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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Datasheet - MAP3612
2-CH Average Current Control Buck Controller for LED Backlight

General Description Features

MAP3612 is a 2 channel average-mode current  8.5V to 18V Input Voltage Range
control buck controller for LED backlight application. It  Average-Mode Current Control
does not require an additional dimming MOSFET and  Programmable Constant Off-time
utilizes constant off-time control and average current - Independent Setting per Channel
control feedback without external loop compensation  Up to 3V Analog Dimming Input
or high-side current sensing.  1% CS Voltage Accuracy
MAP3612 features ±1% CS voltage accuracy and  Independent Direct PWM Dimming Input
has dedicated analog dimming input up to 3V. It can  Fault Output
be powered from 8.5V ~ 18V supply. - MOSFET Drain-Source Short
MAP3612 provides MOSFET DS short detection(FLT  Short Circuit Protection
output), SCP, ODP and UVLO.  Over-Duty Protection
MAP3612 is available 16 leads SOIC with Halogen-  UVLO
free (fully RoHS compliant).  16 Leads SOIC Package with Halogen-free

Applications
 High Brightness white LED backlighting for LCD
TVs
 General LED lighting applications

Ordering Information
1
Top Ambient
Part Number Package RoHS Status
Marking Temperature Range
MAP3612SIRH MAP3612 -40℃ to +85℃ 16Leads SOIC Halogen Free

Typical Application

TOFF1 TOFF2

GATE1 GATE2

CS1 CS2

PGND1 PGND2

VCC
VCC

SEL FLT
SEL FLT
MODE
MODE
PWM1
PWM1
PWM2
PWM2
ADIM
ADIM GND

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Pin Configuration

1 CS1 PGND1 16

2 PWM1 GATE1 15

3 TOFF1 ADIM 14

4 FLT VCC 13
MAP3612
5 GND SEL 12

6 TOFF2 MODE 11

7 PWM2 GATE2 10

8 CS2 PGND2 9

SOIC-16L

Pin Description

16leads
Name Description
SOIC
2
1 CS1 External current sense for CH1(Note 1).
2 PWM1 PWM signal input for CH1.
3 TOFF1 Setting for GATE off-time for CH1(Note 2)
4 FLT Fault Output
5 GND Ground
6 TOFF2 Setting for GATE off-time for CH2(Note 2)
7 PWM2 PWM signal input for CH2.
8 CS2 External current sense for CH2(Note 3).
9 PGND2 Power GND for CH2
10 GATE2 GATE driver output to drive external NMOSFET for CH2
11 MODE Enable logic input for Over-Duty protection. Default logic ‘Low’ (Note 4)
12 SEL Logic input for selecting OD1 or OD2 protection. Default logic ‘Low’ (Note 5)
13 VCC Power supply input. Need external bypass capacitor
14 ADIM Setting for LED current thru external DC voltage
15 GATE1 GATE driver output to drive external NMOSFET for CH1
16 PGND1 Power GND for CH1

Note 1: Connect external resistor to PGND1 to sense the external power MOSFET source current as shown in typical application
Note 2: Connect external resistor to GND to set GATE off-time as shown in typical application
Note 3: Connect external resistor to PGND2 to sense the external power MOSFET source current as shown in typical application
Note 4: Logic ‘H’  ODP disable, Logic ‘L’ or floating  ODP enable
Note 5: Logic ‘H’  OD1 protection, Logic ‘L’ or floating  OD2 protection

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Functional Block Diagram

Internal
VCC LDO
supply
GND

+ POR
POR PGND1
UVLO -

Current Off-
TOFF1 Mirror Timer
S Q
GATE1
R

ADIM AV PWM1
Average-
Mode
Control
Logic
CS1 LEB MODE
ODP
SEL
SCP

MOSFET
DS Short FLT
POR

SCP GATE2

CS2 LEB PWM2

Average-
Mode R Q
Control
Logic S PGND2
3 AV

Current Off-
TOFF2 Mirror Timer

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Absolute Maximum Ratings(Note 1)
Symbol Parameter Min Max Unit
VVCC, VGATE1, VGATE2,VPWM1, VPWM2, VCC, GATE1, GATE2, PWM1, PWM2, MODE, SEL pins
-0.3 20 V
VMODE, VSEL Voltage
VCS1, VCS2, VTOFF1, VTOFF2, VADIM, VFLT CS1, CS2, TOFF1, TOFF2, ADIM, FLT pins Voltage -0.3 5 V
TPAD Soldering Lead/ Pad Temperature 10sec 300 °C
TJ Junction Temperature -40 +150 °C
TS Storage Temperature -65 +150 °C
HBM on All Pins (Note 2) -2000 +2000
ESD V
MM on All Pins (Note 3) -200 +200
Note 1: Stresses beyond the above listed maximum ratings may damage the device permanently. Operating above the recommended
conditions for extended time may stress the device and affect device reliability. Also the device may not operate normally above the
recommended operating conditions. These are stress ratings only.
Note 2: ESD tested per JESD22A-114.
Note 3: ESD tested per JESD22A-115.

Recommended Operating Conditions (Note 1)

Parameter Min Max Unit
VVcc Supply Input Voltage 8.5 18.0 V
VADIM ADIM Input Range 0.5 3.0 V
TA Ambient Temperature (Note 2) -40 +85 °C
Note 1: Normal operation of the device is not guaranteed if operating the device over outside range of recommended conditions.
Note 2: The ambient temperature may have to be derated if used in high power dissipation and poor thermal resistance conditions.

Package Thermal Resistance (Note 1)

4
Parameter θJA θJC Unit
MAP3612SIRH 16 Leads SOIC 65.1 25.3 ℃/W
Note 1: Multi-layer PCB based on JEDEC standard (JESD51-7)

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Electrical Characteristics
Unless noted, VVCC = 12V, CVCC = 1.0F, and typical values are tested at TA = 25C.
Parameter Test Condition Min Typ Max Unit
Supply
VVCC Input Voltage Range 8.5 18 V
IQ Quiescent Current VPWM = 5V, VCS = 0V 3.4 mA
Under Voltage Lockout Release threshold(rising VVCC) 7.5 8.0 8.5
VUVLO V
Threshold Voltage on VCC pin Lockout hysteresis(falling VVCC) 0.5 1.0 1.5
OFF Timer
RTOFFx=52kΩ 4.5 5.0 5.5
tOFFx GATE1/2 Off-time us
RTOFFx=104kΩ 9 10 11
tON_MIN Min. On-Time 300 ns
tON_MAX Max. On-Time VADIM = 3V 37 us
tOFF_MIN Min. Off-Time 1.2 1.5 us
DMAX Max. Duty Cycle VADIM = 3V, tOFF=1.2us 97 %
GATE Driver
ISOURCE GATE1/2 Source Current VGATE1/2 = 0V, 400 mA
ISINK GATE1/2 Sink Current VGATE1/2 = VVCC=12V 800 mA
tRISE GATE1/2 Output Rising Time CGATE1/2=1nF, VVCC = 12V 50 85 ns
tFALL GATE1/2 Output Falling Time CGATE1/2=1nF, VVCC = 12V 25 45 ns
Current Sense & Dimming
VADIM ADIM Input Voltage Range 0.5 3.0 V
AV VADIM to CS1/2 Voltage Ratio 0.5075 V/V
VADIM = 0.5V 0.2512 0.2563
VCS1/2 CS1/2 Voltage V
VADIM = 3.0V 1.5073 1.5377
tLEB Leading Edge Blanking Time 300 ns
Logic Interface
5 Logic Input Level on VPWM1/2_L : Logic Low 0.8
VPWM1/2 V
PWM1/2 pins VPWM1/2_H : Logic High 2.0
RPWM1/2 Pull-down Resistor on PWM1/2 pins VPWM1/2 = 4V 50 100 150 kΩ
VMODE_L : Logic Low 0.8
VMODE Logic Input Level on MODE pin V
VMODE_H : Logic High 2.0
RMODE Pull-down Resistor on MODE pin VMODE = 4V 50 100 150 kΩ
VSEL_L : Logic Low 0.8 V
VSEL Logic Input Level on SEL pin
VSEL_H : Logic High 2.0
RSEL Pull-down Resistor on SEL pin VSEL = 4V 50 100 150 kΩ
Protection
AVSCP VADIM to SCP Voltage Ratio 0.5 <= VADIM <= 2.5V 1.7 V/V
VADIM = 0.5V 0.8075 0.8500 0.8925
SCP Detection Threshold Voltage
VSCP VADIM = 1.0V 1.6150 1.7000 1.7850 V
on CS1/2 pins
VADIM = 2.5V 4.0375 4.2500 4.4625
tDELAY SCP Delay Time 300 ns
tRESTART Restart Time 1 ms
MOSFET DS Short Detection VADIM = 0.5V (Note 1, 2) 0.25
VSCPDS V
Threshold Voltage on CS1/2 pins VADIM = 2.5V (Note 1, 2) 1.25
VFLT FLT pin High Voltage 4.5 5 V
RFLT FLT pin Internal Resistance VFLT : Logic High 2.5 5 kΩ
DOD1 Protection Duty for OD1 55 57 59 %
DOD2 Protection Duty for OD2 35 37 39 %
tOD Auto-Restart time for OD1/2 VMODE = GND or Floating 100 ms

Note 1: These parameters, although guaranteed by design, are not tested in mass production.
Note 2: At start-up(VVCC >= VUVLO release threshold)

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Typical Operating Characteristics
Unless otherwise noted, VVCC = 12V and TA = 25C.

Set ILED=425mA/CH
L=4mH

Set ILED=425mA/CH Set ILED=425mA/CH

L=4mH

VUVLO(RELEASE) vs. Temp VUVLO(HYS) vs. Temp.

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Typical Operating Characteristics
Unless otherwise noted, VVCC = 12V and TA = 25C.

AV(VADIM=0.5V) vs. Temp AV(VADIM=3.0V) vs. Temp

tOFF1 vs. Temp t OFF2 vs. Temp

VSCP vs. Temp

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Typical Operating Characteristics
Unless otherwise noted, VVCC = 12V and TA = 25C.

Constant Current Control Min. Dimming(COUT=330nF)

PWMx 5V/div
GATEx 20V/div
ILED1
ILED2 50mA/div
GATE1 10V/div
ILx 0.2A/div
GATE2 10V/div
ILEDx 20us/div 0.2A/div

Soft-start(PWM Dimming, COUT=330nF) Soft-start(Initial, COUT=330nF)

VLEDx 20V/div VLEDx 20V/div

VCSx 0.2V/div
ILx 0.2A/div
VCSx 0.5V/div ILx 0.2A/div
ILEDx 20us/div 0.2A/div ILEDx
50us/div
0.2A/div

UVLO Release UVLO Lockout

GATEx 10V/div
VCC 2V/div

VCC 2V/div
ILx 0.1A/div

0.2A/div
ILx GATE1 20V/div
GATE2 20V/div

VADIM Off SCP(Inductor Short)

ADIM 0.2V/div GATEx 20V/div

ILEDx 0.1A/div
1ms/div
GATE1 20V/div VCSx 1V/div
GATE2 20V/div ILx 0.5A/div

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Typical Operating Characteristics
Unless otherwise noted, VVCC = 12V and TA = 25C.

SCP(Catch Diode Short) SCP(LED All Short)

GATEx 20V/div GATEx 20V/div
2ms/div

VLEDx 10V/div

1ms/div
VCSx 1V/div VCSx 1V/div
ILx 0.5A/div ILx 0.5A/div

FLT Output(@ PWM On @ Running) FLT Output(@ PWM Off @ Running)

PWMx 5V/div PWMx 5V/div

FLT 5V/div FLT 5V/div

20us/div 20us/div
VCSx 0.5V/div VCSx 1V/div

FLT Output(@ PWM On @ Start-up) FLT Output(@ PWM Off @ Start-up)

PWMx 5V/div PWMx 5V/div

FLT 5V/div FLT 5V/div

VCC 2/div VCC 2/div

2ms/div 2ms/div
VCSx 1/div VCSx 1V/div

OD1 Protection OD2 Protection

100ms/div 100ms/div
PWM12 5V/div PWM12 5V/div

ILED1 0.1A/div ILED1 0.1A/div

0.1A/div 0.1A/div
ILED2 ILED2

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Functional Description TOFF SETTING

GENERAL DESCRIPTION The off-time of the GATE driver is programmed by an

external resistor connected between the TOFFx pin
The MAP3612 is a 2-channel low-side single switch and ground. Do not leave this pin open. The off-time is
control, constant off-time buck controller optimized to calculated by following equation.
LED backlight applications. The IC employs unique
average-mode current control architecture which 0.4  tOFF [us] 1000
provides precise LED current accuracy. It does not RTOFFx  [k]
38.4
require any external loop compensation or high side
current sensing. It can be set independently for each channels.
The IC operates at continuous conduction mode to
reduce output ripple, thus small output capacitor is
LED CURRENT
available. The off-time is user adjustable through the
selection of an external resistor, this allows the design
The LED current is calculated by following equation.
to be optimized for a given switching frequency range
and supports wide range of input voltages.
0.5075  V ADIM
I LED  [ A]
MAX. ON-TIME RCS
The max. on-time of GATE is limited according to The ADIM voltage range is from 0.5V to 3V.
ADIM voltage as following graph. In terms of total system accuracy of LED current,
larger inductance and slower switching frequency are
recommendable to get better accuracy.

PWM DIMMING

The brightness control of the LEDs is performed by a

10 pulse-width modulation. The GATE output is valid only
at PWM on period. This means that the GATE
maintains off-state as long as PWM signal is logic low.
Care should be taken to test at low PWM duty-cycle
because the output capacitor can affect rising and
falling time of LED current due to its charging and
discharging time.

SOFT-START

The MAP3612 operates at peak current mode at initial

Care should be taken to choose input voltage which start-up and every rising edge of PWM input to smooth
should not exceed this on-time limit(especially OD2 inductor current ramp-up(output capacitor charging
mode). phase). The number of peak-controlled switch cycles is
The on-time of GATE can be calculated by following 8 times at initial start-up and 2 times at every PWM
equations. rising edge as following figure.

VLED
D UVLO_H
VIN VCC

38.4
tOFF [us]   RTOFF [k]
400 PWM

D  tOFF GATE

tON  VADIM*0.5075
1 D VCS

8 times 2 times
Finally, tON < tON_MAX_Min Value
IL

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
OVER-DUTY PROTECTION UVLO

The MAP3612 provides over-duty protection for PWM The MAP3612 has an Internal LDO regulator to
inputs in case the MODE pin is logic ‘LOW’ or floated. supply internal circuit and GATE driver. This LDO is
In general, this status is 3D mode in TV applications. powered up when the VCC voltage rises to UVLO
The logic status on the SEL pin decides the protection release threshold.
duty of PWM inputs as following table. If the voltage on the VCC pin falls below UVLO
lockout threshold, the device turns-off the GATE output
Available Duty Duty Protection and be reset. This ensures fail-safe operation for VCC
input voltage falling.
OD1 Up to 55% ODP over 56%
OD2 Up to 35% ODP over 36%

Following table summarizes the relationship between

MODE, SEL pins and ODP.

Input HIGH LOW or FLOATING

MODE 2D 3D
SEL OD1 OD2

At the ODP status, the MAP3612 rechecks the

protection status at every 100ms. If the error is removed,
the IC status will be automatically recovered.

SCP
If the CS voltage rises VSCP during normal operation,
11 the MAP3612 turns-off the GATE output after tDELAY(typ.
300ns) time. The auto-restart time is typ. 1ms(tRESTART).
This protects for hard instantaneous short such as
catch diode, inductor or LED bar short.

tDELAY tDELAY

GATE

VSCP
CS

tRESTART

The SCP voltage varies according to ADIM voltage as

following graph.

4.42V
4V

VADIM*1.7
VSCP

1V

0.5V 2.6V 3.0V

VADIM

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MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
MOSFET D-S Short Detection & FLT Output

In case the following drain-source short events of external MOSFET occur, the FLT pin goes to logic HIGH state
immediately. This shuts off the whole system power supply. The protection status is latched and can be cleared by
applying a complete power-on-reset(POR).

CASE(1) : At start-up - Regardless of PWM logic state, if VCS is equal or over than 0.5*VADIM and last over 4us.
FLT pin voltage goes HIGH level before the first GATE output if PWM is logic HIGH state.
CASE(2) : At dimming(PWM=logic HIGH) - At first, SCP will be occured. Even though the GATE is off-state by SCP,
if the CS voltage is equal or over than 1.7*VADIM and last over 30us.
CASE(3) : At other condition(PWM=logic LOW) - If the CS voltage is equal or over than 1.8V and lasts over 4us.

VCC
UVLO_H
UVLO_L

PWM

GATE
4us

30us 1.8V
4us 1.7 X VADIM

VCS
12 0.5 X VADIM

FLT CASE(1) CASE(2) CASE(3)

The FLT pin is at logic low state when no error is detected.

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Physical Dimensions

13

16 Leads SOIC

MagnaChip Semiconductor Ltd. doesn’t not recommend the use of its products in hostile environments, including, without limitation,
aircraft, nuclear power generation, medical appliances, and devices or systems in which malfunction of any product can reasonably
be expected to result in a personal injury. Seller’s customers using or selling Seller’s products for use in such applications do so at
their own risk and agree to fully defend and indemnify Seller.
MagnaChip reserves the right to change the specifications and circuitry without notice at any time. MagnaChip does not consider
responsibility for use of any circuitry other than circuitry entirely included in a MagnaChip product.

is a registered trademark of MagnaChip Semiconductor Ltd.

MagnaChip Semiconductor Ltd.
891, Daechi-Dong, Kangnam-Gu, Seoul, 135-738 Korea
Tel : 82-2-6903-3451 / Fax : 82-2-6903-3668 ~9
www.magnachip.com

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Datasheet Version 1.0

MAP3612 – 2-CH Average Current Control Buck Controller for LED Backlight
Datasheet Revision History

Date Version Changes

2015-12-02 Version 1.0 Initial release

14

Dec 02nd 2015