Datasheet SAA1502ATS Datasheet (Philips)

INTEGRATED CIRCUITS

DATA SH EET

SAA1502ATS

Safety IC for Li-ion

Preliminary specification
File under Integrated Circuits, IC11

1998 Jan 15

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

FEATURES

• Integrated power switches

• Temperature protection

• Zero voltage start-up

• Discharge and charge overcurrent protection

• Automatic release of current protection at removal of

charger or load

• Extremely low current consumption when battery
voltage is lower than 2.3 V

• Low current consumption in normal operation mode

• Accurate voltage detection levels

• Low resistance in current path

• Able to accommodate 17.5 V charge voltage

• Read out of charge disable status

• Small package (SSOP16)

• Low external components count

• Continuous monitoring of the battery voltage and

(dis)charge current.

GENERAL DESCRIPTION

The SAA1502ATS is manufactured in a Bipolar, CMOS
and DMOS (BCD) Power Logic 70 process and is intended
to be used as a protection circuit for single cell Li-ion
battery packs. The current and voltage ratings are
especially designed for use in battery packs for portable
telephones such as GSM.
The circuit monitors the battery voltage, current and
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
lifetime

• Overcharge protection for safety reasons

• Overcurrent protection on charge as well as discharge

current rate

• Temperature protection for preventing charge or
discharge at high temperatures.

It must be stated that the unit is a safety unit to be
integrated inside a battery pack. It is not intended as an
end of charge provision.

ORDERING INFORMATION

TYPE

NUMBER

SAA1502ATS SSOP16 plastic shrink small outline package; 16 leads; body width 5.3 mm SOT338-1

NAME DESCRIPTION VERSION

PACKAGE

1998 Jan 15 2

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1998 Jan 15 3

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BLOCK DIAGRAM

Safety IC for Li-ion SAA1502ATS

Philips Semiconductors Preliminary specification

V

V

n.c.

V

SS1

SS2

ST

CC

LF

V

15

LEVEL

ESD

SW2

SHIFTER

ESD

V

ESD

ref

4.18 V

3.95 V

3.6 V

2.3 V

V

ref

set
temperature
protection

charge

disable

charge
enable

discharge

enable

discharge

disable

V

ref

1, 16

2

14

5, 6

4, 13

7, 8,
9, 10

d

VM

ESD 6.8 V

C

LOGIC

ext

3

reset
temperature
protection

CHARGE

PUMP

LEVEL

SHIFTER

CURRENT

PROTECTION

V

ref

SAA1502ATS

V

ref

V

cp

V

ref

VM

SW1

11, 12

MGM307

Fig.1 Block diagram.

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

PINNING

SYMBOL PIN DESCRIPTION

n.c. 1, 16 not connected
V

CC

C

ext

LF 4, 13 leadframe connection

V

SS2

V

d

VM 11, 12 negative sense input
V

SS1

ST 15 status output

2 positive battery sense input
3 external delay capacitor

control circuit

5, 6 negative battery input and

power ground

7, 8, 9, 10 drain voltage of SW1 and

SW2

14 ground for the control circuit

handbook, halfpage

V
V

n.c.

V
C

SS2
SS2

CC

ext

LF

V
V

d
d

1
2
3
4

SAA1502ATS

5
6
7
8

MGM308

16

n.c.

15

ST
V

14

SS1

13

LF

12

VM

11

VM
V

10

d

V

9

d

FUNCTIONAL DESCRIPTION

Figure 3 gives the connection diagram of a Li-ion battery
pack. All that is contained within the solid perimeter is the
safety IC SAA1502ATS. It is a Multichip Module (MCM),
containing two separate but interconnected chips, one is
the control IC and the other contains two vertical power
NMOS transistors which are connected in anti series. Both
transistors have their backgate connected to their source,
resulting in two backgate diodes in anti series.
The basic function of the SAA1502ATS is to protect a
single Li-ion cell against overcharge and overdischarge for
reasons of lifetime and safety. The voltage across the cell
terminals is monitored continuously and compared to an
accurate internal reference voltage. For battery voltages
between 3.6 and 4.18 V and a (dis)charge current below
the current protection level, the safety unit is in normal
operating mode (see Fig.4). In this state both switches are
driven with an elevated supply voltage (with a charge
pump) which guarantees a low resistance in the main
current path. This is important for fully utilizing the high
energy density of Li-ion battery technology.

The discharge PowerMOS transistor SW2 is disabled to
block further discharge, when the battery is discharged
below 2.3 V. The battery voltage will increase stepwise,
because of the sudden disconnection of the load. The unit
will not re-enter the normal operation mode at this event

Fig.2 Pin configuration.

unless the battery voltage exceeds the voltage restarting
level of 3.6 V.

When no charger is present in the discharge inhibit mode,
the system will switch to the Power-down mode.

The current consumption of the unit (SAA1502ATS and
the Li-ion cell) is then reduced to a typical value of 0.1 µA
for minimizing the discharge of the battery pack.

Connecting a charger in the Power-down mode is detected
by a voltage difference between V

and VM of more than

CC

3 V. The system will then return to the discharge inhibit
mode. After a short transition phase characterized by
conduction of the backgate diode between the drain and
source leads of SW2, the system goes to the normal
operating mode and SW2 is powered again.

At zero voltage start-up, the system will start at the reset
mode. A special circuit keeps the charge transistor SW1
on as much as possible.

When the battery is charged to a voltage level of 4.18 V it
will enter the charge inhibit mode and the charge
PowerMOS transistor SW1 is switched off, disabling
charging. Connecting a load is then detected by the
reversal of the voltage across SW1 (I

> 1.5 mA) and will

dch

immediately reactivate SW1, entering the discharge
enable state.

1998 Jan 15 4

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

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 system will remain in the discharge enable mode
unless:

• The battery voltage drops below 3.95 V, which results in
re-entering normal operation. This transition is not
externally noticeable, because both switches remain low
ohmic.

• A charger is connected which will immediately
deactivate SW1 if Ich> 280 mA. As an additional safety
precaution also VCC> 4.18 V yields the same reaction,
because a small current of a charger may be undetected
with the condition of Ich> 280 mA, leading to
overcharging the Li-ion cell.

Current protection will deactivate both switches and is
detected by a voltage drop or rise of VVM when both
switches are activated. A release of this state can only be
achieved by removing the load (or charger).

The temperature protection overrules all other states and
yields deactivation of both switches. This situation is
activated at a junction temperature of 130 °C and released
at a junction temperature of 60 °C. The temperature
protection is followed by a return to its preceding mode.

Normal mode

In case of correct temperature, battery voltage and
(dis)charge current, the system will be in the normal
operation mode. Both the charge and discharge output will
be active high, so both switches are conducting
(SW1 = SW2 = 1).

is charged at a voltage below 2.3 V, an extra condition of
V

> 2.3 V is included going from the discharge inhibit to

bat

the normal operation mode.

Power-down mode

At low battery voltage the supply current is reduced to
100 nA for minimizing the discharge of the battery by the
SAA1502ATS.

At the Power-down mode all analog circuitry, except
circuitry for detecting a charger present (V

− VVM> 3 V),

CC

is disabled. The Power-down mode is entered when the
system is in the discharge inhibit mode and no charger is
present. The discharge inhibit mode will be entered again
as soon as a charger is connected.

The detection of a charger is accomplished by detecting a
voltage difference of 3 V between V

and VM. In this

CC

mode the voltage difference (see Fig.5) is:
VCC− VVM=V

− VR1+V

bat

j(DO)+Vds(CO)

≈ V

bat

+ 0.6 V.

So in the application the battery has to be charged in the
Power-down mode until such a voltage that
VCC− VVM=3V.

Reset mode

If the battery voltage is below 1.9 V, the system will be in
the reset mode. Because in this mode the charge pump is
disabled and battery charging should be possible, the
charge FET is switched on with a reduced V

voltage.

gs

As soon as the battery voltage exceeds 2.25 V the system
will switch to the discharge inhibit mode and the charge
pump will be activated again.

Discharge inhibit mode

If the battery drops below 2.3 V, the system will switch to
the discharge inhibit mode. In this mode only charging of
the battery is allowed (SW1 = 1, SW2 = 0). The system will
return to the normal operation mode as soon as the battery
voltage will exceed 3.6 V, or by detection of a charge
current.

The overdischarge detection of 2.3 V has a delay of 40 ms
typical. The voltage detection level 3.6 V has a delay of
50 ms typical. Because a charge current is necessary to
increase the battery voltage, the system will normally
switch to the normal operation mode at V

= 2.3 V by

CC

detecting a charge current. But if the charge current is too
small to detect, the 3.6 V detection is a backup.

To prevent an instable situation between the normal
operation and the discharge inhibit mode when the battery

1998 Jan 15 5

Zero voltage start-up

The system has to be able to charge the battery at ‘0 Volt’.
This means that when connecting a charger in case of a
complete empty battery, the charge FET has to be active.
In the reset mode the charge FET (SW1) is connected via
a diode to V

, so that the charge FET will be active when

CC

the VVM voltage is negative. The discharge inhibit mode
will be entered as soon as a battery voltage exceeds

2.25 V.

Charge inhibit mode

If the battery voltage exceeds 4.18 V, the charge inhibit
mode will be entered. At this mode the battery can only be
discharged (SW1 = 0, SW2 = 1). The overcharge
detection has a delay of 40 ms. This delay can be
increased by an external capacitor. The delay time is then

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

defined as:
td= 40 + (37 × C

) [ms], with C

ext

ext

in nF.

The system will return to the normal operation mode from
the charge inhibit mode when the battery voltage drops
below 3.95 V.

From the discharge enable mode the charge inhibit mode
will also be entered as soon as a charge current is
detected.

Discharge enable mode

When the system is in the charge inhibit mode, charging of
the battery is disabled because switch SW1 is turned off.
Discharge of the battery will then occur via the backgate
diode of SW1. So the output voltage will be approximately

0.6 V lower and also dissipation of the backgate diode of

SW1 occurs. It would be preferable to turn both switches
on at that time without allowing charging of the battery until
the battery voltage has dropped to 3.95 V.

If a discharge current larger than 1.5 mA is detected in the
charge inhibit mode, the system will activate the discharge
enable mode, activating both switches. From the
discharge enable mode the charge inhibit mode will be
re-entered as soon as a charge current is detected larger
than 280 mA or the battery voltage exceeds 4.18 V.

The detection of a higher voltage than 4.18 V is a backup.
If the battery is charged with a lower charge current than
280 mA, the system will not switch from the discharge
enable mode to the charge inhibit mode. Eventually, if the
battery is overcharged because of a small charge current,
the battery voltage will exceed 4.18 V and the system will
switch to the charge inhibit mode.

The system will return to the normal operation mode from
the discharge enable mode when the battery voltage drops
below 3.95 V.

If the system is in the charge inhibit mode, it will mostly go
to the normal mode via the discharge enable mode. But if
the system is in the charge inhibit state and the system is
stored for several years, the battery voltage can drop
because of the battery discharge by the SAA1502ATS 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 operation mode should also be
entered from the charge inhibit state when the battery
voltage is below 3.95 V and not only from the discharge
enable mode. In this way, charging a battery is always
possible if the battery voltage is below 3.95 V.

Temperature protection

Internally the system will switch between the different
modes as given in the state diagram, independent of the
temperature. As the junction temperature exceeds 130 °C,
the output signals will be overruled and switched to zero
(SW1 = SW2 = 0).

The supply current will be reduced to approximately
100 nA when the Power-down or reset mode is activated.
In these modes the temperature protection is deactivated.

When the junction temperature drops below 60 °C, the
output signals will not be overruled any more.

Overcurrent protection

When the (dis)charge current exceeds the specified
maximum value, the current protection mode is entered.

An extra condition of SW1 = SW2 = 1 is necessary
because of the next situation:

If the system is in the discharge inhibit and a charge
current is detected (e.g. V

= −0.6 V) the normal

VM

operation mode will be entered. Because of a minimum
time in which the gate capacitors have to be charged, the
VVM voltage will be −0.6 V for a short period, when the
system is already in the normal operation mode. A V

VM

voltage of −0.6 V could also occur when the system is
charged with current exceeding the maximum charge
current. To prevent that a maximum charge current is
detected when coming from the discharge inhibit state, the
system waits until both SW1 and SW2 are fully charged
before a maximum (dis)charge current is detected.

So the voltages at SW1 and SW2 are measured to be sure
that the normal operation mode is stabilized before the
current protection mode can be entered.

The same applies when entering the discharge enable
state from the charge inhibit state by detecting a discharge
current.

The delay of the current protection as function of the
(dis)charge current is given in Fig.8.

1998 Jan 15 6

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

handbook, full pagewidth

charger/load

charger/load

C

ext

3

1 kΩ

0.22
µF

V

bat

V

V

V

SS1

SS2

CC

2

14

5, 6

SAA1502ATS

CONTROL

CIRCUIT

DO CO VM

SW2

SW1

7, 8, 9, 10 11, 12

d

15

VMV

ST

MGM309

Fig.3 Connection diagram.

handbook, full pagewidth

current protection

SW1, SW2

current protection

SW1, SW2

I

or Ich> I

dch

no charger/load

I

or Ich> I

dch
no charger/load

(except from power down and reset)

prot

prot

T

start(prot)

discharge enable

VCC < 3.95 V

normal operation

from all states

≥ 130 °C

temperature protection

SW1, SW2

SW1, SW2

(Ich > 1.5 mA and VCC > 2.3 V)

back to previous state
T

rel(prot)

SW1, SW2

Fig.4 Flow diagram.

1998 Jan 15 7

VCC > 4.18 V or Ich > 280 mA

I

> 1.5 mA

dch

VCC > 4.18 V

VCC < 3.95 V

VCC < 2.3 V

VCC > 3.6 V

or

< 60 °C

from all states

VCC < 1.9 V

discharge inhibit

SW1, SW2

VCC > 2.25 V

charge inhibit

SW1, SW2

no charger present

charger present

reset

SW1, SW2

power down

SW1, SW2

MGM310

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

handbook, full pagewidth

V

CHARGER

VM

bat

V

j(DO)

V

ds(CO)

+

V

bat

−

+

−
+

−

R1

g

s

SW2

d
d

SW1

sg

C1

Fig.5 Circuit diagram of charging a Li-ion pack.

V

CC

CONTROL

CIRCUIT

CO

DO

MGM311

1998 Jan 15 8

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1998 Jan 15 9

discharge enable

V

bat

4.18

3.95

2.25

SW1

SW2

3.6

2.3

discharge inhibit

reset

on
off

on
off

normal operation

t

ec(det)

discharge enable

charge inhibit

t

ec(rel)

charge inhibit

t

ed(det)

normal operation

book, full pagewidth

via discharge inhibit

to power down

via discharge inhibit

to normal operation

t

d

current protection

normal operation

t

ec(det)

discharge enable

charge inhibit

current protection

discharge enable

t

d

t

ec(rel)

normal operation

TIMING DIAGRAM

Safety IC for Li-ion SAA1502ATS

Philips Semiconductors Preliminary specification

+V

−V

VM

diode

diode

V

bat

0

− 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

prot

no charger; no load

charger present

load present

I

load present

no charger; no load

dch

> I

prot

no charger; no load

load present

MGM315

Fig.6 Timing diagram.

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC 134); voltages with respect to pin V

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

V

CC

V

CC(clamp)

I

CC

V

VM

V

ST

I

Rpath

T

amb

T

stg

I

VSS−VM

positive battery sense input voltage DC constant −0.3 +4.5 V
VCC clamping voltage t < 60 ms and ICC=7mA − 8.5 V
maximum current through the VCC clamp − 7mA
negative sense input voltage VCC− 17.5 V
status output voltage V

VM

current through SW1 and SW2−27 A
operating ambient temperature −25 +80
storage temperature −55 +150°C

 maximum body diode current (DC value) − 800 mA

THERMAL CHARACTERISTICS

SS2

.

V

CC

V

CC

V

°

C

SYMBOL PARAMETER CONDITIONS VALUE UNIT

R

th(j-a)

R

th(j-pin)

thermal resistance from junction to ambient in free air 165 K/W
thermal resistance from junction to pin 22 K/W

1998 Jan 15 10

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

CHARACTERISTICS

T

=25°C; all voltages with respect to V

j

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT
Supply behaviour

V

CC

I

CC

I

q

V

CC−VVM

positive battery sense input voltage 0 − 4.5 V
supply current VCC= 4.0 V; −13.5 V ≤VVM≤ 0 4.0 7.0 10 µA
quiescent current Power-down/reset mode

minimum charge voltage at zero charge 1.8

Voltage detection

V

ec(det)

t

ec(det)

V

ec(rel)

t

ec(rel)

V

ed(det)

t

ed(det)

V

ed(rel)

t

ed(rel)

I

VSS−VM

V

VM

V

CC−VVM

V

CC

t

d(on)

t

d(off)

excess charge detection voltage measured at terminals of the

excess charge delay time V

excess charge release voltage 3.82
excess charge delay time V
excess discharge detection voltage 2.2
excess discharge delay time V
excess discharge release voltage 3.3
excess discharge delay time V

 (dis)charge current detection charge inhibit state 0.05 1.5 37.5 mA

negative sense input voltage discharge inhibit state;

charge present detection voltage Power-down mode 2.4
positive battery sense input voltage start of reset mode 1.7 1.9 2.1 V

switch-on delay time SW1/SW2 VCC= 4.0 V − 100 −µs
switch-off delay time SW1/SW2 VCC= 4.0 V − 100 −µs

; positive currents flow into the IC.

SS2

(VCC= 2.0 V)

battery and Tj=25°C
measured at terminals of the

= −5 to +55 °C

j

ec(det)

ec(rel)

ed(det)

ed(rel)

battery and T
C

not connected 20 40 60 ms

ext

C

= 33 nF (±10%) 0.5

ext

discharge enable state 150 280 475 mA
discharge inhibit state 0.05 1.5 37.5 mA

no charge current
current protection mode

no load detection 70 90 120 mV
no charger detection −7 −12 −20 mV

excess of reset mode 2.05 2.25 2.45 V

0.03

4.15

4.145

0.1

2.4

4.18

4.18

1.25

3.95

0.3 µA

3.0 V

4.20 V

4.21 V

2s

4.08 V

25 50 75 ms

2.3

2.4 V

20 40 60 ms

3.6

3.9 V

25 50 75 ms

−7 −12 −20 mV

3.0

3.6 V

1998 Jan 15 11

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT
Power transistors

R

path

main current path resistance VCC= 2.5 V; I

SW1 transistor

R

path(SW1)

current path resistance VCC= 2.5 V; I

SW2 transistor

R

path(SW2)

current path resistance VCC= 2.5 V; I

Temperature protection

T

start(prot)

T

rel(prot)

start of the temperature protection 120
release of the temperature protection 50

Current detection at VCC=4V;see Fig.8

= 4.0 V; I

V

CC

VCC= 4.0 V; I

VCC= 4.0 V; I

VSS−VM
VSS−VM

VSS−VM
VSS−VM

VSS−VM
VSS−VM

=2A 52
=2A 48

=2A 26
=2A 24

=2A 26
=2A 24

66
60

33
30

33
30

130
60

80 mΩ
72 mΩ

40 mΩ
36 mΩ

40 mΩ
36 mΩ

140 °C
70 °C

I

prot(min)

t

d

t

d(min)

minimum current protection level DC level 3.5 5 7 A
delay time at I

= 8 A 2 20 200 ms

prot

minimum delay time 190 − 430 µs
Status; see Table 1 and Fig.7
I

ST

V

ST

output current ST = 1; VCC− VVM= 17.5 V;

output voltage ST = 1; IST=40µA;

Table 1 Functional table of the status output (ST);

note 1

CONDITIONS OUTPUT

Normal operation 0
Charge inhibit 1
Discharge enable 0
Discharge inhibit 0
Power-down 0
Current protection 1
Temperature protection 1

VST− VVM= 0.5 V
ST = 1; V

− VVM=4V;

CC

VST− VVM= 0.5 V

VCC− VVM= 17.5 V
ST = 1; I

=10µA;

ST

VCC− VVM=4V

40 − 200 µA

10 − 100 µA

−−0.5 V

−−0.5 V

Note

1. At which: ‘0’ is active off, and ‘1’ is active on.

1998 Jan 15 12

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

handbook, full pagewidth

VST − V

(V)

VM

VCC − VVM = 4 V

VCC − VVM = 17.5 V

0.5

10 40

MGM313

IST (µA)

Fig.7 Status output current at different charge voltages.

2

10

handbook, halfpage

t

d

(s)

10

MGM312

1

−1

10

−2

10

typ

−3

10

−4

10

Ich (A)

min min

15 5

Fig.8 Current protection delay.

1998 Jan 15 13

maxmax

05 15

typ

I

dch

2525

(A)

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

APPLICATION INFORMATION

handbook, full pagewidth

Li-ion

B+

VM

(sense)

R2
10 MΩ

C3
100 nF

MGM314

R1
1 kΩ

V

CC

C1

1 µF

B−'B−

(sense)

C2 33 nF

n.c. n.c.

1

V

CC

2

C

ext

3

LF LF

4

SS2
SS2

V
V

d
d

SAA1502ATS

5
6
7
8

V
V

16
15
14
13
12
11
10

ST
V

SS1

VM
VM

V

d

V

d

9

(charger/load)

+

C4
100 nF

ST

V

SS1

−

(charger/load)

Fig.9 Connection diagram application board.

V

SS1

30

−

handbook, full pagewidth

Dimensions in mm.

PHILIPS

B+

+

1

C2 C1

ST

Fig.10 Application printed-circuit board.

1998 Jan 15 14

SAA1502PHILIPS

VM

C3 C4 R2 R1

B−'

V

CC

−

B

MGM316

6

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

PACKAGE OUTLINE

SSOP16: plastic shrink small outline package; 16 leads; body width 5.3 mm

D

c

y

Z

16

pin 1 index

9

A

2

A

E

H

E

1

SOT338-1

A

X

v M

A

Q

(A )

L

p

L

A

3

θ

1

e

DIMENSIONS (mm are the original dimensions)

mm

OUTLINE
VERSION

SOT338-1

A

max.

2.0

0.21

0.05

b

p

3

1.80

1.65

IEC JEDEC EIAJ

0.25

0.38

0.25

UNIT A1A2A

Note

1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.

8

b

p

cD

0.20

0.09

REFERENCES

MO-150AC

w M

0 2.5 5 mm

scale

(1)E(1)

6.4

5.4

6.0

0.65 1.25

5.2

1998 Jan 15 15

detail X

eHELLpQZywv θ

7.9

7.6

1.03

0.63

0.9

0.7

EUROPEAN

PROJECTION

0.130.2 0.1

(1)

1.00

0.55

ISSUE DATE

94-01-14
95-02-04

o

8

o

0

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

SOLDERING
Introduction

There is no soldering method that is ideal for all IC
packages. Wave soldering is often preferred when
through-hole and surface mounted components are mixed
on one printed-circuit board. However, wave soldering is
not always suitable for surface mounted ICs, or for
printed-circuits with high population densities. In these
situations reflow soldering is often used.

This text gives a very brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our

“IC Package Databook”

Reflow soldering

Reflow soldering techniques are suitable for all SSOP
packages.

Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied
to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement.

Several techniques exist for reflowing; for example,
thermal conduction by heated belt. Dwell times vary
between 50 and 300 seconds depending on heating
method. Typical reflow temperatures range from
215 to 250 °C.

Preheating is necessary to dry the paste and evaporate
the binding agent. Preheating duration: 45 minutes at
45 °C.

Wave soldering

Wave soldering is not recommended for SSOP packages.
This is because of the likelihood of solder bridging due to
closely-spaced leads and the possibility of incomplete
solder penetration in multi-lead devices.

(order code 9398 652 90011).

If wave soldering cannot be avoided, the following
conditions must be observed:

• A double-wave (a turbulent wave with high upward

pressure followed by a smooth laminar wave)
soldering technique should be used.

• The longitudinal axis of the package footprint must

be parallel to the solder flow and must incorporate
solder thieves at the downstream end.

Even with these conditions, only consider wave
soldering SSOP packages that have a body width of

4.4 mm, that is SSOP16 (SOT369-1) or
SSOP20 (SOT266-1).

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.

Maximum permissible solder temperature is 260 °C, and
maximum duration of package immersion in solder is
10 seconds, if cooled to less than 150 °C within
6 seconds. 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.

Repairing soldered joints

Fix the component by first soldering two diagonally­opposite end leads. Use only a low voltage soldering iron
(less than 24 V) 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.

1998 Jan 15 16

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

DEFINITIONS

Data sheet status

Objective specification This data sheet contains target or goal specifications for product development.
Preliminary specification This data sheet contains preliminary data; supplementary data may be published later.
Product specification This data sheet contains final product specifications.

Limiting values

Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). 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.

1998 Jan 15 17

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

NOTES

1998 Jan 15 18

Philips Semiconductors Preliminary specification

Safety IC for Li-ion SAA1502ATS

NOTES

1998 Jan 15 19

Philips Semiconductors – a worldwide company

Argentina: see South America
Australia: 34 Waterloo Road, NORTH RYDE, NSW 2113,

Tel. [phone], Fax. [phone]
Austria: Computerstr. 6, A-1101 WIEN, P.O. Box 213, Tel. [phone],

Fax. [phone]
Belarus: Hotel Minsk Business Center, Bld. 3, r. 1211, Volodarski Str. 6,

220050 MINSK, Tel. [phone], Fax. [phone]

Belgium: see The Netherlands
Brazil: seeSouth America
Bulgaria: Philips Bulgaria Ltd., Energoproject, 15thfloor,

51 James Bourchier Blvd., 1407 SOFIA,
Tel. [phone], Fax. [phone]

Canada: PHILIPS SEMICONDUCTORS/COMPONENTS,
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China/Hong Kong: 501 Hong Kong Industrial Technology Centre,
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Czech Republic: see Austria
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Tel. [phone], Fax. [phone]

Indonesia: see Singapore
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Tel. [phone], Fax. [phone]
Israel: RAPAC Electronics, 7 Kehilat Saloniki St, PO Box 18053,

TEL AVIV 61180, Tel. [phone], Fax. [phone]
Italy: PHILIPS SEMICONDUCTORS, Piazza IV Novembre 3,

20124 MILANO, Tel. [phone], Fax. [phone]
Japan: Philips Bldg 13-37, Kohnan 2-chome, Minato-ku, TOKYO 108,

Tel. [phone], Fax. [phone]
Korea: Philips House, 260-199 Itaewon-dong, Yongsan-ku, SEOUL,

Tel. [phone], Fax. [phone]
Malaysia: No. 76 Jalan Universiti, 46200 PETALING JAYA, SELANGOR,

Tel. [phone], Fax. [phone]
Mexico: 5900 Gateway East, Suite 200, EL PASO, TEXAS 79905,

Tel. [phone]

Middle East: see Italy

Netherlands: Postbus 90050, 5600 PB EINDHOVEN, Bldg. VB,

Tel. [phone], Fax. [phone]
New Zealand: 2 Wagener Place, C.P.O. Box 1041, AUCKLAND,

Tel. [phone], Fax. [phone]
Norway: Box 1, Manglerud 0612, OSLO,

Tel. [phone], Fax. [phone]
Philippines: Philips Semiconductors Philippines Inc.,

106 Valero St. Salcedo Village, P.O. Box 2108 MCC, MAKATI,
Metro MANILA, Tel. [phone], Fax. [phone]

Poland: Ul. Lukiska 10, PL 04-123 WARSZAWA,
Tel. [phone], Fax. [phone]

Portugal: see Spain
Romania: see Italy
Russia: Philips Russia, Ul. Usatcheva 35A, 119048 MOSCOW,

Tel. [phone], Fax. [phone]
Singapore: Lorong 1, Toa Payoh, SINGAPORE 1231,

Tel. [phone], Fax. [phone]

Slovakia: see Austria
Slovenia: see Italy
South Africa: S.A. PHILIPS Pty Ltd., 195-215 Main Road Martindale,

2092 JOHANNESBURG, P.O. Box 7430 Johannesburg 2000,
Tel. [phone], Fax. [phone]

South America: Al. Vicente Pinzon, 173, 6th floor,
04547-130 SÃO PAULO, SP, Brazil,
Tel. [phone], Fax. [phone]

Spain: Balmes 22, 08007 BARCELONA,
Tel. [phone], Fax. [phone]

Sweden: Kottbygatan 7, Akalla, S-16485 STOCKHOLM,
Tel. [phone], Fax. [phone]

Switzerland: Allmendstrasse 140, CH-8027 ZÜRICH,
Tel. [phone], Fax. [phone]

Taiwan: Philips Semiconductors, 6F, No. 96, Chien Kuo N. Rd., Sec. 1,
TAIPEI, Taiwan Tel. [phone], Fax. [phone]

Thailand: PHILIPS ELECTRONICS (THAILAND) Ltd.,
209/2 Sanpavuth-Bangna Road Prakanong, BANGKOK 10260,
Tel. [phone], Fax. [phone]

Turkey: Talatpasa Cad. No. 5, 80640 GÜLTEPE/ISTANBUL,
Tel. [phone], Fax. [phone]

Ukraine: PHILIPS UKRAINE, 4 Patrice Lumumba str., Building B, Floor 7,
252042 KIEV, Tel. [phone], Fax. [phone]

United Kingdom: Philips Semiconductors Ltd., 276 Bath Road, Hayes,
MIDDLESEX UB3 5BX, Tel. [phone], Fax. [phone]

United States: 811 East Arques Avenue, SUNNYVALE, CA 94088-3409,
Tel. [phone]

Uruguay: see South America
Vietnam: see Singapore
Yugoslavia: PHILIPS, Trg N. Pasica 5/v, 11000 BEOGRAD,

Tel. [phone], Fax.[phone]

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. [phone]

© Philips Electronics N.V. 1998 SCA57
All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner.

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.

Internet: http://www.semiconductors.philips.com

Printed in The Netherlands 297027/1200/01/pp20 Date of release: 1998 Jan 15 Document order number: 9397 750 02706