MIC1555_10 MICREL | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 10

Technical content

Features

  • +2.7V to +18V operation
  • Low current − <1µA typical shutdown mode (MIC1557) − 200µA typical (TRG and THR low) at 3V supply
  • Timing from microseconds to hours
  • “Zero” leakage trigger and threshold inputs
  • 50% square wave with one Resistor, one Capacitor
  • Threshold input precedence over trigger input
  • <15 Ω output on resistance
  • No output cross-conduction current spikes
  • <0.005%/°C temperature stability
  • <0.055%/V supply stability
  • Small SOT-23-5 surface mount package

Applications

  • Precision timer
  • Pulse generation
  • Sequential timing
  • Time-delay generation
  • Missing pulse detector
  • Micropower oscillator to 5MHz
  • Charge-pump driver
  • LED blinker
  • Voltage converter
  • Linear sweep generator
  • Variable frequency and duty cycle oscillator
  • Isolated feedback for power supplies Typical Application Standby Trigger VS OUT MIC1555 GND THR +5V Output TRG 100µs 0.1µF 8kHz Enabled Disabled VS CS MIC1557 GND +5V OUT T/T Output 0.1µF Monostable (One-Shot) Astable (Oscillator)

Micrel, Inc. MIC1555/1557 May 2010 2 M9999-052610-D

Ordering Information

Standard Pb-Free Standard Pb-Free Temperature Range Package MIC1555BM5 MIC1555YM5 T10 T1 0 –40° to +85°C 5-Pin SOT-23 MIC1557BM5 MIC1557YM5 T11 T1 1 –40° to +85°C 5-Pin SOT-23 Note: Under bar ( __ ) may not be to scale. Pin Configuration VS THRTRG OUT T10 Part Identification GND Part Identification T/T OUTVS CS T11 GND MIC1555 5-Pin SOT-23 (M) MIC1557 5-Pin SOT-23 (M) Pin Description Pin Number MIC1555 Pin Number MIC1557 Pin Name Pin Name 1 4 VS Supply (Input): +2.7 to +18V supply. 2 2 GND Ground: Supply return. 3 CS Chip Select/Reset (Input): Active high at >2/3VS. Output off when low at<1/3VS. 3 5 OUT Output: CMOS totem-pole output. 4 TRG Trigger (Input): Sets output high. Active low (at ≤ 2/3VS nominal). 5 THR Threshold (Dominant Input): Sets output low. Active high (at ≥ 2/3VS nominal).

1 T/T Trigger/Threshold (Input): Internally connected to both

threshold and trigger functions. See TRG and THR.

Micrel, Inc. MIC1555/1557 May 2010 3 M9999-052610-D Absolute Maximum Ratings Operating Ratings Package Thermal Resistance

Electrical Characteristics

TA = 25°C, bold values indicate –40°C< TA < +85°C, unless noted. Parameter Condition Min Typ Max Units VS = 5V 240 300 µA Supply current VS = 15V 350 400 µA RA = 10k, C =0.1µF, VS = 5V 2 % Monostable Timing Accuracy RA = 10k, C =0.1µF, VS = 5V 858 1161 µs VS = 5V, –55 ≤ TA ≤ +125°C, Note 1 100 ppm/°C VS = 10V, –55 ≤ TA ≤ +125°C, Note 1 150 ppm/°C Monostable Drift over Temp VS = 15V, –55 ≤ TA ≤ +125°C, Note 1 200 ppm/°C Monostable Drift over Supply VS = 5V to 15V, Note 1 0.5 %/V RA = RB = 10k, C = 0.1µF, VS = 5V 2 % Astable Timing Accuracy RA = RB = 10k, C = 0.1µF, VS = 5V 1717 2323 µs Maximum Astable Frequency R T = 1k, CT = 47pF, VS = 8V 5 MHz VS = 5V, –55 ≤ TA ≤ +125°C, Note 1 100 ppm/°C VS = 10V, –55 ≤ TA ≤ +125°C, Note 1 150 ppm/°C Astable Drift over Temp VS = 15V, –55 ≤ TA ≤ +125°C, Note 1 200 ppm/°C Astable Drift over Supply VS = 5V to 15V, Note 1 0.5 %/V Threshold Voltage V S = 15V 61 67 72 %/VS Trigger Voltage V S = 15V 27 32 37 %/VS Trigger Current V S = 15V 50 nA Threshold Current V S = 15V 50 nA on > 2/3 VS 50 67 72 %/VS Chip Select off > 1/3 VS 28 33 50 %/VS VS = 15V, ISINK = 20mA 0.3 1.25 V VS = 5V, ISINK = 3.2mA 0.08 0.5 V VS = 15V, ISOURCE = 20mA 14.1 14.7 V Output Voltage Drop VS = 5V, ISOURCE = 3.2mA 3.8 4.7 V Supply Voltage functional operation, Note 1 2.7 18 V Output Rise Time RL = 10M, CL = 10pF, VS = 5V, Note 1 15 ns Output Fall Time RL = 10M, CL = 10pF, VS = 5V, Note 1 15 ns General Note: Devices are ESD protected, however handling precautions recommended. Note 1. Not tested.

Micrel, Inc. MIC1555/1557 May 2010 4 M9999-052610-D Typical Characteristics (TA = 25°C, VIN = +5) - 4 0 - 2 00 2 04 06 08 0 1 0 0 (ECNATSISERNO ) TEMPERATURE (°C) On Resistance vs. Temperature 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 10 100 1000 ROTCAFk RC (µs) k Factors Times RC f=1k1 RC t=k2 RC 3 6 9 1 21 51 8 )V(EGATLOVTCELESPIHC SUPPLY VOLTAGE (V) MIC1557 Chip Select vs. Supply Voltage ON OFF

Micrel, Inc. MIC1555/1557 May 2010 5 M9999-052610-D Functional Diagram S R Q OUT GND Output TRG THR Standby Trigger VS VSUPPLY MIC1555 0.1µF <100µs Bias 100µs MIC1555 Block Diagram with External Components (Monostable Configuration) S R Q T/T OUT VS Bias GND CS VSUPPLY MIC1557 Output 0.1µF 8kHz MIC1557 Block Diagram with External Components (Astable Configuration)

Micrel, Inc. MIC1555/1557 May 2010 6 M9999-052610-D Functional Description Refer to the block diagrams. The MIC1555/7 provides the logic for creating simple RC timer or oscillator circuits. The MIC1555 has separate THR (threshold) and TRG (trigger) connections for monostable (one-shot) or astable (oscillator) operation. The MIC1557 has a single T/T (threshold and trigger) connection for astable (oscillator) operation only. The MIC1557 includes a CS (chip select/reset) control. Supply VS (supply) is rated for +2.7V to +18V. An external capacitor is recommended to decouple noise. Resistive Divider The resistive voltage divider is constructed of three equal value resistors to produce 1/3VS and 2/3VS voltage for trigger and threshold reference voltages. Chip Select/Reset (MIC1557 only) CS (chip select/reset) controls the bias supply to the oscillator’s internal circuitry. CS must be connected to CMOS logic-high or logic-low levels. Floating CS will result in unpredictable oper ation. When the chip is deselected, the supply current is less than 1µA. Forcing CS low resets the MIC1557 by setting the flip flop, forcing the output low. Threshold Comparator The threshold comparator is connected to S (set) on the RS flip-flop. When the threshold voltage (2/3V S) is reached, the flip-flop is set, making the output low. THR is dominant over TRG. Trigger Comparator The trigger comparator is connected to R (reset) on the RS flip-flop. When TRG (t rigger) goes below the trigger voltage (1/3V S), the flip-flop resets, making the output high. Flip-Flop and Output A reset signal causes Q to go low, turning on the P- channel MOSFET and turning off the N-channel MOSFET. This makes the output rise to nearly VS. A set signal causes Q to go high, turning off the P- channel MOSFET, and turning on the N-channel MOSFET, grounding OUT. Basic Monostable Operation Refer to the MIC1555 functional diagram. A momentary low signal applied to TRG causes the output to go high. The external capacitor charges slowly through the external resi stor. When VTHR (threshold voltage) reaches 2/3V S, the output is switched off, discharging the capacitor. During power-on, a single pulse may be generated. Basic Astable Operation Refer to the MIC1557 functional diagram. The MIC1557 starts with T/T low, causing the output to go high. The external capacitor charges slowly through the external resistor. When VT/T reaches 2/3V S (threshold voltage), the output is switched off, slowly discharging the capacitor. When VT/T decreases to 1/3V S (trigger voltage), the output is switched on, causing VT/T to rise again, repeating the cycle.

Micrel, Inc. MIC1555/1557 May 2010 10 M9999-052610-D

Package Information

5-Pin SOT-23 (M) MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2004 Micrel, Incorporated.