Nokia 8550 Service Manual

NSM–3/3D

System Module

PAMS Technical Documentation

Page  13

Issue 4  02/2002

 Nokia Corporation

BTEMP

0

1.4

V

Battery temperature indication

 Phone has a 100k (+–5%) pullup resistor,

Battery package has a NTC pulldown resistor: 

47k+–5%@+25C  ,  B=4050+–3%

2.1

5

10

3

20

V

ms

 Phone power up by battery (input)

 Power up pulse width

1.9

90

100

2.85

200

V

ms

 Battery power up by phone (output)

 Power up pulse width

0

1

kohm

Local mode initialization (in production)

BGND

0

0

V

Battery ground

The SIM card connector is located on the engine board beside the battery
pack.

4

GND

 GND

0

0

V

Ground

3, 5

VSIM

5V SIM Card

3V SIM Card

4.8

2.8

5.0

3.0

5.2

3.2

V

Supply voltage

6

DATA

5V Vin/Vout

3V Vin/Vout

4.0

0

2.8

0

”1”

”0”

”1”

”0”

VSIM

0.5

VSIM

0.5

V

SIM data

Trise/Tfall max 1us

2

SIMRST

5V SIM Card

3V SIM Card

4.0

2.8

”1”

”1”

VSIM

VSIM

V

SIM reset

1

SIMCLK

Frequency

Trise/Tfall

3.25

25

MHz

ns

SIM clock

The RTC block in CCONT needs a power backup to keep the clock run-
ning when the phone battery is disconnected. The backup power is sup-
plied from a rechargable polyacene battery that can keep the clock run-
ning ten minutes minimum. The backup battery is charged from the main
battery through CHAPS.

VBACK

Backup battery charg-
ing from CHAPS

3.02

3.15

3.28

V

Backup battery charg-
ing from CHAPS

100

200

500

uA

Vout@VBAT–0.2V

VBACK

Backup battery supply
to CCONT

2

3.28

V

Backup battery supply
to CCONT

80

uA