IEEC -Motorola Tango Two-Way Pager

Motorola Tango Two-Way Pager

A previous bulletin featured the teardown of the Motorola Gold Line Pen Pager, a numeric pager that used advanced techniques to package all paging functions into a pen format. In that bulletin, we discussed paging technologies and markets, and outlined that every pager requires a receiver, decoder, display, controls, and power source so as to receive and display messages.

In addition to the above, the Motorola Tango two-way pager provides the capability to respond to incoming pages with a reply: The alphanumeric Tango receives pages at 940-941 MHz and 6400 bps, and it responds with receipt acknowledgement or user-defined replies by transmitting at 901-902 MHz and 9600 bps. A built-in transmitter and antenna can broadcast with one watt power to the nearest paging base station.

The Tango's transmit capabilities allows the paging system to automatically verify that a pager received a message, and it will continue to retransmit messages until the pager acknowledges receipt. Furthermore, the user can respond to messages by transmitting short replies. Such replies can be selected from the built-in menu ("Stuck in traffic"), or from a choice of replies the sender provides along with his message. Alternatively, the pager can be connected to an external keypad so that the user can formulate his own replies.

The following is an abbreviated description of the construction of the Motorola Tango pager and the evolution of pagers in general. For a detailed discussion of these issues please contact the IEEC or Prismark Partners.

Motorola Tango Pager

The Tango is approximately the size and shape of a standard alphanumeric pager, but it is considerably heavier at 190.1 grams. The transmit antenna alone, which is located in the fold-down lid and is based on Rogers Corp's TMM3 material, adds 31 grams. The additional power requirements for transmitting replies dictate a second AAA battery weighing 14 grams.

The Tango contains two full-size printed circuit boards which are placed on top of each other and nestled into the casing without additional fasteners. This construction is similar to that of previous Motorola pagers, except that the boards are more complex. The RF board in particular is larger and more populated, reflecting the additional transmit capabilities of the Tango.

The logic printed circuit board contains all the digital circuitry on one side, and the LCD and keypads on the other side. It is a six layer, thin board with very fine geometries and high hole density. Passives are of the 0402 type, or smaller.

The logic board includes a glob top BGA device, where the silicon is wirebonded to a two-layer, FR4 carrier. X-rays show that this device is connected to the logic board via 86 eutectic solder balls.

The RF printed circuit board is connected to the logic board via a 25 pin connector. It is a six-layer, thin board of less complexity than the logic board. Parts of the board are covered with individual metal lids.

The Tango pager uses a number of very interesting LCC devices. One of these is a multi chip device that packages several separate components, including bare die, a second LCC device and passive components.
Cross-section of Multi-Chip LCC Device

(Note: Wirebonded bare die and passive components in LCC package. A second LCC is in this package, but not shown.)

The Evolution of Pagers

The Motorola Tango pager is the latest in the ongoing evolution of pagers spearheaded on a technological and marketing basis by Motorola. The earlier bulletin on the Motorola Gold Line Pen Pager described the history and market development of pagers; this bulletin will outline the evolution of Motorola pagers from an assembly/packaging point of view.

Motorola's line of paging products covers the following distinct systems:

Bravo -- A numeric, 12 digit display pager in the typical belt clip format.

Advisor -- An alphanumeric, 80 digit display pager, also in belt clip format.

Pen Pager -- A numeric, 12 digit display pager in miniature, pen shape format.

InfoTAC -- A two-way Ardis communicator in military "brick" format.

Tango -- An alphanumeric, 80 digit display two-way pager in belt clip format.

While these pagers were designed over the course of a couple of years, it is nevertheless interesting to compare their constructions. Note that all pagers in belt clip format (Bravo, Advisor, Tango) share the same overall design: one logic board and one RF board stacked on top of each other in a tight 3D package.

In summary, throughout the evolution of pagers:

The board area shrinks.

The boards become more complex as the layer count increases and thickness and other geometries decrease.

The number of components (ICs and passives) intially increases as functionality is added, then shrinks as silicon integration kicks in.

The ICs become more complex, and array packages and bare die are used.

The number of display drivers decreases, and they are packaged in smaller formats (although we have yet to see chip-on-glass, as is common in cellular phones, for example).

The Next Step

Motorola has already announced the next step in paging: The Tenor pager -- due out this year -- will receive and playback messages in the sender's actual voice, and store up to four minutes worth of messages. Since voice messages require a much greater bandwidth, they can not be simulcast like regular pages. Instead the Tenor pager will register automatically with the nearest base station, and only that base station will download the message. Zone registration requires the pager to have two-way capabilities, so that message receipt acknowledgement is included just as with the Tango pager.

All this will be packaged into a belt clip format (3.6" x 2.5" x 1.0"), weighing just 5.5 oz including the battery. Expect to see this teardown in a future bulletin.

Please contact Prismark Partners to discuss this bulletin, and the opportunities and challenges paging and advanced communications systems present to your business.

Copyright 1996 Integrated Electronics Engineering Center and Prismark Partners LLC.

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Warranty Disclaimer -- All information used in the preparation of this report was obtained from sources believed to be reliable at the time the information was collected. Prismark Partners LLC, its employees, its agents, and assignees have exercised their best efforts in preparing this report. Prismark Partners LLC extends no warranties with respect to this information and shall bear no liability whatsoever to the report recipient or to any other party as a result of the use of this report or the information contained herein.