RH-25 is a handportable dual band TDMA and AMPS DCT-4 generation phone for the
smart classic segment.
The RH-25 Baseband consists of the DCT4 common Baseband chipset having some product-specific blocks of its own, such as pop-port system connector (also unofficially
known as "Tomahawk"), IHF, IrDA, and a color display.
The Baseband engine consists basically of two major ASICs:
•Universal Energy Management IC (UEM), including the analog audio circuits, the
charge control, and the voltage regulators.
•Universal Phone Processor (UPP), containing DSP, MCU, and some internal memory.
Baseband Block Diagram
The system block diagram below shows the main BB functional blocks.
Following voltages are assumed as normal and extreme voltages for the BLD-3 battery
used in RH-25:
•Nominal voltage: 3.6 V
•Lower extreme voltage:3.1 V
•Higher extreme voltage (fast charging):4.4 V
Temperature Conditions
Operational temperature range (all specifications met within this range)
-10°C..+55°C
Functional temperature range (Reduced performance)-30°C..+70°C
Storage temperature range:-30°C..+85°C
Humidity
Relative humidity range is 5...95%.
The Baseband module is not protected against water. Condensed or splashed water may
cause interim or permanent phone malfunction.
Submergence of the phone in water will likely cause permanent damage to the phone.
Frequencies in Baseband
There are several clock frequencies at the baseband part. The following table lists all
available frequencies. The asynchronous and diagnostic busses are not included.
RH-25 supports data connectivity via an infrared link. An IR module is integrated into
the phone, connected to the IR interface of the UPP ASIC.
Energy Management
The energy management of RH-25 is based on BB 4.0 architecture. A semi-fixed battery
(BLD-3) supplies power primarily to UEM ASIC and the RF PA. UEM includes several regulators to supply RF and baseband. It provides the energy management including power
up/down procedure.
Power Supply Modes
The functional behavior of the UEM can be divided into seven different states. Since the
UEM controls the regulated power distribution of the phone, each of these states affects
the general functionality of the phone:
•No supply
•Backup
•Power off
•Reset
•Power on
•Sleep
•Protection
The different states of the UEM are detailed in the sections below.
No Supply
In the NO_SUPPLY mode, the UEM has no supply voltage (VBAT < V
V_BU
tery are either disconnected or both discharged to a low voltage level.
The UEM will recover from NO_SUPPLY into RESET mode if the VBAT voltage level rises
above the V
Backup
In BACK_UP mode the main battery is either disconnected or has a low voltage level
(VBAT < V
and VBACK <
MSTR
). This mode is due to the fact that both the main battery and the backup bat-
COFF-
level by either reconnecting the main battery or charge it to such level.
MSTR+
and VBACK > V_BU
MSTR-
COFF+
).
The regulator VRTC that supplies the real-time clock is disabled in BACK_UP mode.
Instead the unregulated backup battery voltage VBACK supplies the output of the VRTC.
All other regulators are disabled and the phone has no functionality.
The UEM will recover from BACK_UP mode into RESET mode if VBAT rises above V
MSTR+
Power Off
In order for the UEM to be in PWR_OFF mode, it must have supply voltage (VBAT >
V
The regulator VRTC regulator is enabled and supplying the RTC within the UEM. The UEM
will enter RESET mode after a 20 ms delay whenever one of the below listed conditions is
logically true:
•The power button is activated
•Charger connection is detected
•RTC alarm is detected
The UEM will enter PWR_OFF from all other modes except NO_SUPPLY and BACK_UP if
the internal watchdog elapses.
Reset
When the UEM enters RESET mode from PWR_OFF mode, the watchdog is enabled. If the
VBAT fails to rise above the power-up voltage level V
(3.1 V) before the watchdog
COFF+
elapses, the UEM will enter PWR_OFF mode. Otherwise, after a 200 ms delay, the regulator VFLASH1 will be enabled and after an additional delay of 500 µs, the regulators
VANA, VIO, VCORE, and VR3 will be enabled. All other regulators( i.e., VFLASH2, VSIM,
VR1, VR2, and VR4 - VR7) are software controlled and disabled by default. After an additional delay of 20 ms, the UEM enters PWR_ON mode.
Power On
In PWR_ON, the UEM is fully functional in the sense that all internal circuits are powered up or can be by means of software. The UEM will enter PWR_OFF mode if VBAT
drops below V
enter PWR_OFF mode if either of the watchdogs Operational State Machine (approx. 100
µs), Security (32 sec.), or Power Key (4 sec.) elapses or if any of the regulators trigger the
thermal protection circuitry
Sleep
The UEM can be forced into SLEEP mode by the UPP by setting the input SLEEPX low for
more than 60 µs. This state is entered when the external UPP activity is low (phone in
sleep) and thereby lowering the internal current consumption of the UEM. The regulator
VANA is disabled and VR1 - VR7 are either disabled or in low quiescent mode.
From SLEEP the UEM enters PWR_ON if SLEEPX goes high, PWR_OFF mode if watchdog
elapses or BACK_UP mode if VBAT drops below V
Protection Mode
The UEM has two separate protection limits for over temperature conditions: one for the
charging switch and one for the regulators. The temperature circuitry measures the onchip temperature. In case of charging over temperature, the circuit turns the charging
switch off. In case of over temperature in any of the regulators, the UEM powers off.
for a period of time longer than 5 µs. The UEM will furthermore
COOF-
.
MSTR-
Battery BLD-3
RH-25 uses the BLD-3 Li-ion battery with a capacity of 780mAh. BLD-3 is a case-less
battery; the main advantage of a case-less battery type is the overall size, particularly
the thickness and the number of contact terminals.
BLD-3 has a four-pin connector. BSI resistor value is 75Kohm.
Power Distribution
Under normal conditions, the battery powers the baseband module. Individual regulators
located within the UEM regulate the battery voltage VBAT. These regulators supply the
different parts of the phone. Eight regulators are dedicated to the RF module of the
phone, and six to the baseband module.
The regulator VCORE is likewise adjustable and controlled by registers written by the
MCU. VCORE supplies the core of the UPP and can be adjusted on the fly by the MCU if
DSP capacity is inadequate. Higher VCORE supply (1.8 V) results in faster core operations
in the UPP.
Regulators VANA, VFLASH1, and VIO are solely controlled by the UEM and cannot be
enabled or disabled by the MCU. Furthermore, VFLASH1 and VIO are both ON, though in
low quiescent mode when phone is in sleep mode. An output current of 500 µA can be
drawn from the regulators. VIO supplies the UPP, FLASH and LCD, VFLASH1 supplies LCD
and the IrDA module. VANA is supplying analog parts internally in the UEM as well as the
baseband audio circuitry and pull-up resistors on the input of the UEM slow AD converters.
System connector provides a voltage to supply accessories. The white LED's need a higher
voltage supply as the battery can provide in bad condition. Separate external regulators
supply both consumers.
The regulators VR1A, VR1B, VR2 - VR7 and IPA1 - IPA4 are controlled by the DSP via
the DBus. VR4 - VR7 are controlled by the UEM as well and are disabled in sleep regardless of DSP writings.
VBAT/VBATTRF is furthermore distributed, unregulated, to the RF power amplifier, audio
power amplifier and external baseband regulators.
The CHACON module in the UEM controls the charging of the main battery. Furthermore
it contains a 3.2 Vdc regulator for charging of the backup battery and a 1.8 Vdc regulator
supplying the internal real time clock.
1The second current value indicates the maximum possible output current of the
regulator when in low quiescent mode.
2The output voltages are split into two different current categories. The upper part
is the lower range of output current, and the lower part is the higher range of
output current.
3Condition in sleep-mode depends on MCU writings to UEM regulator register
solely.
4Condition in sleep-mode depends on DSP writings to UEM register.
When the accessory regulator, N100, is active, it will turn Vout ON (2.8V) and provide
70mA current.
Audio Circuitry
This section describes the audio-HW inside the Baseband. (External audio components
and acoustics are not considered with the details in this section.)
The main topology comes from other phones using BB4.0 engine, where the audio-HW is
mostly integrated into the UEM-ASIC. The biggest difference is that RH-25 has integrated hands-free (IHF).
RH-25 uses an earpiece, which is also referred to as a PICO speaker. This is a 32 ohm
speaker with the diameter of 8 mm.
Earpiece is fed by the differential signals EARP and EARN from UEM. The signals run
quite directly from UEM to the earpiece, only some passive ands EMC protection components are needed
The external earpiece signals are fed by the HF and HFCM pins.
The level (swing) of earpiece-signals can be adjusted by register values inside UEM. These
signals have a common voltage level of 1.35 V (0.8 V for HF) at UEM pins.
Microphones
An EMC-improved type of microphone is used as internal microphone in RH-25, diameter
of which is 2.2mm.
Internal microphone circuitry is driven single-ended. Microphone needs bias voltage,
which is provided by UEM and is fed through a resistor to the microphone. A resistor is
also needed to the other side of the microphone, (i.e., between microphone and GND), in
order to provide the differential signals to UEM. Audio signals are AC-coupled from the
microphone.
For the external microphone a differential input is used.
MIC1N and MIC1P (audio signals) and MICB1 (bias voltage) are used for the internal
microphone. MIC2N and MIC2P and MICB2 are used for external microphone.
Integrated Hands-free (IHF)
The speaker used for IHF is a 16 mm diameter speaker with 8 Ohm impedance, also
known as a MALT speaker.
IHF circuitry uses differential outputs from UEM.
Depending on the audio mode, the IHF amplifier is driven either from UEM HF / HFCM or
XEAR audio outputs. The IHF audio power amplifier (APA) LM4855 has a bridge-tied-load
(BTL) output in order to get the maximum use of supply voltage. The supply voltage for
driving circuitry of speaker is VBAT, thus the swing across the speaker is (VBAT.
The shutdown of the IHF PA is controlled by UPP using GENIO14.
Audio Accessory Receive Path
In RH-25, the accessory receive path is directly driven from UEM HF / HFCM differential
audio outputs, the output signal complies with the Pop-port accessory interface.
For EMC protection, ferrites are connected in series to the earpiece; for ESD protection,
varistors are used.
Audio Control Signals
The HEADINT signal is needed for recognizing the external device (e.g., headset) connected to the system. The recognition is based on the ACI-pin on the system connector,
which is shorted to ground inside the external device.
The button of the external device generates HOOKINT. This is used to answer or to end a
phone call.
Acoustics
Earpiece Acoustic
RH-25 uses the PICO 8mm earpiece.
This earpiece is mounted into the UI-shield assembly, the sealing of the front volume is
achieved using a foam gasket mounted on the front of the speaker. The UI shield is sealed
using a rubber sealing between UI shield and A-cover to create an acoustic path.
IHF Speaker Acoustics
The MALT speaker is used in RH-25 for integrated hands-free and ringing tone applications.
The IHF speaker is mounted to the IHF enclosure on a foam sealing ring. The IHF enclo-