Datasheet SAA1501T Datasheet (Philips)

INTEGRATED CIRCUITS

DATA SH EET

SAA1501T

Battery charge level indicator

Objective specification
File under Integrated Circuits, IC11

Philips Semiconductors

December 1994

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

FEATURES

• High level of integration to allow assembly in intelligent
battery packs

• Accurate charge and discharge account

• Large dynamic range of charge and discharge currents

• Independent settings of charge and discharge efficiency

• 2 V minimum supply voltage (2 cell operation)

• Temperature protection of batteries during charging

• Temperature controlled self-discharge

• Accurate charge current regulation

• Two charge amount display modes, LCD and LED.

GENERAL DESCRIPTION

The SAA1501T is intended to be used as a battery monitor
and charge current control circuit in rechargeable battery
systems.

The SAA1501T is processed in BiCMOS technology
where the benefits of mixed bipolar and CMOS technology
is fully utilized to achieve high accuracy measurements
and digital signal processing in the same device. The
general function of the integrated circuit is a Coulomb
counter. During battery charging, the charge current and
charge time are registered in a Coulomb counter. During
discharge, the discharge current and time are recorded.
The momentary charge amount of the batteries can be
displayed either on an LCD screen or on an LED bargraph.
Using the SAA1501T, intelligent batteries or intelligent
battery powered systems can be easily designed with only
a few external components.

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

CC

I

CC

supply voltage 2.0 3.0 4.3 V
supply current VCC=3V;

− 1.2 1.7 mA

Ic=Id=60µA

I

CCstb

f

osc

V

i(s)

T

amb

supply current in standby mode VCC=3 V;

V

CSI=VDSI

fixed oscillator frequency C

osc

R

ref

= 820 pF;

= 51.5 kΩ

=0V

−− 100 µA

− 4.2 − kHz

input sense voltage (pins 9 and 10) 0 − VCC− 1.6 V
operating ambient temperature 0 − +70 °C

ORDERING INFORMATION

PACKAGE

TYPE NUMBER

NAME DESCRIPTION VERSION

SAA1501T SO24 plastic small outline package; 24 leads; body width 7.5 mm SOT137-1

December 1994 2

Philips Semiconductors Objective specification

B

BBB

B

BBB

BBBB

B
B
B

BBBB

BBB

B
B
B

BBB

B
B
B

BBB

B
B
B

BBB

B
B
B

B
B

B

BBBBBBB

B
B
B

B
B

B
B
B

B
B
B
B
B
B

BBB
B

B

BBB

B
B

B
B

BB

B
B
B
B
B
B

B
B
B
B
B
B

Battery charge level indicator SAA1501T

BLOCK DIAGRAM

B
B

BBBBBB

BB

BB

BB
BB

BB
BB

BB

BB
BB
BB

BBB
BBB
BBB

B
B
B
B
B
B

BB
BB

B

B
B

B
B

B
B

B
B

B
B

B

Fig.1 Block diagram.

December 1994 3

BB

BB

B
B
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Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

PINNING

SYMBOL PIN DESCRIPTION

V

CC

EN 2 enable output
C

cy

C

CC

I

ch

R

ref

R

DCC

R

CCC

CSI 9 charge sense input
DSI 10 discharge sense input
R

TEMP1

R

TEMP2

C

osc

BUZ 14 buzzer output
FULL 15 battery full indication output
L100 16 100% segment indication output
L80 17 80% segment indication output
L60 18 60% segment indication output
L40 19 40% segment indication output
L20 20 20% segment indication output
BP 21 LCD back plane drive
BLI 22 battery low indicator LED output
POL 23 power-on LED output
GND 24 power ground

1 supply voltage

3 duty cycle capacitor output
4 charge counter capacitor output
5 maximum average charge current

setting input
6 current reference resistor input
7 discharge current conversion resistor

input
8 charge current conversion resistor

input

11 temperature sensing resistor 1 input
12 temperature sensing resistor2 input
13 oscillator capacitor input

Fig.2 Pin configuration.

December 1994 4

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

FUNCTIONAL DESCRIPTION

The most important function of the SAA1501T is the
charge account in rechargeable battery systems. Both
NiCd and NiMH batteries in all sizes can be used. The
system can operate alone as a charge monitor with a
charge amount display function or, can operate in
conjunction with a charger. If the SAA1501T operates
together with a charger, it delivers a control signal at output
EN, for charge current regulation or for battery voltage
regulation.

Fast charging systems and charge current regulation

The SAA1501T is especially designed to be used in fast
charging systems. In fast charging systems, the charge
time is lowered by raising the charge current. Signal EN
controls the charger current. The counters register the
state of charge of the batteries and at the 80% level the
charge current is reduced via a smaller duty cycle
regulation of signal EN. The second (slow) level fully
charges the batteries which is not possible with the first
(fast) level. After the slow charge mode the counter
switches over to an even smaller duty cycle of EN and thus
enters the third (trickle) charge mode, to overcome the
self-discharge of the batteries.

Current sensing and charge account

The charge current is sensed by means of a very low
resistance (e.g. 70 mΩ) sense resistor R

(see Fig.8) to

sc

save power at high charge rates. Via the V/I charge
converter and external resistor R

(see Fig.8), the

CCC

sensed voltage is converted into a charge current Ic (the
same is applicable for the discharge current). In the I/F
converter the charge current is converted into a frequency
for up-counting the counter. For the discharge current (Id)
the converted frequency is used for down-counting. The
up and down counting is registered in counters CNT1 and
CNT2, depending on the actual charge and discharge
current levels of the batteries. This is called dynamic
charge account.

Charge display

The charge amount represented by the Coulomb counter
can be displayed via an LCD screen or via an LED
bargraph. If the charge amount is reduced to 0%, the
battery low indicator (BLI) LED is turned on at the end of a
battery discharge session. A flashing BLI, in combination
with a repeating buzzer alarm, informs the user about the
low charge state. A new charge session should then be
started.

Protections

In the temperature control block, the absolute temperature
is used as a protection to end the fast charge cycle. Fast
charging at high temperature is not permitted because of
degradation of the battery cells. If the batteries are
disconnected, an open-battery condition is recognized and
the SAA1501T enters the standby mode.

Mode detection

The mode detector detects whether there are any charge
or discharge currents, whether the system is powered,
whether loads are connected or whether the system is in
the standby mode. If power is connected, the power-on
LED (POL) is on. In the standby mode, the Coulomb
counter will count down in accordance with the
self-discharge speed of the batteries, which is temperature
controlled. The following subsections describe the various
blocks of the block diagram in more detail.

Supply and reference

During the period when VCC rises from 0 V to the internal
reset level, all counters are reset. The internal reset is
released before VCC reaches 1.7 V. The operating supply
voltage ranges from 2 V to the open battery level of

4.3 V (min). The characteristics are guaranteed at
VCC= 3 V. In order to protect the SAA1501T against high
supply voltages during open battery in a flyback converter,
a voltage clamp circuit is made active at 6.35 V (typ). The
clamping current must not exceed 80 mA. A band gap
reference block is included to generate accurate voltages
i.e. for the oscillator. Moreover, together with R

, accurate

ref

currents are generated which are used in the I/F and V/I
converters and the oscillator block. In the standby mode
only the oscillator and the digital parts are active to limit the
discharge current of the batteries to a current level of less
than 100 mA. The circuits that are needed temporarily are
switched on and off during standby (see “Timing
characteristics” t

som

).

Voltage-to-current charge and discharge

In the V/I converter, the input charge current is translated
into acceptable levels for the circuit. The conversion
formula is:

I

ch earg

=

---------------------------------------

c

Rsc×()

R

CCC

; where R

CCC>Rsc

(see Fig.7)I

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Battery charge level indicator SAA1501T

With R

, the charge efficiency can be manipulated

CCC

depending on the charge level. The restriction of the
SAA1501T is a maximum average charge current of 60 µA
and a minimum momentary charge current of 0.6 µA. The
same formula is applicable for the discharge current. The
discharge efficiency can now also be changed by R

DCC

depending on the discharge current levels, but
independent of the charge current. As both sense levels
are referenced to ground, the sensing elements could be
combined into one. The outputs are used combined as

1

⁄6× (Ic− Id) in the I/F converter and combined as (Ic− Id)
in the pulse width modulator block and made separately
available in the mode detector. The conversion is made
lower by a factor of 6 in the I/F converter block, thereby
enabling the use of poor leakage capacitors on pin 4. All
V/I converter pins are sensitive to capacitive loading
(C

out

× R

< 1 ms), the conversion resistors should be

conv

mounted as close as possible to the output pins.

I/F converter

This block produces up-counts while charging and
down-counts while discharging. The I/F converter
translates the charge/discharge currents into a frequency.
This frequency is determined by

I(

C(

CC

cd()Rsense

∆V

oscRCCC RDCC()

f

=

----------------------------------------------------------------------------------- -

6 )××

)××

During the time period ‘t’, the charge current, expressed as
a ‘Charge Parcel’, will be counted in the Coulomb counters
(CNT1 and CNT2). During discharge the ‘Charge Parcel’ is
the product of the discharge current and the ‘t’ from the I/F
converter generated frequency. The momentary contents
of the Coulomb counter is a multiple of the ‘Charge
Parcels’.

Coulomb counters CNT1 and CNT2

The SAA1501T has been designed for average maximum
charge and discharge current levels of 5 C and minimum
charge and discharge current levels of 0.05 C. This means
that counter CNT1 will be full, or empty, after a minimum
time period of 12 minutes at maximum charge and
discharge currents at the recommended oscillator
frequency. Higher charge and discharge rates than 5 C
are possible, but only by changing the oscillator frequency.
It should be noted that the self-discharge time and the
display functions are influenced by a higher oscillator
frequency. The SAA1501T enables top-up charging in
order to account for the decrease of charge efficiency at
high charge rates. The SAA1501T switches to the slow
charge mode at full recognition when CNT1 is at its
maximum. As soon as the batteries are completely full
(when CNT2 is at its maximum), the SAA1501T switches

to the trickle charge mode to overcome the self-discharge
of the batteries. The top-up charge volume of
CNT2 = 0.2 × CNT1 = 0.2 C (where Q is rated as Ampere
hours of the battery). The slow and trickle charge current
levels are dependent on the k-factor. Signal EN controls
the external charger e.g. TEA1400 (see Fig.8). When an
LED bargraph display is used, the LED currents are also
considered as a battery discharge current, and therefore
influence the duty cycle of the charge current regulation
signal EN. The SAA1501T also enables temperature
protection. In the event that the battery temperature
exceeds a certain maximum temperature level
(T

battery>Tmax

), which can be set by an external NTC
resistor, the SAA1501T switches to the slow charge mode.
In the standby mode (self-discharge mode), which is
recognized by the SAA1501T in the mode detector when
both the charge and discharge currents are zero
(Ic=Id= 0), the self-discharge of the batteries is registered
by counting down in 200 days (based on f
T

battery<Tself

T

battery>Tself

or in 100 days (based on f
. T

is also set by means of an external NTC

self

osc

= 4 kHz) if

osc

= 4 kHz) if

resistor.

Band gap generation

From the band gap voltage block, two reference voltages
are derived V
reference currents, I
detector) and I
current I

and V

ref

(oscillator). Voltage V

ref3

which is used in the pulse width modulation

max

. Voltage V

max

(I/F converter); I

ref1

at pin R

ref

ref2

max

ref

(mode
sets the

sets the

block to accurately control the charge current.

Charge current regulation

While charging, the SAA1501T produces a charge current
regulation signal EN in the pulse width modulation block
which is used for controlling an external charger. This
digital signal EN is derived from the signal produced at pin

. The duty cycle is determined by

C

cy

×

kI

max

=

δ

------------------- -

–

I

cId

in which the value of k depends on the state of the
counters CNT1 and CNT2:

CNT1 is not full; k = 1 (fast charging).
CNT1 is full; CNT2 is not full; k = 0.1 (slow charging).
CNT1 and CNT2 are full; k = 0.025 (trickle charging).

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Battery charge level indicator SAA1501T

Mode detector

This block differentiates between the available modes of
operation. The modes are given below:

Charge mode; power charge (POCH).
Discharge mode; battery load (BATLD).
Power load mode (POLD); the batteries are charged

while the load is also active.
Self discharge mode; (STANDBY).

To detect power in a regulated system (see Fig.8) the EN
signal is used for sensing. The POCH mode is recognized
when the converted charge current I

c>Iref2

(when in the
power mode, change of mode can only be recognised if
EN is HIGH). The BATLD mode is recognized when
Id>I
Id>I
and Id<I

; the POLD mode is recognized when Ic>I

ref2

; the standby mode is recognized when Ic<I

ref2

. In the standby mode, if the advised frequency

ref2

ref2

and

ref2

(4 kHz) is applied, it takes 0.5 s to determine another
mode (in all other modes, a change of mode is sensed
continuously). In all other modes an eventual change of
mode is done continuously. To save supply current during
standby, the V/I converters are switched off. With the
specific fixed intervals, the SAA1501T checks whether
power or load is connected again. This checking is
synchronized by the sensing signal of the V/I converters.
The SAA1501T can handle a DC charge current as well as
a discontinuous charge current (SMSP charger). The load
current can also be DC or interrupted, e.g. produced by a
motor. The digital filtering of both signals, to overcome
faulty mode detections, restricts the conditions in which
power and load are recognized. Because of the very
sensitive input detection level of the mode detector for a
charge current (power) in combination with the high
interference levels of motor driving, the detection level for
power (Ic>I

) is raised by a factor of 25 when the

ref2

batteries are loaded.

Prescaler/controller

In the prescaler, a new system clock is created (CLK)
which is used for all timing blocks. Many frequencies are
derived from the basic oscillator at the standard frequency
of 4 kHz (1/T

), such as the self-discharge times and the

osc

modulation frequency for the buzzer, the drive voltage
frequency for the LCD screen and the pulse trains for
temperature measurements and power/load sensing
measurements in the mode detector.

Temperature

In the temperature control block two temperature
measurements are performed. In order to switch off fast
charging when the battery temperature exceeds an
adjustable maximum temperature (T

), a maximum

max

temperature measurement is performed. A second
temperature measurement is performed in the standby
mode. This temperature measurement is input to the
temperature control block to switch over the self-discharge
rate from a count down of 200 days (based on f
if T

battery<Tself

on f

osc

= 4 kHz) if T

, to a count down rate of 100 days (based

battery>Tself

. In all modes the

= 4 kHz)

osc

temperature is measured periodical. The temperature
circuit which controls the above mentioned functions is a
bridge configuration synthesis, as illustrated in Fig.3.

Oscillator

As the oscillator has to operate in all modes, including the
standby mode, the current consumption of the oscillator
must be very low. The same applies for the band gap
generator block, because the band gap delivers accurate
reference voltages and currents to the oscillator block.
Apart from the low current consumption, the accuracy of
the period time is important. The period time of the
oscillator is:

–()

V

t

osc

2C

×

osc

HVL

-------------------------- ­I

ref3

5.6 C

××=×=

oscRref

December 1994 7

Fig.3 Temperature circuit.

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

Display decoder driver

The counters are used to output the battery charge
amount via a decoder and driver stage to the display
outputs L100, L80, L60, L40 and L20 to drive an LCD
screen or an LED bargraph. A 64 Hz (based on
f

= 4 kHz) block signal at output BP (back plane) must

osc

be connected to the back plane of the LCD bar. If pin BP
is connected to ground, the display outputs L20 to L100
will produce signals for an LED bargraph. Output signal
POL (power-on LED) indicates when the batteries are in
the charge mode. When the counter is not at its maximum
state, POL is on and flickers at 2 Hz (based on

= 4 kHz) when the counter is at its maximum. The

f

osc

waveforms illustrated in Fig.4 depict operation of the
monitor display. The outputs BLI (battery low indication),
BUZ (buzzer) and FULL indicate the extreme status
(empty or full) of the counters and the batteries. The
waveforms of the signals BLI and BUZ if one switches over
from BATLD to standby when BLI is active, are given in
Fig.4.

The BLI sequence is as follows. If during discharge the
charge state falls below 0%, the red BLI LED is turned on.
Changing mode from discharge to standby means that the
BLI LED and the buzzer (BUZ) are activated as indicated
in Fig.4. If after a 0% passing recharge is activated, the red
BLI LED is turned on again for as long as the counter
remains below 10%. Switch-over in the 0 to 10% range to
standby will activate BLI and BUZ again.

The LEDs of the LED bargraph are activated as a result of
each operational mode change, starting with a step-up
pattern. Step-up means that LEDs are activated
successively one after the other, in accordance with the
charge status each

⁄8s (based on f

= 4 kHz). After the

osc

1

step-up, the LEDs will be on for 8 s (based on
f

= 4 kHz), except for the POCH mode, where the LEDs

osc

will be on continuously to inform the user about the charge
state of the batteries. The LCD display is, apart from the
LED mode, always visible.

Figure 5 shows the legend for Fig.6. Figure 6 shows the
operation of the monitor display.

BUZ

Fig.4 BLI and buzzer timing.

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Battery charge level indicator SAA1501T

Open battery protection

Open battery protection is active when VCC= 4.5 V (typ.).
The SAA1501T will then react as if the system is in the
standby mode. This means that the LEDs are turned off in
the LED mode, in the LCD mode the flickering is stopped
and the enable pin (EN) is switched to floating.

Testing

A user test facility is built-in for checking if the LCD and/or
LED displays are mounted correctly. Pin R

is used as

CCC

a test pin. Raising the voltage above 1 V during the set-up
time will activate the test. The test mode can only be
started in the standby mode. In the test mode all counters
are reset and will be active successively in the sequence
BLI, L20, L40, L60, L80, L100 and FULL with an interval
period determined by T
the following methods:

Power-on; the Coulomb counter retains the latest data
displayed.

Automatically after the test cycle time; the Coulomb
counter is reset.

. The test mode can be exited via

osc

Fig.5 Legend for Fig.6.

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Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

Fig.6 Charge state of counter shown by LCD or LED display.

December 1994 10

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC 134). All voltages with respect to GND (pin 24); input
currents are positive; pins 5, 6 and 21 are not allowed to be voltage driven; the voltage ratings are valid provided other
ratings are not being violated.

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

V

CC

V

n1

V

n2

∆V voltage difference between pins 10 and

I

CC

I

GND

I

n

P

tot

T

stg

T

j

T

amb

supply voltage −0.5 +5.5 V
input voltage at pins 9 to 12 −0.5 +1.0 V
input voltage at pins 2 to 4, 13 to 20, 22

−0.5 V

CC

V

and 23

−2.0 +2.0 V

7 and between pins 9 and 8
supply current − 80 mA
power ground supply current −−80 mA
supply current at pins 5 to 8 −−1mA
total power dissipation T

=70°C − 0.75 W

amb

storage temperature −55 +150 °C
junction temperature − +150 °C
operating ambient temperature −10 +75 °C

QUALITY SPECIFICATION

In accordance with SNW-FQ-611 part E. The numbers of the quality specification can be found in the “

Handbook”

. The Handbook can be ordered using the code 9398 510 63011.

Quality Reference

THERMAL CHARACTERISTICS

SYMBOL PARAMETER VALUE UNIT

R

th j-a

thermal resistance from junction to ambient in free air 75 K/W

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Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

CHARACTERISTICS

VCC=3V; T
(0.1%); I

ref=Vref/Rref

specified.

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

Supply

V

CC

V

CC(ir)

I

CC

I

CCstb

V

ref

I

ref

V

max

TC temperature coefficient of

V

clamp

Voltage-to-current charge/discharge

I

4

I

3

I

4/I3

V

i(s)

I

o(s)

V

os

=25°C; R

amb

; I

= 51.5 kΩ (0.1%); C

ref

max=Vmax/Rmax

= 820 pF (0.1%); R

osc

CCC=RDCC

= 3.65 kΩ (0.1%); R

max

; the minimum and maximum values are 4 sigma limits; unless otherwise

supply voltage note 1 2.0 3.0 4.3 V
supply voltage internal

− 1.2 1.7 V

reset
supply current Ic=Id=60µA 0.6 − 1.7 mA
supply current in standby

V

CSI=VDSI

=0V −−100 mA

mode
reference voltage note 2 204 211 217 mV
reference current notes 1 and 2 3.5 − 8 µA
maximum voltage note 2 204 211 217 mV

−6

T=0to100°C 0 25 × 10

100 × 10−6°C

reference voltage
clamping level voltage ICC= 50 mA 5.8 6.3 6.8 V

voltage-to-current
charge/discharge current
accuracy

voltage-to-current
charge/discharge current
accuracy

V9=7mV; V4= 1.5 V −259 −324 −389 nA

= 7 mV; V4= 1.5 V 262 328 394 nA

V

10

= 200 mV; V4= 1.5 V −8.93 −9.13 −9.32 µA

V

9

= 200 mV; V4= 1.5 V 8.93 9.13 9.32 µA

V

10

V9= 7 mV; R

max

= 400 kΩ;

−1.55 −1.94 −2.32 µA

k = 0.025
V

= 7 mV; R

10

= 400 kΩ;

max

1.57 1.97 2.36 µA

k = 0.025

relative current accuracy

= 200 mV;

V

9

R

= 400 kΩ; k = 0.025

max

= 200 mV;

V

10

R

= 400 kΩ; k = 0.025

max

V9= V10= 200 mV − 1.0 2.5 %

−53.5 −54.7 −56 µA

53.5 54.7 56 µA

of voltage-to-current in
charge counter capacitor

input sense voltage at
pins 9 and 10

DC output sense current

V

CC(max)

3.7<V

= 3.7 V; note 1 0 − VCC− 1.6 V

< 4.4 V; note 1 −−2.1 V

CC

0.6 − 60 µA

(pins 8 and 7)
offset voltage −−1.8 mV

= 3.48 kΩ

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Battery charge level indicator SAA1501T

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

I/F converter

I

a multiplication factor for

I

ref1

V

clamp

V

CCC(H)

clamping voltage (pin 4) Ic= 0; Id=60 µA;

HIGH level reference
voltage (pin 4)

V

CCC(L)

LOW level reference
voltage (pin 4)

Pulse width modulator

ACC accuracy for I
I

max

I

d/Imax

V

CCY

maximum DC current I
k factor k = 1; Vd= 1.5 V; idle mode 0.95 0.98 1.01

start up-clamping voltage

max

at C

(pin 3)

V

CCY

V

CCY(H)

clamping voltage (pin 3) open-circuit at pin 3;

HIGH level switching
voltage

V

CCY(L)

LOW level switching
voltage

I

Z

3-state enable current V2= 1.5 V −−1 µA

Mode detector

I

ref2

mode detection level at
pins 7 and 8

I

ref4

mode detection level at
pin 7

=a×I

ref1

ref

(where a is constant);
V4= 1.26 V; idle mode

I4=10µA

15 < I

cy

max=Vmax/Rmax

k = 0.1; V

<60µA −−±3%

max

; note 1 0.6 − 60 mA

= 1.5 V; idle

d

mode
k = 0.025; V

= 1.5 V;

d

idle mode
Id=10µA; Ic= 0 0.7 0.9 1.1 V

pin 5 = VCC;
±(Ic− Id)=60µA

I

≥ e × I

ref2

ref

(where e is constant)
I

≥ I

ref2

;

ref4

in modes POLD and BATLD

2.35 2.5 2.65

0.7 0.9 1.1 V

1.58 1.66 1.74 V

1.26 1.33 1.4 V

0.094 0.099 0.104

0.023 0.025 0.027

−−V

− 0.6 V

CC

1.60 1.77 1.86 V

1.28 1.32 1.37 V

− 0.15I

− 25I

ref2

ref

−

−

Oscillator (pin 13)

Q

c

Q

d

charge amount I
discharge amount I

ref1(sink)
ref1(source)

× T

clk

× T

clk

∆Q difference between

charge and discharge
charge amount

b multiplication factor for

I

ref3

∆V

osc

voltage swing

I

=b×I

ref3

ref

(where b is constant)

HIGH-to-LOW transition

December 1994 13

142 150 158 nC
142 150 158 nC

0.95 1.0 1.05

− 0.75 −

− 440 − mV

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

f

osc

Temperature control (pins 11 and 12)

V

i

I

TEMP2/ITEMP1

I

TEMP2/ITEMP1

c multiplication factor for

d multiplication factor for

Open battery protection

V

CC(ob)

Testing

V

test

Display decoder driver

I

OL1

I

OBP

I

LED(CF)

I

OL2

I

OBP(tot)

I

LED(CF)

I

OL

I

OL(14,15)

I

OL(22,23)

I

OL(21)

I

OH

I

OH(21)

oscillator frequency 3.9 4.3 4.7 kHz

input voltage 0 − 900 mV
detection at T
detection at T

I

TEMP1

I

TEMP2

max
self

V11=V12= 300 mV 9.7 10.0 10.3
V11=V12= 300 mV 15 16 17
I

TEMP1

=c×I

ref

0.45 0.54 0.63
(where c is constant);
V

TEMP1=VTEMP2

I

=d×I

TEMP2

ref

= 300 mV

4.5 5.4 6.3
(where d is constant);
V

TEMP1=VTEMP2

= 300 mV

open-battery level voltage 4.3 4.5 4.65 V

test level voltage 1.0 − 2.0 V

LOW level output current
(pin 20 LED),

VOL= 0.6 V; L40 to L100 off;
VCC= 2.4 V

71012mA

(LED 20 is on)
output LED sense current

(pin 21 LED),

V

= 0.1 V; L40 to L100

OBP

off; VCC= 2.4 V

63 82 100 µA

(LED 20 is on)
LED current

I

OL1/IOBP

; VCC= 2.4 V 110 121 132

compensation factor
LOW level output current

(pins 20 to 16 LED),

all LEDs on; VOL= 0.7 V;
VCC= 2.8 V

7.5 11 14 mA

(all LEDs are on)
total output sense current

(pins 21)
LED current

V

= 0.1 V; VCC= 2.8 V;

OBP

L20 to L100 on
5I

OL2/IOBP(tot)

350 452 560 µA

115 125 135

compensation factor
output current

VOL= 0.5 V; VCC= 2.8 V 350 480 640 µA

(pins 20 to 16 LCD)
LOW level output current

VOL= 0.4 V; VCC= 2.4 V 0.9 1.2 1.7 mA

(pins 14 and 15)
LOW level output current

VOL= 0.4 V; VCC= 2.1 V 7 10 12 mA

(pins 22 and 23 LED)
LOW level output current

VOL= 0.4 V; VCC= 2.8 V 572 849 1214 µA

(pin 21 LCD)
HIGH level output current

VOH= 2.4 V; VCC= 2.8 V 261 378 526 µA

(pins 20 to 16 LED)
HIGH level output current

VOH= 2.4 V; VCC= 2.8 V 239 378 565 µA

(pin 21 LED)

December 1994 14

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

OH(14)

I

OH(15)

I

OH(22,23)

I

LO

Notes

1. Not measured by the industrial measuring program, but guaranteed by design.

2. Internally detected from band gap generator.

HIGH level output current
(pin 14)

HIGH level output current
(pin 15)

HIGH level output current
(pins 22 and 23)

output leakage current
(pin 21)

VOH=2V; VCC= 2.4 V 0.7 1.6 2.5 µA

VOH= 2 V; VCC= 2.4 V 0.99 1.67 2.69 mA

VOH= 2.4 V; VCC= 2.4 V 260 450 708 µA

VOH= 0 to V

CC

−−±1µA

December 1994 15

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

TIMING CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS VALUE

T

osc

T

clk

t

som

t

som(p)

t

rec

t

self

t

battery(s)

t

battery(p)

t

su

t

id

t

pd

t

su:LED

t

LED(ON)

f

BP

f

BUZ

oscillator cycle time note 1 T
clock cycle time 64t
sense operation mode time note 2 1.5 × 27T
sense operation mode period

note 2 212T

time
recognition time power; note 3 >32t

load; note 4 >20t

self discharge counter time T

battery>Tself

(100 days at f
T

battery>Tself

(200 days at f

osc

osc

= 4 kHz)

= 4 kHz)

battery temperature
measurement sense time

battery temperature
measurement period time

display test set-up time 211T
interval display test time 210T
period display test time 1.5 × 218T
LED set-up time 29T
LEDs-on time after change of mode

(except POCH mode)

drive voltage frequency for back
plane

modulation frequency for auto
buzzer

osc

235T

236T

27T

216T

215T

2−4T

1

⁄2T

=2C

osc

osc

osc

osc

osc
osc

osc

osc

osc

osc

<t<1.5×218T

osc

osc

osc

osc

osc

osc

osc

× V

osc/Iref3

osc

Notes

1. ; where V

t

osc

2C

osc

×=

----------­I

ref3

= 440 mV and I

osc

ref3

= 0.75.

V

osc

2. Applies to all converters and enable signal.

3. For charge current AC or DC: f >1⁄2f

4. For discharge current AC: f >1⁄4f

osc

.

osc

.

December 1994 16

Philips Semiconductors Objective specification

B
B
B
B

BBBBBBBBBBBB

BBBBBBBBBB

B
B

BBBBBBBBBB

B
B

Battery charge level indicator SAA1501T

APPLICATION INFORMATION

BBBBBBBBBBB
BBBBBBBBBBB
BBBBBBBBBBB
BBBBBBBBBBB

Fig.7 Battery pack application diagram; with camcorder.

BBBB
BBBB

BBBBBBBBB
BBBBBBBBB

Fig.8 State-of-charge indicator and charge current regulation.

December 1994 17

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

PACKAGE OUTLINE

handbook, full pagewidth

S

pin 1

index

112

0.9

0.4

(4x)

15.6

15.2

1.27

0.49

0.36

0.1 S

1324

0.25 M

(24x)

2.45

2.25

0.3

0.1

10.65

10.00

detail A

7.6

7.4

1.1

0.5

1.1

1.0

0.32

0.23

0 to 8

MBC235 - 1

A

2.65

2.35

o

Dimensions in mm.

Fig.9 Plastic small outline package; 24 leads; body width 7.5 mm (SO24; SOT137-1).

December 1994 18

Philips Semiconductors Objective specification

Battery charge level indicator SAA1501T

SOLDERING
Plastic small-outline packages

YWAVE

B
During placement and before soldering, the component

must be fixed with a droplet of adhesive. After curing the
adhesive, the component can be soldered. The adhesive
can be applied by screen printing, pin transfer or syringe
dispensing.

Maximum permissible solder temperature is 260 °C, and
maximum duration of package immersion in solder bath is
10 s, if allowed to cool to less than 150 °C within 6 s.
Typical dwell time is 4 s at 250 °C.

A modified wave soldering technique is recommended
using two solder waves (dual-wave), in which a turbulent
wave with high upward pressure is followed by a smooth
laminar wave. Using a mildly-activated flux eliminates the
need for removal of corrosive residues in most
applications.

Y SOLDER PASTE REFLOW

B
Reflow soldering requires the solder paste (a suspension

of fine solder particles, flux and binding agent) to be

applied to the substrate by screen printing, stencilling or
pressure-syringe dispensing before device placement.

Several techniques exist for reflowing; for example,
thermal conduction by heated belt, infrared, and
vapour-phase reflow. Dwell times vary between 50 and
300 s according to 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 min at 45 °C.

EPAIRING SOLDERED JOINTS (BY HAND-HELD SOLDERING

R

IRON OR PULSE

-HEATED SOLDER TOOL)

Fix the component by first soldering two, diagonally
opposite, end pins. Apply the heating tool to the flat part of
the pin only. Contact time must be limited to 10 s at up to
300 °C. When using proper tools, all other pins can be
soldered in one operation within 2 to 5 s at between 270
and 320 °C. (Pulse-heated soldering is not recommended
for SO packages.)

For pulse-heated solder tool (resistance) soldering of VSO
packages, solder is applied to the substrate by dipping or
by an extra thick tin/lead plating before package
placement.

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.

December 1994 19

Philips Semiconductors – a worldwide company

Argentina: IEROD, Av. Juramento 1992 - 14.b, (1428)

BUENOS AIRES, Tel. [phone], Fax. [phone]

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Tel. [phone], Fax. [phone]

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Tel. [phone], Fax. [phone]

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Tel. [phone], Fax. [phone]

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th

floor, Suite 51,

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Exchange Bldg. ST-2/A, Block 9, KDA Scheme 5, Clifton,
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Fax. [phone].

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For all other countries apply to: Philips Semiconductors,
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SCD35 © Philips Electronics N.V. 1994

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other industrial or intellectual property rights.

Printed in The Netherlands

373061/1500/01/pp20 Date of release: December 1994
Document order number: 9397 743 50011

Philips Semiconductors