SSL21084AT/1,118 - NXP Semiconductors

1. General description

The SSL21084AT is a high-voltage Integrated Circuit (IC) for driving retrofit LED lamps in

general lighting applications. It enables the implementation of a very compact low-cost

system solution . Th e IC ha s an inte gr at ed inte rn al HV switch an d wor k as Bou n dary

Conduction Mode (BCM) buck converter.

The SSL21084AT is supplied by a start-up bleeder resistor, a dV/dt supply using

capacitive coupling from the drain or any other auxiliary supply. The IC supply current is

low. An internal clamp limits the supply voltage.

The IC has accurate output current control and can be operated using Pulse-Width

Modulation (PWM) d imming. In additio n, several protection featur es are availab le such as

easy external temperature feedback.

The main benefits of this IC include:

•Small Printed-Circuit Board (PCB) footprint and compact solution

•High efficiency (up to 90 %) for non-dimmable high power factor solutions

•High power factor (>0.9)

•Ease of integration and many protection features

•Low electronic Bill Of Materials (BOM)

•Mains phase-cut dimmable using external components

•Highly flexible IC for use in buck, buck/boost mode

•Single inductor used for non-isolated configurations because of internal

demagnetization detection and dV/dt supply

The SSL21084AT is designed to start up directly from the HV supply using an internal

high-volt age current source. An internal clamp limits the supply voltage.

SSL21084AT

Mains dimmable LED driver IC

Rev. 6 — 3 October 2013 Product data sheet

Product data sheet Rev. 6 — 3 October 2013 2 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

2. Features and benefits

LED driver IC for driving strings of LEDs or high-voltage LED modules from a rectified

mains supply

Power-efficient boundary conduction mode operation with:

No reverse recovery losses in freewheel diode

Zero-Current Switching (ZCS) for switch turn-on

Zero-voltage or valley switching for switch turn-off

Minimal required inductance value and size

Fast transient response through cycle-by-cycle current control:

No overshoot or undershoot in the LED current

Simple high input power factor solution (>0.9)

Internal Protection features:

UnderVoltage LockOut (UVLO)

Leading-Edge Blanking (LEB)

OverCurrent Protection (OCP)

Internal OverTemperature Protection (OTP)

Brownout protection

Output Short Protection (OSP)

Mains phase cut dimmable LED driver solution:

Supports both leading-edge and trailing-edge dimmers

Easy external temperature protection with a single NTC

Open output protection using external comp onents

Compatible with wall switches with built-in indication light during standby

IC lifetime easily matches or surpasses LED lamp lifetime

Input current distributed evenly over the phase, reducing required output capacitor

size and bleeder dissipation

3. Applications

The SSL21084AT is intended for mains dimmable compact LED lamps for single mains

input voltages. Mains input voltages include 100 V (AC), 120 V (AC) and 230 V (AC).

Product data sheet Rev. 6 — 3 October 2013 3 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

4. Quick reference data

[1] An internal clamp sets the supply voltage. The current into the VCC pin must not exceed the maximum IDD

value (see Table 4).

5. Ordering information

Table 1. Quick reference data

Symbol Parameter Conditions Min Typ Max Unit

VCC supply voltage operating rang e [1] 8 - 16 V

RDSon drain-source

on-state resistance Tj = 25 C 4 5 6 

Tj = 125 C 6 7.5 9

IDRAIN current on pin

DRAIN 1 - +1 A

VDRAIN voltage on pin

DRAIN 0.4 -+600 V

fconv conversion

frequency -100 -kHz

Table 2. Ordering information

Type number Package

Name Description Version

SSL21084AT SO12 plastic small package outline body; 12 leads; body width

3.9 mm SOT1196-1

Product data sheet Rev. 6 — 3 October 2013 4 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

6. Block diagram

Fig 1. SSL21084AT block diagram

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Product data sheet Rev. 6 — 3 October 2013 5 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

7. Pinning information

7.1 Pinning

7.2 Pin description

Fig 2. SSL21084AT pin configuration

HV DRAIN

GND GND

SOURCE GND

VCC DVDT

NTC TONMOD

GND GND

001aan703

6 7

Table 3. Pin description

Symbol Pin Description

HV 1high-voltage supply pin

GND 2, 6,7, 10, 11 ground

SOURCE 3low-side external switch

VCC 4supply voltage

NTC 5temperature protection inp ut

TONMOD 8on-time mo dulation input

DVDT 9AC supply pin

DRAIN 12 high-side external switch

Product data sheet Rev. 6 — 3 October 2013 6 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

8. Functional description

8.1 Introduction

The SSL21084AT is a driver IC solution for small form factor mains phase-cut dimmable

LED lamps in isolated and non-isolated applications.

8.2 Converter operation

The converter in the SSL21084AT is a Boundary Conduction Mode (BCM), peak current

controlled system. See Figure 3 for the basic application diagram. See Figure 4 for

relevant the waveforms.

This converter type operates at the boundary between continuous and discontinuous

mode. Energy is stored in inductor L each period that the switch is on. The inductor

current IL is zero when the MOSFET is switched on. The amplitude of the current b uild-up

in L is proportional to the voltage drop over the inductor and the time that the MOSFET

switch is on. When the MOSFET is switched of f, the energy in the inductor is released

towards the output. The current then falls at a rate proportional to the value of VO. The

LED current ILED depends on the peak current through the inductor (SSL21084AT

controlled) and on the dimmer angle while it is optimized for a high-power factor. A new

cycle is started once the inductor current IL is zero. This quasi-resonant operation results

in higher efficiency.

Fig 3. SSL21084AT basic application d iag ram

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Product data sheet Rev. 6 — 3 October 2013 7 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

8.3 Valley detection

A new cycle starts when the primary switch is switched on (see Figure 4). In the following

sections, “on” represents the conductive state and off the non-conductive state.

Following time t1, when the peak current is detected on the SOURCE pin, the switch is

turned off and the secondary stroke start s at t2. When the secondary stroke is completed

with the coil current at t3 equaling zero, the drain voltage starts to oscillate at

approximately the Vi  VO level. The peak-to-peak amplitude equals 2  VO. In a tapped

buck topology, this amplitude is multiplied by the ratio of the windings.

A special feature, called valley detection is an integrated part of the SSL21084AT circuitry.

Dedicated built-in circuitry connected to the DRAIN pin, senses when the voltage on the

drain of the switch reaches its lowest value. The next cycle start s at t00 and as a result the

capacitive switching losses are reduced. If both the frequency of the oscillations and the

voltage swing are within the range specified (fring and Vvrec(min)) for detec tion, a valley is

detected and accepted . If a va lid valley is not detecte d, the se condary stro ke is co ntinued

until the maximum off-time (toff(high)) is reached, then the ne xt cycle is started.

Fig 4. Waveforms and va lley detection

aaa-001744

demagnetization

VIN

valley

VGATE

VDRAIN

VOUT

magnetization

t0t00

t2t3

Product data sheet Rev. 6 — 3 October 2013 8 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

8.4 Protective features

The IC has the following protective features:

•UnderVoltage LockOut (UVLO)

•Leading-Edge Blanking (LEB)

•OverCurrent Protection (OCP)

•Internal OverTemperature Protection (OTP)

•Brownout protection

•LED overtemperature control and protection

•An optional output OverVoltage Protection circuit is implemented using external

components and the NTC pin.

•Output Short Protection (OSP)

The internal OTP and L ED o ver tem per atur e pr otections are safe-r estart protections. The

IC halts, causing VCC to drop to below VCC(stop) and triggers a start-up. When VCC drops to

below VCC(rst), the IC resets the latch protection mod e. If VCC drops to below VCC(stop), the

IC halts. Switching starts only when no fault condition exists.

8.4.1 UnderVoltage LockOut (UVLO)

When the voltage on the VCC pin < VCC(stop), the IC stops switching. An attempt is then

made to restart by supplying VCC from the HV pin voltage.

8.4.2 Leading-Edge Blanking (LEB)

To prevent false detection of the short-winding or overcurrent, a blanking time following

switch-on is implemented. When the MOSFET switch switches on there can be a short

current spike due to capacitive discharge of voltage over the drain and source and the

charging of the gate to source capacitance. During the LEB time (tleb), the spike is

disregarded.

8.4.3 OverCurrent Protection (OCP)

The SSL21084AT contains a highly accurate peak current detector. It triggers when the

voltage on the SOURCE pin reaches the peak level Vth(ocp)SOURCE. The current through

the switch is sensed using a resistor connected to the SOURCE pin. The sense circuit is

activated following LEB time tleb. As the LED current is half the peak current (by design), it

automatically provides protection for maximum LED current during operation. There is a

propagation delay (td(ocp-swoff)) between the overcurrent detectio n and the actual switching

off of the switch. Due to the delay, the actual peak current is slightly higher than the OCP

level set by the resistor in series to the SOURCE pin.

8.4.4 OverTemperature Protection (OTP)

When the internal OTP function is triggered at a certain IC temperature (Tth(act)otp), the

converter stops operating. The OTP safe-restart protection and the IC restart with

switching resuming when the IC temperature drops below Tth(rel)otp.

Product data sheet Rev. 6 — 3 October 2013 9 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

8.4.5 Brownout protection

Brownout protection is designed to limit the lamp power when the input voltage drops

close to the outp ut voltage l evel. The input power must remain constan t. The input current

would otherwise increase to a level that is too high for the input circuitry. In the

SSL21084AT, there is a maximum limit on the on-time of switch ton(high).

In buck mode, the rate of current rise in the coil during the on-phase is proportional to the

difference between input voltage and output voltage. There fore, the peak current cannot

be reached before ton(high) and as a result the average output current to the LEDs is

reduced.

8.4.6 ton control

The ton(high) can be lowered by connecting a capacitor to the TONMOD pin. The external

capacitor is charged during the primary stroke with Ioffset(TONMOD). If the Vth(TONMOD) level

is reached before the ton(high) time, the switch is turned off an d the secondary stroke st arts.

When a capacitor is not co nnecte d to the pin, V th(TONMOD) is reach ed quickly, shorter than

the minimum limit of 1 s. In thi s ca se or wh en t he T O NMOD pin is groun ded, the internal

time constant, ton(high) d e te rm ine s th e ma xim u m on -t ime . Th is fu nct i on is used to contr o l

the converter operation over the mains cycle which enables the design of a mains

dimmable driver.

8.4.7 Output Short-circuit Protection (OSP)

During the secondary stroke (switch-off time), if a valley is not detected within the of f-time

limit (toff(high)), then typically the output voltage is less than the minimum limit allowed in

the application. This condition can occur either during start- up or due to a short-circuit. A

timer tdet(sc) is started when toff(high) is detected. Timer tdet(sc) is reset when a valid valley

detection occurs in one of the subsequent cycles or when VCC drops to below VCC(stop).

The timer can also be reset if the maximum limit on the on-time of the switch (ton(high)) is

reached, which is usually the case at start-up (brownout protection). If no valley is

detected and (ton(high)) is not reached before tdet(sc), then it is concluded that a real

short-circuit exists. The IC enters latched protection. If VCC drops to below VCC(rst), the IC

resets the latched protection mode (see Figure 5). During PWM dimming, the OSP timer

is paused during the off cycle.

The value of ton(high) depends on the capacito r connected to the T ONMOD pin. An open or

shorted TONMOD pin sets ton(high) to 15 s (see Section 8.4.6 and Table 6).

Fig 5. OSP logi c diagram

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Product data sheet Rev. 6 — 3 October 2013 10 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

8.5 VCC supply

The SSL21084AT can be supplied using three methods:

•Under normal operation, the voltage swing on the DVDT pin is internally rectified to

provide current on the VCC pin

•At start-up, there is an internal current source connected to the HV pin. The current

source provides internal power until either the dV/dt supply or an external current on

the VCC pin provides the supply.

•Using an auxiliary winding, the volt age can be rectified and connected to the VCC pin

via a series resistor.

The IC starts up when the voltage at the VCC pin exceeds VCC(startup). The IC locks out

(stops switching) when the voltage on the VCC pin is lower than VCC(stop). The hysteresis

between the start and stop levels allows the IC to be supplied by a buffer capacitor until

the external supply is stable. The SSL21084AT has an internal VCC clamp, which is an

internal active Zener (or shunt regulator). This internal active Zener limit s the voltage on

the supply VCC pin to the maximum value of VCC. If the maxim u m cu rr ent of the supply

minus the current consumption of the IC (determined by the load on the gate drivers), is

lower than the maxim um value of IDD, an e xternal Zen er diode i s not needed in the su pply

circuit.

8.5.1 VCC regulator

During supply dips, the input voltage can drop too low to supply the required IC current.

Under these con d itio ns, if the VCC voltage drops lower than VCC(swon)reg level, a second

regulator is started. Its function is to fill in the required supply current which the external

supply does not deliver. It prevents the IC going into UVLO. When the VCC voltage

exceeds VCC(swon)reg level, the regulator is turned off.

8.6 DVDT pin supply (dV/dt)

The DVDT pin is connected to an internal single-sided rectification stage. When an

alternating voltage with sufficient amplitude is supplied to this pin, the IC can be powered

without another external power con nection. This provides a compact and ef fective solution

without introducing high power losses and without requiring an additional inductor

winding.

8.7 NTC functionality and PWM dimm ing

The NTC pin can be used as a control method for LED thermal protection. Alternative ly,

the pin can be used as an input to disable/enable light output using a digital signal (PWM

dimming). The pin has an internal current source that generates the current of Ioffset(NTC).

An NTC resistor to monitor the LED tempe ratu re can be dir ec tly co nn ec te d to th e NT C

pin. Depending on the resistance value and the corresponding voltage on the NTC pin,

the converter reacts as shown in Figure 6.

During start-up, before VCC reaches VCC(startup) the voltage on the NTC pin must be less

than the minimum value of Vact(tmr)NTC. This is valid when the voltage on the NTC pin is

derived from the VCC using a resistive divider and a PTC in series with the resistor

between pins VCC and NTC.

If an NTC resistor is connected between the NTC pin a nd ground, the volt age on the NTC

pin is 0 V when VCC reaches VCC(startup).

Product data sheet Rev. 6 — 3 October 2013 11 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

When the voltage on the NTC pin exceeds Vth(high)NTC (see Figure 6 (4)), the converter

delivers nominal output current. When th e voltage is lower than this level, the peak current

is gradually reduce d un til Vth(low)NTC is reached (see Figure 6 (3)). The peak current is

now half the peak cur rent o f nominal opera tion. When Vact(tmr)NTC is passed (see Figure 6

(2)) a timer starts to run to distinguish between the following situations:

•If the low-level Vdeact(tmr)NTC is not reached within time tto(deact)NTC, (see Figure 6 (1))

LED overtemperature is detected. The IC stops switching and attempts to restart from

the HV pin volt age. The conver ter resta rts from an NTC protection shutdo wn when the

voltage on the NTC pin exceeds Vth(high)NTC (see Figure 6 (4)). It is assumed that the

reduction in peak current does not result in a lower NTC temperature and LED OTP is

activated.

•If the low-level Vdeact(tmr)NTC is reached within the time tto(deact)NTC, (see Figure 6 (1)) it

is assumed that the pin is pulled do wn extern ally. The rest art function is not tr iggered.

Instead, the output curre nt is reduced to zero. PWM dimming can be implemented this

way. The output current rises again when the voltage is higher than Vth(low)NTC.

8.7.1 Soft-start function

The NTC pin can be used to make a soft start function. During switch-on, the level on the

NTC pin is low. By connecting a capacitor (in parallel with the NTC resistor), a time

constant can be defined. The time constant causes the level on the NTC pin to increase

slowly. When passing level Vth(low)NTC (see Figure 6 (3)), the conver tor starts with half of

the maximum current. The output current slowly increases to maximum when Vth(high)NTC

(see Figure 6 (4)) is reached.

Fig 6. NTC control curve

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2 3 4 5

Ipk

Peak current

Ipk / 2

Vth(ocp)SOURCE = 500 mV

Vth(ocp)SOURCE = 250 mV

VNTC

Vth(high)NTC

Vth(low)NTC

Vact(tmr)NTC

Vdeact(tmr)NTC

Product data sheet Rev. 6 — 3 October 2013 12 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

8.8 Heat sink

In SSL21084AT applications, the PCB copper acts as the heat sink. The IC has thermal

leads (GND pins 2, 6, 10 and 11) for enhanced heat transfer from die to the PCB copper

heat sink. The thermal lead connection can drastically reduce thermal resistance.

Equation 1 shows the relationship be tween the maximum allowable power dissipation and

the thermal resistance from junction to ambient.

(1)

Where:

Rth(j-a) = thermal resistance from junction to ambient

Tj(max) = maximum junction temperature

Tamb = ambient temperature

P = Power dissipation

Rth j a–

Tjmax

Tamb

–

---------------------------------------

Product data sheet Rev. 6 — 3 October 2013 13 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

9. Limiting values

[1] The current flowing into the VCC pin must not exceed the maximum IDD value.

[2] An internal clamp sets the supply voltage.

[3] Human body model: equivalent to discharging a 100 pF capacitor through a 1.5 k series resistor.

[4] Charged device model: equivalent to charging the IC up to 1 kV and the subsequent discharging of each

pin down to 0 V over a 1 resistor.

Table 4. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter Conditions Min Max Unit

General

SR slew rate on pin DRAIN 5+5 V/ns

Ptot total power dissipation SO12 package - 1 W

Tamb ambient temperature 40 +125 C

Tjjunction temperature 40 +150 C

Tstg storage temperature 55 +150 C

Voltages

VCC supply voltage continuous [1] 0.4 +20 V

VDRAIN voltage on pin DRAIN 0.4 +600

VHV voltage on pin HV current limited 0.4 +600 V

VSOURCE voltage on pin SOURCE current limited 0.4 +5.2 V

VNTC voltage on pin NTC current limited 0.4 +5.2 V

VTONMOD voltage on pin TONMOD current limited 0.4 +5.2 V

Currents

IDD supply current on pin VCC [2] -20 mA

IDRAIN current on pin DRAIN 1+1 A

ISOURCE current on pin SOURCE 1+1 A

IDVTD current on pin DVDT duration 20 s

maximum -1.3 A

Electrostatic discharge

VESD electrostatic discharge

voltage human body

model; pins

DRAIN and HV

[3] 1+1 kV

human body

model; all other

pins

2+2 kV

charged device [4] 500 +500 V

Product data sheet Rev. 6 — 3 October 2013 14 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

10. Thermal characteristics

11. Characteristics

Table 5. Thermal characteristics

Symbol Parameter Conditions Typ Unit

Rth(j-a) thermal resistance from junction to

ambient in free air; PCB: 2 cm 3 cm; 2-layer; 35 m

Cu per layer 121 K/W

in free air; PCB: JEDEC 2s2p 53 K/W

j-top thermal characterization parameter

from junction to top of package top package temperature measured at the

warmest point on top of the case 3.4 K/W

Table 6. Characteristics

Values specified at Tamb = 25



C unless otherwise specified; all voltages are measured with respect to ground; currents are

positive when flowing into the IC.

Symbol Parameter Conditions Min Typ Max Unit

fconv conversion frequency -100 -kHz

High-voltage

Ileak(DRAIN) leakage current on pi n DRAIN VDRAIN = 600 V - - 10 A

Ileak(HV) leakage current on pin HV VHV = 600 V - - 30 A

Supply

VCC supply voltage operating range [1] 8 - 16 V

VCC(startup) start-up supply voltage 11 12 13 V

VCC(stop) stop supply voltage 8 9 10 V

VCC(hys) hysteresis of supply voltage between VCC(startup) and VCC(stop) 2 - 4.5 V

VCC(rst) reset supply voltage 4.5 55.5 V

VCC(swon)reg regulator switch-on supply voltage 8.75 9.25 9.75 V

VCC(swoff)reg regulator switch-off supply voltage 9.5 10 10.5 V

VCC(reg)hys regulator supply voltage hysteresis VCC(swoff)reg VCC(swon)reg 0.3 - - V

VCC(regswon-stop) supply voltage difference between

regulator switch-on and stop VCC(swon)reg VCC(stop) 0.3 - - V

Consumption

Istb(HV) standby current on pin HV during start-up or in protection;

VHV = 100 V 300 350 400 A

ICC(INT) internal supply current normal operation -1.3 -mA

Capability

Isup(high)HV high supply current on pin HV Standby: VHV = 40 V;

VCC < VCC(stop)

11.3 1.6 mA

Regulator on: VHV = 40 V;

VCC < VCC(swon)reg after start-up 22.3 2.6 mA

Product data sheet Rev. 6 — 3 October 2013 15 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

[1] An internal clamp sets the supply voltage. The current into the VCC pin must not exceed the maximum IDD value (see Table 4).

[2] This parameter is not tested during production. It is guaranteed by design.

Current protection

Vth(ocp)SOURCE overcurrent protection threshold

voltage on pin SOURCE V/t = 0.1 V/s480 500 520 mV

V/t = 0.1 V/s; VNTC = 0.325 V 230 250 270 mV

td(ocp-swoff) delay time from overcurrent

protection to switch-off V/t = 0.1 V/s - 75 100 ns

tleb leading edge blanking time overcurrent protection 260 300 340 ns

Valley detection

(V/t)vrec valley recognition voltage change

with time on pin DRAIN 30 20 10 V/s

fring ringing frequency [2] 200 550 1000 kHz

Vvrec(min) minimum valley recognition

voltage difference voltage drop on pin DRAIN 15 20 25 V

td(vrec-swon) valley recognition to switch-on

delay time -100 -ns

Brownout detection

Vth(TONMOD) threshold voltage on pin TONMOD 3.75 44.25 V

Ioffset(TONMOD) offset current on pin TONMOD 37 43 48 A

ton(high) high on-time 12.5 15 17.5 s

MOSFET output stage

VBR(DRAIN) breakdown voltage on pin DRAIN Tj > 0 C600 - - V

RDSon drain-source on-state resistance Tj = 25 C 4 5 6 

Tj = 125 C 6 7.5 9

dV/dt)f(DRAIN) fall rate of change of voltage on pin

DRAIN CDRAIN = 75 pF;

RSOURCE = 2.2 

[2] -1.5 -V/ns

NTC functionality

Vth(high)NTC high threshold voltage on pin NTC 0.47 0.5 0.53 V

Vth(low)NTC low threshold voltage on pin NTC 0.325 0.35 0.375 V

Vact(tmr)NTC timer activation voltage on pin NTC 0.26 0.3 0.325 V

Vdeact(tmr)NTC timer deactivation voltage on pin

NTC 0.17 0.2 0.23 V

tto(deact)NTC deactivation time-out time on pin

NTC 33 46 59 s

Ioffset(NTC) offset current on pin NTC -47 -A

Temperature protection

Tth(act)otp overtemperature protection

activation threshold temperature 160 170 180 C

Tth(rel)otp overtemperature protection

release threshold temperature 90 100 110 C

Table 6. Characteristics …continued

Values specified at Tamb = 25



C unless otherwise specified; all voltages are measured with respect to ground; currents are

positive when flowing into the IC.

Symbol Parameter Conditions Min Typ Max Unit

Product data sheet Rev. 6 — 3 October 2013 16 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

12. Package outline

Fig 7. Package outline SOT1196-1 (SO12)

References

Outline

version

European

projection Issue date

IEC JEDEC JEITA

SOT1196-1 - - -

MS-012 Compliant

- - -

sot1196-1_po

11-02-15

11-02-16

Unit

max

nom

min

1.75 0.25

0.18

0.10

0.25

0.49

0.43

0.36

0.25

0.22

0.10

8.75

8.65

8.55

2.54 1.27 1.05 0.25

0.7

0.5

0.3

Dimensions

Note

1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.

2. Plastic interlead protrusions of 0.25 mm maximum per side are not included.

SO12: plastic small outline package; 12 leads; body width 3.9 mm SOT1196-1

A1A2

1.45

1.35

1.25

A3bpcD

(1)

8°

4°

0°

E(1)

4.0

3.9

3.8

e1e2HE

6.2

6.0

5.8

1.0

0.7

0.4

0.70

0.65

0.60

0.25

0.1

(2) θ

012345 mm

scale

detail X

A2A3

12 7

e1w

pin 1 index

Product data sheet Rev. 6 — 3 October 2013 17 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

13. Abbreviations

14. References

[1] AN11041 — SSL21081, SSL21083, and SSL2109 non-dimmable buck converter in

low ripple configurations

[2] AN11263 — 230 V (AC) mains dimmable LED driver using the SSL2129AT or

SSL21084AT

Table 7. Abbreviations

Acronym Description

BCM Boundary Conduction Mode

LEB Leading-Edge Blanking

LED Light Emitting Diode

MOSFET Metal-Oxide Semiconductor Field-Effect Transistor

OCP OverCurrent Protection

OTP OverTemperature Protection

PCB Printed-Circuit Board

PWM Pulse-Width Modulation

TVS Transient Voltage Suppression

UVLO UnderVoltage LockOut

ZCS Zero-Current Switching

Product data sheet Rev. 6 — 3 October 2013 18 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

15. Revision history

Table 8. Revision history

Document ID Release date Data sheet status Change notice Supersedes

SSL21084AT v.6 20131003 Prod uct data sheet -SSL21082_SSL21084 v.5

Modifications: •Text and drawings have been updated throughout the data sheet.

SSL21082_SSL21084 v.5 20121214 Product data sheet -SSL2108_SER v.4

SSL2108_SER v.4 20120508 Product data sheet -SSL21081T_2T_3T_4T v.3.1

SSL21081T_2T_3T_4T v.3.1 20120222 Product data sheet -SSL21081T_2T_3T_4T v.3

SSL21081T_2T_3T_4T v.3 20120214 Product data sheet -SSL21081T_2T_3T_4T v.2

SSL21081T_2T_3T_4T v.2 20111206 Preliminary data sheet -SSL2108X v.1

SSL2108X v.1 20110909 Preliminary data sheet - -

Product data sheet Rev. 6 — 3 October 2013 19 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

16. Legal information

16.1 Data sheet status

[1] Please consult the most recently issued document before initiating or completing a design.

[2] The term ‘short data sheet’ is explained in section “Definitions”.

[3] The product status of de vice(s) descr ibed in th is docume nt may have cha nged since this docume nt was publis hed and ma y dif fer in case of multiple devices. The latest product status

information is available on the Internet at URL http://www.nxp.com.

16.2 Definitions

Draft — The document is a draft version only. The content is still under

internal review and subject to formal approval, which may result in

modifications or additions. NXP Semiconductors does not give any

representations or warranties as to the accuracy or completeness of

information included herein and shall have no liab ility for the consequences of

use of such information.

Short data sheet — A short data sheet is an extract from a full data sheet

with the same product type number(s) and tit le. A short data sh eet is intended

for quick reference only and shou ld not be rel ied u pon to cont ain det ailed and

full information. For detailed and full information see the relevant full data

sheet, which is available on request via the local NXP Semiconductors sales

office. In case of any inconsistency or conflict with the short data sheet, the

full data sheet shall pre vail.

Product specificatio n — The information and data provided in a Product

data sheet shall define the specification of the product as agreed between

NXP Semiconductors and its customer, unless NXP Semiconductors and

customer have explicitly agreed otherwise in writing. In no event however,

shall an agreement be valid in which the NXP Semiconductors product is

deemed to off er functions and qualities beyond those described in the

Product data sheet.

16.3 Disclaimers

Limited warr a nty and liability — Information in this document is believed to

be accurate and reliable. However, NXP Semiconductors does not give any

representations or warranties, expressed or implied, as to the accuracy or

completeness of such information and shall have no liability for the

consequences of use of such information. NXP Se miconductors takes no

responsibility for the content in this document if provided by an inf ormation

source outside of NXP Semiconductors.

In no event shall NXP Semiconductors be liable for any indirect, incidental ,

punitive, special or consequ ential damages (including - wit hout limitatio n - lost

profits, lost savings, business interruption, costs related to the removal or

replacement of any products or rework charges) whether or not such

damages are based on tort (including negligence), warranty, breach of

contract or any other legal theory.

Notwithstanding any damages that customer might incur for any reason

whatsoever, NXP Semiconduct ors’ aggregate and cumulat ive liability toward s

customer for the products described herein shall be limited in accordance

with the Terms and conditions of commercial sale of NXP Semicondu ctors.

Right to make changes — NXP Semiconductors reserves the right to make

changes to information published in this document, including without

limitation specifications and product descripti ons, at any time and without

notice. This document supersedes and replaces all informa tion supplied prior

to the publication hereof .

Suitability for use — NXP Semiconductors products are not designed,

authorized or warranted to be suitable for use in life support, life-critical or

safety-critical systems or equipment, nor in applications where failure or

malfunction of an NXP Semiconductors product can reasonably be expected

to result in perso nal injury, death or severe property or environmental

damage. NXP Semiconductors and its suppliers accept no liability for

inclusion and/or use of NXP Semiconducto rs products in such equipment or

applications and ther efore such inclu sion and/or use is at the cu stomer’s own

risk.

Applications — Applications that are described herein for any of these

products are for illustrative purposes only. NXP Semiconductors makes no

representation or warranty tha t such application s will be suitable for the

specified use without further testing or modification.

Customers are responsible for the design and ope ration of their applications

and products using NXP Semicondu ctors products , and NXP Semiconductors

accepts no liability for any assistance with applications or customer product

design. It is customer’s sole responsibility to determine whether the NXP

Semiconductors product is suit able and fit for the custome r’s applications and

products planned, as well as fo r the planned application and use of

customer’s third party customer(s). Customers should provide appropriate

design and operating safeguards to minimize the risks associate d with t heir

applications and products.

NXP Semiconductors does not accept any liability related to any default,

damage, costs or problem which is based on any weakness or default in the

customer’s applications or products, or the application or use by customer’s

third party customer(s). Customer is responsible for doing all necessary

testing for th e customer’s applications and products using NXP

Semiconductors products in order to avoid a default of the applications and

the products or of the application or use by cu stomer’s third party

customer(s). NXP does not accept any liability in this respect.

Limiting values — Stress above one or more limiting values (as defined in

the Absolute Maximum Ratings System of IEC 60134) will cause permanent

damage to the device. Limiting values are stress rating s only and (proper)

operation of the device at these or any other conditions above those given in

the Recommended operating conditions section (if present) or the

Characteristics sections of this document is not warranted. Constant or

repeated exposure to limiting values will permanent ly and irreversibly affect

the quality and reliability of the device.

Terms and conditions of commercial sale — NXP Semiconductors

products are so ld subject to the general terms and conditions of commercial

sale, as published at http://www.nxp.com/profile/terms, unless otherwise

agreed in a valid written individua l agreement. In case an individual

agreement is concluded only the term s and conditions of the respective

agreement shall apply. NXP Semiconductors hereby expressly objects to

applying the customer’s general terms and conditions with regard to the

purchase of NXP Semiconductors products by customer.

No offer to sell or license — Nothing i n this document may be interpreted or

construed as an of fer t o sell product s that is open for accept ance or t he grant,

conveyance or implication of any license under any copyrights, patents or

other industrial or intellectual property rights.

Document status[1][2] Product status[3] Definition

Objective [short] data sheet Development This document contains data from the objective specification for product development.

Preliminary [short] dat a sheet Qualification This document contains data from the preliminary specification.

Product [short] dat a sheet Production This document contains the product specification.

Product data sheet Rev. 6 — 3 October 2013 20 of 21

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

Export control — This document as well as the item(s) described herein

may be subject to export control regulations. Export might require a prior

authorization from competent authorities.

Quick reference data — The Quick reference data is an extract of the

product data given in the Limiting values and Characte ristics sections of this

document, and as such is not complete, exhaustive or legally binding.

Non-automotive qualified products — Unless this data sheet expressly

states that this specific NXP Semiconductors product is automoti ve qualified,

the product is not suitable for automotive use. It i s neit her qua lified nor tested

in accordance with automotive testing or application requirements. NXP

Semiconductors accepts no liability for inclusion and/or use of

non-automotive qualified products in automotive equipment or applications.

In the event that customer uses the product for design-in and use in

automotive applications to automot ive specifications and standard s, customer

(a) shall use the product without NXP Semiconductors’ warranty of the

product for such automotive applications, use and specifications, and (b)

whenever customer uses the product for automotive applications beyond

NXP Semiconductors’ specifications such use shall be solely at customer’s

own risk, and (c) customer fully indemnifies NXP Semiconductors for any

liability, damages or failed product claims resulting from customer design an d

use of the product for automotive applications beyond NXP Semiconductors’

standard warranty and NXP Semiconductors’ product specifications.

Translations — A non-English (translated) version of a document is for

reference only. The English version shall prevail in case of any discrepancy

between the translated and English versions.

16.4 Trademarks

Notice: All referenced b rands, produc t names, service names and trademarks

are the property of their respect i ve ow ners.

GreenChip — is a trademark of NXP B.V.

17. Contact information

For more information, please visit: http://www.nxp.com

For sales office addresses, please send an email to: salesaddresses@nxp.com

NXP Semiconductors SSL21084AT

Mains dimmable LED driver IC

For more information, please visit: http://www.nxp.co m

For sales office addresses, please send an email to: salesaddresses@nxp.com

Date of release: 3 October 2013

Document identifier: SSL21084AT

Please be aware that important notices concerning this document and the product(s)

described herein, have been included in section ‘Legal information’.

18. Contents

1 General description. . . . . . . . . . . . . . . . . . . . . . 1

2 Features and benefits . . . . . . . . . . . . . . . . . . . . 2

3 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

4 Quick reference data . . . . . . . . . . . . . . . . . . . . . 3

5 Ordering information. . . . . . . . . . . . . . . . . . . . . 3

6 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 4

7 Pinning information. . . . . . . . . . . . . . . . . . . . . . 5

7.1 Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

7.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 5

8 Functional description . . . . . . . . . . . . . . . . . . . 6

8.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

8.2 Converter operation . . . . . . . . . . . . . . . . . . . . . 6

8.3 Valley detection. . . . . . . . . . . . . . . . . . . . . . . . . 7

8.4 Protective features . . . . . . . . . . . . . . . . . . . . . . 8

8.4.1 UnderVoltage LockOut (UVLO) . . . . . . . . . . . . 8

8.4.2 Leading-Edge Blanking (LEB) . . . . . . . . . . . . . 8

8.4.3 OverCurrent Protection (OCP) . . . . . . . . . . . . . 8

8.4.4 OverTemperature Protection (OTP) . . . . . . . . . 8

8.4.5 Brownout protection . . . . . . . . . . . . . . . . . . . . . 9

8.4.6 ton control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8.4.7 Output Short-circuit Protection (OSP). . . . . . . . 9

8.5 VCC supply. . . . . . . . . . . . . . . . . . . . . . . . . . . 10

8.5.1 VCC regulator. . . . . . . . . . . . . . . . . . . . . . . . . 10

8.6 DVDT pin supply (dV/dt). . . . . . . . . . . . . . . . . 10

8.7 NTC functionality and PWM dimming. . . . . . . 10

8.7.1 Soft-start function . . . . . . . . . . . . . . . . . . . . . . 11

8.8 Heat sink. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

9 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 13

10 Thermal characteristics . . . . . . . . . . . . . . . . . 14

11 Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . 14

12 Package outline . . . . . . . . . . . . . . . . . . . . . . . . 16

13 Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . 17

14 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

15 Revision history. . . . . . . . . . . . . . . . . . . . . . . . 18

16 Legal information. . . . . . . . . . . . . . . . . . . . . . . 19

16.1 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 19

16.2 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

16.3 Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . . 19

16.4 Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 20

17 Contact information. . . . . . . . . . . . . . . . . . . . . 20

18 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

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