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Information as of 2000-01-10
 Latest information online
UMA1021M; Low-voltage frequency synthesizer for radio telephones
| Description |  |
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The UMA1021M BICMOS device integrates a prescaler,
programmable dividers, and a phase comparator to
implement a phase-locked loop.
The device is designed to operate from 3 NiCd cells, in
pocket phones, with low current and nominal 3 V supplies.
The synthesizer operates at RF input frequencies up to
2.2 GHz, with a fully programmable reference divider.
All divider ratios are supplied via a 3-wire serial
programming bus.
Separate power and ground pins are provided to the
analog (charge-pump) and digital circuits. The ground
leads should be externally short-circuited to prevent large
currents flowing across the die and thus causing damage.
VDD1 and VDD2 must also be at the same potential (VDD).
VCC must be equal to or greater than VDD (e.g. VDD =3 V
and VCC = 5 V for wider VCO control voltage range).
The phase detector has two charge-pump outputs, CP and
CPF, the latter of which is enabled directly at pin FAST.
This permits the design of adaptive loops. The charge
pump currents (phase detector gain) are fixed by an
external resistance at pin ISET and via the serial interface.
Only a passive loop filter is necessary; the charge pumps
function within a wide voltage compliance range to
improve the overall system performance.
| Features | |
- Low phase noise
- Low current from 3 V supply
- Fully programmable main divider
- 3-line serial interface bus
- Independent fully programmable reference divider,
driven from external crystal oscillator
- Dual charge pump outputs
- Hard and soft power-down control.
| Applications | |
- 900 MHz and 2 GHz mobile telephones
- Portable battery-powered radio equipment.
| Datasheet | |
| Products, packages, availability and ordering | |
Please note, devices listed in the "Products, packages, availability and ordering" table marked with "WIT" are discontinued. Devices marked with "DOD" will be in the near future.
Contact your nearest sales or distributor office for the latest information on product status and availability.
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UMA1021M links to the similar products page containing an overview of products that are similar in function or related to the part number(s) as listed on this page. The similar products page includes products from the same catalog tree(s) , relevant selection guides and products from the same functional category.
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