Datasheet

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LT1964

1964fb

TYPICAL APPLICATION

DESCRIPTION

200mA, Low Noise,

Low Dropout Negative

Micropower Regulator

The LT

1964 is a micropower low noise, low dropout nega-

tive regulator. The device is capable of supplying 200mA

of output current with a dropout voltage of 340mV. Low

quiescent current (30μA operating and 3μA shutdown)

makes the LT1964 an excellent choice for battery-pow-

ered applications. Quiescent current is well controlled in

dropout.

Other features of the LT1964 include low output noise.

With the addition of an external 0.01μF bypass capacitor,

output noise is reduced to 30μV

RMS

over a 10Hz to 100kHz

bandwidth. The LT1964 is capable of operating with small

capacitors and is stable with output capacitors as low

as 1μF. Small ceramic capacitors can be used without

the necessary addition of ESR as is common with other

regulators. Internal protection circuitry includes reverse

output protection, current limiting, and thermal limiting.

The device is available with a ﬁ xed output voltage of –5V

and as an adjustable device with a –1.22V reference volt-

age. The LT1964 regulators are available in a low proﬁ le

(1mm) ThinSOT and the low proﬁ le (0.75mm) 8-pin

(3mm × 3mm) DFN packages.

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ThinSOT is

a trademark of Linear Technology Corporation. All other trademarks are the property of their

respective owners.

FEATURES

APPLICATIONS

Low Noise: 30μV

RMS

(10Hz to 100kHz)

Low Quiescent Current: 30μA

Low Dropout Voltage: 340mV

Output Current: 200mA

Fixed Output Voltage: –5V

Adjustable Output from –1.22V to –20V

Positive or Negative Shutdown Logic

3μA Quiescent Current in Shutdown

Stable with 1μF Output Capacitor

Stable with Aluminum, Tantalum, or Ceramic

Capacitors

Thermal Limiting

Low Proﬁ le (1mm) ThinSOT™ and (0.75mm) 8-Pin

3mm × 3mm DFN Packages

Battery-Powered Instruments

Low Noise Regulator for Noise-Sensitive

Instrumentation

Negative Complement to LT1761 Family of

Positive LDOs

–5V Low Noise Regulator

10Hz to 100kHz Output Noise

1964 TA01a

GND

SHDN BYP

OUT

LT1964-5

1μF

10μF

0.01μF

–5.4V

TO –20V

–5V AT 200mA

30μV

RMS

NOISE

OUT

100μV/DIV

1ms/DIV

1964 TA01b

30μV

RMS

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Summary of content (16 pages)

PAGE 1
LT1964 200mA, Low Noise, Low Dropout Negative Micropower Regulator FEATURES DESCRIPTION n The LT®1964 is a micropower low noise, low dropout negative regulator. The device is capable of supplying 200mA of output current with a dropout voltage of 340mV. Low quiescent current (30μA operating and 3μA shutdown) makes the LT1964 an excellent choice for battery-powered applications. Quiescent current is well controlled in dropout.
PAGE 2
LT1964 ABSOLUTE MAXIMUM RATINGS (Note 1) IN Pin Voltage ........................................................ ±20V OUT Pin Voltage (Note 11) ......................................±20V OUT to IN Differential Voltage (Note 11) ........ –0.5V, 20V ADJ Pin Voltage (with Respect to IN Pin) (Note 11)............. –0.5V, 20V BYP Pin Voltage (with Respect to IN Pin)..................................... ±20V SHDN Pin Voltage (with Respect to IN Pin) (Note 11)............. –0.
PAGE 3
LT1964 ORDER INFORMATION LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT1964ES5-SD LT1964ES5-SD#TR LTVX 5-Lead Plastic SOT-23 –40°C to 125°C LT1964ES5-BYP LT1964ES5-BYP#TR LTVY 5-Lead Plastic SOT-23 –40°C to 125°C LT1964ES5-5 LT1964ES5-5#TR LTVZ 5-Lead Plastic SOT-23 –40°C to 125°C LT1964EDD LT1964EDD#TR LDVM 8-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C LT1964IS5-SD LT1964IS5-SD#TR LTVX 5-Lead Plastic SOT-23 –40°C to 125°C LT1964IS5-BYP
PAGE 4
LT1964 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. Output Voltage Noise COUT = 10μF, CBYP = 0.01μF, ILOAD = –200mA, BW = 10Hz to 100kHz 30 ADJ Pin Bias Current (Notes 2, 7) 30 100 nA Minimum Input Voltage (Note 12) ILOAD = –200mA LT1964-BYP LT1964-SD l l –1.9 –1.6 –2.8 –2.
PAGE 5
LT1964 TYPICAL PERFORMANCE CHARACTERISTICS Guaranteed Dropout Voltage 450 450 400 TJ = 125°C 350 300 250 TJ = 25°C 200 150 Dropout Voltage 500 = TEST POINT 450 400 TJ ≤ 125°C DROPOUT VOLTAGE (mV) 500 DROPOUT VOLTAGE (mV) DROPOUT VOLTAGE (mV) Typical Dropout Voltage 500 350 300 250 TJ ≤ 25°C 200 150 350 250 IL = –100mA 200 IL = –50mA 150 100 100 50 50 50 0 0 –40 –80 –120 –160 OUTPUT CURRENT (mA) –200 0 –40 –80 –120 –160 OUTPUT CURRENT (mA) –50 VIN = –6V RL = 250k (∞ FOR L
PAGE 6
LT1964 TYPICAL PERFORMANCE CHARACTERISTICS LT1964 GND Pin Current TJ = 25°C; VSHDN = VIN; *FOR VOUT = –1.22V VIN = VOUT(NOMINAL) – 1V 2.0 –2.0 RL = 12.2Ω IL = –100mA* –1.5 –1.0 RL = 24.4Ω IL = –50mA* –0.5 RL = 122Ω IL = –10mA* 0 –2.5 TJ = 25°C –2.0 TJ = 125°C –1.5 –1.0 0 SHDN Pin Input Current 0 –40 –80 –120 –160 OUTPUT CURRENT (mA) SHDN PIN INPUT CURRENT (μA) SHDN PIN INPUT CURRENT (μA) –1.
PAGE 7
LT1964 TYPICAL PERFORMANCE CHARACTERISTICS Current Limit Current Limit –600 ΔVOUT = 100mV VIN = –7V VOUT = 0V –400 –300 –200 –100 –400 –300 –200 –100 –4 –8 –12 –16 INPUT/OUTPUT DIFFERENTIAL (V) 0 –50 –20 –25 0 25 50 75 TEMPERATURE (°C) 1964 G16 MINIMUM INPUT VOLTAGE (V) RIPPLE REJECTION (dB) VIN = VOUT(NOMINAL) – 1V + 0.
PAGE 8
LT1964 TYPICAL PERFORMANCE CHARACTERISTICS Load Regulation IL = –1mA TO –200mA LOAD REGULATION (mV) 25 LT1964-5 15 10 5 LT1964 0 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 140 10 120 CBYP = 1000pF CBYP = 100pF 1 CBYP = 0 0.1 CBYP = 0.
PAGE 9
LT1964 LT1964-5, 10Hz to 100kHz Output Noise, CBYP = 1000pF LT1964-5, 10Hz to 100kHz Output Noise, CBYP = 0.01μF VOUT 100μV/DIV VOUT 100μV/DIV COUT = 10μF ILOAD = –200mA 1964 G28 1ms/DIV COUT = 10μF ILOAD = –200mA LT1964-5, Transient Response, CBYP = 0.01μF 0.1 OUTPUT VOLTAGE DEVIATION (V) VIN = –6V CIN = 10μF COUT = 10μF 0.2 0 –0.1 –0.
PAGE 10
LT1964 PIN FUNCTIONS ADJ (Adjustable Devices only): For the Adjustable LT1964, this is the Input to the Error Ampliﬁer. The ADJ pin has a bias current of 30nA that ﬂows out of the pin. The ADJ pin voltage is –1.22V referenced to ground, and the output voltage range is –1.22V to –20V. A parasitic diode exists between the ADJ pin and the input of the LT1964. The ADJ pin cannot be pulled more negative than the input during normal operation, or more than 0.
PAGE 11
LT1964 APPLICATIONS INFORMATION The LT1964 is a 200mA negative low dropout regulator with micropower quiescent current and shutdown. The device is capable of supplying 200mA at a dropout voltage of 340mV. Output voltage noise can be lowered to 30μVRMS over a 10Hz to 100kHz bandwidth with the addition of a 0.01μF reference bypass capacitor. Additionally, the reference bypass capacitor will improve transient response of the regulator, lowering the settling time for transient load conditions.
PAGE 12
LT1964 APPLICATIONS INFORMATION Extra consideration must be given to the use of ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior across temperature and applied voltage. The most common dielectrics used are speciﬁed with EIA temperature characteristic codes of Z5U, Y5V, X5R and X7R.
PAGE 13
LT1964 APPLICATIONS INFORMATION amounts of noise, especially when a ceramic capacitor is used for noise bypassing. A ceramic capacitor produced Figure 4’s trace in response to light tapping from a pencil. Similar vibration induced behavior can masquerade as increased output voltage noise. For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces.
PAGE 14
LT1964 APPLICATIONS INFORMATION IOUT(MAX) • (VIN(MAX) – VOUT) + (IGND • VIN(MAX)) where, IOUT(MAX) = –100mA VIN(MAX) = –8V IGND at (IOUT = –100mA, VIN = –8V) = –2mA so, P = –100mA • (–8V + 5V) + (–2mA • –8V) = 0.32W The thermal resistance (junction to ambient) will be in the range of 125°C/W to 150°C/W for the SOT-23 package depending on the copper area. So the junction temperature rise above ambient will be approximately equal to: 0.32W • 140°C/W = 44.
PAGE 15
LT1964 PACKAGE DESCRIPTION S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 1.90 BSC 0.09 – 0.20 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4.
PAGE 16
LT1964 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1120 125mA Micropower Low Dropout Regulator with Comparator and Shutdown Includes 2.5V Reference and Comparator, VIN: 3.5V to 36V, IQ = 40μA, N8 Package LT1121 150mA Micropower Low Dropout Regulator VIN: 4.2V to 30V, IQ = 30μA; ThinSOT, S8 and MS8 Packages LT1129 700mA Micropower Low Dropout Regulator VIN: 4.5V to 30V, IQ = 50μA; DD and S8 Packages LT1175 800mA Negative Low Dropout Micropower Regulator VIN: 4.5V to 20V, IQ = 45μA, 0.