aat3129 drive de rgb

AAT3129High Efficiency 1X/1.5X/2X Charge Pump

for RGB Color LED Applications

3129.2007.01.1.4 1

ChargePump™General DescriptionThe AAT3129 is a high efficiency charge pumpDC/DC converter with tri-mode load switch (1X)fractional (1.5X) and doubling (2X) conversion forcolor LED applications. A single current source out-put provides a regulated current to drive R, G, andB LEDs via three internal switches. With a simplesingle wire serial bus, the RGB module can be eas-ily controlled to display 4096 colors.

AnalogicTech's Advanced Simple Serial Control™(AS2Cwire™) serial digital input is used to enable,disable, and set the duty cycle of each internalMOSFET switch. Low external parts count (two1μF flying capacitors and two small bypass capac-itors at VIN and OUT) makes the AAT3129 ideallysuited for small battery-powered applications.

The AAT3129 has a thermal management systemto protect the device in the event of a short-circuitcondition on any of the output pins. Built-in soft-start circuitry prevents excessive inrush currentduring start-up. High switching frequency enablesthe use of small external capacitors. A low currentshutdown feature disconnects the load from VINand reduces quiescent current to less than 1μA.

The AAT3129 is available in a Pb-free, 12-pinTSOPJW package.

Features• VIN Range: 2.7V to 5.5V• Common Anode RGB LED Control• 4096 Color with Single Wire Digital Control• 40mA to 180mA Fixed Current Source• AS2Cwire Digital Brightness Control• Low Noise Constant Frequency Operation• Small Application Circuit• Regulated Output Current• No Inductors• 1MHz Switching Frequency• IQ <1μA in Shutdown• 12-Pin TSOPJW Package

Applications• Fashion RGBs• Mobile Handsets• MP3 Players• PDAs• Portable Devices • RGB Color LEDs• RGB Photo Flash• Smart Phones

Typical Application

CIN

1μFVBAT

CCP

1μF

C1

1μF

C21μF

VIN

CP

C1+

C1-

C2+

C2-

DRDGDB

EN/SETEN/SET

GND

AAT3129GR B

ISRC

Pin Descriptions

Pin ConfigurationTSOPJW-12(Top View)

1

2

3

4

5

6

12

11

10

9

8

7

C2+CPC1-C1+

ISRCEN/SET

C2-INGNDDRDGDB

Pin # Symbol Function1 C2+ Flying capacitor 2 positive terminal. Connect a 1μF capacitor between C2+ and C2-.

2 CP Charge pump output. Requires 1μF capacitor connected between this pin andground.

3 C1- Flying capacitor 1 negative terminal.

4 C1+ Flying capacitor 1 positive terminal. Connect a 1μF capacitor between C1+ and C1-.

5 ISRC Current source output.

6 EN/SET AS2Cwire control pin.

7 DB Open drain switch blue diode cathode.

8 DG Open drain switch green diode cathode.

9 DR Open drain switch red diode cathode.

10 GND Ground.

11 IN Input power supply. Requires 1μF capacitor connected between this pin and ground.

12 C2- Flying capacitor 2 negative terminal.



2 3129.2007.01.1.4

Absolute Maximum Ratings1

Thermal Information

Symbol Description Value UnitsPD Maximum Power Dissipation2, 3 625 mWθJA Thermal Resistance 160 °C/W

Symbol Description Value UnitsVIN Input Voltage -0.3 to 6 VVCP Charge Pump Output -0.3 to 6 V

VEN/SET EN/SET to GND Voltage -0.3 to 6 VVEN/SET(MAX) Maximum EN/SET to Input Voltage 0.3 V

TJ Operating Junction Temperature Range -40 to 150 °CTLEAD Maximum Soldering Temperature (at leads, 10 sec) 300 °C



3129.2007.01.1.4 3

1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.

2. Mounted on an FR4 board.3. Derate 6.25mW/°C above 25°C.

Electrical Characteristics1

VIN = 3.5V, CIN = CCP = C1 = C2 = 1μF; TA = -40°C to +85°C. Unless otherwise noted, typical values are TA = 25°C.

Symbol Description Conditions Min Typ Max UnitsInput Power Supply

VIN Operation Range 2.7 5.5 VICC Operating Current 3.0 ≤ VIN ≤ 5.5, CP = 1.5X, 1 3 mA

No Load CurrentISHDN Shutdown Current EN = 0 1 μAISRC Output Current Accuracy 3.0 ≤ VIN ≤ 5.5 -5 5 %

Charge PumpTS Start-Up Delay Time 200 μs

FCLK Clock Frequency 1 MHzη Efficiency VIN = 3.5V 93 %

SwitchesRDS(ON) Switch On Resistance VIN = 3.5V, TA = 25°C 1.5 Ω

EN/SETVEN(L) Enable Threshold Low VIN = 2.7V 0.4 VVEN(H) Enable Threshold High VIN = 5.5V 1.4 V

TEN/SET LO EN/SET Low Time 0.3 75 μsTEN/SET HI MIN Minimum EN/SET High Time 50 ns

TOFF EN/SET Off Timeout 500 μsTLAT EN/SET Latch Timeout 500 μs

IEN/SET EN/SET Input Leakage VEN/SET = 5.5V, VIN = 5.5V -1 1 μA



4 3129.2007.01.1.4

1. The AAT3129 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assuredby design, characterization, and correlation with statistical process controls.

Typical Characteristics

Turn-Off from 1.5X Mode

(VIN = 3.6V; Addr = 2; Data = 16)

100μμs/div

EN/SET

(2V/div)

IISRC

(50mA/div)

VISRC

(2V/div)

Turn-On to 2X Mode

(VIN = 2.8V; ISRC = 60mA)

100μμs/div

EN/SET

(2V/div)

CP

(2V/div)

IISRC

(50mA/div)

Turn-On to 1.5X Mode


100μμs/div

EN/SET

(2V/div)

CP

(2V/div)

IISRC

(50mA/div)

Turn-On to 1X Mode


100μμs/div

EN/SET

(2V/div)

CP

(2V/div)

IISRC

(50mA/div)



3129.2007.01.1.4 5


Line Response

(1X, 1.5X Mode; IISRC = 60mA)

1ms/div

VIN

(1V/div)

VCP

(1V/div)

IISRC

(50mA/div)

VISRC

(1V/div)

3.5V 3.9V

Line Response

(1X Mode; IISRC = 60mA)

1ms/div

VIN

(1V/div)

VCP

(1V/div)

IISRC

(50mA/div)

VISRC

(1V/div)

3.7V 4.2V

Operating Characteristics

(VIN = 3.6V; DR in 1X Mode; DG and DB in 1.5X Mode)

100μμs/div

CP

(1V/div)

IISRC

(50mA/div)

VISRC

(1V/div)

5.3V

3.5V


(VIN = 3.9V; DR and DG in 1X Mode; DB in 1.5X Mode)

100μμs/div

CP

(1V/div)

IISRC

(50mA/div)

VISRC

(1V/div)

5.2V3.8V


(VIN = 4.2V; DR, DB, and DG in 1X Mode)

100μμs/div

CP

(1V/div)

IISRC

(50mA/div)

VISRC

(1V/div)

4.1V



6 3129.2007.01.1.4


TOFF vs. VIN

Input Voltage (V)

TO

FF (

μμs)

50

100

150

200

250

300

350

2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5

-40°C

+25°C +85°C

TLAT vs. VIN

Input Voltage (V)

TL

AT (

μμs)

0

50

100

150

200

250

300

350

400

450

2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5

-40°C

+25°C +85°C

IISRC vs. VF

(VIN = 3.5V)

VF (V)

I ISR

C (

mA

)

54

55

56

57

58

59

60

61

62

63

64

1.0 1.5 2.0 2.5 3.0 3.5 4.0

+25°C

+85°C

-40°C

IISRC vs. VIN

(VF = 3.5V)

VIN (V)

I ISR

C (

mA

)

54

55

56

57

58

59

60

61

62

63

64

2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5

+25°C

+85°C

-40°C

Shutdown Current vs. Temperature

Temperature (°°C)

Sh

utd

ow

n C

urr

en

t (μ

A)

0.001

0.01

0.1

1

-40 -20 0 20 40 60 80 100

Oscillator Frequency vs. Temperature

Temperature (°°C)

FO

SC (

MH

z)

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

-40 -20 0 20 40 60 80 100



3129.2007.01.1.4 7


VIL vs. VIN

Input Voltage (V)

VIL

(m

V)

550

600

650

700

750

800

850

900

950

1000

1050

2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5

-40°C

+25°C +85°C

VIH vs. VIN

Input Voltage (V)

VIH

(m

V)

550

600

650

700

750

800

850

900

950

1000

1050

2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5

-40°C

+25°C +85°C

Switch Resistance vs. Supply Voltage

Supply Voltage (V)

Sw

itc

h R

es

ista

nc

e (

ΩΩ)

0.2

0.4

0.6

0.8

1.0

1.2

1.4

2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5

+85°C

+25°C -40°C



8 3129.2007.01.1.4



3129.2007.01.1.4 9

Functional Block Diagram

Voltage

Reference

Soft Start

1MHzOscillator

1X

1.5X

2X

Charge

Pump

AS2CwireInterface

Control

C1-

C2+

C2-

CP

ISRC

DR

DG

DB

GND

EN/SET

VIN

C1+

Functional DescriptionThe AAT3129 is a tri-mode load switch (1X) andhigh efficiency (1.5X or 2X) charge pump deviceintended for fashion color LED lighting applications.To maximize power conversion efficiency, an inter-nal sensing circuit monitors the voltage required onthe constant current source output and sets theload switch and charge pump modes based on theinput battery voltage and the current source outputvoltage. As the battery discharges over time, theAAT3129 charge pump is enabled when the currentsource output nears dropout. The charge pump ini-tially starts in 1.5X mode. If the charge pump out-put drops enough for the current source output to

become close to dropout, the charge pump willautomatically transition to 2X mode.

The AAT3129 requires only four external compo-nents: two 1μF ceramic capacitors for the chargepump flying capacitors (C1 and C2), one 1μFceramic input capacitor (CIN), and one 0.33μF to1μF ceramic output capacitor (CP).

The color and brightness of an RGB color LED ismaintained by PWM signals, which are pro-grammed via the AS2Cwire interface. The controlblock generates three gate drive PWM signals forthe N-channel MOSFET switches. Please refer tothe interface description and timing in the followingsection for details.

Applications Information AS2Cwire Serial Interface The Advanced Simple Serial Control digital interfaceis used to set the color, overall intensity, and methodof update for the R, G, and B channels. The intensi-ty for each channel is set by dedicated 4-bit registersgiving each channel 16 levels of brightness andresulting in 4096 possible color combinations. Inaddition to the three color registers, there is an inten-sity register and a mode register. The intensity reg-ister sets the overall intensity and provides 16 glob-al brightness levels. The mode register toggles themethod of update between two possibilities.Depending on the mode register setting, theAAT3129 will update the R, G, and B channelsimmediately or update them only when the intensityregister is updated.

AS2Cwire relies on the number of rising edges of theEN/SET pin to address and load the registers.AS2Cwire latches data or address after the EN/SET

pin has been held high for time TLAT. Address ordata is differentiated by the number of EN/SET risingedges. Since the data registers are 4 bits each, thedifferentiating number of pulses is 24 or 16, so thataddress 1 is signified by 17 rising edges, address 2by 18 rising edges, and so forth. Data is set to anynumber of rising edges between 1 and including 16.A typical write protocol is a burst of EN/SET risingedges, signifying a particular address, followed by apause with EN/SET held high for the TLAT timeoutperiod, a burst of rising edges signifying data, and aTLAT timeout for the data registers. Once an addressis set, then multiple writes to the corresponding dataregister are allowed.

When EN/SET is held low for an amount of timegreater than TOFF, the AAT3129 enters into shut-down mode and draws less than 1μA from the sup-ply. Address 1 is the default address on the first ris-ing edge after the AAT3129 has been disabled.When shutdown mode is entered, the Address andData registers are reset to 1.

AS2Cwire Serial Interface Timing

AS2Cwire Serial Interface Addressing

Address EN/SET Rising Edges Data Register Description1 17 R Red2 18 G Green3 19 B Blue4 20 T Intensity5 21 M Mode

Address Data

1

EN/SET

2 17 18

Address

G

R, B, T, M

1 2 . . . n <= 16

1 2

1

1

n

THI

TLO

TLAT

TLAT



10 3129.2007.01.1.4



3129.2007.01.1.4 11

Color Registers R, G, and BThe individual color brightness is set using thethree R, G, and B registers. The data register con-tents determine the on-time for each color channelduring a PWM cycle. The first level is 0, or off, andis set with a single EN/SET rising edge. This settingeliminates a given color from the spectrum. Theremaining 15 levels progressively increase thebrightness for a particular color by increasing thatchannel’s on-time. Using the red channel as anexample, the resulting on-time is

on-time = (R - 1) · 128μs

where R is the data setting (from 1 to 16). Thesame applies to G and B.

Intensity Register TThe overall intensity level is set by the T register.Once a particular mixing of colors is set to producethe desired color, the overall intensity can beadjusted while keeping constant the ratio of colorsto one another. The brightest level is set by pro-gramming the T register with 1 edge. Programmingthe T register with 16 edges produces the dimmestsetting. The T register adjusts the overall intensityby controlling the PWM off-time. Under thedimmest setting, the off-time is the longest. The off-time that results from the data in the T register is

off-time = (T - 1) · 512μs

Diode Current Timing

(R - 1) · 128μs

(T - 1) · 512μs 128μs

(G - 1) · 128μs

128μs

(B - 1) · 128μs

128μs

ISRC

ISRC

Red

Green

Blue

ISRC

ISRC

Mode Register MThe mode register determines the method ofupdate for the R, G, and B channels. When themode register is set to 1, the addressed colorupdates immediately. When the mode register isset to 2, the colors will update when the T registeris written (synchronized updating).

Under immediate updating, an addressed channelwill update as soon as new data has latched for it.Under synchronized updating, the channels thathave been assigned new data will not update untildata for the T register latches.

By using synchronized updating, discrete changesin color can be achieved. Synchronized updatingallows the intensity for all three colors to be updat-ed simultaneously. All three color registers can beloaded with new data prior to the update. Then,upon loading the T register, all three colors willchange to their new states together. This allows auser to transition from one mixed color to anotherwithout having to traverse intermediate colors.Under immediate updating color changes can onlybe achieved serially, or one color at a time.



12 3129.2007.01.1.4

Mode Register Settings - Address 5

LED CurrentThe resulting DC current for each of the R, G, and B channels depends on the overall system settings. Using theoverall settings, the current for a particular channel is calculated as

B - 1

4 · (T - 1) + (R - 1) + (G - 1) + (B - 1) + CHLS_ONIB = ISRC ·

G - 1

4 · (T - 1) + (R - 1) + (G - 1) + (B - 1) + CHLS_ONIG = ISRC ·

R - 1

4 · (T - 1) + (R - 1) + (G - 1) + (B - 1) + CHLS_ONIR = ISRC ·

M Setting Action1 R, G, B, T Registers Latched Independently2 R, G, B Registers Synchronized to T Register Latch

where ISRC is the factory programmed current andCHLS_ON is the number of channels programmedto operate. Whenever a channel is programmed toData = 1, that channel is programmed to off andmust be removed from the CHLS_ON count.

Capacitor SelectionCareful selection of the four external capacitorsCIN, C1, C2, and COUT is important because theywill affect turn-on time, output ripple, and transientperformance. Optimum performance will beobtained when low equivalent series resistance(ESR) ceramic capacitors are used. In general, lowESR may be defined as less than 100mΩ. For bestoverall performance, 1μF capacitors are recom-mended. Depending on ripple requirements, theinput and output capacitor values can be increasedor decreased accordingly. If lower ripple is desired,increase the capacitor value. The peak-to-peak rip-ple seen at the input or output increases ordecreases with capacitor size.

Capacitor CharacteristicsCeramic composition capacitors are highly recom-mended over all other types of capacitors for usewith the AAT3129. Ceramic capacitors offer manyadvantages over their tantalum and aluminumelectrolytic counterparts. A ceramic capacitor typi-cally has very low ESR, is lowest cost, has a small-er PCB footprint, and is non-polarized. Low ESRceramic capacitors help maximize charge pumptransient response. Since ceramic capacitors arenon-polarized, they are not prone to incorrect con-nection damage.

Equivalent Series ResistanceESR is an important characteristic to considerwhen selecting a capacitor. ESR is a resistanceinternal to a capacitor that is caused by the leads,internal connections, size or area, material compo-sition, and ambient temperature. Capacitor ESR istypically measured in milliohms for ceramic capac-itors and can range to more than several ohms fortantalum or aluminum electrolytic capacitors.



3129.2007.01.1.4 13

Ceramic Capacitor MaterialsCeramic capacitors less than 0.1μF are typicallymade from NPO or C0G materials. NPO and C0Gmaterials typically have tight tolerance and are sta-ble over temperature. Larger capacitor values aretypically composed of X7R, X5R, Z5U, or Y5Vdielectric materials. Large ceramic capacitors, typi-cally greater than 2.2μF, are often available in low-cost Y5V and Z5U dielectrics, but capacitorsgreater than 1μF are typically not required forAAT3129 applications.

Capacitor area is another contributor to ESR.Capacitors that are physically large will have alower ESR when compared to a smaller capacitormade from an equivalent material. These largerdevices can improve circuit transient responsewhen compared to an equal value capacitor in asmaller package size.

Layout ConsiderationsThe AAT3129 is a high-performance device thatoperates with a high switching frequency. To ensureoptimal device performance and accommodate thefast transients generated by the AAT3129 specialattention should be given to the board layout.

The recommended layout is illustrated in Figure 1.The traces connecting C1 and C2 experience fastcurrent transients. As a result, the trace lengths forC1 and C2 should be minimized by placing thecomponents as closely as possible to the IC. Thiswill minimize path resistance and reduce ringingdue to the inductance associated with trace length.For best IC performance, CIN and COUT are placedas closely as possible to the IN and CP pins andare connected to a solid ground.

Figure 1: Optimal PCB Layout.

GND

GNDC1

C2

CIN

COUT



14 3129.2007.01.1.4

Ordering Information

Package Information

All dimensions in millimeters.

0.20 + 0.10 - 0.05

0.055 ± 0.045 0.45 ± 0.15

7° NOM

4° ± 4°

3.00 ± 0.10

2.40

± 0

.10

2.85

± 0

.20

0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC

0.15

± 0

.05

0.96

25 ±

0.0

375

1.00

+ 0

.10

- 0

.065

0.04 REF

0.010

2.75 ± 0.25

All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree.

Output Current Package Marking1 Part Number (Tape and Reel)2

60mA TSOPJW-12 NNXYY AAT3129ITP-60-T1

1. XYY = assembly and date code.2. Sample stock is held on part numbers listed in BOLD.

Advanced Analogic Technologies, Inc.830 E. Arques Avenue, Sunnyvale, CA 94085Phone (408) 737-4600Fax (408) 737-4611

© Advanced Analogic Technologies, Inc.

AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold sub-ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTechwarrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con-trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.

AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are regis-tered trademarks or trademarks of their respective holders.



3129.2007.01.1.4 15

aat3129 drive de rgb

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