Philips
Semiconductors
NE57600
One-cell Lithium-ion battery protection
with over/undercharge and overcurrent
protection
Product data
File under Integrated Circuits, Standard Analog
2001 Oct 03
INTEGRATED CIRCUITS
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2
2001 Oct 03
853-2294 27198
GENERAL DESCRIPTION
The NE57600 series is a family of small, high-precision lithium-ion
battery protection devices that provide protection against the
damaging effects of overcharging, overdischarging, short circuit, and
excessive current consumption such as happens if the consumer
uses the battery for an apparatus it was not meant to power. The
NE57600 is a single-cell Li-ion protection IC.
The NE57600 over and under voltage accuracy is trimmed to within
25 mV (5%) and is available to match the requirements of all
lithium-ion cells manufactured in the market today.
FEATURES
Trimmed overvoltage trip point to within
25 mV
Programmable overvoltage trip time delay
Trimmed undervoltage trip point to within
25 mV
Very Low undervoltage sleep quiescent current 0.05 mA
Discharge overcurrent cutoff
Low operating current (10
m
A)
Very small SOT-26A package
APPLICATIONS
Protecting one-cell Li-ion battery packs for mobile phones or
palmtop devices
SIMPLIFIED SYSTEM DIAGRAM
SL01548
6
5
4
3
2
1
VM
CF
GND
DF
V+
V
NE57600
DISCHARGE
FET
CHARGE
FET
C
DLY
V
CC
Li-ION CELL
CHARGER
OR
LOADER
+
Figure 1.
Simplified system diagram.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
3
ORDERING INFORMATION
TYPE NUMBER
PACKAGE
TEMPERATURE
TYPE NUMBER
NAME
DESCRIPTION
RANGE
NE57600XD
SOT-26A
small outline plastic surface mount, 6-pin
20 to +70
C
NOTE:
The device has ten protection parameter options, indicated by the X on the order code, and defined in the following table.
TYPICAL PROTECTION PARAMETERS IN THE NE57600 FAMILY
Part Number
Overcharge
detection voltage (V)
Overcharge
detection hysteresis
voltage (mV)
Over-discharge
detection voltage
(V)
Over-discharge
resumption voltage
(V)
Overcurrent
detection voltage
(mV)
NE57600Y
4.200
200
2.3
3.00
200
NE57600D
4.200
200
2.3
3.90
200
NE57600E
4.250
200
2.3
3.00
200
NE57600F
4.250
150
2.4
3.00
150
NE57600C
4.280
200
2.3
2.90
120
NE57600G
4.295
150
2.4
3.00
150
NE57600W
4.300
150
2.4
3.00
150
NE57600H
4.325
200
2.5
3.00
200
NE57600J
4.325
200
2.5
3.00
200
NE57600B
4.350
200
2.4
3.00
200
Part number marking
Each device is marked with a four letter code. The first three letters
designate the product. The fourth letter, represented by "x", is a date
tracking code.
Part Number
Marking
NE57600YD
A F A x
NE57600BD
A F B x
NE57600CD
A F C x
NE57600DD
A F D x
NE57600ED
A F E x
NE57600FD
A F F x
NE57600GD
A F G x
NE57600HD
A F H x
NE57600WD
A F J x
NE57600JD
A F K x
PIN CONFIGURATION
2
3
1
5
4
6
VM
V
CC
C
DLY
CF
GND
DF
SL01549
Figure 2.
Pin configuration.
PIN DESCRIPTION
PIN
SYMBOL
DESCRIPTION
1
VM
Monitor pin. Detects overcurrent and the
presence of a charger.
2
V
CC
Positive supply voltage input pin. Connect to
positive terminal of the cell.
3
C
DLY
Charge Time Delay pin. The capacitor
connected to this pin sets the delay.
4
CF
Charge FET pin. This drives the gate of the
charge control N-ch FET.
5
GND
Ground pin. Connect to negative terminal of
the cell.
6
DF
Discharge detection pin. This drives the gate
of the discharge N-ch FET.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
4
MAXIMUM RATINGS
SYMBOL
PARAMETER
MIN.
MAX.
UNIT
V
IN
Input voltage
0.3
+18
V
V
CF(max)
CF pin voltage
V
CC
28
V
V
VM(max)
VM pin voltage
V
CC
28
V
T
amb
Operating ambient temperature range
20
+70
C
T
stg
Storage temperature
40
+125
C
P
D
Power dissipation
200
mW
ELECTRICAL CHARACTERISTICS
Characteristics measured with T
amb
= 25
C, unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
Min.
Typ.
Max.
UNIT
I
CC1
Current consumption 1
V
CC
= 3.6 V: Set
between CFGND: 910 k
connected
10.0
14.0
A
I
CC2
Current consumption 2
V
CC
= 3.6 V: IC only
between CFGND: 910 k
connected
6.0
10.0
A
I
CC3
Current consumption 3
V
CC
= 3.6 V: Discharge FET OFF
between CFGND: 910 k
not connected
TBD
TBD
A
I
CC4
Current consumption 4
V
CC
= 1.9 V: Discharge FET OFF
between CFGND: 910 k
not connected
0.05
0.3
A
I
CC5
Current consumption 5
V
CC
= 4.5 V: Set
between CFBG: 910 k
connected
35
60
A
V
OV(th)
Over-charge voltage
T
amb
= 0
C
50
C
V
CC
: L
H
4.325
4.350
4.375
V
V
OV(hyst)
Over-charge hysteresis
V
CC
: H
L
100
200
300
mV
V
UV(th)
Over-discharge voltage
V
CC
: H
L
2.30
2.40
2.50
V
V
UV(rel)
Release over-discharge mode
2.88
3.00
3.12
V
V
OC(th)
Over-current detect level
V
VM
: L
H
174
200
226
mV
V
OC(rel)
Release over-current level
V
VM
: H
L
130
mV
Condition of release over-current mode
Load condition
50
M
V
SC
Short detect level
1.3
V
t
DLY(OD)
Over-discharge dead time
7.0
10.0
15.0
ms
t
OC(DT)
Over-current dead time
VM: 0 V
0.5 V
7.0
10.0
15.0
ms
t
DLY(SC)
Short detect delay time
VM: 0 V
2 V
0.02
0.20
ms
t
OLY(OV)
Over-charge dead time
C
TD
= 0.01
F
50
100
150
ms
V
GDH
DF pin LOW level
V
CC
= 3.6 V
V
CC
0.3
V
CC
0.1
V
CC
V
I
DFH1
DF pin source current 1
V
DF
= V
CC
1.0 V
100
30
A
I
DFH2
DF pin source current 2
V
DF
= V
CC
0.3 V
0.40
0.07
A
I
DFL1
DF pin sink current 1
V
VM
> 1.0 V; V
DF
= 1.0 V
50
300
A
I
DFL2
DF pin sink current 2
V
VM
> 1.0 V; V
DF
= 0.3 V
30
100
A
I
CF1
CF pin source current 1
V
CF
= V
CC
1.0 V
20
10
A
I
CF2
CF pin source current 2
V
CF
= V
CC
0.3 V
15
5
A
V
ST
Start trigger voltage
V
VM
: 0 V
0.5 V
0.2
0.1
0
V
V
PRO
Over-voltage charger protection
V
CC
= 3.6 V, between GNDVM voltage
1.5
2.5
3.0
V
V
OV
OV charge minimum voltage
V
CC
= 0 V; Charger voltage
2.0
3.0
V
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
5
TYPICAL PERFORMANCE CURVES
SL01550
Overcharge dead time (seconds)
0.01
0.1
1
10
0.01
0.1
1
EXTERNAL CAPACITOR (
F)
Figure 3.
Over-voltage time delay versus
external capacitor.
SL01551
0
10
20
30
40
50
60
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Supply voltage, V
CC
(V)
V
CC
: H
L
Supply current, Icc (
A)
Figure 4.
Supply current versus supply voltage.
SL01552
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Supply current, Icc (
A)
Supply voltage, V
CC
(V)
Figure 5.
Supply current versus supply voltage.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
6
TECHNICAL DISCUSSION
Lithium Cell Safety
Lithium-ion and lithium-polymer cells have a higher energy density
than that of nickel-cadmium or nickel metal hydride cells and have a
much lighter weight. This makes the lithium cells attractive for use in
portable products. However, lithium cells require a protection circuit
within the battery pack because certain operating conditions can be
hazardous to the battery or the operator, if allowed to continue.
Lithium cells have a porous carbon or graphite anode where lithium
ions can lodge themselves in the pores. The lithium ions are
separated, which avoids the hazards of metallic lithium.
If the lithium cell is allowed to become overcharged, metallic lithium
plates out onto the surface of the anode and volatile gas is
generated within the cell. This creates a rapid-disassembly hazard
(the battery ruptures). If the cell is allowed to over-discharge (V
cell
less than approximately 2.3 V), then the copper metal from the
cathode goes into the electrolyte solution. This shortens the cycle
life of the cell, but presents no safety hazard. If the cell experiences
excessive charge or discharge currents, as happens if the wrong
charger is used, or if the terminals short circuit, the internal series
resistance of the cell creates heating and generates the volatile gas
which could rupture the battery.
The protection circuit continuously monitors the cell voltage for an
overcharged condition or an overdischarged condition. It also
continuously monitors the output for an overcurrent condition. If
any of these conditions are encountered, the protection circuit opens
a series MOSFET switch to terminate the abnormal condition. The
lithium cell protection circuit is placed within the battery pack very
close to the cell.
Charging control versus battery protection
The battery pack industry does not recommend using the pack's
internal protection circuit to end the charging process. The external
battery charger should have a charge termination circuit in it, such
as that provided by the SA57611. This provides two levels of
overcharge protection, with the primary protection of the external
charge control circuit and the backup protection from the battery
pack's protection circuit. The charge termination circuit will be set to
stop charging at a level around 50 mV less than the overvoltage
threshold voltage of the battery pack's own protection circuit.
Lithium Cell Operating Characteristics
The internal resistance of lithium cells is in the 100 m
range,
compared to the 520 m
of the nickel-based batteries. This makes
the Lithium-ion and polymer cells better for lower battery current
applications (less than 1 ampere) as found in cellular and wireless
telephones, palmtop and laptop computers, etc.
The average operating voltage of a lithium-ion or polymer cell is
3.6 V as compared to the 1.2 V of NiCd and NiMH cells. The typical
discharge curve for Lithium cell is shown in Figure 6.
SL01553
100
50
2.0
OPEN-CIRCUIT
CELL
VOL
T
AGE
(V)
3.0
4.0
NORMALIZED CELL CAPACITY (%)
V
UV
V
OV
Figure 6.
Lithium discharge curve.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
7
Charging Lithium Cells
The lithium cells must be charged with a dedicated charging IC such
as the NE57600. These dedicated charging ICs perform a
current-limited, constant-voltage charge, as shown in Figure 7.
The charger IC begins charging with a current that is typically the
rating of the cell (1C) or the milliampere rating of the cell. As the cell
approaches its full-charge voltage rating (V
OV
), the current entering
the cell decreases, and the charger IC provides a constant voltage.
When the charge current falls below a preset amount, 50 mA for
example, the charge is discontinued.
If charging is begun below the overdischarged voltage rating of the
cell, it is important to slowly raise the cell voltage up to this
overdischarged voltage level. This is done by a reconditioning
charge. A small amount of current is provided to the cell (50 mA for
example), and the cell voltage is allowed a period of time to rise to
the overdischarged voltage. If the cell voltage recovers, then a
normal charging sequence can begin. If the cell does not reach the
overdischarged voltage level, then the cell is too damaged to charge
and the charge is discontinued.
To take advantage of the larger energy density of lithium cells it is
important to allow enough time to completely charge the cell . When
the charger switches from constant current to constant voltage
charge (Point B, Figure 7) the cell only contains about 80 percent of
its full capacity. When the cell is 100 mV less than its full rated
charge voltage the capacity contained within the cell is 95 percent.
Hence, allowing the cell to slowly complete its charge takes
advantage of the larger capacity of the lithium cells.
SL01554
CHARGE CURRENT
(%C)
1.0
0.5
1.0
2.0
OPEN-CIRCUIT
CELL
VOL
T
AGE
(V)
3.0
4.0
1.0
2.0
Point B
Vov
TIME (HOURS)
TIME (HOURS)
CONSTANT
VOLTAGE
CONSTANT
CURRENT
Figure 7.
Lithium cell charging curves.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
8
SL01555
Hysteresis
Dead Time
Cell Voltage
Undervoltage
Over-voltage Threshold
CF Voltage
DF Voltage
VM Voltage
GND Level
Charge Mode
Charge
Discharge Mode
Excess
Excess Discharge
Over-voltage time delay
Discharge
Discharge
Mode
Mode
Mode
Current Mode
Threshold
VOLTAGE
t
DLY(OV)
Over-discharge
time delay
Figure 8.
Timing diagram.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
9
APPLICATION INFORMATION
The NE57600 drives the series N-Channel MOSFETs to states
determined by the cell's voltage and the battery pack load current.
During normal operation, both the discharge and charge MOSFETs
are ON, allowing bidirectional current flow.
If the battery pack is being charged, and the cell's voltage exceeds
the overvoltage threshold, then the charge MOSFET is turned OFF.
The cell's voltage must fall lower than the overvoltage hysteresis
voltage (V
OV(Hyst)
) before the charge MOSFET is again turned ON.
If the battery pack is being discharged and the undervoltage
threshold (V
UV(Th)
) is exceeded, then the discharge MOSFET is
turned OFF. It will not turn back ON until a charger is applied to the
pack's external terminals AND the cell's voltage rises above the
undervoltage hysteresis voltage (V
UV(Hyst)
).
When the battery pack is being discharged, if the load current
causes the voltage across the discharge MOSFET to exceed the
overcurrent threshold voltage (V
OC(TH)
), then the discharge
MOSFET is turned OFF after a fixed 718 ms delay. If short-circuit
is placed across the pack's terminals, then the discharge MOSFET
is turned OFF after a 100300 ms delay to avoid damaging the
MOSFETs.
The R-C filter on the V
CC
pin
An R-C filter is needed on the V
CC
pin, primarily to shield the IC
from electrostatic energy and spikes on the terminals of the battery
pack. A secondary need is during the occurrence of a short-circuit
across the battery pack terminals. Here, the Li-ion cell voltage could
collapse and cause the IC to enter an unpowered state. The R-C
filter provides power during the first instant of the short circuit,
allowing the IC to turn OFF the discharge MOSFET before the IC
loses power. The R-C filter also filters any voltage noise caused by
noisy load current. The values shown in Figure 9 are adequate for
these purposes.
SL01556
NE57600
6
5
4
3
2
1
VM
CF
GND
DF
CHARGER
DETECTOR
OC REF
OV DEADTIME
CONTROL
UV DEADTIME
CONTROL
OV REF
UV REF
C
DLY
V
CC
V
CC
V
CC
V
CC
Figure 9.
Functional diagram.
SL01557
6
5
4
3
2
1
VM
CF
GND
DF
V+
V
NE57600
DISCHARGE
FET
CHARGE
FET
C
DLY
V
CC
Li-ION CELL
CHARGER
OR
LOADER
+
4.7 k
910 k
1.0
F
1.0
F
330
Figure 10.
Typical application circuit.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
10
FET STATUS FOR NORMAL AND ABNORMAL
CONDITIONS
Operating Mode and
Charging Condition
Charge
FET (CF)
Discharge
FET (DF)
Normal (charging or discharging)
ON
ON
Overcharge (charging)
OFF
ON
Overcharge (discharging)
ON
ON
Overdischarge (discharging)
OFF
OFF
Overdischarge (charging)
ON
ON
Overcurrent (charging or discharging)
OFF
OFF
Normal mode:
Overdischarge detection voltage < battery
voltage <overcharge detection voltage
Discharge current < overcurrent detection
level
Overcharge mode:
Battery voltage > overcharge detection
voltage
Overdischarge mode:
Overdischarge detection voltage > battery
voltage
Overcurrent mode:
Discharge current > overcurrent detection
level
voltage between VM and GND =
discharge current
FET ON resistance
(discharge or charge FET)
Selecting the Optimum MOSFETs
For a single-cell battery pack, a logic-level MOSFET should be
used. These MOSFETs have turn-on thresholds of 0.9 V and are
considered full-on at 4.5 V VGS. Some problem may be
encountered in not having enough gate voltage to fully turn-ON the
series MOSFETs over the battery pack entire operating voltage. If
one deliberately selects an N-Channel MOSFET with a much
greater current rating, a lower RDS
(on)
over the entire range can be
attained.
The MOSFETs should have a voltage rating greater than 20 V and
should have a high avalanche rating to survive any spikes
generated across the battery pack terminals.
The current rating of the MOSFETs should be greater than four
times the maximum "C-rating" of the cells. The current rating,
though, is more defined by the total series resistance of the battery
pack. The total resistance of the battery pack is given by Equation 1.
R
bat(tot)
= RDS
(on)
+ R
cell
(Equation 1)
The total pack resistance is typically determined by the system
requirements. The total pack resistance directly determines how
much voltage droop will occur during pulses in load current.
Another consideration is the forward-biased safe operating area of
the MOSFET. During a short-circuit, the discharge current can easily
reach 1015 times the "C-rating" of the cells. The MOSFET must
survive this current prior to the discharge MOSFET can be turned
OFF. So having an FBSOA envelope that exceeds 20 amperes for
5 ms would be safe.
PACKING METHOD
SL01305
TAPE DETAIL
COVER TAPE
CARRIER TAPE
REEL
ASSEMBLY
TAPE
GUARD
BAND
BARCODE
LABEL
BOX
Figure 11.
Tape and reel packing method.
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
11
SOT-26A: plastic small outline package; 6 leads; body width 1.8 mm
1.15
1.2
1.0
0.025
0.55
0.41
0.22
0.08
3.00
2.70
1.70
1.50
0.55
0.35
6
SOT-26A
Philips Semiconductors
Product data
NE57600
One-cell Lithium-ion battery protection with
over/undercharge and overcurrent protection
2001 Oct 03
12
Definitions
Short-form specification -- The data in a short-form specification is extracted from a full data sheet with the same type number and title. For
detailed information see the relevant data sheet or data handbook.
Limiting values definition -- Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one
or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or
at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended
periods may affect device reliability.
Application information -- Applications that are described herein for any of these products are for illustrative purposes only. Philips
Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or
modification.
Disclaimers
Life support -- These products are not designed for use in life support appliances, devices or systems where malfunction of these products can
reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications
do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application.
Right to make changes -- Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard
cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no
responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these
products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless
otherwise specified.
Contact information
For additional information please visit
http://www.semiconductors.philips.com.
Fax: +31 40 27 24825
For sales offices addresses send e-mail to:
sales.addresses@www.semiconductors.philips.com.
Koninklijke Philips Electronics N.V. 2001
All rights reserved. Printed in U.S.A.
Date of release: 10-01
Document order number:
9397 750 08981
Philips
Semiconductors
Data sheet status
[1]
Objective data
Preliminary data
Product data
Product
status
[2]
Development
Qualification
Production
Definitions
This data sheet contains data from the objective specification for product development.
Philips Semiconductors reserves the right to change the specification in any manner without notice.
This data sheet contains data from the preliminary specification. Supplementary data will be
published at a later date. Philips Semiconductors reserves the right to change the specification
without notice, in order to improve the design and supply the best possible product.
This data sheet contains data from the product specification. Philips Semiconductors reserves the
right to make changes at any time in order to improve the design, manufacturing and supply.
Changes will be communicated according to the Customer Product/Process Change Notification
(CPCN) procedure SNW-SQ-650A.
Data sheet status
[1] Please consult the most recently issued data sheet before initiating or completing a design.
[2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL
http://www.semiconductors.philips.com.
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