MCP1664 Data Sheet

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 2015 Microchip Technology Inc.

DS20005408A-page 1

MCP1664

Features

• 36V,  400 m

 Integrated Switch

• Up to 92% Efficiency

• Drive LED Strings in Constant Current

• 1.8A Peak Input Current Limit:

- I

LED

 up to 200 mA at 3.3V V

IN

, 4 White LEDs

- I

LED 

up to 300 mA at 5.0V V

IN

, 4 White LEDs

- I

LED

 up to 150 mA at 4.2V V

IN

, 8 White LEDs

• Input Voltage Range: 2.4V to 5.5V

• Undervoltage Lockout (UVLO):

- UVLO at V

IN

 Rising: 2.3V, typical

- UVLO at V

IN

 Falling: 1.85V, typical

• Shutdown Current (EN = GND): 40 nA Typical

• PWM Operation: 500 kHz Switching Frequency

• Cycle-by-Cycle Current Limiting

• Internal Compensation

• Open Load Protection (OLP) in the event of:

- Feedback Pin Shorted to GND (Prevent 

Excessive Current into LEDs)

- Disconnected LED String (Prevent 

Overvoltage to the Converter’s Output and 
SW Pin)

• Overtemperature Protection

• Available Packages:

- 5-Lead SOT-23

- 8-Lead 2x3 TDFN

Applications

• Two and Three-Cell Alkaline or NiMH/NiCd White 

LED Driver for Backlighting Products

• Li-Ion Battery LED Lightning Application

• Camera Flash

• LED Flashlights and Backlight Current Source

• Medical Equipment

• Portable Devices:

- Hand-Held Gaming Devices

- GPS Navigation Systems

- LCD  Monitors

- Portable DVD Players

General Description

The MCP1664 is a compact, space-efficient,
fixed-frequency, non-synchronous step-up converter
optimized to drive multiple strings of LEDs with
constant current powered from two and three-cell
alkaline or NiMH/NiCd as well as from one-cell Li-Ion or
Li-Polymer batteries.

The device integrates a 36V, 400 m

 low-side switch,

which is protected by the 1.8A cycle-by-cycle inductor
peak current limit operation. The MCP1664 starts up
without high inrush current or output overshoot. All
compensation and protection circuitry is integrated to
minimize the number of external components.

The internal feedback (V

FB

) voltage is set to 300 mV for

low power dissipation when sensing and regulating the
LED current. A single resistor sets the LED current.

The device features an UVLO which avoids start-up
with low inputs or discharged batteries for two
cell-powered applications.

The MCP1664 features an open load protection (OLP)
which turns off the operation in situations when the
LED string is accidentally disconnected or the feedback
pin is short-circuited to GND.

While in Shutdown mode (EN = GND), the device stops
switching, and consumes 40 nA typical of input current.

Package Types

* Includes Exposed Thermal Pad (EP); see 

Table 3-1

SW

EN

V

IN

1

GND 2

P

GND

V

IN

NC

EN

V

FB

S

GND

SW

NC

MCP1664 SOT-23

V

FB

3

4

5

MCP1664 2x3 TDFN*

1

2

3

4

8

7

6

5

EP

9

High-Voltage Step-Up LED Driver with UVLO and Open Load Protection

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MCP1664

DS20005408A-page 2

 2015 Microchip Technology Inc.

Typical Application

V

IN

GND

V

FB

C

OUT

10 µF

C

IN

4.7 – 30 µF

L

4.7 – 10 µH

SW

EN

+

-

ALKAL

INE

ON

OFF

+

-

ALAKL

INE

V

IN

2.4V – 3.0V

LED6 

12

R

SET

LED1 

I

LED

= 25 mA

I

LED

=

0.3V

R

SET

LED2 

Max. 32V

V

FB

= 0.3V

V

OUT

0

50

100

150

200

250

300

350

2

2.5

3

3.5

4

4.5

5

5.5

I

OUT

(mA)

V

IN

(V)

4 wLEDs, L = 4.7 µH

8 wLEDs, L = 10 µH

L = 4.7 µH for maximum 4 white LEDs

L = 10 µH for 5 to 10 white LEDs

C

IN

= 4.7 – 10 µF  for  V

IN

> 2.5V

C

IN

= 20 – 30 µF for V

IN

< 2.5V

D

MBRM140

MCP1664

 

Maximum LED Current in Regulation vs. Input Voltage, T

A

 = +25°C

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 2015 Microchip Technology Inc.

DS20005408A-page 3

MCP1664

1.0

ELECTRICAL 
CHARACTERISTICS

Absolute Maximum Ratings †

V

SW

– GND .....................................................................+36V

EN, V

IN

– GND ...............................................................+6.0V

V

FB

...............................................................................+0.35V

Power Dissipation  ....................................... Internally Limited
Storage Temperature ....................................-65°C to +150°C
Ambient Temperature with Power Applied ....-40°C to +125°C
Operating Junction Temperature...................-40°C to +150°C
ESD Protection On All Pins:

HBM ................................................................. 4 kV
MM ..................................................................400V

† Notice: Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of
the device at those or any other conditions above those
indicated in the operational sections of this
specification is not intended. Exposure to maximum
rating conditions for extended periods may affect
device reliability.

DC AND AC CHARACTERISTICS

Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature 
T

A

= +25°C,  V

IN

= 3.3V, V

OUT

loaded with 3 white LEDs (V

F

= 2.65V at I

F

= 100 mA),  I

LED

= 20 mA, 

C

IN

= C

OUT

= 10 µF, X7R ceramic, L = 4.7 µH.

Boldface specifications apply over the controlled T

A

 range of -40°C to +125°C.

Parameters

Sym.

Min.

Typ.

Max.

Units

Conditions

Input Voltage Range

V

IN

2.4

5.5

V

Note 1

Undervoltage Lockout (UVLO)

UVLO

START

2.3

V

V

IN

 rising, I

LED

= 20 mA

UVLO

STOP

1.85

V

V

IN

 falling, I

LED

= 20 mA

Maximum Output Voltage

V

OUTmax

32

V

Note 1

Maximum Output Current

I

OUT

150

mA

4.2V  V

IN

, 8 LEDs

200

mA

3.3V V

IN

, 4 LEDs

300

mA

5.0V V

IN

, 4 LEDs

Feedback Voltage Reference

V

FB

275

300

325

mV

Feedback Input Bias Current

I

VFB

0.025

µA

Shutdown Quiescent Current

I

QSHDN

0.04

µA

EN = GND

NMOS Peak Switch Current 
Limit

I

N(MAX)

1.8

A

Note 2

NMOS Switch Leakage

I

NLK

0.4

µA

V

IN

= V

SW

= 5V;

V

OUT

=   5.5V 

V

EN

= V

FB

= GND

NMOS Switch ON Resistance

R

DS(ON)

0.4

V

IN

= 5V,

I

LED

= 100 mA,

4 series white LEDs

Note 2

Feedback Voltage Line 
Regulation

|(

V

FB

/V

FB

)/

V

IN

|

0.5

1

%/V

V

IN

= 3.3V to 5V

Maximum Duty Cycle

DC

MAX

90

%

Note 2

Switching Frequency

f

SW

425

500

575

kHz

±15%

EN Input Logic High

V

IH

85

% of V

IN

EN Input Logic Low

V

IL

7.5

%  of  V

IN

EN Input Leakage Current

I

ENLK

0.025

µA

V

EN

= 5V

Note 1:

Minimum input voltage in the range of V

IN

 (V

IN

< 5.5V < V

OUT

) depends on the maximum duty cycle 

(DC

MAX

) and on the output voltage (V

OUT

), according to the boost converter equation: 

V

INmin

= V

OUT

x (1 – DC

MAX

). Output voltage is equal to the LED voltage plus the voltage on the sense 

resistor (V

LED

+ V_R

SET

). Recommended (V

OUT

 - V

IN

) > 1V.

2:

Determined by characterization, not production tested.

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MCP1664

DS20005408A-page 4

 2015 Microchip Technology Inc.

Start-Up Time

t

SS

100

s

EN Low to High,
90% of I

LED

(

Note 2

Figure 2-10

)

Thermal Shutdown Die 
Temperature

T

SD

150

°C

Note 2

Die Temperature Hysteresis

T

SDHYS

20

°C

Note 2

TEMPERATURE SPECIFICATIONS

Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature 
T

A

= +25°C,  V

IN

= 3.0V, I

OUT

= 20 mA,  V

OUT

= 12V,  C

IN

= C

OUT

= 10 µF, X7R ceramic, L = 4.7 µH.

Boldface specifications apply over the air-forced T

A

 range of -40°C to +125°C.

Parameters

Sym.

Min.

Typ.

Max.

Units

Conditions

Temperature Ranges

Operating Junction Temperature 
Range

T

J

-40

+125

°C

Steady State

Storage Temperature Range

T

A

-65

+150

°C

Maximum Junction Temperature

T

J

+150

°C

Package Thermal Resistances

Thermal Resistance, 5L SOT-23

JA

201.0

°C/W

Thermal Resistance, 8L 2x3 TDFN

JA

52.5

°C/W

DC AND AC CHARACTERISTICS (CONTINUED)

Electrical Specifications: Unless otherwise specified, all limits apply for typical values at ambient temperature 
T

A

= +25°C,  V

IN

= 3.3V, V

OUT

loaded with 3 white LEDs (V

F

= 2.65V at I

F

= 100 mA),  I

LED

= 20 mA, 

C

IN

= C

OUT

= 10 µF, X7R ceramic, L = 4.7 µH.

Boldface specifications apply over the controlled T

A

 range of -40°C to +125°C.

Parameters

Sym.

Min.

Typ.

Max.

Units

Conditions

Note 1:

Minimum input voltage in the range of V

IN

 (V

IN

< 5.5V < V

OUT

) depends on the maximum duty cycle 

(DC

MAX

) and on the output voltage (V

OUT

), according to the boost converter equation: 

V

INmin

= V

OUT

x (1 – DC

MAX

). Output voltage is equal to the LED voltage plus the voltage on the sense 

resistor (V

LED

+ V_R

SET

). Recommended (V

OUT

 - V

IN

) > 1V.

2:

Determined by characterization, not production tested.

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 2015 Microchip Technology Inc.

DS20005408A-page 5

MCP1664

2.0

TYPICAL PERFORMANCE CURVES

Note: Unless otherwise indicated: V

IN

= 3.3V,  I

LED

= 20 mA,  V

OUT

loaded with 4 white LEDs

(V

F

= 2.9V at I

F

= 100 mA),  C

IN

= C

OUT

= 10 µF, X7R ceramic, L = 4.7 µH.

FIGURE 2-1:

Four White LEDs, I

LED

 vs. 

V

IN

.

FIGURE 2-2:

Four White LEDs, I

LED

 vs. 

Ambient Temperature.

FIGURE 2-3:

Eight White LEDs, I

LED

 vs. 

Ambient Temperature.

FIGURE 2-4:

Four White LEDs, Efficiency 

vs. I

LED

.

FIGURE 2-5:

Eight White LEDs, Efficiency 

vs. I

LED

.

FIGURE 2-6:

Maximum I

LED

 vs. V

IN

.

Note:

The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.

0

20

40

60

80

100

120

140

160

2.3

2.7

3.1

3.5

3.9

4.3

4.7

5.1

5.5

LED Current 

(mA)

Input Voltage (V)

R

SET

= 15.2ȍ

R

SET

= 6ȍ

R

SET

= 2.1ȍ

R

SET

= 3ȍ

0

20

40

60

80

100

120

140

160

-40 -25 -10 5

20 35 50 65 80 95 110 125

LED Cur

rent 

(mA)

Ambient Temperature (

o

C)

R

SET

= 15.2ȍ

R

SET

= 6ȍ

R

SET

= 3ȍ

R

SET

= 2.1ȍ

0

20

40

60

80

100

120

140

160

-40 -25 -10 5

20 35 50 65 80 95 110 125

LED Current (mA)

Ambient Temperature (

o

C)

R

SET

= 15.2ȍ

8 x wLED, L = 10μH, V

IN

= 4.2V

R

SET

= 6ȍ

R

SET

= 3ȍ

R

SET

= 2.1ȍ

0

10

20

30

40

50

60

70

80

90

100

0

50

100

150

200

250

300

350

Efficien

cy

 (%

)

I

LED

(mA)

V

IN

= 3.0V

V

IN

= 4.0V

V

IN

= 5.5V

0

10

20

30

40

50

60

70

80

90

100

0

50

100

150

200

250

Eff

ici

ency (%

)

I

LED

(mA)

V

IN

= 4.0V

V

IN

= 5.5V

V

IN

= 3.0V

8 x wLED
L = 10 µH

0

50

100

150

200

250

300

350

400

2.3

2.7

3.1

3.5

3.9

4.3

4.7

5.1

5.5

LED Current 

(m

A)

Input Voltage (V)

8 wLEDs, L = 10 µH

4 wLEDs, L = 4.7µH

5 wLEDs, L = 10µH

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MCP1664

DS20005408A-page 6

 2015 Microchip Technology Inc.

Note: Unless otherwise indicated: V

IN

= 3.3V,  I

LED

= 20 mA,  V

OUT

loaded with 4 white LEDs

(V

F

= 2.9V at I

F

= 100 mA),  C

IN

= C

OUT

= 10 µF, X7R ceramic, L = 4.7 µH.

FIGURE 2-7:

Undervoltage Lockout 

(UVLO) vs. Ambient Temperature.

FIGURE 2-8:

Shutdown Quiescent 

Current,

 

I

QSHDN

, vs. V

IN

 (EN = GND).

FIGURE 2-9:

Switching Frequency, 

f

SW

 vs. Ambient Temperature.

FIGURE 2-10:

Start-Up Time vs.

 LED Number.

FIGURE 2-11:

Start-Up When 

V

IN

= V

ENABLE

.

FIGURE 2-12:

Start-Up After Enable.

1.5

1.6

1.7

1.8

1.9

2

2.1

2.2

2.3

2.4

2.5

-40 -25 -10

5

20

35

50

65

80

95 110 125

UVLO Thresholds  (V)

Ambient Temperature (

o

C)

UVLO Stop

UVLO Start

0

10

20

30

40

50

2.5 2.8 3.1 3.4 3.7 4.0 4.3 4.6 4.9 5.2 5.5

Shutdow

n I

Q

(nA)

Input Voltage (V)

450

475

500

525

550

-40 -25 -10

5

20

35

50

65

80

95 110 125

Sw

itching Frequency

 (kHz)

Ambient Temperature (°C)

0

25

50

75

100

125

150

175

200

3

4

5

6

7

8

S

o

ft Sta

rt 

T

ime

 (µ

s)

Number of LEDs

Blue Bars: I

LED 

= 20 mA

Red Bars:  I

LED

= 40 mA

C

OUT

= 10 µF

I

LED

10 mA/div

EN
2V/div

V

IN

2V/div

80µs/div

3 wLEDs

I

LED

10 mA/div

EN
2V/div

V

IN

2V/div

80µs/div

3 wLEDs

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DS20005408A-page 7

MCP1664

Note: Unless otherwise indicated: V

IN

= 3.3V,  I

LED

= 20 mA,  V

OUT

loaded with 4 white LEDs

(V

F

= 2.9V at I

F

= 100 mA),  C

IN

= C

OUT

= 10 µF, X7R ceramic, L = 4.7 µH.

FIGURE 2-13:

100 Hz PWM Dimming, 

15% Duty Cycle.

FIGURE 2-14:

100 Hz PWM Dimming,

85% Duty Cycle.

FIGURE 2-15:

Open Load (LED Fail or FB 

to GND) Response.

FIGURE 2-16:

Three White LEDs PWM 

Discontinuous Mode Waveforms.

FIGURE 2-17:

Three White LEDs PWM 

Continuous Mode Waveforms.

FIGURE 2-18:

Line Step Response. 

V

IN

 steps from 2.5V to 4.5V.

I

LED

10 mA/div

SW
5V/div

EN
2V/div

2 ms/div

3 wLEDs

I

LED

10 mA/div

SW
5V/div

EN
2V/div

2 ms/div

3 wLEDs

I

LED

10 mA/div

SW
5V/div

V

FB

200mV/div

10 ms/div

3 wLEDs

I

LED

AC Coupled

SW
5V/div

V

OUT

5V/div

1 µs/div

3 wLEDs

2 mA/div

I

LED

= 20 mA

I

LED

AC Coupled

SW
5V/div

V

OUT

5V/div

1 µs/div

3 wLEDs

10 mA/div

I

LED

= 145 mA

I

LED

AC Coupled

V

IN

2V/div

1 ms/div

Line Step

2 mA/div

2.5V to 4.5V
3 wLEDs
I

LED

= 20mA

Step from 2.5V to 4.5V

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MCP1664

DS20005408A-page 8

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NOTES:

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 2015 Microchip Technology Inc.

DS20005408A-page 9

MCP1664

3.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in 

Table 3-1

.

3.1

Feedback Voltage Pin (V

FB

)

The V

FB

 pin is used to regulate the voltage across the

R

SET

 sense resistor to 300 mV to keep the output LED

current in regulation. Connect the cathode of the LED
to the V

FB

 pin.

3.2

Signal Ground Pin (S

GND

)

The signal ground pin is used as a return for the
integrated reference voltage and error amplifier. 

3.3

Switch Node Pin (SW)

Connect the inductor from the input voltage to the SW
pin. The SW pin carries inductor current and has a
typical value of 1.8A. The integrated N-Channel switch
drain is internally connected to the SW node.

3.4

Not Connected (NC)

This is an unconnected pin.

3.5

Power Supply Input Voltage Pin 
(V

IN

)

Connect the input voltage source to V

IN

. The input

source should be decoupled from GND with a 4.7 µF
minimum capacitor.

3.6

Power Ground Pin (P

GND

)

The power ground pin is used as a return for the
high-current N-Channel switch. The P

GND

 and S

GND

pins are connected externally. The signal ground and
power ground must be connected externally in one
point.

3.7

Enable Pin (EN)

The EN pin is a logic-level input used to enable or
disable device switching and lower quiescent current
while disabled. A logic high (>85% of V

IN

) will enable

the regulator output. A logic low (<7.5% of V

IN

) will

ensure that the regulator is disabled.

3.8

Exposed Thermal Pad (EP)

There is no internal electrical connection between the
Exposed Thermal Pad (EP) and the S

GND

 and P

GND

pins. They must be connected to the same potential on
the Printed Circuit Board (PCB).

3.9

Ground Pin (GND)

The ground or return pin is used for circuit ground
connection. The length of the trace from the input cap
return, the output cap return and the GND pin must be
as short as possible to minimize noise on the GND pin.
The SOT-23 5-lead package uses a single ground pin.

TABLE 3-1:

PIN FUNCTION TABLE

MCP1664

SOT-23

MCP1664

2x3 TDFN

Symbol

Description

3

1

V

FB

Feedback Voltage Pin

2

S

GND

Signal Ground Pin (TDFN only)

1

3

SW

Switch Node, Boost Inductor Pin

4, 6

NC

Not Connected

5

5

V

IN

Input Voltage Pin

7

P

GND

Power Ground Pin (TDFN only)

4

8

EN

Enable Control Input Pin

9

EP

Exposed Thermal Pad (EP); must be connected to Ground.
(TDFN only)

2

GND

Ground Pin (SOT-23 only)

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MCP1664

DS20005408A-page 10

 2015 Microchip Technology Inc.

NOTES:

Maker
Microchip Technology Inc.
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