Range . . . . . . . . . .-65°C to +150°C
Pb-free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions
Ambient Temperature Range . . . . . . . . . . . . . . . . . . .-40°C to +85°C
Supply Voltage (VIN. . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3V to 5.5V
Operating Current Range. . . . . . . . . . . . . . . . . . . . . . . . . . 0A to 2A
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and
result in failures not covered by warranty.
NOTES:
1. The maximum voltage rating for the VB pin under continuous operating conditions is 5.5V. All other pins are allowed to operate continuously at
the absolute maximum ratings.
2. θJA 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 θJC, the “case temp” location is the center of the exposed metal pad on the package underside.
Electrical Specifications
Typical values are tested at VIN = 5.0V and TA = +25°C, maximum and minimum values are guaranteed over
the recommended operating conditions, unless otherwise noted.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
2.40
2.58
2.70
V
POWER-ON RESET
Rising VIN Threshold
VPOR
POR Hysteresis
-
0.10
-
V
When Enabled
0.75
0.90
1.10
mA
When Disabled
30
60
100
µA
5.65
5.85
6.00
V
-
0.06
0.10
V
Input OVP Falling Threshold
5.55
-
-
V
Input OVP Propagation Delay
-
-
1
µs
VIN Bias Current
IVIN
VIN Bias Current
PROTECTIONS
Input Overvoltage Protection (OVP)
VOVP
Input OVP Hysteresis
0.93
1.00
1.07
A
Overcurrent Protection Blanking Time
BtOCP
-
170
-
µs
Battery Overvoltage Protection Threshold
VBOVP
4.280
4.340
4.400
V
-
0.030
-
V
4.225
-
-
V
-
180
-
µs
Overcurrent Protection
IOCP
VVB = 3V, RILIM = 25kΩ
Battery OVP Threshold Hysteresis
Battery OVP Falling Threshold
Battery OVP Blanking Time
BtBOVP
-
-
20
nA
Over-Temperature Protection Rising Threshold
VVB = 4.4V
-
140
-
°C
Over-Temperature Protection Falling Threshold
-
90
-
°C
EN Input Logic HIGH
1.5
-
-
V
EN Input Logic LOW
-
-
0.4
V
kΩ
VB Pin Leakage Current
LOGIC
EN Internal Pull-Down Resistor
WRN Output Logic Low
Sink 5mA current
WRN Output Logic High Leakage Current
100
200
400
-
0.35
0.80
V
-
-
1
µA
-
170
280
mΩ
POWER MOSFET
ON-Resistance
rDS(ON)
2
4.6V < VIN < 5.5V
FN6489.1
January 16, 2009
ISL9209C
Pin Descriptions
VB (Pin 8)
VIN (Pin 1, 2)
Battery voltage monitoring input. This pin is connected to the
battery pack positive terminal via an isolation resistor.
The input power source. The VIN can withstand 30V input.
ILIM (Pin 9)
GND (Pin 3)
Overcurrent protection threshold setting pin. Connect a
resistor between this pin and GND to set the OCP threshold.
System ground reference.
WRN (Pin 4)
OUT (Pin 10, 11)
WRN is an open-drain logic output that turns LOW when any
protection event occurs.
Output pin.
EPAD
NC (Pin 5, 6, 12)
The exposed pad at the bottom of the TDFN package for
enhancing thermal performance. Must be electrically
connected to the GND pin.
No connection and must be left floating.
EN (Pin 7)
Enable input. Pull this pin to low or leave it floating to enable
the IC and force it to high to disable the IC.
Typical Applications
INPUT
VIN
ISL6292
BATTERY
CHARGER
OUT
C1
PART
ISL9209C
VB
ILIM
RVB
25kΩ
RVB
200kΩ to 1MΩ
1µF/16V X5R ceramic capacitor
BATTERY
PACK
WRN
GND
RILIM
C1
EN
RILIM
DESCRIPTION
Block Diagram
INPUT
OUT
VIN
Q1
Q2
R1
POR
PRE-REG
Pre-reg
REF
Ref
FET
DRIVER
Driver
Q3
ISL6292
Battery
BATTERY
CHARGER
Charger
ILIM
RILIM
CP2
EA
0.8V
CP1
R2
CP3
Logic
LOGIC
1.2V
VB
Q4
R4
Q5
WRN
GND
RVB
R3 BUF
R5
EN
FIGURE 1. BLOCK DIAGRAM
3
FN6489.1
January 16, 2009
ISL9209C
Typical Operating Performance
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25°C,
RILIM = 25.5kΩ, RVB = 200kΩ, Unless Otherwise Noted.
VIN
VIN(2V/DIV)
(2V/div)
VIN (1V/DIV)
VIN
(1V/div)
OUT (1V/DIV)
OUT
(1V/div)
OUT
OUT(2V/DIV)
(2V/div)
Load
LOADCurrent
CURRENT
200mA/DIV
(200mA/div)
WRN
WRN(5V/DIV)
(5V/div)
TIME:
Time:5µs/DIV
5μs/div
TIME:
Time:5ms/DIV
5ms/div
FIGURE 2. CAPTURED WAVEFORMS FOR POWER-UP. THE
OUTPUT IS LOADED WITH A 10Ω RESISTOR
Time:500ms/DIV
500ms/div
TIME:
FIGURE 3. CAPTURED WAVEFORMS WHEN THE INPUT
VOLTAGE STEPS FROM 5.5V TO 9.5V
VIN(2V/DIV)
(2V/div)
VIN
VIN (2V/DIV)
VIN
(2V/div)
OUT
(2V/div)
OUT (2V/DIV)
OUT (2V/DIV)
OUT
(2V/div)
WRN (5V/DIV)
WRN
(5V/div)
WRN
(5V/div)
WRN (5V/DIV)
Time:
5ms/div
TIME: 5ms/DIV
FIGURE 4. CAPTURED WAVEFORMS WHEN THE INPUT
GRADUALLY RISES TO THE INPUT
OVERVOLTAGE THRESHOLD
VIN(2V/DIV)
(2V/div)
VIN
FIGURE 5. TRANSIENT WHEN THE INPUT VOLTAGE STEPS
FROM 6.5V TO 5.5V
Time:20s/DIV
20s/div
TIME:
VIN (1V/div)
(1V/DIV)
VIN
VB(1V/DIV)
(1V/div)
VB
OUT
OUT(2V/DIV)
(2V/div)
ILIM
ILIM(1V/DIV)
(1V/div)
OUT (1V/DIV)
OUT
(1V/div)
WRN
(5V/div)
WRN (5V/DIV)
WRN (5V/DIV)
Time:500µs/DIV
500μs/div
WRN
(5V/div) TIME:
FIGURE 6. TRANSIENT WAVEFORMS WHEN INPUT STEPS
FROM 0V TO 9V
4
FIGURE 7. BATTERY OVERVOLTAGE PROTECTION. THE IC
IS LATCHED OFF AFTER 16 COUNTS OF
PROTECTION. VB VOLTAGE VARIES BETWEEN
4.3V TO 4.5V
FN6489.1
January 16, 2009
ISL9209C
Typical Operating Performance
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25°C,
RILIM = 25.5kΩ, RVB = 200kΩ, Unless Otherwise Noted. (Continued)
TIME: 200ms/DIV
Time:
200ms/div
Time:10ms/DIV
10ms/div
TIME:
VIN(1V/DIV)
(1V/div)
VIN
VIN
(1V/div)
VIN (1V/DIV)
OUT (1V/DIV)
OUT
(1V/div)
LoadCURRENT
Current
LOAD
(500mA/div)
500mA/DIV
Load CURRENT
Current
LOAD
(500mA/div)
500mA/DIV
OUT
OUT (1V/DIV)
(1V/div)
WRN (5V/DIV)
WRN
(5V/div)
WRN (5V/DIV)
WRN
(5V/div)
FIGURE 9. ZOOMED-IN VIEW OF FIGURE 8 (BLUE: LOAD
CURRENT; PINK: OUT PIN VOLTAGE)
1000
1000
900
900
800
800
700
ENABLED
CURRENT (µA)
INPUT BIAS CURRENT (µA)
FIGURE 8. POWER-UP WAVEFORMS WHEN OUTPUT IS
SHORT-CIRCUITED
600
500
400
DISABLED
300
700
600
400
200
200
100
100
0
5
10
15
20
25
30
0
-50
35
30V/ENABLED
500
300
0
4.3V/ENABLED
5V/ENABLED
30V/DISABLED
5V/DISABLED
-20
INPUT VOLTAGE (V)
70
100
130
FIGURE 11. INPUT BIAS CURRENT AT DIFFERENT INPUT
VOLTAGES WHEN ENABLED AND DISABLED
2.82
5.86
2.80
5.84
2.78
RISING THRESHOLD
2.76
5.82
2.74
VOVP (V)
VPOR (V)
40
TEMPERATURE (°C)
FIGURE 10. INPUT BIAS CURRENT vs INPUT VOLTAGE
WHEN ENABLED AND DISABLED
2.72
2.70
2.68
RISING THRESHOLD
5.80
5.78
FALLING THRESHOLD
5.76
FALLING THRESHOLD
2.66
5.74
2.64
2.62
-50
10
4.3V/DISABLED
-20
10
40
70
100
TEMPERATURE (°C)
FIGURE 12. VPOR vs TEMPERATURE
5
130
5.72
-50
-20
10
40
70
100
130
TEMPERATURE (°C)
FIGURE 13. INPUT OVERVOLTAGE PROTECTION
THRESHOLDS vs TEMPERATURE
FN6489.1
January 16, 2009
ISL9209C
Typical Operating Performance
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25°C,
RILIM = 25.5kΩ, RVB = 200kΩ, Unless Otherwise Noted. (Continued)
1040
200
CURRENT
LIMIT = 1A
1030
195
5V
190
185
4.3V
1010
BtOCP (µs)
IOCP (mA)
1020
3V
1000
990
180
175
170
165
160
5.5V
980
155
970
-50
-20
10
40
70
100
150
-50
130
-20
TEMPERATURE (°C)
FIGURE 14. OVERCURRENT PROTECTION THRESHOLDS vs
TEMPERATURE AT VARIOUS INPUT VOLTAGES
100
130
4.370
4.3V
RISING MAX
4.360
510
3V
4.350
505
4.340
5V
VB
IOCP (mA)
70
4.380
CURRENT
515 LIMIT = 0.5A
495
4.330
4.320
490
5.5V
4.310
485
4.300
480
4.290
475
-50
-20
10
40
70
100
FALLING MIN
4.280
130
-60 -40 -20
TEMPERATURE (°C)
FIGURE 16. OVERCURRENT PROTECTION THRESHOLDS vs
TEMPERATURE AT VARIOUS INPUT VOLTAGES
100 120 140
3.0
VB PIN LEAKAGE CURRENT (nA)
195
190
185
180
175
170
165
160
155
150
-50
0
20 40 60 80
TEMPERATURE (°C)
FIGURE 17. BATTERY VOLTAGE OVP THRESHOLDS vs
TEMPERATURE AT VARIOUS INPUT VOLTAGES
200
BtBOVP (µs)
40
FIGURE 15. OVERCURRENT PROTECTION BLANKING TIME
vs TEMPERATURE
520
500
10
TEMPERATURE (°C)
-20
10
40
70
100
TEMPERATURE (°C)
FIGURE 18. BATTERY OVP BLANKING TIME
6
130
TESTED AT 5V
2.5
2.0
1.5
1.0
0.5
0
-50
-20
10
40
70
TEMPERATURE (°C)
100
130
FIGURE 19. VB PIN LEAKAGE CURRENT vs TEMPERATURE
FN6489.1
January 16, 2009
ISL9209C
Typical Operating Performance
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25°C,
RILIM = 25.5kΩ, RVB = 200kΩ, Unless Otherwise Noted. (Continued)
2.0
EN PIN INTERNAL PULL-DOWN (kΩ)
250
1.8
EN THRESHOLD (V)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
-50
-20
10
40
70
100
240
230
220
210
200
190
180
170
160
150
130
-50
-20
10
40
70
100
130
TEMPERATURE (°C)
TEMPERATURE (°C)
FIGURE 20. EN INPUT THRESHOLD vs TEMPERATURE
FIGURE 21. EN PIN INTERNAL PULL-DOWN RESISTANCE
0.5
rDS(ON) (Ω)
0.4
3V
4.3V
0.3
0.2
5V
0.1
5.5V
0
-50
-20
10
40
70
100
130
TEMPERATURE (°C)
FIGURE 22. ON-RESISTANCE vs TEMPERATURE AT DIFFERENT INPUT VOLTAGES
Theory of Operation
Power-up
The ISL9209C is an integrated circuit (IC) optimized to
provide a redundant safety protection to a Li-ion battery from
charging system failures. The IC monitors the input voltage,
the battery voltage, and the charge current. When any of the
above three parameters exceeds its limit, the IC turns off an
internal P-Channel MOSFET to remove the power from the
charging system. In addition to the above protected
parameters, the IC also monitors its own internal
temperature and turns off the P-Channel MOSFET when the
temperature exceeds +140°C. Together with the battery
charger IC and the protection module in a battery pack, the
charging system has triple-level protection from
overcharging the Li-ion battery and is two-fault tolerant. The
ISL9209C protects up to 30V input voltage.
The ISL9209C has a power-on reset (POR) threshold of
2.6V with a built-in hysteresis of 125mV. Before the input
voltage reaches the POR threshold, the internal power PFET
is off. Approximately 10ms after the input voltage exceeds
the POR threshold, the IC resets itself and begins the softstart. The 10ms delay allows any transients at the input
during a hot insertion of the power supply to settle down
before the IC starts to operate. The soft-start slowly turns on
the power PFET to reduce the in-rush current as well as the
input voltage drop during the transition. The power-up
behavior is illustrated in Figure 2.
7
Input Overvoltage Protection (OVP)
The input voltage is monitored by the comparator CP1 in the
“Block Diagram” on page 3 (Figure 1). CP1 has an accurate
reference of 1.2V from the bandgap reference. The OVP
threshold is set by the resistive divider consisting of R1 and
R2. The protection threshold is set to 5.85V. When the input
FN6489.1
January 16, 2009
ISL9209C
voltage exceeds the threshold, the CP1 outputs a logic
signal to turn off the power PFET within 1µs (see Figure 3) to
prevent the high input voltage from damaging the electronics
in the handheld system. The hysteresis for the input OVP
threshold is given in the “Electrical Specifications” table on
page 2. When the input overvoltage condition is removed,
the ISL9209C re-enables the output by running through the
soft-start, as shown in Figure 5. Because of the 10ms delay
before the soft-start, the output is never enabled if the input
rises above the OVP threshold quickly, as shown in Figure 6.
the enable pin is toggled. Figure 8 and Figure 9 illustrate the
waveforms during the power-up when the output is
short-circuited to ground.
Battery Overvoltage Protection
External Enable Control
The battery voltage OVP is realized with the VB pin. The
comparator CP3, as shown in Figure 1, monitors the VB pin
and issues an overvoltage signal when the battery voltage
exceeds the 4.34V (nominal) battery OVP threshold. The
threshold has 30mV built-in hysteresis. The comparator CP3
has a built-in 180µs blanking time to prevent any transient
voltage from triggering the OVP. If the OVP situation still
exists after the blanking time, the power PFET is turned off.
The control logic contains a 4-bit binary counter that if the
battery overvoltage event occurs 16 times, the power PFET
is turned off permanently, as shown in Figure 7. Recycling
the input power or toggling the enable (EN) input will reset
the counter and restart the ISL9209C.
The ISL9209C offers an enable (EN) input. When the EN pin
is pulled to logic HIGH, the protection IC is shut down. The
internal control circuit as well as the power PFET are turned
off. Both 4-bit binary counters for the battery OVP and the
OCP are reset to zero when the IC is re-enabled. The EN pin
has an internal 200kΩ pull-down resistor. Leaving the EN pin
floating or driving it to below 0.4V enables the IC.
The resistor between the VB pin and the battery (RVB) as
shown in the “Typical Application Circuit” on page 1, is an
important component. This resistor provides a current limit in
case the VB pin is shorted to the input voltage under a failure
mode. The VB pin leakage current under normal operation is
negligible to allow a resistance of 200kΩ to 1MΩ be used.
Applications Information
Overcurrent Protection (OCP)
The current in the power PFET is limited to prevent charging
the battery with an excessive current. The current is sensed
using the voltage drop across the power FET after the FET is
turned on. The reference of the OCP is generated using a
sensing FET (Q2), as shown in Figure 1. The current in the
sensing FET is forced to the value programmed by the ILIM
pin. The size of the power FET (Q1) is 31,250 times the size
of the sensing FET. Therefore, when the current in the power
FET is 31,250 times the current in the sensing FET, the drain
voltage of the power FET falls below that of the sensing FET.
The comparator CP2 then outputs a signal to turn off the
power FET.
The OCP threshold can be calculated using Equation 1:
0.8V
25000
I LIM = --------------- ⋅ 31250 = ---------------R ILIM
R ILIM
(EQ. 1)
where the 0.8V is the regulated voltage at the ILIM pin. The
OCP comparator CP2 has a built-in 170µs delay to prevent
false triggering by transient signals. The OCP function also
has a 4-bit binary counter that accumulates during an OCP
event. When the total count reaches 16, the power PFET is
turned off permanently, unless the input power is recycled or
8
Internal Over-Temperature Protection
The ISL9209C monitors its own internal temperature to
prevent thermal failures. When the internal temperature
reaches +140°C, the IC turns off the P-Channel power
MOSFET. The IC does not resume operation until the
internal temperature drops below +90°C.
Warning Indication Output
The WRN pin is an open-drain output that indicates a LOW
signal when any of the three protection events happens. This
allows the microprocessor to give an indication to the user to
further enhance the safety of the charging system.
The ISL9209C is designed to meet the “Lithium-Safe” criteria
when operating together with the ISL6292 family Li-ion
battery chargers. The “Lithium-Safe” criteria requires the
charger output to fall within the green region shown in
Figure 23 under normal operating conditions and NOT to fall
in the red region when there is a single fault in the charging
system. Taking into account the safety circuit in a Li-ion
battery pack, the charging system is allowed to have two
faults without creating hazardous conditions for the battery
cell. The output of any ISL6292 family chargers, such as the
ISL6292C, has a typical I-V curve shown with the blue lines
under normal operation, which is within the green region.
The function of the ISL9209C is to add a redundant
protection layer such that, under any single fault condition,
the charging system output does not exceed the I-V limits
shown with the red lines. As a result, the charging system
adopting the ISL9209C and the ISL6292C chip set can
easily pass the “Lithium-Safe” criteria test procedures.
The ISL9209C is a simple device that requires only three
external components, in addition to the ISL6292 charger
circuit, to meet the “Lithium-Safe” criteria, as shown in the
“Typical Application Circuit” on page 1. The selection of the
current limit resistor RILIM is given in “Overcurrent Protection
(OCP)” on page 8.
FN6489.1
January 16, 2009
ISL9209C
RVB Selection
The RVB prevents a large current from the VB pin to the
battery terminal, in case the ISL9209C fails. The
recommended value should be between 200kΩ to 1MΩ.
With 200kΩ resistance, the worst case current flowing from
the VB pin to the charger output is:
ISL9209C
MCU
VIO
RPU
WRN
Q4
RWRN
( 30V – 4.2V ) ⁄ ( 200kΩ = 130μA )
(EQ. 2)
assuming the VB pin voltage is 30V under a failure mode
and the battery voltage is 4.2V. Such a small current can be
easily absorbed by the bias current of other components in
the handheld system. Increasing the RVB value reduces the
worst case current, but at the same time increases the error
for the 4.34V battery OVP threshold.
The error of the battery OVP threshold is the original
accuracy at the VB pin given in the “Electrical Specifications”
table on page 2 plus the voltage built across the RVB by the
VB pin leakage current. The VB pin leakage current is less
than 20nA, as given in the Electrical Specifications table.
With the 200kΩ resistor, the worst-case additional error is
4mV and with a 1MΩ resistor, the worst-case additional error
is 20mV.
1000
CHARGE CURRENT (mA)
ISL9209 C
LIMITS
ISL6292C
LIMITS
EN
Q5
REN
R5
FIGURE 24. DIGITAL SIGNAL INTERFACE BETWEEN
ISL9209C AND MCU
Capacitor Selection
The input capacitor (C1 in the “Typical Application Circuit” on
page 1) is for decoupling. Higher value reduces the voltage
drop or the overshoot during transients.
Two scenarios can cause the input voltage overshoot. The
first one is when the AC adapter is inserted live (hot
insertion) and the second one is when the current in the
power PFET of the ISL9209C has a step-down change.
Figure 25 shows an equivalent circuit for the ISL9209C
input. The cable between the AC/DC converter output and
the handheld system input has a parasitic inductor. The
parasitic resistor is the lumped sum of various components,
such as the cable, the adapter output capacitor ESR, the
connector contact resistance, and so on.
C1
L
R
AC/DC
0
1
2
3
4
5
ISL9209C
6
BATTERY VOLTAGE (V)
FIGURE 23. LITHIUM-SAFE OPERATING REGIONS
Interfacing to MCU
The ISL9209C has the enable (EN) and the warning (WRN)
digital signals that can be interfaced to a microcontroller unit
(MCU). Both signals can be left floating if not used. When
interfacing to an MCU, it is highly recommended to insert a
resistor between the ISL9209C signal pin and the MCU
GPIO pin, as shown in Figure 24. The resistor creates an
isolation to limit the current, in case a high voltage shows up
at the ISL9209C pins under a failure mode. The
recommended resistance ranges from 10kΩ to 100kΩ. The
selection of the REN is dependent on the IO voltage (VIO) of
the MCU. REN should be selected so that the ISL9209C EN
pin voltage is above the disable threshold when the GPIO
output of the MCU is high.
9
C2
ADAPTER
CABLE
HANDHELD SYSTEM
FIGURE 25. EQUIVALENT CIRCUIT FOR THE ISL9209C INPUT
During the load current step-down transient, the energy
stored in the parasitic inductor is used to charge the input
decoupling capacitor C2. The ISL9209C is designed to turn
off the power PFET slowly during the OCP, the battery OVP
event, and when the device is disabled via the EN pin.
Because of such design, the input overshoot during those
events is not significant. During an input OVP, however, the
PFET is turned in less than 1µs and can lead to significant
overshoot. Higher capacitance reduces this type of
overshoot.
The overshoot caused by a hot insertion is not very
dependent on the decoupling capacitance value. Especially
when ceramic type capacitors are used for decoupling. In
theory, the overshoot can rise up to twice of the DC output
FN6489.1
January 16, 2009
ISL9209C
voltage of the AC adapter. The actual peak voltage is
dependent on the damping factor that is mainly determined
by the parasitic resistance (R in Figure 25).
In practice, the input decoupling capacitor is recommended
to use a 16V X5R dielectric ceramic capacitor with a value
between 0.1µF to 1µF.
The output of the ISL9209C and the input of the charging
circuit typically share one decoupling capacitor. The
selection of that capacitor is mainly determined by the
requirement of the charging circuit. When using the ISL6292
family chargers, a 1µF, 6.3V, X5R capacitor is
recommended.
10
Layout Recommendation
The ISL9209C uses a thermally enhanced DFN package.
The exposed pad under the package should be connected to
the ground plane electrically as well as thermally. A grid of
1.0mm to 1.2mm pitch thermal vias in two rows and 4 to 5
vias per row is recommended (refer to the ISL9200EVAL1
evaluation board layout). The vias should be about 0.3mm to
0.33mm in diameter. Use some copper on the component
layer if possible to further improve the thermal performance
but it is not mandatory.
Since the ISL9209C is a protection device, the layout should
also pay attention to the spacing between tracks. When the
distance between the edges of two tracks is less than
0.76mm, an FMEA (failure mechanism and effect analysis)
should be performed to ensure that a short between those
two tracks does not lead to the charger output exceeding the
“Lithium-Safe” region limits. Intersil will have the FMEA
document for the solution using the ISL9209C and the
ISL6292C chip set but the layout FMEA should be added as
part of the analysis.
FN6489.1
January 16, 2009
ISL9209C
Thin Dual Flat No-Lead Plastic Package (TDFN)
L12.4x3A
12 LEAD THIN DUAL FLAT NO-LEAD PLASTIC PACKAGE
(COMPLIANT TO JEDEC MO-229-WGED-4 ISSUE C)
2X
0.15 C A
A
D
MILLIMETERS
2X
0.15 C B
SYMBOL
0.70
A1
-
A3
E
b
6
INDEX
AREA
D2
B
//
A
SIDE VIEW
C
SEATING
PLANE
0.10
0.08
A3
7
8
-
-
0.05
-
0.23
0.30
5,8
4.00 BSC
3.15
3.30
3.40
7,8
3.00 BSC
1.55
e
1.70
1.80
7,8
0.50 BSC
-
k
0.20
-
-
-
L
0.30
0.40
0.50
8
N
12
2
Nd
6
3
1. Dimensioning and tolerancing conform to ASME Y14.5-1994.
2. N is the number of terminals.
3. Nd refers to the number of terminals on D.
2
4. All dimensions are in millimeters. Angles are in degrees.
NX k
5. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
E2
6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
(DATUM A)
E2/2
7. Dimensions D2 and E2 are for the exposed pads which provide
improved electrical and thermal performance.
NX L
N
N-1
NX b
e
8. Nominal dimensions are provided to assist with PCB Land
Pattern Design efforts, see Intersil Technical Brief TB389.
5
(Nd-1)Xe
REF.
BOTTOM VIEW
NX (b)
C
NOTES
0.80
Rev. 0 1/06
D2/2
1
C
MAX
0.75
NOTES:
D2
(DATUM B)
8
0.18
E
E2
NOMINAL
0.20 REF
D
TOP VIEW
6
INDEX
AREA
MIN
A
0.10
M C A B
CL
(A1)
L
5
e
SECTION "C-C" TERMINAL TIP
FOR EVEN TERMINAL/SIDE
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets 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.
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11
FN6489.1
January 16, 2009