User's Manual Part 1

MC75 Hardware Interface Description

Strictly confidential / Draft

MC75_V00.190a Page 35 of 91 15.02.2005

Figure 8 shows the circuit diagram of a typical

battery pack design that includes the protection

elements described above.

Figure 8: Battery pack circuit diagram

Table 2: Specifications of battery packs suitable for use with MC75

Battery type Rechargeable Lithium Ion or Lithium Polymer battery

Nominal voltage 3.6V / 3.7V

Capacity Recommended: 1000mAh to 1200mAh

Minimum: 500mAh

NTC 10k ± 5% @ 25°C

B value range: B (25/85)=3423K to B =3435K ± 3%

Overcharge detection voltage 4.325 ± 0.025V

Overdischarge detection voltage 2.5 ± 0.05V

Overcurrent detection 3 ± 0.5A

Overcurrent detection delay time 4ms

Short detection delay time 50µs

Internal resistance <130m

Note: A maximum internal resistance of 150m should not

be exceeded even after 500 cycles and under extreme

conditions.

3.4.2 Batteries Recommended for Use with MC75

When you choose a battery for your MC75 application you can take advantage of one of the

following two batteries offered by VARTA Microbattery GmbH. Both batteries meet all

requirements listed above. They have been thoroughly tested by Siemens and proved to be

equally suited for MC75.

• LIP 633450A1B PCM.STB, type Lithium Ion

This battery is listed in the standard product range of VARTA. Incorporated in a shrink

sleeve, the battery is CE approved. Therefore it has been chosen for integration into the

reference setup submitted for Type Approval of Siemens GSM modules.

• LPP 503759CA PCM.NTC.LT50, type Lithium Polymer

This battery has been especially designed by VARTA for use with Siemens GSM

modules. It has the same properties as the above Li-Ion battery, except that it is type

Polymer, is smaller, comes without casing and is not CE approved.

Specifications, construction drawings and sales contacts for both VARTA batteries can be

found in Section 9.3.

to BATT_TEMP to GND

NTC

Polyfuse

Protection Circuit

Battery cell

to BATT+