SD8016
Shouding
Description
Features
SD8016 is a complete constant-current &
constant voltage linear charger for single cell
lithium-ion and Lithium-Polymer batteries.
Its
SOT-23 package and low external component count
make SD8016 ideally suited for portable
applications.
Furthermore, the SD8016 is
specifically designed to work within USB power
specification. At the same time, SD8016 can also
be used in the standalone lithium-ion and
Lithium-polymer battery chargers.
No external sense resistor is needed, and no
blocking diode is required due to the internal
MOSFET architecture.
Thermal feedback
regulates the charge current to limit the die
temperature during high power operation or high
ambient temperature. The charge voltage is fixed
at 4.22V, and the charge current can be
programmed externally with a single resistor. The
SD8016 automatically terminates the charge cycle
when the charge current drops to 1/10th the
programmed value after the final float voltage is
reached.
When the input supply (wall adapter or USB
supply) is removed, the SD8016 automatically
enters a low current stage, dropping the battery
drain current to less than 2uA. The SD8016 can
be put into shutdown mode, reducing the supply
current to 20uA.
Other features include charge current monitor,
undervoltage lockout, automatic recharge and a
status pin to indicate charge termination and the
presence of an input voltage. SD8016 is
intentionally designed to have slightly negative
Tempco. This provides extra protection to Lithium
battery during charging.
Programmable Charge Current Up to 800mA.
No MOSFET, Sense Resistor or Blocking Diode
Required.
Constant-Current/Constant-Voltage Operation
with Thermal Protection to Maximize Charge
Rate without Risk of Overheating.
Charges Single Cell Li-Ion Batteries Directly
from USB Port.
Preset 4.22V Charge Voltage with ±1%
Accuracy.
20uA Supply Current in Shutdown.
2.9V Trickle Charge Threshold
Soft-Start Limits Inrush Current.
Available in 5-Lead SOT-23 Package.
100% Lead (Pb)-Free
Application
Cellular Telephones, PDA’s, MP3 Players.
Charging Docks and Cradles
Bluetooth Applications
Application Diagram
Pin Configuration
Marking
Marking:016*,*is A-Z
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SD8016
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Absolute Maximum Rating (1)
Parameter
Symbol
Value
Units
Input Supply Voltage
VCC
7
V
PROG Voltage
VPROG
VCC+0.3
V
BAT Voltage
VBAT
7
V
CHRG Voltage
VCHRG
7
V
BAT Short-Circuit Duration
Continuous
Thermal Resistance, Junction-to-Ambient
ΘJA
250
°C/W
BAT Pin Current
IBAT
800
mA
PROG Pin Current
IPROG
800
A
Maximum Junction Temperature
TJ
125
°C
Storage Temperature
TS
-65 to +125
°C
300
°C
Lead Temperature (Soldering, 10 sec)
Operating Rating (2)
Parameter
Symbol
Value
Units
Supply Input Voltage
VIN
-0.3 to +7
V
Junction Temperature
TJ
-40 to +85
°C
Electrical Characteristics
VIN = 5V; TJ = 25°C; unless otherwise specified.
Symbol
VCC
ICC
Parameter
Conditions
Input Supply Voltage
Input Supply Current
Min
Typ
Max
Unit
6
V
500
µA
3.5
(3)
Charge Mode , RPROG = 10k
110
Standby Mode (Charge Terminated)
70
20
40
µA
µA
4.15
4.22
4.3
V
90
110
130
mA
+/-1
+/-5
mA
µA
+/-0.5
+/-5
µA
+/-1
+/-5
µA
Shutdown Mode(RPROG Not Connected,
VCC < VBAT, or VCC < VUV)
VFLOAT
Regulated Output (Float) Voltage
IBAT = 30mA, ICHRG = 5mA
IBAT
BAT Pin Current
RPROG = 10k, Current Mode
RPROG = 2k, Current Mode
Standby Mode, VBAT = 4.2V
500
0
Shutdown Mode (RPROG Not Connected)
Sleep Mode, VCC = 0V
ITRIKL
Trickle Charge Current
VBAT < VTRIKL, RPROG = 10k
VTRIKL
Trickle Charge Threshold Voltage
RPROG = 10k, VBAT Rising
10
2.8
2.9
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mA
3.0
V
SD8016
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Electrical Characteristics (Continued)
VIN = 5V; TJ = 25°C; unless otherwise specified
Symbol
Parameter
Conditions
VUV
VCC Undervoltage Lockout Threshold
VUVHYS
VCC Undervoltage Lockout Hysteresis
VMSD
Manual Shutdown Threshold Voltage
From VCC Low to High
VCC – VBAT Lockout Threshold Voltage
VASD
ITERM
Min
C/10 Termination Current Threshold
Typ
Max
Unit
3.4
V
100
mV
PROG Pin Rising
1.25
V
PROG Pin Falling
1.2
V
VCC from Low to High
100
mV
VCC from High to Low
30
mV
0.1
mA/mA
0.1
mA/mA
RPROG = 10k
(4)
RPROG = 2k
VPROG
PROG Pin Voltage
RPROG = 10k, Current Mode
0.9
1.03
1.1
V
ICHRG
CHRG Pin Weak Pull-Down Current
VCHRG = 3V
15
µA
VCHRG
CHRG Pin Output Low Voltage
ICHRG = 5mA
0.6
V
ΔVRECHRG
Recharge Battery Threshold Voltage
VFLOAT - VRECHRG
100
mV
TLIM
Thermal Protection Temperature
120
°C
tSS
Soft-Start Time
IBAT = 0 to 1000V/RPROG
100
µs
tRECHARGE
Recharge Comparator Filter Time
VBAT High to Low
1
ms
tTERM
Termination Comparator Filter Time
IBAT Falling Below ICHG/10
1000
µs
IPROG
PROG Pin Pull-Up Current
1
µA
Note 1: Exceeding the absolute maximum rating may damage the device.
Note 2: The device is not guaranteed to function outside its operating rating.
Note 3: Supply current includes PROG pin current (approximately 100µA) but does not include any current delivered to the battery
through the BAT pin (approximately 100mA).
Note 4: ITERM is expressed as a fraction of measured full charge current with indicated PROG resistor.
Pin Functions
Pin
Pin Function Description
Pin
P Positive Input Supply Voltage. Provides
VCC
power to the charger. VCC can range
from 3.5 to 6.5V and should be
Open-Drain Charge Status Output. When the battery is charging, the
CHRG
Ground.
CHRG pin is pulled low by an internal N-channel MOSFET. When the
charge cycle is completed, a weak pull-down of approximately 20uA is
connected to the CHRG pin, indicating an ―AC present‖ condition.
bypassed with at least a 1F capacitor.
GND
Pin Function Description
PROG
Charge Current Program, Charge Current Monitor and Shutdown Pin.
Charge Current Output. Provides
BAT
charge current to the battery and
regulates the final float voltage to
4.22V.
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SD8016
BLOCK DIAGRAM
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SD8016
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Float Voltage vs Supply Voltage
Charge Current vs Supply Voltage
4.230
600
4.225
500
TA=25℃
IBAT (mA)
4.215
VBAT (V)
RPROG=2k
RPROG=10k
4.220
4.210
4.205
4.200
ONSET OF
THERMAL
REGULATION
400
VBAT=4V
300
TA=25℃
200
4.195
100
4.190
4.185
4.0
4.5
5.0
5.5
VCC (V)
6.0
RPROG=10k
0
4.0
6.5
4.5
5.0
5.5
6.0
6.5
7.0
VCC (V)
Float Voltage vs Temperature
Trickle Charge Current vs Supply Voltage
4.215
70
60
4.210
RPROG=2k
50
ITRIKL (mA)
VFLOAT (V)
4.205
40
VBAT=2.5V
TA=25℃
30
4.195
20
RPROG=10k
10
0
4.0
4.200
4.190
4.185
4.5
5.0
5.5
VCC (V)
6.0
6.5
7.0
20
40
60
80
Temperature (℃)
100
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120
SD8016
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Operation
The SD8016 is a single cell lithium-ion battery
current are calculated using the following equations:
R PROG
charger using a constant-current/constant-voltage
algorithm. It can deliver up to 800mA of charge
1100 V
1100 V
, I CHG
,
R PROG
I CHG
current (using a good thermal PCB layout) with a
The charge current out of the BAT pin can be
final float voltage accuracy of ±2%. The SD8016
determined at any time by monitoring the PROG pin
includes an internal P-channel power MOSFET and
voltage using the following equation:
thermal regulation circuitry. No blocking diode or
I BAT
external current sense resistor is required; thus, the
V PROG
1100
R PROG
basic charger circuit requires only two external
This actual current will vary from IC to IC. The typical
components. Furthermore, the SD8016 is capable
variation is within +/-20%.
of operating from a USB power source.
Normal Charge Cycle
Charge Termination
A charge cycle begins when the voltage at the VCC
A charge cycle is terminated when the charge current
pin rises above the UVLO threshold level and a 1%
falls to 1/10th the programmed value after the final
program resistor is connected from the PROG pin to
float voltage is reached. This condition is detected by
ground or when a battery is connected to the
using an internal, filtered comparator to monitor the
charger output. If the BAT pin is less than 2.8V, the
PROG pin. When the PROG pin voltage falls below
charger enters trickle charge mode. In this mode,
100mV for longer than tTERM (typically 1ms), charging
the SD8016 supplies approximately 1/10 the
is terminated. The charge current is latched off and
programmed charge current to bring the battery
the SD8016 enters standby mode, where the input
voltage up to a safe level for full current charging.
supply
When the BAT pin voltage rises above 2.8V, the
termination is disabled in trickle charging and thermal
charger enters constant-current mode, where the
limiting modes).
programmed charge current is supplied to the
When charging, transient loads on the BAT pin can
battery. When the BAT pin approaches the final
cause the PROG pin to fall below 100mV for short
float
enters
periods of time before the DC charge current has
constant-voltage mode and the charge current
dropped to 1/10th the programmed value. The 1ms
begins to decrease. When the charge current drops
filter time (tTERM) on the termination comparator
to 1/10 of the programmed value, the charge cycle
ensures that transient loads of this nature do not
ends.
result in premature charge cycle termination. Once
voltage
(4.22V),
the
SD8016
current
drops
to
200mA.
(Note:
C/10
the average charge current drops below 1/10th the
Programming Charge Current
programmed value, the SD8016 terminates the
The charge current is programmed using a single
charge cycle and ceases to provide any current
resistor from the PROG pin to ground. The battery
through the BAT pin. In this state, all loads on the
charge current is 1100 times the current out of the
BAT pin must be supplied by the battery.
PROG pin. The program resistor and the charge
The SD8016 constantly monitors the BAT pin voltage
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SD8016
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in standby mode. If this voltage drops below the
Undervoltage Lockout (UVLO)
4.05V recharge threshold (VRECHRG), another charge
An internal undervoltage lockout circuit monitors the
cycle begins and current is once again supplied to the
input voltage and keeps the charger in shutdown
battery. To manually restart a charge cycle when in
mode until VCC rises above the undervoltage lockout
standby mode, the input voltage must be removed
threshold. The UVLO circuit has a built-in hysteresis
and reapplied, or the charger must be shut down and
of 200mV. Furthermore, to protect against reverse
restarted using the PROG pin. Figure 1 shows the
current in the power MOSFET, the UVLO circuit
state diagram of a typical charge cycle.
keeps the charger in shutdown mode if VCC falls to
within 30mV of the battery voltage. If the UVLO
Charge Status Indicator (CHRG)
comparator is tripped, the charger will not come out of
The charge status output has three different states:
shutdown mode until VCC rises 100mV above the
strong pull-down (~10mA), weak pull-down (~20A)
battery voltage.
and high impedance. The strong pull-down state
indicates that the SD8016 is in a charge cycle. Once
the charge cycle has terminated, the pin state is
determined by undervoltage lockout conditions. A
Power On
weak pull-down indicates that VCC meets the UVLO
VBAT2.8V
voltage is applied to the VCC pin.
Thermal Limiting
Shutdown Mode
CC/CV Charge Mode
ICC Drops to < 20A
Full Current
VBAT>2.8V
Chrg: Hi-Z In UVLO
WeakPull-Dn
Otherwise
Chrg LED: Strong Pull-Dn
An internal thermal feedback loop reduces the
VPROGVBAT>2.8V
capability of a given circuit board without risk of
damaging the SD8016. The charge current can be set
according
to
typical
(not
worst-case)
Figure1.
State Diagram of a Typical Charge Cycle
ambient
temperature with the assurance that the charger will
automatically reduce the current in worst-case
conditions.
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Application Hints
Power Dissipation
Stability Considerations
The conditions that cause the SD8016 to reduce
The constant-voltage mode feedback loop is stable
without an output capacitor provided a battery is
connected to the charger output. With no battery
present, an output capacitor is recommended to
reduce ripple voltage. When using high value, low
ESR ceramic capacitors, it is recommended to add
a 1Ω resistor in series with the capacitor. No series
resistor is needed if tantalum capacitors are used.
In constant-current mode, the PROG pin is in the
feedback loop, not the battery. The constant-current
mode stability is affected by the impedance at the
PROG pin. With no additional capacitance on the
charge current through thermal feedback can be
approximated by considering the power dissipated
in the IC. Nearly all of this power dissipation is
generated
by
the
internal
MOSFET—this
is
calculated to be approximately:
PD = (VCC – VBAT) • IBAT
The approximate ambient temperature at which the
thermal feedback begins to protect the IC is:
TA = 120°C – PDθJA
TA = 120°C – (VCC – VBAT) • IBAT • θJA
PROG pin, the charger is stable with program
resistor values as high as 20k. However, additional
Thermal Considerations
capacitance on this node reduces the maximum
allowed program resistor. The pole frequency at the
PROG pin should be kept above 100kHz.
Because of the small size of the thin SOT23
package, it is very important to use a good thermal
PC board layout to maximize the available charge
current. The thermal path for the heat generated by
VCC Bypass Capacitor
the IC is from the die to the copper lead frame,
Many types of capacitors can be used for input
through the package leads, (especially the ground
bypassing, however, caution must be exercised
lead) to the PC board copper. The PC board copper
when using multilayer ceramic capacitors. Because
is the heat sink. The footprint copper pads should
of the self-resonant and high Q characteristics of
be as wide as possible and expand out to larger
some types of ceramic capacitors, high voltage
copper areas to spread and dissipate the heat to
transients can be generated under some start-up
the surrounding ambient. Other heat sources on the
conditions, such as connecting the charger input to
board, not related to the charger, must also be
a live power source. Adding a 1.5Ω resistor in series
considered when designing a PC board layout
with a ceramic capacitor will minimize start-up
because they will affect overall temperature rise and
voltage transients.
the maximum charge current.
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SD8016
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OUTLINE DRAWING SOT-23-5L
K
B
H
D
A
F
E
C
J
N
DIM
A
B
C
D
E
F
H
J
K
DIMENSIONS
INCHES
MM
MIN MAX MIN MAX
0.110
0.059
0.036
0.014
0.0035
0.102
0.120
0.070
0.051
0.020
0.037
0.075
0.006
0.008
0.118
2.80
1.50
0.90
0.35
0.090
2.60
3.05
1.75
1.30
0.50
0.95
1.90
0.15
0.20
3.00
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