AnalogTalk

The buzz this week is the newest iPhone, it’s lack of reception, and of course Steve Job’s you’re holding it wrong response (more accurately he stated “just don’t hold it that way“), despite Apple themselves depicting the natural way to hold the phone.

Antenna placement these days is affected on FCC rules on how much energy a device can send into a user’s head.  That’s the reason most antennas are around the bottom of phones nowadays. Similarly, the antennas in the new iPhone are on the sides of the phone, which means that when you go to grasp the phone to make a call or play on its touch screen a lot of the transmit energy is being absorbed.

Solution?  Use a blue tooth headset and walk around like you have a roach creeping up your ear.

The MCP1640 regulator’s operating voltage of down to 0.35V and start-up voltage of 0.65V allows use with even a single, completely drained Alkaline, NiMH or NiCd battery cell. A PWM/PFM option enables the device’s low quiescent and shutdown currents, and provides up to 96% efficiency, allowing for longer battery run times. The regulator’s two integrated FET transistors reduce component count, resulting in smaller overall designs.

The key here is the low operating voltages: 0.35V operating and 0.65V start up.  This means you can get more from a battery cell as it’s drained.   The MCP1640 can boost low voltages to keep the product running where previous designs had to accept that a cell was no good when ~0.9V was reached.

Other Info:

Quiescent current as low as 19 uA and output currents up to 350 mA, the 500 kHz MCP1640 regulator enables compact, longer-lasting battery applications in the consumer electronics market (e.g., electric razors, toothbrushes, GPS devices and portable music players), among others.

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MCP1640

A nice addition to Microchip’s LDO line, which once suffered from a lack of high voltage output LDOs.   The MCP1804 is a 28V, 150 mA LDO family.  The wide input operating voltage range allows the MCP1804 LDO to be used with standard 12V and 24V power rails, and it’s wide output voltage range, available from 1.8V to 18V, provides greater design flexibility. The MCP1804 LDO is ceramic capacitor stable down to the low value of 0.1 μF, allowing for smaller sized ceramic capacitors.  This helps to reduce space and cost.  Available packages include 3-pin SOT-89 and SOT-223, as well as 5-pin SOT-23 and SOT-89, which feature a shutdown pin to lower current consumption to just 0.01 microamperes.

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MCP1804

If you have interest in the previous post on overvoltage protection (OVP) let us suggest the recently introduced family of battery chargers, the MCP73113, MCP73114 and MCP73213 Lithium-Ion (Li-Ion); and MCP73123, MCP73223 Lithium Iron Phosphate (LiFePO4) 1.1A Chargers, all have built-in Overvoltage Protection. The devices have a maximum input voltage of 18V and come with various OVP set points—5.8V and 6.5V for the single-cell MCP73114 and MCP73113/23 chargers; or 13V for the dual-cell MCP73213 and MCP73123 chargers.

To provide more flexibility, the MCP73113, MCP73114 and MCP73213 devices provide a variety of charging-voltage options for Li-Ion batteries—4.1 to 4.4V for the single-cell and 8.2 to 8.8V for the dual-cell devices.  The MCP73123 and MCP73223 devices target LiFePO4 batteries, and offer charging-voltage options of 3.6 and 7.2V, respectively.

With the option for various charging voltages, it is possible to target different batteries depending on their requirements. The LiFePO4 option provides designers the flexibility to try out one of the up-and-coming battery technologies with built-in smoke release resilience and higher current capabilities.

For more on these chargers, head on over here

The open-loop response  of an operational amplifier provides insight into it’s performance. Two important specifications in Open-loop , i.e. no feedback, are:

1. DC Gain – the gain at DC. ( The higher, the more accurate the amplifier is )
2. First-Pole Frequency, fp1 ( the frequency where the open-loop begins to fall)

A direct result of fp1 and the DC Gain is the Unity-Gain Frequency, fu.  This is the frequency where the open-loop gain falls to 1 V/V. The greater the fu, the faster your op amp can respond to input signals.  This leads us to Microchip Technology’s most recent and fastest op amp to date.

Yes, there exists faster op amps in the industry, but it is still a significant step for Microchip , who are showing that they have the know how to design as well as any of the analog companies out there.  Along with auto-zeroed and auto-calibration (mCal) op amps, they have just recently announced a family of amplifiers featuring 60 MHz of  gain bandwidth product and high output current drive  of 90 mA. These amplifiers are optimized for high speed, low noise and distortion, single-supply operation with rail-to-rail output and an input that includes the negative rail. This family is offered in single (MCP661), single with Chip Select (MCP663), dual (MCP662) and dual with two Chip Select pins (MCP665).

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MCP66x

How you ask…..well…..

Non-volatile EEPROM provides designers the flexibility to Program DAC input codes, Configuration bits and I2C™ address bits to the EEPROM using I2C serial-interface commands.  The result is that this data is held during power-off time, making the MCP4728 DAC’s configuration and outputs available immediately after power-up.

What DAC has the power to do this?

The new MCP4728 Quad DAC w/EEPROM.  In addition here are some other benefits related to power consumption:

Each channel in the MCP4728 DAC can be individually shut down, thereby reducing power consumption to as low as 0.04 microamperes, which helps to extend battery life. Further, the on-chip precision output amplifier enables a rail-to-rail analog output, for utilization of the entire voltage range.

Want to learn more?

MCP4728

Microchip Technology Inc., a leading provider of microcontroller and analog semiconductors, today announced the MCP6561/2/4/6/7/9 (MCP656X) family of high-speed (45 nS) comparators. With rail-to-rail input and output, low operating voltage down to 1.8V, low quiescent current and package options with push-pull and open-drain outputs, the new devices provide a high level of performance for a wide variety of applications.  Read more in the Press Release

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Comparator Product Family

The MCP73871 USB/AC load-sharing Li-Ion/Polymer charger was reviewed recently.  Check it out if you’re into portable applications.

Dual-source single-chip battery chargers are not unique and we have seen a number of ac/USB versions over the last two years. Microchip, however, comes in with a fresh mindset and offers some feature combination that I have not seen elsewhere.

The full EN-Genious review here:
http://www.en-genius.net/site/zones/lowpowerZONE/product_reviews/lpwrp_090108

Brief Description:
The  MCP73871 charge-management controller—a Li-Ion/Li-Polymer charger with an intelligent charge management feature that enables simultaneous AC-DC-adapter or USB-port charging and powering of devices. The single-chip charger features an integrated pass transistor, and numerous battery and termination-voltage options—making it ideal for complex, space-constrained portable applications.