Objective specification
File under Integrated Circuits, IC17
2000 Mar 07
Page 2
Philips SemiconductorsObjective specification
Safety ICSAA1504T
FEATURES
• Zero voltage start-up
• Discharge and charge overcurrent protection
• Automatic release of current protection at removal of
charger or load
• Low current consumption in normal operating mode
• Very low current consumption when battery voltage is
lower than 2.3 V
• Accurate voltage detection levels
• Continuous monitoring of batteryvoltage and charge or
discharge current
• External power FETs are driven with an elevated supply
voltage, reducing the on-resistance
• Able to accommodate 20 V charge voltage
• Read out of charge (disable) status
• Small package (SO8)
• Low external components count
• Temperature protection
• Charger reverse connection protection.
GENERAL DESCRIPTION
The SAA1504T is manufactured in a BCD Power Logic 70
process and is intended to be used as a protection circuit
forsingle cell Li-ion batterypacks. The current and voltage
ratings are especially designed for use in battery packs for
portable telephones such as GSM.
The circuit continuously monitors the battery voltage,
current and junction temperature and will disconnect the
battery in case of an overload situation:
• Overdischarge protection prevents deep discharge of
the cell; deep discharge of a Li-ion cell degrades the life
cycle
• Overcharge protection for safety reasons
• Overcurrent protection on charge or discharge current
rate
• Temperature protection for preventing charge or
discharge at high temperatures
• Short circuit protection.
It must be stated that this is a safety IC to be integrated
inside a battery pack. It is not primarily intended as an end
of charge provision.
ORDERING INFORMATION
TYPE
NUMBER
SAA1504TSO8plastic small outline package; 8 leads; body width 3.9 mmSOT96-1
NAMEDESCRIPTIONVERSION
PACKAGE
2000 Mar 072
Page 3
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2000 Mar 073
handbook, full pagewidth
CEXT
BLOCK DIAGRAM
Philips SemiconductorsObjective specification
Safety ICSAA1504T
LOGIC
7
ESD
reset
disable
mode
CHARGE
SHIFTER
−185 mV
V
CC
PUMP
LEVEL
CURRENT
PROTECTION
V
ref
V
cp
SAA1504T
K2 × V
ptat
ESD
ESD
2
DO
3
CO
5
ST
ESD
CC
SS
8
ESD6.8 V
6
1
4
V
n.c.
V
VM
LEVEL
SHIFTER
K1 × V
ptat
4.18 V
ESD
2.3 V
3.95 V
V
ref
set
disable
mode
175 mV
Fig.1 Block diagram.
MGS969
Page 4
Philips SemiconductorsObjective specification
Safety ICSAA1504T
PINNINGFUNCTIONAL DESCRIPTION
SYMBOL PINDESCRIPTION
V
SS
1ground supply
DO2output to gate of discharge power FET
CO3output to gate of charge power FET
VM4negative sense input
ST5status output
n.c.6not connected
CEXT7connection for external delay capacitor
V
CC
handbook, halfpage
8positive battery sense input
V
1
SS
2
SAA1504T
3
CO
4
VM
MGS970
V
8
CC
CEXTDO
7
n.c.
6
ST
5
Fig.2 Pin configuration.
The basic function of the SAA1504T is to protect a single
Li-ion cell against overcharge and overdischarge for
reasons of life time and safety. The voltage across the cell
terminals (V
) is monitored continuously and compared
bat
to an accurate internal reference voltage.
The circuit diagram (see Fig.3) of a Li-ion battery pack
shows the SAA1504T and 2 power NMOS transistors
which are connected in anti series. Both transistors must
have their backgate connected to their source, resulting in
2 backgate diodes in anti series.
The timing diagram (see Fig.6) shows the detection levels
for the various modes of operation.
Battery voltage between 2.6 and 4.18 V
The safety IC is in the normal operating mode for
V
= 2.6 to 4.18 V, a charge or discharge current below
bat
the current-protection level and a junction temperature
below the temperature protection activation level. In this
mode transistors SW1 and SW2 are driven with an
elevated supply voltage (with a charge pump) which
guarantees a low on-resistance in the main current path.
This is important for fully utilizing the high energy density
of the Li-ion battery technology.
handbook, full pagewidth
+ charger/load
− charger/load
V
bat
R1
1 kΩ
SW2
SW1
Fig.3 Safety IC connection diagram.
2000 Mar 074
C1
0.47 µF
C2
CEXT
V
SS
DO
CO
7
1
2
SAA1504T
3
V
CC
8
ST
5
4
VM
MGS971
Page 5
Philips SemiconductorsObjective specification
Safety ICSAA1504T
Battery voltage below 2.3 V
When V
< 2.3 V the safety IC is in the Power-down
bat
mode: SW2 is open to block a further discharge.
The battery voltage will increase stepwise, because of the
sudden disconnection of the load. The safety IC will not
re-enter the normal operating mode at this event unless
the battery voltage exceeds the power-down release level
of 2.6 V and a charge current is present. So when no
charger is present in the Power-down mode, the safety IC
stays in this mode, independent of the battery voltage.
ConnectingachargerinthePower-downmodeisdetected
by a negative voltage on pin VM. Because the voltage at
pin VM is defined by a charge current via the backgate
diode of SW2, a charge current of a few nAs is already
detected. When a charge current is detected and
V
> 2.6 V, the system will go from the Power-down
bat
mode to the normal operating mode.
In the Power-down mode the supply current is reduced to
150 nA (typical value) for minimizing the discharge of the
battery by the safety IC. This is achieved by disabling all
analog circuitry, except the circuitry for detecting the
presence of a charger and for detecting V
bat
> 2.6 V.
Because the charge pump is disabled and battery
charging should be possible, SW1 is switched on with a
reduced Vgs voltage.
Zero voltage start-up
The safety IC has to be able to charge the battery at 0 V.
This means that when connecting a charger in case of a
completely empty battery, SW1 has to be open.
In the Power-down mode output CO is connected via a
diode to VCC, so that the charge transistor will be active
when VVM is negative.
Maximum charge or discharge current and
temperature protection
When the maximum charge or discharge current is
exceeded or when the maximum temperature is detected
the disable mode is activated and will open both switches.
Exceeding the maximum charge or discharge current is
detected by a voltage drop or rise on pin VM when both
switches are closed.
A release of this mode can only be achieved by removing
the load (or charger) and at a junction temperature below
60 °C. The disable mode is followed by a return to its
previous mode.
Normal operating mode
In case of correct temperature, battery voltage and charge
or discharge current, the system will be in the normal
operating mode (see Fig.4).
Battery voltage above 4.18 V
When the battery is charged to V
> 4.18 V, the safety IC
bat
will enter the charge inhibit mode: SW1 is open and
charging is disabled.
Connecting a load in the charge inhibit mode is detected
by the reversal of the voltage across SW1 and will
immediately close SW1, so entering the discharge enable
mode. A short time is needed to charge the gate of SW1.
During this time the backgate diode between drain and
source of SW1 conducts.
The safety IC will remain in the discharge enable mode
unless:
• V
< 3.95 V, which results in re-entering the normal
bat
operating mode. This transition is not externally
noticeable, because both switches remain closed.
• A charger is connected, which will immediately open
SW1. As an additional safety precaution V
> 4.18 V
bat
also yields the same reaction, because otherwise a
smallcurrentof a charger may be undetected, leading to
overcharging the Li-ion cell.
Both the charge and discharge outputs will be HIGH
(CO = 1 and DO = 1), so both switches are closed.
Power-down mode
When V
< 2.3 V the safety IC will enter the Power-down
bat
mode(seeFig.4).Thepower-down detection level of 2.3 V
hasadelay of 5 ms (typical value). The Power-down mode
will also be entered without delay when V
bat
< 1.9 V.
In this mode only charging of the battery is allowed
(CO = 1 and DO = 0).
The safety IC will return to the normal operating mode as
soon as V
> 2.6 V and a charge current is detected at
bat
the same time.
2000 Mar 075
Page 6
Philips SemiconductorsObjective specification
Safety ICSAA1504T
Charge inhibit mode
When V
> 4.18 V, the charge inhibit mode will be
bat
entered (see Fig.4). At this mode the battery can only be
discharged (CO = 0 and DO = 1).
The excess charge delay can be set by means of an
external capacitor. The delay is then defined as:
t
ed(det)
When V
=30×C
< 3.95 V, the safety IC will return from the
bat
CEXT
with t
in ms and C
ed(det)
CEXT
in nF.
charge inhibit mode to the normal operating mode.
The charge inhibit mode will also be entered as soon as a
charge current is detected in the discharge enable mode
Discharge enable mode
When the safety IC is in the charge inhibit mode, charging
of the battery is disabled because SW1 is open. Initially
discharge of the battery will then occur via the backgate
diodeofSW1.Theloadvoltagewillbeapproximately0.6 V
lower and dissipation of the backgate diode of SW1 will
occur. It is preferable to close both switches at that time
without allowing charging of the battery until V
< 3.95 V.
bat
If a discharge current is detected in the charge inhibit
mode,the system will activate the discharge enablemode,
closing both switches.
From the discharge enable mode the charge inhibit mode
will be entered again as soon as a charge current is
detected or V
> 4.18 V. The detection of a higher
bat
voltage than 4.18 V is necessary. If the battery is charged
with a very low charge current, the safety IC will not switch
from the discharge enable mode to the charge inhibit
mode.Eventually,thesafety ICwill enter the charge inhibit
mode if the battery is overcharged to V
> 4.18 V
bat
because of a small charge current.
When V
< 3.95 V the safety IC will return from the
bat
discharge enable to the normal operating mode.
If the safety IC is in the charge inhibit mode, it will usually
go to the normal operating mode via the discharge enable
mode. But if the system is in the charge inhibit mode and
the battery pack is stored for several years, the battery
voltage can drop because of the battery discharge by the
safety IC and the self discharge of the battery. So a
voltage drop of the battery is possible, without detecting a
discharge current. Because of this, the normal operating
mode should also be entered from the chargeinhibit mode
whenV
< 3.95 Vandnotonlyfromthedischarge enable
bat
mode. In this way, charging a battery is always possible if
V
< 3.95 V.
bat
handbook, full pagewidth
to previous mode
(1) Minimum time in the disable mode is about 5 ms.
T > 100
or
I > I
max
disable mode
CO, DO
(1)
−185 mV < VVM < 175 mV
and
T < 60
°C
°C
discharge enable
CO, DO
V
< 3.95 V
bat
normal operating
CO, DO
V
> 2.6 V
bat
and
VVM <−185 mV
power down
CO, DO
Fig.4 Flow diagram.
VVM > 480 mV
V
> 4.18 V
bat
or
VVM <−10 mV
V
> 4.18 V
bat
from all modes
V
bat
V
< 2.3 V at 5 ms
bat
V
bat
< 1.9 V
or
charge inhibit
CO, DO
< 3.95 V
MGS973
2000 Mar 076
Page 7
Philips SemiconductorsObjective specification
Safety ICSAA1504T
Disable mode
When the charge or discharge current exceeds the
specified maximum value, the disable mode is entered.
Detection of the maximum charge or discharge current is
only activated when the outputs are HIGH (CO = 1 and
DO = 1) as explained next.
If the safety IC is in the Power-down mode and a charge
current is detected (e.g. VVM= −0.6 V) the normal
operating mode will be entered when V
bat
> 2.6 V.
Because of a minimum time in which the gate capacitors
have to be charged,VVM= −0.6 V for a smallperiod, when
the safety IC is already in the normal operating mode.
VVM= −0.6 Vcould also occur when the batteryischarged
with a current exceeding the maximum charge current.
To prevent that a maximum charge current is detected
when coming from the Power-down mode a delay is
included to ensure charging of both outputs CO and DO.
So entering of the disable mode is enabled when both
outputs CO and DO are fully charged or after a certain
delay. The delay is necessary to activate the current
protection even in case the outputs CO or DO can not be
fully charged.
The same applies for entering the disable mode when the
safety IC is in the discharge enable mode.
The delay of the current protection as a function of the
sense voltage VVM (for charge and discharge) is given in
Fig.5.
The disable mode is also entered when the junction
temperature exceeds 100 °C. When the temperature
dropsbelow60 °Cand at the absence of a charger or load,
the safety IC will return to its previous mode.
Status output
The status of the safety IC is available on pin ST.
Table 1 Functional table of the status output
MODEOUTPUT PIN ST
Normal operatingLOW
Charge inhibitHIGH
Discharge enableLOW
Power-downLOW
DisableHIGH (note 1)
Note
1. Only when a charger is connected.
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 60134); voltages measured with respect to pin VSS.
SYMBOLPARAMETERCONDITIONMIN.MAX.UNIT
V
CC
V
CC(clamp)
I
CC(clamp)
V
rev
V
VM
V
ST
T
amb
T
stg
positive battery sense input voltageDC constant−0.3+4.5V
clamping voltageI
start of temperature protectiondisable mode90100110°C
release of temperature protection506070°C
minimum current-protection voltageDC level on pin VM150250350mV
delayminimum value100200400µs
= 510 mV248ms
at V
VM
2000 Mar 078
Page 9
Philips SemiconductorsObjective specification
Safety ICSAA1504T
SYMBOLPARAMETERCONDITIONSMIN.TYP.MAX. UNIT
Status output on pin ST
I
O
Notes
1. The voltages are measured at the terminals of the battery. This voltage equals the voltage across series resistor
R1 = 1 kΩ plus the voltage on pin VCC (see Fig.3).
2. For both charge and discharge state.
output currentpin ST = HIGH; see Table 1;
VST=VVM+ 0.5 V
− VVM= 20 V131721µA
V
CC
V
− VVM= 4 V91215µA
CC
10
handbook, halfpage
t
d
(s)
1
−1
10
−2
10
−3
10
−4
10
−1−0.501
chargedischarge
0.5
VVM (V)
Fig.5 Current-protection delay.
MGS972
2000 Mar 079
Page 10
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2000 Mar 0710
handbook, full pagewidth
TIMING DIAGRAM
Philips SemiconductorsObjective specification
Safety ICSAA1504T
+V
−V
V
SW1
SW2
VM
V
diode
diode
bat
4.18
3.95
2.6
2.3
bat
discharge enable
normal operating
power-down
t
ec(det)
on
off
on
off
0
discharge enable
charge inhibit
charge inhibit
normal operating
t
ed(det)
power-down
normal operating
disable mode
t
d
normal operating
t
ec(det)
discharge enable
charge inhibit
discharge enable
disable mode
t
d
normal operating
− V
V
charger
bat
charger present
charger present
load present
no charger; no load
no charger; no load
no charger; no load
load present
no charger; no load
charger present
charger present
I
ch
> I
max
no charger; no load
charger present
load present
I
load present
no charger; no load
dch
> I
max
no charger; no load
load present
MGS974
Fig.6 Timing diagram.
Page 11
Philips SemiconductorsObjective specification
Safety ICSAA1504T
PACKAGE OUTLINE
SO8: plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
y
Z
8
pin 1 index
1
D
c
5
A
2
A
1
4
e
w M
b
p
E
H
E
detail X
A
X
v M
A
Q
(A )
L
p
L
A
3
θ
02.55 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
mm
OUTLINE
VERSION
SOT96-1
A
A1A2A3b
max.
0.25
1.75
0.10
0.010
0.069
0.004
p
1.45
1.25
0.057
0.049
IEC JEDEC EIAJ
076E03 MS-012
0.25
0.01
0.49
0.36
0.019
0.014
0.25
0.19
0.0100
0.0075
UNIT
inches
Notes
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
2. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
(1)E(2)
cD
5.0
4.8
0.20
0.19
REFERENCES
4.0
3.8
0.16
0.15
1.27
0.050
2000 Mar 0711
eHELLpQZywv θ
1.05
1.0
0.4
0.039
0.016
0.7
0.6
0.028
0.024
0.250.10.25
0.010.010.0410.004
EUROPEAN
PROJECTION
6.2
5.8
0.244
0.228
(1)
0.7
0.3
0.028
0.012
ISSUE DATE
97-05-22
99-12-27
o
8
o
0
Page 12
Philips SemiconductorsObjective specification
Safety ICSAA1504T
SOLDERING
Introduction to soldering surface mount packages
Thistextgivesavery brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our
“Data Handbook IC26; Integrated Circuit Packages”
(document order number 9398 652 90011).
There is no soldering method that is ideal for all surface
mount IC packages. Wave soldering is not alwayssuitable
for surface mount ICs, or for printed-circuit boards with
high population densities. In these situations reflow
soldering is often used.
Reflow soldering
Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied
tothe printed-circuit board by screen printing, stencillingor
pressure-syringe dispensing before package placement.
Several methods exist for reflowing; for example,
infrared/convection heating in a conveyor type oven.
Throughput times (preheating, soldering and cooling) vary
between 100 and 200 seconds depending on heating
method.
Typical reflow peak temperatures range from
215 to 250 °C. The top-surface temperature of the
packages should preferable be kept below 230 °C.
Wave soldering
Conventional single wave soldering is not recommended
forsurfacemountdevices(SMDs)orprinted-circuitboards
with a high component density, as solder bridging and
non-wetting can present major problems.
To overcome these problems the double-wave soldering
method was specifically developed.
If wave soldering is used the following conditions must be
observed for optimal results:
• Use a double-wave soldering method comprising a
turbulent wave with high upward pressure followed by a
smooth laminar wave.
• For packages with leads on two sides and a pitch (e):
– larger than or equal to 1.27 mm, the footprint
longitudinal axis is preferred to be parallel to the
transport direction of the printed-circuit board;
– smaller than 1.27 mm, the footprint longitudinal axis
must be parallel to the transport direction of the
printed-circuit board.
The footprint must incorporate solder thieves at the
downstream end.
• Forpackageswithleadsonfoursides,thefootprintmust
be placed at a 45° angle to the transport direction of the
printed-circuit board. The footprint must incorporate
solder thieves downstream and at the side corners.
During placement and before soldering, the package must
be fixed with a droplet of adhesive. The adhesive can be
applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the
adhesive is cured.
Typical dwell time is 4 seconds at 250 °C.
A mildly-activated flux will eliminate the need for removal
of corrosive residues in most applications.
Manual soldering
Fix the component by first soldering two
diagonally-opposite end leads. Use a low voltage (24 V or
less) soldering iron applied to the flat part of the lead.
Contact time must be limited to 10 seconds at up to
300 °C.
When using a dedicated tool, all other leads can be
soldered in one operation within 2 to 5 seconds between
270 and 320 °C.
2000 Mar 0712
Page 13
Philips SemiconductorsObjective specification
Safety ICSAA1504T
Suitability of surface mount IC packages for wave and reflow soldering methods
1. All surface mount (SMD) packages are moisture sensitive. Depending upon the moisture content, the maximum
temperature (with respect to time) and body size of the package, there is a risk that internal or external package
cracks may occur due to vaporization of the moisture in them (the so called popcorn effect). For details, refer to the
Drypack information in the
2. These packages are not suitable for wave soldering as a solder joint between the printed-circuit board and heatsink
(at bottom version) can not be achieved, and as solder may stick to the heatsink (on top version).
3. If wave soldering is considered, then the package must be placed at a 45° angle to the solder wave direction.
The package footprint must incorporate solder thieves downstream and at the side corners.
4. Wave soldering is only suitable for LQFP, TQFP and QFP packages with a pitch (e) equal to or larger than 0.8 mm;
it is definitely not suitable for packages with a pitch (e) equal to or smaller than 0.65 mm.
5. Wave soldering is only suitable for SSOP and TSSOP packages with a pitch (e) equal to or larger than 0.65 mm; it is
definitely not suitable for packages with a pitch (e) equal to or smaller than 0.5 mm.
DEFINITIONS
Data sheet status
Objective specificationThis data sheet contains target or goal specifications for product development.
Preliminary specificationThis data sheet contains preliminary data; supplementary data may be published later.
Product specificationThis data sheet contains final product specifications.
Limiting values
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
Where application information is given, it is advisory and does not form part of the specification.
LIFE SUPPORT APPLICATIONS
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 customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such
improper use or sale.
2000 Mar 0713
Page 14
Philips SemiconductorsObjective specification
Safety ICSAA1504T
NOTES
2000 Mar 0714
Page 15
Philips SemiconductorsObjective specification
Safety ICSAA1504T
NOTES
2000 Mar 0715
Page 16
Philips Semiconductors – a w orldwide compan y
Argentina: see South America
Australia: 3 Figtree Drive, HOMEBUSH, NSW 2140,
United States: 811 East Arques Avenue, SUNNYVALE, CA 94088-3409,
Tel. +1 800 234 7381, Fax. +1 800 943 0087
Uruguay: see South America
Vietnam: see Singapore
Yugoslavia: PHILIPS, Trg N. Pasica 5/v, 11000 BEOGRAD,
Tel. +381 11 3341 299, Fax.+381 11 3342 553
For all other countries apply to: Philips Semiconductors,
International Marketing & Sales Communications, Building BE-p, P.O. Box 218,
5600 MD EINDHOVEN, The Netherlands, Fax. +31 40 27 24825
The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed
without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license
under patent- or other industrial or intellectual property rights.
2000
Internet: http://www.semiconductors.philips.com
69
Printed in The Netherlands403506/25/01/pp16 Date of release: 2000 Mar 07Document order number: 9397 750 06537
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